rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/bucket/bandwidth/measurement.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bandwidth
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+const (
+	// betaBucket is the weight used to calculate exponential moving average
+	betaBucket = 0.1 // Number of averages considered = 1/(1-betaObject)
+)
+
+// bucketMeasurement captures the bandwidth details for one bucket
+type bucketMeasurement struct {
+	lock                 sync.Mutex
+	bytesSinceLastWindow uint64    // Total bytes since last window was processed
+	startTime            time.Time // Start time for window
+	expMovingAvg         float64   // Previously calculate sliding window
+}
+
+// newBucketMeasurement creates a new instance of the measurement with the initial start time.
+func newBucketMeasurement(initTime time.Time) *bucketMeasurement {
+	return &bucketMeasurement{
+		startTime: initTime,
+	}
+}
+
+// incrementBytes add bytes reported for a bucket.
+func (m *bucketMeasurement) incrementBytes(bytes uint64) {
+	atomic.AddUint64(&m.bytesSinceLastWindow, bytes)
+}
+
+// updateExponentialMovingAverage processes the measurements captured so far.
+func (m *bucketMeasurement) updateExponentialMovingAverage(endTime time.Time) {
+	// Calculate aggregate avg bandwidth and exp window avg
+	m.lock.Lock()
+	defer func() {
+		m.startTime = endTime
+		m.lock.Unlock()
+	}()
+
+	if endTime.Before(m.startTime) {
+		return
+	}
+
+	duration := endTime.Sub(m.startTime)
+
+	bytesSinceLastWindow := atomic.SwapUint64(&m.bytesSinceLastWindow, 0)
+
+	if m.expMovingAvg == 0 {
+		// Should address initial calculation and should be fine for resuming from 0
+		m.expMovingAvg = float64(bytesSinceLastWindow) / duration.Seconds()
+		return
+	}
+
+	increment := float64(bytesSinceLastWindow) / duration.Seconds()
+	m.expMovingAvg = exponentialMovingAverage(betaBucket, m.expMovingAvg, increment)
+}
+
+// exponentialMovingAverage calculates the exponential moving average
+func exponentialMovingAverage(beta, previousAvg, incrementAvg float64) float64 {
+	return (1-beta)*incrementAvg + beta*previousAvg
+}
+
+// getExpMovingAvgBytesPerSecond returns the exponential moving average for the bucket in bytes
+func (m *bucketMeasurement) getExpMovingAvgBytesPerSecond() float64 {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	return m.expMovingAvg
+}

internal/bucket/bandwidth/monitor.go

@@ -0,0 +1,155 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bandwidth
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"github.com/minio/madmin-go"
+)
+
+// throttleBandwidth gets the throttle for bucket with the configured value
+func (m *Monitor) throttleBandwidth(ctx context.Context, bucket string, bandwidthBytesPerSecond int64, clusterBandwidth int64) *throttle {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	throttle, ok := m.bucketThrottle[bucket]
+	if !ok {
+		throttle = newThrottle(ctx, bandwidthBytesPerSecond, clusterBandwidth)
+		m.bucketThrottle[bucket] = throttle
+		return throttle
+	}
+	throttle.SetBandwidth(bandwidthBytesPerSecond, clusterBandwidth)
+	return throttle
+}
+
+// Monitor implements the monitoring for bandwidth measurements.
+type Monitor struct {
+	lock sync.Mutex // lock for all updates
+
+	activeBuckets map[string]*bucketMeasurement // Buckets with objects in flight
+
+	bucketMovingAvgTicker *time.Ticker // Ticker for calculating moving averages
+
+	bucketThrottle map[string]*throttle
+
+	doneCh <-chan struct{}
+}
+
+// NewMonitor returns a monitor with defaults.
+func NewMonitor(doneCh <-chan struct{}) *Monitor {
+	m := &Monitor{
+		activeBuckets:         make(map[string]*bucketMeasurement),
+		bucketMovingAvgTicker: time.NewTicker(2 * time.Second),
+		bucketThrottle:        make(map[string]*throttle),
+		doneCh:                doneCh,
+	}
+	go m.trackEWMA()
+	return m
+}
+
+// SelectionFunction for buckets
+type SelectionFunction func(bucket string) bool
+
+// SelectBuckets will select all the buckets passed in.
+func SelectBuckets(buckets ...string) SelectionFunction {
+	if len(buckets) == 0 {
+		return func(bucket string) bool {
+			return true
+		}
+	}
+	return func(bucket string) bool {
+		for _, b := range buckets {
+			if b == "" || b == bucket {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// GetReport gets the report for all bucket bandwidth details.
+func (m *Monitor) GetReport(selectBucket SelectionFunction) *madmin.BucketBandwidthReport {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	return m.getReport(selectBucket)
+}
+
+func (m *Monitor) getReport(selectBucket SelectionFunction) *madmin.BucketBandwidthReport {
+	report := &madmin.BucketBandwidthReport{
+		BucketStats: make(map[string]madmin.BandwidthDetails),
+	}
+	for bucket, bucketMeasurement := range m.activeBuckets {
+		if !selectBucket(bucket) {
+			continue
+		}
+		bucketThrottle, ok := m.bucketThrottle[bucket]
+		if !ok {
+			continue
+		}
+		report.BucketStats[bucket] = madmin.BandwidthDetails{
+			LimitInBytesPerSecond:            bucketThrottle.clusterBandwidth,
+			CurrentBandwidthInBytesPerSecond: bucketMeasurement.getExpMovingAvgBytesPerSecond(),
+		}
+	}
+	return report
+}
+
+func (m *Monitor) trackEWMA() {
+	for {
+		select {
+		case <-m.bucketMovingAvgTicker.C:
+			m.updateMovingAvg()
+		case <-m.doneCh:
+			return
+		}
+	}
+}
+
+func (m *Monitor) getBucketMeasurement(bucket string, initTime time.Time) *bucketMeasurement {
+	bucketTracker, ok := m.activeBuckets[bucket]
+	if !ok {
+		bucketTracker = newBucketMeasurement(initTime)
+		m.activeBuckets[bucket] = bucketTracker
+	}
+	return bucketTracker
+}
+
+func (m *Monitor) updateMovingAvg() {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	for _, bucketMeasurement := range m.activeBuckets {
+		bucketMeasurement.updateExponentialMovingAverage(time.Now())
+	}
+}
+
+// track returns the measurement object for bucket and object
+func (m *Monitor) track(bucket string, object string) *bucketMeasurement {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	return m.getBucketMeasurement(bucket, time.Now())
+}
+
+// DeleteBucket deletes monitoring the 'bucket'
+func (m *Monitor) DeleteBucket(bucket string) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	delete(m.activeBuckets, bucket)
+	delete(m.bucketThrottle, bucket)
+}

internal/bucket/bandwidth/monitor_test.go

@@ -0,0 +1,159 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bandwidth
+
+import (
+	"context"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/minio/madmin-go"
+)
+
+const (
+	oneMiB uint64 = 1024 * 1024
+)
+
+func TestMonitor_GetThrottle(t *testing.T) {
+	type fields struct {
+		bucketThrottles map[string]*throttle
+		bucket          string
+		bpi             int64
+	}
+	t1 := newThrottle(context.Background(), 100, 1024*1024)
+	t2 := newThrottle(context.Background(), 200, 1024*1024)
+	tests := []struct {
+		name   string
+		fields fields
+		want   *throttle
+	}{
+		{
+			name: "Existing",
+			fields: fields{
+				bucketThrottles: map[string]*throttle{"bucket": t1},
+				bucket:          "bucket",
+				bpi:             100,
+			},
+			want: t1,
+		},
+		{
+			name: "new",
+			fields: fields{
+				bucketThrottles: map[string]*throttle{"bucket": t1},
+				bucket:          "bucket2",
+				bpi:             200,
+			},
+			want: t2,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			m := &Monitor{
+				bucketThrottle: tt.fields.bucketThrottles,
+			}
+			if got := m.throttleBandwidth(context.Background(), tt.fields.bucket, tt.fields.bpi, 1024*1024); got.bytesPerInterval != tt.want.bytesPerInterval {
+				t.Errorf("throttleBandwidth() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMonitor_GetReport(t *testing.T) {
+	type fields struct {
+		activeBuckets map[string]*bucketMeasurement
+		endTime       time.Time
+		update2       uint64
+		endTime2      time.Time
+	}
+	start := time.Now()
+	m0 := newBucketMeasurement(start)
+	m0.incrementBytes(0)
+	m1MiBPS := newBucketMeasurement(start)
+	m1MiBPS.incrementBytes(oneMiB)
+	tests := []struct {
+		name   string
+		fields fields
+		want   *madmin.BucketBandwidthReport
+		want2  *madmin.BucketBandwidthReport
+	}{
+		{
+			name: "ZeroToOne",
+			fields: fields{
+				activeBuckets: map[string]*bucketMeasurement{
+					"bucket": m0,
+				},
+				endTime:  start.Add(1 * time.Second),
+				update2:  oneMiB,
+				endTime2: start.Add(2 * time.Second),
+			},
+			want: &madmin.BucketBandwidthReport{
+				BucketStats: map[string]madmin.BandwidthDetails{"bucket": {LimitInBytesPerSecond: 1024 * 1024, CurrentBandwidthInBytesPerSecond: 0}},
+			},
+			want2: &madmin.BucketBandwidthReport{
+				BucketStats: map[string]madmin.BandwidthDetails{"bucket": {LimitInBytesPerSecond: 1024 * 1024, CurrentBandwidthInBytesPerSecond: (1024 * 1024) / start.Add(2*time.Second).Sub(start.Add(1*time.Second)).Seconds()}},
+			},
+		},
+		{
+			name: "OneToTwo",
+			fields: fields{
+				activeBuckets: map[string]*bucketMeasurement{
+					"bucket": m1MiBPS,
+				},
+				endTime:  start.Add(1 * time.Second),
+				update2:  2 * oneMiB,
+				endTime2: start.Add(2 * time.Second),
+			},
+			want: &madmin.BucketBandwidthReport{
+				BucketStats: map[string]madmin.BandwidthDetails{"bucket": {LimitInBytesPerSecond: 1024 * 1024, CurrentBandwidthInBytesPerSecond: float64(oneMiB)}},
+			},
+			want2: &madmin.BucketBandwidthReport{
+				BucketStats: map[string]madmin.BandwidthDetails{"bucket": {
+					LimitInBytesPerSecond:            1024 * 1024,
+					CurrentBandwidthInBytesPerSecond: exponentialMovingAverage(betaBucket, float64(oneMiB), 2*float64(oneMiB))}},
+			},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			thr := throttle{
+				bytesPerSecond:   1024 * 1024,
+				clusterBandwidth: 1024 * 1024,
+			}
+			m := &Monitor{
+				activeBuckets:  tt.fields.activeBuckets,
+				bucketThrottle: map[string]*throttle{"bucket": &thr},
+			}
+			m.activeBuckets["bucket"].updateExponentialMovingAverage(tt.fields.endTime)
+			got := m.GetReport(SelectBuckets())
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetReport() = %v, want %v", got, tt.want)
+			}
+			m.activeBuckets["bucket"].incrementBytes(tt.fields.update2)
+			m.activeBuckets["bucket"].updateExponentialMovingAverage(tt.fields.endTime2)
+			got = m.GetReport(SelectBuckets())
+			if !reflect.DeepEqual(got, tt.want2) {
+				t.Errorf("GetReport() = %v, want %v", got, tt.want2)
+			}
+		})
+	}
+}

internal/bucket/bandwidth/reader.go

@@ -0,0 +1,80 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bandwidth
+
+import (
+	"context"
+	"io"
+)
+
+// MonitoredReader monitors the bandwidth
+type MonitoredReader struct {
+	opts              *MonitorReaderOptions
+	bucketMeasurement *bucketMeasurement // bucket measurement object
+	reader            io.Reader          // Reader to wrap
+	throttle          *throttle          // throttle the rate at which replication occur
+	monitor           *Monitor           // Monitor reference
+	lastErr           error              // last error reported, if this non-nil all reads will fail.
+}
+
+// MonitorReaderOptions provides configurable options for monitor reader implementation.
+type MonitorReaderOptions struct {
+	Bucket               string
+	Object               string
+	HeaderSize           int
+	BandwidthBytesPerSec int64
+	ClusterBandwidth     int64
+}
+
+// NewMonitoredReader returns a io.Reader that reports bandwidth details.
+func NewMonitoredReader(ctx context.Context, monitor *Monitor, reader io.Reader, opts *MonitorReaderOptions) *MonitoredReader {
+	return &MonitoredReader{
+		opts:              opts,
+		bucketMeasurement: monitor.track(opts.Bucket, opts.Object),
+		reader:            reader,
+		throttle:          monitor.throttleBandwidth(ctx, opts.Bucket, opts.BandwidthBytesPerSec, opts.ClusterBandwidth),
+		monitor:           monitor,
+	}
+}
+
+// Read wraps the read reader
+func (m *MonitoredReader) Read(p []byte) (n int, err error) {
+	if m.lastErr != nil {
+		err = m.lastErr
+		return
+	}
+
+	p = p[:m.throttle.GetLimitForBytes(int64(len(p)))]
+
+	n, err = m.reader.Read(p)
+	if err != nil {
+		m.lastErr = err
+	}
+
+	update := n + m.opts.HeaderSize
+	unused := len(p) - update
+
+	m.bucketMeasurement.incrementBytes(uint64(update))
+	m.opts.HeaderSize = 0 // Set to 0 post first read
+
+	if unused > 0 {
+		m.throttle.ReleaseUnusedBandwidth(int64(unused))
+	}
+
+	return
+}

internal/bucket/bandwidth/throttle.go

@@ -0,0 +1,121 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bandwidth
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+const (
+	throttleInternal = 250 * time.Millisecond
+)
+
+// throttle implements the throttling for bandwidth
+type throttle struct {
+	generateTicker   *time.Ticker    // Ticker to generate available bandwidth
+	freeBytes        int64           // unused bytes in the interval
+	bytesPerSecond   int64           // max limit for bandwidth
+	bytesPerInterval int64           // bytes allocated for the interval
+	clusterBandwidth int64           // Cluster wide bandwidth needed for reporting
+	cond             *sync.Cond      // Used to notify waiting threads for bandwidth availability
+	goGenerate       int64           // Flag to track if generate routine should be running. 0 == stopped
+	ctx              context.Context // Context for generate
+}
+
+// newThrottle returns a new bandwidth throttle. Set bytesPerSecond to 0 for no limit
+func newThrottle(ctx context.Context, bytesPerSecond int64, clusterBandwidth int64) *throttle {
+	if bytesPerSecond == 0 {
+		return &throttle{}
+	}
+	t := &throttle{
+		bytesPerSecond:   bytesPerSecond,
+		generateTicker:   time.NewTicker(throttleInternal),
+		clusterBandwidth: clusterBandwidth,
+		ctx:              ctx,
+	}
+
+	t.cond = sync.NewCond(&sync.Mutex{})
+	t.SetBandwidth(bytesPerSecond, clusterBandwidth)
+	t.freeBytes = t.bytesPerInterval
+	return t
+}
+
+// GetLimitForBytes gets the bytes that are possible to send within the limit
+// if want is <= 0 or no bandwidth limit set, returns want.
+// Otherwise a value > 0 will always be returned.
+func (t *throttle) GetLimitForBytes(want int64) int64 {
+	if want <= 0 || atomic.LoadInt64(&t.bytesPerInterval) == 0 {
+		return want
+	}
+	t.cond.L.Lock()
+	defer t.cond.L.Unlock()
+	for {
+		var send int64
+		freeBytes := atomic.LoadInt64(&t.freeBytes)
+		send = want
+		if freeBytes < want {
+			send = freeBytes
+			if send <= 0 {
+				t.cond.Wait()
+				continue
+			}
+		}
+		atomic.AddInt64(&t.freeBytes, -send)
+
+		// Bandwidth was consumed, start generate routine to allocate bandwidth
+		if atomic.CompareAndSwapInt64(&t.goGenerate, 0, 1) {
+			go t.generateBandwidth(t.ctx)
+		}
+		return send
+	}
+}
+
+// SetBandwidth sets a new bandwidth limit in bytes per second.
+func (t *throttle) SetBandwidth(bandwidthBiPS int64, clusterBandwidth int64) {
+	bpi := int64(throttleInternal) * bandwidthBiPS / int64(time.Second)
+	atomic.StoreInt64(&t.bytesPerInterval, bpi)
+}
+
+// ReleaseUnusedBandwidth releases bandwidth that was allocated for a user
+func (t *throttle) ReleaseUnusedBandwidth(bytes int64) {
+	atomic.AddInt64(&t.freeBytes, bytes)
+}
+
+// generateBandwidth periodically allocates new bandwidth to use
+func (t *throttle) generateBandwidth(ctx context.Context) {
+	for {
+		select {
+		case <-t.generateTicker.C:
+			if atomic.LoadInt64(&t.freeBytes) == atomic.LoadInt64(&t.bytesPerInterval) {
+				// No bandwidth consumption stop the routine.
+				atomic.StoreInt64(&t.goGenerate, 0)
+				return
+			}
+			// A new window is available
+			t.cond.L.Lock()
+			atomic.StoreInt64(&t.freeBytes, atomic.LoadInt64(&t.bytesPerInterval))
+			t.cond.Broadcast()
+			t.cond.L.Unlock()
+		case <-ctx.Done():
+			return
+		}
+	}
+}

internal/bucket/encryption/bucket-sse-config.go

@@ -0,0 +1,159 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"encoding/xml"
+	"errors"
+	"io"
+	"net/http"
+
+	"github.com/minio/minio/internal/crypto"
+	xhttp "github.com/minio/minio/internal/http"
+)
+
+const (
+	// AES256 is used with SSE-S3
+	AES256 SSEAlgorithm = "AES256"
+	// AWSKms is used with SSE-KMS
+	AWSKms SSEAlgorithm = "aws:kms"
+)
+
+// SSEAlgorithm - represents valid SSE algorithms supported; currently only AES256 is supported
+type SSEAlgorithm string
+
+// UnmarshalXML - Unmarshals XML tag to valid SSE algorithm
+func (alg *SSEAlgorithm) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	var s string
+	if err := d.DecodeElement(&s, &start); err != nil {
+		return err
+	}
+
+	switch s {
+	case string(AES256):
+		*alg = AES256
+	case string(AWSKms):
+		*alg = AWSKms
+	default:
+		return errors.New("Unknown SSE algorithm")
+	}
+
+	return nil
+}
+
+// MarshalXML - Marshals given SSE algorithm to valid XML
+func (alg *SSEAlgorithm) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	return e.EncodeElement(string(*alg), start)
+}
+
+// EncryptionAction - for ApplyServerSideEncryptionByDefault XML tag
+type EncryptionAction struct {
+	Algorithm   SSEAlgorithm `xml:"SSEAlgorithm,omitempty"`
+	MasterKeyID string       `xml:"KMSMasterKeyID,omitempty"`
+}
+
+// SSERule - for ServerSideEncryptionConfiguration XML tag
+type SSERule struct {
+	DefaultEncryptionAction EncryptionAction `xml:"ApplyServerSideEncryptionByDefault"`
+}
+
+const xmlNS = "http://s3.amazonaws.com/doc/2006-03-01/"
+
+// BucketSSEConfig - represents default bucket encryption configuration
+type BucketSSEConfig struct {
+	XMLNS   string    `xml:"xmlns,attr,omitempty"`
+	XMLName xml.Name  `xml:"ServerSideEncryptionConfiguration"`
+	Rules   []SSERule `xml:"Rule"`
+}
+
+// ParseBucketSSEConfig - Decodes given XML to a valid default bucket encryption config
+func ParseBucketSSEConfig(r io.Reader) (*BucketSSEConfig, error) {
+	var config BucketSSEConfig
+	err := xml.NewDecoder(r).Decode(&config)
+	if err != nil {
+		return nil, err
+	}
+
+	// Validates server-side encryption config rules
+	// Only one rule is allowed on AWS S3
+	if len(config.Rules) != 1 {
+		return nil, errors.New("only one server-side encryption rule is allowed at a time")
+	}
+
+	for _, rule := range config.Rules {
+		switch rule.DefaultEncryptionAction.Algorithm {
+		case AES256:
+			if rule.DefaultEncryptionAction.MasterKeyID != "" {
+				return nil, errors.New("MasterKeyID is allowed with aws:kms only")
+			}
+		case AWSKms:
+			if rule.DefaultEncryptionAction.MasterKeyID == "" {
+				return nil, errors.New("MasterKeyID is missing with aws:kms")
+			}
+		}
+	}
+
+	if config.XMLNS == "" {
+		config.XMLNS = xmlNS
+	}
+	return &config, nil
+}
+
+// Apply applies the SSE bucket configuration on the given HTTP headers and
+// sets the specified SSE headers.
+//
+// Apply does not overwrite any existing SSE headers. Further, it will
+// set minimal SSE-KMS headers if autoEncrypt is true and the BucketSSEConfig
+// is nil.
+func (b *BucketSSEConfig) Apply(headers http.Header, autoEncrypt bool) {
+	if _, ok := crypto.IsRequested(headers); ok {
+		return
+	}
+	if b == nil {
+		if autoEncrypt {
+			headers.Set(xhttp.AmzServerSideEncryption, xhttp.AmzEncryptionKMS)
+		}
+		return
+	}
+
+	switch b.Algorithm() {
+	case xhttp.AmzEncryptionAES:
+		headers.Set(xhttp.AmzServerSideEncryption, xhttp.AmzEncryptionAES)
+	case xhttp.AmzEncryptionKMS:
+		headers.Set(xhttp.AmzServerSideEncryption, xhttp.AmzEncryptionKMS)
+		headers.Set(xhttp.AmzServerSideEncryptionKmsID, b.KeyID())
+	}
+}
+
+// Algorithm returns the SSE algorithm specified by the SSE configuration.
+func (b *BucketSSEConfig) Algorithm() SSEAlgorithm {
+	for _, rule := range b.Rules {
+		return rule.DefaultEncryptionAction.Algorithm
+	}
+	return ""
+}
+
+// KeyID returns the KMS key ID specified by the SSE configuration.
+// If the SSE configuration does not specify SSE-KMS it returns an
+// empty key ID.
+func (b *BucketSSEConfig) KeyID() string {
+	for _, rule := range b.Rules {
+		return rule.DefaultEncryptionAction.MasterKeyID
+	}
+	return ""
+}

internal/bucket/encryption/bucket-sse-config_test.go

@@ -0,0 +1,141 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"bytes"
+	"encoding/xml"
+	"errors"
+	"testing"
+)
+
+// TestParseBucketSSEConfig performs basic sanity tests on ParseBucketSSEConfig
+func TestParseBucketSSEConfig(t *testing.T) {
+	actualAES256NoNSConfig := &BucketSSEConfig{
+		XMLName: xml.Name{
+			Local: "ServerSideEncryptionConfiguration",
+		},
+		Rules: []SSERule{
+			{
+				DefaultEncryptionAction: EncryptionAction{
+					Algorithm: AES256,
+				},
+			},
+		},
+	}
+
+	actualAES256Config := &BucketSSEConfig{
+		XMLNS: xmlNS,
+		XMLName: xml.Name{
+			Local: "ServerSideEncryptionConfiguration",
+		},
+		Rules: []SSERule{
+			{
+				DefaultEncryptionAction: EncryptionAction{
+					Algorithm: AES256,
+				},
+			},
+		},
+	}
+
+	actualKMSConfig := &BucketSSEConfig{
+		XMLNS: xmlNS,
+		XMLName: xml.Name{
+			Local: "ServerSideEncryptionConfiguration",
+		},
+		Rules: []SSERule{
+			{
+				DefaultEncryptionAction: EncryptionAction{
+					Algorithm:   AWSKms,
+					MasterKeyID: "arn:aws:kms:us-east-1:1234/5678example",
+				},
+			},
+		},
+	}
+
+	testCases := []struct {
+		inputXML       string
+		expectedErr    error
+		shouldPass     bool
+		expectedConfig *BucketSSEConfig
+	}{
+		// 1. Valid XML SSE-S3
+		{
+			inputXML:       `<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr:    nil,
+			shouldPass:     true,
+			expectedConfig: actualAES256Config,
+		},
+		// 2. Valid XML SSE-KMS
+		{
+			inputXML:       `<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>aws:kms</SSEAlgorithm><KMSMasterKeyID>arn:aws:kms:us-east-1:1234/5678example</KMSMasterKeyID></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr:    nil,
+			shouldPass:     true,
+			expectedConfig: actualKMSConfig,
+		},
+		// 3. Invalid - more than one rule
+		{
+			inputXML:    `<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr: errors.New("only one server-side encryption rule is allowed at a time"),
+			shouldPass:  false,
+		},
+		// 4. Invalid XML - master key ID present along with AES256
+		{
+			inputXML:    `<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm><KMSMasterKeyID>arn:aws:kms:us-east-1:1234/5678example</KMSMasterKeyID></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr: errors.New("MasterKeyID is allowed with aws:kms only"),
+			shouldPass:  false,
+		},
+		// 5. Invalid XML - master key ID not provided when algorithm is set to aws:kms algorithm
+		{
+			inputXML:    `<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>aws:kms</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr: errors.New("MasterKeyID is missing with aws:kms"),
+			shouldPass:  false,
+		},
+		// 6. Invalid Algorithm
+		{
+			inputXML:    `<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>InvalidAlgorithm</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr: errors.New("Unknown SSE algorithm"),
+			shouldPass:  false,
+		},
+		// 7. Valid XML without the namespace set
+		{
+			inputXML:       `<ServerSideEncryptionConfiguration><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`,
+			expectedErr:    nil,
+			shouldPass:     true,
+			expectedConfig: actualAES256NoNSConfig,
+		},
+	}
+
+	for i, tc := range testCases {
+		_, err := ParseBucketSSEConfig(bytes.NewReader([]byte(tc.inputXML)))
+		if tc.shouldPass && err != nil {
+			t.Fatalf("Test case %d: Expected to succeed but got %s", i+1, err)
+		}
+
+		if !tc.shouldPass {
+			if err == nil || err != nil && err.Error() != tc.expectedErr.Error() {
+				t.Fatalf("Test case %d: Expected %s but got %s", i+1, tc.expectedErr, err)
+			}
+			continue
+		}
+
+		if expectedXML, err := xml.Marshal(tc.expectedConfig); err != nil || !bytes.Equal(expectedXML, []byte(tc.inputXML)) {
+			t.Fatalf("Test case %d: Expected bucket encryption XML %s but got %s", i+1, string(expectedXML), tc.inputXML)
+		}
+	}
+}

internal/bucket/lifecycle/action_string.go

@@ -0,0 +1,29 @@
+// Code generated by "stringer -type Action lifecycle.go"; DO NOT EDIT.
+
+package lifecycle
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[NoneAction-0]
+	_ = x[DeleteAction-1]
+	_ = x[DeleteVersionAction-2]
+	_ = x[TransitionAction-3]
+	_ = x[TransitionVersionAction-4]
+	_ = x[DeleteRestoredAction-5]
+	_ = x[DeleteRestoredVersionAction-6]
+}
+
+const _Action_name = "NoneActionDeleteActionDeleteVersionActionTransitionActionTransitionVersionActionDeleteRestoredActionDeleteRestoredVersionAction"
+
+var _Action_index = [...]uint8{0, 10, 22, 41, 57, 80, 100, 127}
+
+func (i Action) String() string {
+	if i < 0 || i >= Action(len(_Action_index)-1) {
+		return "Action(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _Action_name[_Action_index[i]:_Action_index[i+1]]
+}

internal/bucket/lifecycle/and.go

@@ -0,0 +1,74 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+)
+
+var errDuplicateTagKey = Errorf("Duplicate Tag Keys are not allowed")
+
+// And - a tag to combine a prefix and multiple tags for lifecycle configuration rule.
+type And struct {
+	XMLName xml.Name `xml:"And"`
+	Prefix  Prefix   `xml:"Prefix,omitempty"`
+	Tags    []Tag    `xml:"Tag,omitempty"`
+}
+
+// isEmpty returns true if Tags field is null
+func (a And) isEmpty() bool {
+	return len(a.Tags) == 0 && !a.Prefix.set
+}
+
+// Validate - validates the And field
+func (a And) Validate() error {
+	emptyPrefix := !a.Prefix.set
+	emptyTags := len(a.Tags) == 0
+
+	if emptyPrefix && emptyTags {
+		return nil
+	}
+
+	if emptyPrefix && !emptyTags || !emptyPrefix && emptyTags {
+		return errXMLNotWellFormed
+	}
+
+	if a.ContainsDuplicateTag() {
+		return errDuplicateTagKey
+	}
+	for _, t := range a.Tags {
+		if err := t.Validate(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// ContainsDuplicateTag - returns true if duplicate keys are present in And
+func (a And) ContainsDuplicateTag() bool {
+	x := make(map[string]struct{}, len(a.Tags))
+
+	for _, t := range a.Tags {
+		if _, has := x[t.Key]; has {
+			return true
+		}
+		x[t.Key] = struct{}{}
+	}
+
+	return false
+}

internal/bucket/lifecycle/error.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"fmt"
+)
+
+// Error is the generic type for any error happening during tag
+// parsing.
+type Error struct {
+	err error
+}
+
+// Errorf - formats according to a format specifier and returns
+// the string as a value that satisfies error of type tagging.Error
+func Errorf(format string, a ...interface{}) error {
+	return Error{err: fmt.Errorf(format, a...)}
+}
+
+// Unwrap the internal error.
+func (e Error) Unwrap() error { return e.err }
+
+// Error 'error' compatible method.
+func (e Error) Error() string {
+	if e.err == nil {
+		return "lifecycle: cause <nil>"
+	}
+	return e.err.Error()
+}

internal/bucket/lifecycle/expiration.go

@@ -0,0 +1,195 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"time"
+)
+
+var (
+	errLifecycleInvalidDate         = Errorf("Date must be provided in ISO 8601 format")
+	errLifecycleInvalidDays         = Errorf("Days must be positive integer when used with Expiration")
+	errLifecycleInvalidExpiration   = Errorf("Exactly one of Days (positive integer) or Date (positive ISO 8601 format) should be present inside Expiration.")
+	errLifecycleInvalidDeleteMarker = Errorf("Delete marker cannot be specified with Days or Date in a Lifecycle Expiration Policy")
+	errLifecycleDateNotMidnight     = Errorf("'Date' must be at midnight GMT")
+)
+
+// ExpirationDays is a type alias to unmarshal Days in Expiration
+type ExpirationDays int
+
+// UnmarshalXML parses number of days from Expiration and validates if
+// greater than zero
+func (eDays *ExpirationDays) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	var numDays int
+	err := d.DecodeElement(&numDays, &startElement)
+	if err != nil {
+		return err
+	}
+	if numDays <= 0 {
+		return errLifecycleInvalidDays
+	}
+	*eDays = ExpirationDays(numDays)
+	return nil
+}
+
+// MarshalXML encodes number of days to expire if it is non-zero and
+// encodes empty string otherwise
+func (eDays ExpirationDays) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if eDays == 0 {
+		return nil
+	}
+	return e.EncodeElement(int(eDays), startElement)
+}
+
+// ExpirationDate is a embedded type containing time.Time to unmarshal
+// Date in Expiration
+type ExpirationDate struct {
+	time.Time
+}
+
+// UnmarshalXML parses date from Expiration and validates date format
+func (eDate *ExpirationDate) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	var dateStr string
+	err := d.DecodeElement(&dateStr, &startElement)
+	if err != nil {
+		return err
+	}
+	// While AWS documentation mentions that the date specified
+	// must be present in ISO 8601 format, in reality they allow
+	// users to provide RFC 3339 compliant dates.
+	expDate, err := time.Parse(time.RFC3339, dateStr)
+	if err != nil {
+		return errLifecycleInvalidDate
+	}
+	// Allow only date timestamp specifying midnight GMT
+	hr, min, sec := expDate.Clock()
+	nsec := expDate.Nanosecond()
+	loc := expDate.Location()
+	if !(hr == 0 && min == 0 && sec == 0 && nsec == 0 && loc.String() == time.UTC.String()) {
+		return errLifecycleDateNotMidnight
+	}
+
+	*eDate = ExpirationDate{expDate}
+	return nil
+}
+
+// MarshalXML encodes expiration date if it is non-zero and encodes
+// empty string otherwise
+func (eDate ExpirationDate) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if eDate.Time.IsZero() {
+		return nil
+	}
+	return e.EncodeElement(eDate.Format(time.RFC3339), startElement)
+}
+
+// ExpireDeleteMarker represents value of ExpiredObjectDeleteMarker field in Expiration XML element.
+type ExpireDeleteMarker struct {
+	val bool
+	set bool
+}
+
+// Expiration - expiration actions for a rule in lifecycle configuration.
+type Expiration struct {
+	XMLName      xml.Name           `xml:"Expiration"`
+	Days         ExpirationDays     `xml:"Days,omitempty"`
+	Date         ExpirationDate     `xml:"Date,omitempty"`
+	DeleteMarker ExpireDeleteMarker `xml:"ExpiredObjectDeleteMarker"`
+
+	set bool
+}
+
+// MarshalXML encodes delete marker boolean into an XML form.
+func (b ExpireDeleteMarker) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if !b.set {
+		return nil
+	}
+	return e.EncodeElement(b.val, startElement)
+}
+
+// UnmarshalXML decodes delete marker boolean from the XML form.
+func (b *ExpireDeleteMarker) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	var exp bool
+	err := d.DecodeElement(&exp, &startElement)
+	if err != nil {
+		return err
+	}
+	b.val = exp
+	b.set = true
+	return nil
+}
+
+// MarshalXML encodes expiration field into an XML form.
+func (e Expiration) MarshalXML(enc *xml.Encoder, startElement xml.StartElement) error {
+	if !e.set {
+		return nil
+	}
+	type expirationWrapper Expiration
+	return enc.EncodeElement(expirationWrapper(e), startElement)
+}
+
+// UnmarshalXML decodes expiration field from the XML form.
+func (e *Expiration) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	type expirationWrapper Expiration
+	var exp expirationWrapper
+	err := d.DecodeElement(&exp, &startElement)
+	if err != nil {
+		return err
+	}
+	*e = Expiration(exp)
+	e.set = true
+	return nil
+}
+
+// Validate - validates the "Expiration" element
+func (e Expiration) Validate() error {
+	if !e.set {
+		return nil
+	}
+
+	// DeleteMarker cannot be specified if date or dates are specified.
+	if (!e.IsDaysNull() || !e.IsDateNull()) && e.DeleteMarker.set {
+		return errLifecycleInvalidDeleteMarker
+	}
+
+	if !e.DeleteMarker.set && e.IsDaysNull() && e.IsDateNull() {
+		return errXMLNotWellFormed
+	}
+
+	// Both expiration days and date are specified
+	if !e.IsDaysNull() && !e.IsDateNull() {
+		return errLifecycleInvalidExpiration
+	}
+
+	return nil
+}
+
+// IsDaysNull returns true if days field is null
+func (e Expiration) IsDaysNull() bool {
+	return e.Days == ExpirationDays(0)
+}
+
+// IsDateNull returns true if date field is null
+func (e Expiration) IsDateNull() bool {
+	return e.Date.Time.IsZero()
+}
+
+// IsNull returns true if both date and days fields are null
+func (e Expiration) IsNull() bool {
+	return e.IsDaysNull() && e.IsDateNull()
+}

internal/bucket/lifecycle/expiration_test.go

@@ -0,0 +1,113 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"fmt"
+	"testing"
+)
+
+// appropriate errors on validation
+func TestInvalidExpiration(t *testing.T) {
+	testCases := []struct {
+		inputXML    string
+		expectedErr error
+	}{
+		{ // Expiration with zero days
+			inputXML: ` <Expiration>
+                                    <Days>0</Days>
+                                    </Expiration>`,
+			expectedErr: errLifecycleInvalidDays,
+		},
+		{ // Expiration with invalid date
+			inputXML: ` <Expiration>
+                                    <Date>invalid date</Date>
+                                    </Expiration>`,
+			expectedErr: errLifecycleInvalidDate,
+		},
+		{ // Expiration with both number of days nor a date
+			inputXML: `<Expiration>
+		                    <Date>2019-04-20T00:01:00Z</Date>
+		                    </Expiration>`,
+			expectedErr: errLifecycleDateNotMidnight,
+		},
+	}
+
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			var expiration Expiration
+			err := xml.Unmarshal([]byte(tc.inputXML), &expiration)
+			if err != tc.expectedErr {
+				t.Fatalf("%d: Expected %v but got %v", i+1, tc.expectedErr, err)
+			}
+		})
+
+	}
+
+	validationTestCases := []struct {
+		inputXML    string
+		expectedErr error
+	}{
+		{ // Expiration with a valid ISO 8601 date
+			inputXML: `<Expiration>
+                                    <Date>2019-04-20T00:00:00Z</Date>
+                                    </Expiration>`,
+			expectedErr: nil,
+		},
+		{ // Expiration with a valid number of days
+			inputXML: `<Expiration>
+                                    <Days>3</Days>
+                                    </Expiration>`,
+			expectedErr: nil,
+		},
+		{ // Expiration with neither number of days nor a date
+			inputXML: `<Expiration>
+                                    </Expiration>`,
+			expectedErr: errXMLNotWellFormed,
+		},
+		{ // Expiration with both number of days and a date
+			inputXML: `<Expiration>
+                                    <Days>3</Days>
+                                    <Date>2019-04-20T00:00:00Z</Date>
+                                    </Expiration>`,
+			expectedErr: errLifecycleInvalidExpiration,
+		},
+		{ // Expiration with both ExpiredObjectDeleteMarker and days
+			inputXML: `<Expiration>
+                                    <Days>3</Days>
+			            <ExpiredObjectDeleteMarker>false</ExpiredObjectDeleteMarker>
+                                    </Expiration>`,
+			expectedErr: errLifecycleInvalidDeleteMarker,
+		},
+	}
+	for i, tc := range validationTestCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			var expiration Expiration
+			err := xml.Unmarshal([]byte(tc.inputXML), &expiration)
+			if err != nil {
+				t.Fatalf("%d: %v", i+1, err)
+			}
+
+			err = expiration.Validate()
+			if err != tc.expectedErr {
+				t.Fatalf("%d: got: %v, expected: %v", i+1, err, tc.expectedErr)
+			}
+		})
+	}
+}

internal/bucket/lifecycle/filter.go

@@ -0,0 +1,178 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"io"
+)
+
+var (
+	errInvalidFilter = Errorf("Filter must have exactly one of Prefix, Tag, or And specified")
+)
+
+// Filter - a filter for a lifecycle configuration Rule.
+type Filter struct {
+	XMLName xml.Name `xml:"Filter"`
+	set     bool
+
+	Prefix Prefix
+
+	And    And
+	andSet bool
+
+	Tag    Tag
+	tagSet bool
+	// Caching tags, only once
+	cachedTags []string
+}
+
+// MarshalXML - produces the xml representation of the Filter struct
+// only one of Prefix, And and Tag should be present in the output.
+func (f Filter) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if err := e.EncodeToken(start); err != nil {
+		return err
+	}
+
+	switch {
+	case !f.And.isEmpty():
+		if err := e.EncodeElement(f.And, xml.StartElement{Name: xml.Name{Local: "And"}}); err != nil {
+			return err
+		}
+	case !f.Tag.IsEmpty():
+		if err := e.EncodeElement(f.Tag, xml.StartElement{Name: xml.Name{Local: "Tag"}}); err != nil {
+			return err
+		}
+	default:
+		// Always print Prefix field when both And & Tag are empty
+		if err := e.EncodeElement(f.Prefix, xml.StartElement{Name: xml.Name{Local: "Prefix"}}); err != nil {
+			return err
+		}
+	}
+
+	return e.EncodeToken(xml.EndElement{Name: start.Name})
+}
+
+// UnmarshalXML - decodes XML data.
+func (f *Filter) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
+	f.set = true
+	for {
+		// Read tokens from the XML document in a stream.
+		t, err := d.Token()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		switch se := t.(type) {
+		case xml.StartElement:
+			switch se.Name.Local {
+			case "Prefix":
+				var p Prefix
+				if err = d.DecodeElement(&p, &se); err != nil {
+					return err
+				}
+				f.Prefix = p
+			case "And":
+				var and And
+				if err = d.DecodeElement(&and, &se); err != nil {
+					return err
+				}
+				f.And = and
+				f.andSet = true
+			case "Tag":
+				var tag Tag
+				if err = d.DecodeElement(&tag, &se); err != nil {
+					return err
+				}
+				f.Tag = tag
+				f.tagSet = true
+			default:
+				return errUnknownXMLTag
+			}
+		}
+	}
+	return nil
+}
+
+// IsEmpty returns true if Filter is not specified in the XML
+func (f Filter) IsEmpty() bool {
+	return !f.set
+}
+
+// Validate - validates the filter element
+func (f Filter) Validate() error {
+	if f.IsEmpty() {
+		return errXMLNotWellFormed
+	}
+	// A Filter must have exactly one of Prefix, Tag, or And specified.
+	if !f.And.isEmpty() {
+		if f.Prefix.set {
+			return errInvalidFilter
+		}
+		if !f.Tag.IsEmpty() {
+			return errInvalidFilter
+		}
+		if err := f.And.Validate(); err != nil {
+			return err
+		}
+	}
+	if f.Prefix.set {
+		if !f.Tag.IsEmpty() {
+			return errInvalidFilter
+		}
+	}
+	if !f.Tag.IsEmpty() {
+		if f.Prefix.set {
+			return errInvalidFilter
+		}
+		if err := f.Tag.Validate(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// TestTags tests if the object tags satisfy the Filter tags requirement,
+// it returns true if there is no tags in the underlying Filter.
+func (f Filter) TestTags(tags []string) bool {
+	if f.cachedTags == nil {
+		tags := make([]string, 0)
+		for _, t := range append(f.And.Tags, f.Tag) {
+			if !t.IsEmpty() {
+				tags = append(tags, t.String())
+			}
+		}
+		f.cachedTags = tags
+	}
+	for _, ct := range f.cachedTags {
+		foundTag := false
+		for _, t := range tags {
+			if ct == t {
+				foundTag = true
+				break
+			}
+		}
+		if !foundTag {
+			return false
+		}
+	}
+	return true
+}

internal/bucket/lifecycle/filter_test.go

@@ -0,0 +1,126 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"fmt"
+	"testing"
+)
+
+// TestUnsupportedFilters checks if parsing Filter xml with
+// unsupported elements returns appropriate errors
+func TestUnsupportedFilters(t *testing.T) {
+	testCases := []struct {
+		inputXML    string
+		expectedErr error
+	}{
+		{ // Filter with And tags
+			inputXML: ` <Filter>
+						<And>
+							<Prefix>key-prefix</Prefix>
+						</And>
+						</Filter>`,
+			expectedErr: errXMLNotWellFormed,
+		},
+		{ // Filter with Tag tags
+			inputXML: ` <Filter>
+						<Tag>
+							<Key>key1</Key>
+							<Value>value1</Value>
+						</Tag>
+						</Filter>`,
+			expectedErr: nil,
+		},
+		{ // Filter with Prefix tag
+			inputXML: ` <Filter>
+							<Prefix>key-prefix</Prefix>
+						</Filter>`,
+			expectedErr: nil,
+		},
+		{ // Filter without And and multiple Tag tags
+			inputXML: ` <Filter>
+							<Prefix>key-prefix</Prefix>
+							<Tag>
+								<Key>key1</Key>
+								<Value>value1</Value>
+							</Tag>
+							<Tag>
+								<Key>key2</Key>
+								<Value>value2</Value>
+							</Tag>
+						</Filter>`,
+			expectedErr: errInvalidFilter,
+		},
+		{ // Filter with And, Prefix & multiple Tag tags
+			inputXML: ` <Filter>
+							<And>
+							<Prefix>key-prefix</Prefix>
+							<Tag>
+								<Key>key1</Key>
+								<Value>value1</Value>
+							</Tag>
+							<Tag>
+								<Key>key2</Key>
+								<Value>value2</Value>
+							</Tag>
+							</And>
+						</Filter>`,
+			expectedErr: nil,
+		},
+		{ // Filter with And and multiple Tag tags
+			inputXML: ` <Filter>
+							<And>
+							<Prefix></Prefix>
+							<Tag>
+								<Key>key1</Key>
+								<Value>value1</Value>
+							</Tag>
+							<Tag>
+								<Key>key2</Key>
+								<Value>value2</Value>
+							</Tag>
+							</And>
+						</Filter>`,
+			expectedErr: nil,
+		},
+		{ // Filter without And and single Tag tag
+			inputXML: ` <Filter>
+							<Prefix>key-prefix</Prefix>
+							<Tag>
+								<Key>key1</Key>
+								<Value>value1</Value>
+							</Tag>
+						</Filter>`,
+			expectedErr: errInvalidFilter,
+		},
+	}
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			var filter Filter
+			err := xml.Unmarshal([]byte(tc.inputXML), &filter)
+			if err != nil {
+				t.Fatalf("%d: Expected no error but got %v", i+1, err)
+			}
+			err = filter.Validate()
+			if err != tc.expectedErr {
+				t.Fatalf("%d: Expected %v but got %v", i+1, tc.expectedErr, err)
+			}
+		})
+	}
+}

internal/bucket/lifecycle/lifecycle.go

@@ -0,0 +1,462 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+)
+
+var (
+	errLifecycleTooManyRules = Errorf("Lifecycle configuration allows a maximum of 1000 rules")
+	errLifecycleNoRule       = Errorf("Lifecycle configuration should have at least one rule")
+	errLifecycleDuplicateID  = Errorf("Lifecycle configuration has rule with the same ID. Rule ID must be unique.")
+	errXMLNotWellFormed      = Errorf("The XML you provided was not well-formed or did not validate against our published schema")
+)
+
+const (
+	// TransitionComplete marks completed transition
+	TransitionComplete = "complete"
+	// TransitionPending - transition is yet to be attempted
+	TransitionPending = "pending"
+)
+
+// Action represents a delete action or other transition
+// actions that will be implemented later.
+type Action int
+
+//go:generate stringer -type Action $GOFILE
+
+const (
+	// NoneAction means no action required after evaluating lifecycle rules
+	NoneAction Action = iota
+	// DeleteAction means the object needs to be removed after evaluating lifecycle rules
+	DeleteAction
+	// DeleteVersionAction deletes a particular version
+	DeleteVersionAction
+	// TransitionAction transitions a particular object after evaluating lifecycle transition rules
+	TransitionAction
+	//TransitionVersionAction transitions a particular object version after evaluating lifecycle transition rules
+	TransitionVersionAction
+	// DeleteRestoredAction means the temporarily restored object needs to be removed after evaluating lifecycle rules
+	DeleteRestoredAction
+	// DeleteRestoredVersionAction deletes a particular version that was temporarily restored
+	DeleteRestoredVersionAction
+)
+
+// Lifecycle - Configuration for bucket lifecycle.
+type Lifecycle struct {
+	XMLName xml.Name `xml:"LifecycleConfiguration"`
+	Rules   []Rule   `xml:"Rule"`
+}
+
+// UnmarshalXML - decodes XML data.
+func (lc *Lifecycle) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
+	switch start.Name.Local {
+	case "LifecycleConfiguration", "BucketLifecycleConfiguration":
+	default:
+		return xml.UnmarshalError(fmt.Sprintf("expected element type <LifecycleConfiguration>/<BucketLifecycleConfiguration> but have <%s>",
+			start.Name.Local))
+	}
+	for {
+		// Read tokens from the XML document in a stream.
+		t, err := d.Token()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		switch se := t.(type) {
+		case xml.StartElement:
+			switch se.Name.Local {
+			case "Rule":
+				var r Rule
+				if err = d.DecodeElement(&r, &se); err != nil {
+					return err
+				}
+				lc.Rules = append(lc.Rules, r)
+			default:
+				return xml.UnmarshalError(fmt.Sprintf("expected element type <Rule> but have <%s>", se.Name.Local))
+			}
+		}
+	}
+	return nil
+}
+
+// HasActiveRules - returns whether policy has active rules for.
+// Optionally a prefix can be supplied.
+// If recursive is specified the function will also return true if any level below the
+// prefix has active rules. If no prefix is specified recursive is effectively true.
+func (lc Lifecycle) HasActiveRules(prefix string, recursive bool) bool {
+	if len(lc.Rules) == 0 {
+		return false
+	}
+	for _, rule := range lc.Rules {
+		if rule.Status == Disabled {
+			continue
+		}
+
+		if len(prefix) > 0 && len(rule.GetPrefix()) > 0 {
+			if !recursive {
+				// If not recursive, incoming prefix must be in rule prefix
+				if !strings.HasPrefix(prefix, rule.GetPrefix()) {
+					continue
+				}
+			}
+			if recursive {
+				// If recursive, we can skip this rule if it doesn't match the tested prefix.
+				if !strings.HasPrefix(prefix, rule.GetPrefix()) && !strings.HasPrefix(rule.GetPrefix(), prefix) {
+					continue
+				}
+			}
+		}
+
+		if rule.NoncurrentVersionExpiration.NoncurrentDays > 0 {
+			return true
+		}
+		if rule.NoncurrentVersionTransition.NoncurrentDays > 0 {
+			return true
+		}
+		if rule.Expiration.IsNull() && rule.Transition.IsNull() {
+			continue
+		}
+		if !rule.Expiration.IsDateNull() && rule.Expiration.Date.Before(time.Now()) {
+			return true
+		}
+		if !rule.Transition.IsDateNull() && rule.Transition.Date.Before(time.Now()) {
+			return true
+		}
+		if !rule.Expiration.IsDaysNull() || !rule.Transition.IsDaysNull() {
+			return true
+		}
+	}
+	return false
+}
+
+// ParseLifecycleConfig - parses data in given reader to Lifecycle.
+func ParseLifecycleConfig(reader io.Reader) (*Lifecycle, error) {
+	var lc Lifecycle
+	if err := xml.NewDecoder(reader).Decode(&lc); err != nil {
+		return nil, err
+	}
+	return &lc, nil
+}
+
+// Validate - validates the lifecycle configuration
+func (lc Lifecycle) Validate() error {
+	// Lifecycle config can't have more than 1000 rules
+	if len(lc.Rules) > 1000 {
+		return errLifecycleTooManyRules
+	}
+	// Lifecycle config should have at least one rule
+	if len(lc.Rules) == 0 {
+		return errLifecycleNoRule
+	}
+	// Validate all the rules in the lifecycle config
+	for _, r := range lc.Rules {
+		if err := r.Validate(); err != nil {
+			return err
+		}
+	}
+	// Make sure Rule ID is unique
+	for i := range lc.Rules {
+		if i == len(lc.Rules)-1 {
+			break
+		}
+		otherRules := lc.Rules[i+1:]
+		for _, otherRule := range otherRules {
+			if lc.Rules[i].ID == otherRule.ID {
+				return errLifecycleDuplicateID
+			}
+		}
+	}
+	return nil
+}
+
+// FilterActionableRules returns the rules actions that need to be executed
+// after evaluating prefix/tag filtering
+func (lc Lifecycle) FilterActionableRules(obj ObjectOpts) []Rule {
+	if obj.Name == "" {
+		return nil
+	}
+	var rules []Rule
+	for _, rule := range lc.Rules {
+		if rule.Status == Disabled {
+			continue
+		}
+		if !strings.HasPrefix(obj.Name, rule.GetPrefix()) {
+			continue
+		}
+		// Indicates whether MinIO will remove a delete marker with no
+		// noncurrent versions. If set to true, the delete marker will
+		// be expired; if set to false the policy takes no action. This
+		// cannot be specified with Days or Date in a Lifecycle
+		// Expiration Policy.
+		if rule.Expiration.DeleteMarker.val {
+			rules = append(rules, rule)
+			continue
+		}
+		// The NoncurrentVersionExpiration action requests MinIO to expire
+		// noncurrent versions of objects x days after the objects become
+		// noncurrent.
+		if !rule.NoncurrentVersionExpiration.IsDaysNull() {
+			rules = append(rules, rule)
+			continue
+		}
+		// The NoncurrentVersionTransition action requests MinIO to transition
+		// noncurrent versions of objects x days after the objects become
+		// noncurrent.
+		if !rule.NoncurrentVersionTransition.IsDaysNull() {
+			rules = append(rules, rule)
+			continue
+		}
+
+		if rule.Filter.TestTags(strings.Split(obj.UserTags, "&")) {
+			rules = append(rules, rule)
+		}
+		if !rule.Transition.IsNull() {
+			rules = append(rules, rule)
+		}
+	}
+	return rules
+}
+
+// ObjectOpts provides information to deduce the lifecycle actions
+// which can be triggered on the resultant object.
+type ObjectOpts struct {
+	Name                   string
+	UserTags               string
+	ModTime                time.Time
+	VersionID              string
+	IsLatest               bool
+	DeleteMarker           bool
+	NumVersions            int
+	SuccessorModTime       time.Time
+	TransitionStatus       string
+	RestoreOngoing         bool
+	RestoreExpires         time.Time
+	RemoteTiersImmediately []string // strictly for debug only
+}
+
+// doesMatchDebugTiers returns true if tier matches one of the debugTiers, false
+// otherwise.
+func doesMatchDebugTiers(tier string, debugTiers []string) bool {
+	for _, t := range debugTiers {
+		if strings.ToUpper(tier) == strings.ToUpper(t) {
+			return true
+		}
+	}
+	return false
+}
+
+// ExpiredObjectDeleteMarker returns true if an object version referred to by o
+// is the only version remaining and is a delete marker. It returns false
+// otherwise.
+func (o ObjectOpts) ExpiredObjectDeleteMarker() bool {
+	return o.DeleteMarker && o.NumVersions == 1
+}
+
+// ComputeAction returns the action to perform by evaluating all lifecycle rules
+// against the object name and its modification time.
+func (lc Lifecycle) ComputeAction(obj ObjectOpts) Action {
+	var action = NoneAction
+	if obj.ModTime.IsZero() {
+		return action
+	}
+	for _, rule := range lc.FilterActionableRules(obj) {
+		if obj.ExpiredObjectDeleteMarker() && rule.Expiration.DeleteMarker.val {
+			// Indicates whether MinIO will remove a delete marker with no noncurrent versions.
+			// Only latest marker is removed. If set to true, the delete marker will be expired;
+			// if set to false the policy takes no action. This cannot be specified with Days or
+			// Date in a Lifecycle Expiration Policy.
+			return DeleteVersionAction
+		}
+
+		if !rule.NoncurrentVersionExpiration.IsDaysNull() {
+			if obj.VersionID != "" && !obj.IsLatest && !obj.SuccessorModTime.IsZero() {
+				// Non current versions should be deleted if their age exceeds non current days configuration
+				// https://docs.aws.amazon.com/AmazonS3/latest/dev/intro-lifecycle-rules.html#intro-lifecycle-rules-actions
+				if time.Now().After(ExpectedExpiryTime(obj.SuccessorModTime, int(rule.NoncurrentVersionExpiration.NoncurrentDays))) {
+					return DeleteVersionAction
+				}
+			}
+
+			if obj.VersionID != "" && obj.ExpiredObjectDeleteMarker() {
+				// From https: //docs.aws.amazon.com/AmazonS3/latest/dev/lifecycle-configuration-examples.html :
+				//   The NoncurrentVersionExpiration action in the same Lifecycle configuration removes noncurrent objects X days
+				//   after they become noncurrent. Thus, in this example, all object versions are permanently removed X days after
+				//   object creation. You will have expired object delete markers, but Amazon S3 detects and removes the expired
+				//   object delete markers for you.
+				if time.Now().After(ExpectedExpiryTime(obj.ModTime, int(rule.NoncurrentVersionExpiration.NoncurrentDays))) {
+					return DeleteVersionAction
+				}
+			}
+		}
+
+		if !rule.NoncurrentVersionTransition.IsDaysNull() {
+			if obj.VersionID != "" && !obj.IsLatest && !obj.SuccessorModTime.IsZero() && !obj.DeleteMarker && obj.TransitionStatus != TransitionComplete {
+				// Non current versions should be transitioned if their age exceeds non current days configuration
+				// https://docs.aws.amazon.com/AmazonS3/latest/dev/intro-lifecycle-rules.html#intro-lifecycle-rules-actions
+				if time.Now().After(ExpectedExpiryTime(obj.SuccessorModTime, int(rule.NoncurrentVersionTransition.NoncurrentDays))) {
+					return TransitionVersionAction
+				}
+
+				// this if condition is strictly for debug purposes to force immediate
+				// transition to remote tier if _MINIO_DEBUG_REMOTE_TIERS_IMMEDIATELY is set
+				if doesMatchDebugTiers(rule.NoncurrentVersionTransition.StorageClass, obj.RemoteTiersImmediately) {
+					return TransitionVersionAction
+				}
+			}
+		}
+
+		// Remove the object or simply add a delete marker (once) in a versioned bucket
+		if obj.VersionID == "" || obj.IsLatest && !obj.DeleteMarker {
+			switch {
+			case !rule.Expiration.IsDateNull():
+				if time.Now().UTC().After(rule.Expiration.Date.Time) {
+					return DeleteAction
+				}
+			case !rule.Expiration.IsDaysNull():
+				if time.Now().UTC().After(ExpectedExpiryTime(obj.ModTime, int(rule.Expiration.Days))) {
+					return DeleteAction
+				}
+			}
+
+			if obj.TransitionStatus != TransitionComplete {
+				switch {
+				case !rule.Transition.IsDateNull():
+					if time.Now().UTC().After(rule.Transition.Date.Time) {
+						action = TransitionAction
+					}
+				case !rule.Transition.IsDaysNull():
+					if time.Now().UTC().After(ExpectedExpiryTime(obj.ModTime, int(rule.Transition.Days))) {
+						action = TransitionAction
+					}
+
+				}
+				// this if condition is strictly for debug purposes to force immediate
+				// transition to remote tier if _MINIO_DEBUG_REMOTE_TIERS_IMMEDIATELY is set
+				if !rule.Transition.IsNull() && doesMatchDebugTiers(rule.Transition.StorageClass, obj.RemoteTiersImmediately) {
+					action = TransitionAction
+				}
+
+				if !obj.RestoreExpires.IsZero() && time.Now().After(obj.RestoreExpires) {
+					if obj.VersionID != "" {
+						action = DeleteRestoredVersionAction
+					} else {
+						action = DeleteRestoredAction
+					}
+				}
+			}
+			if !obj.RestoreExpires.IsZero() && time.Now().After(obj.RestoreExpires) {
+				if obj.VersionID != "" {
+					action = DeleteRestoredVersionAction
+				} else {
+					action = DeleteRestoredAction
+				}
+			}
+
+		}
+	}
+	return action
+}
+
+// ExpectedExpiryTime calculates the expiry, transition or restore date/time based on a object modtime.
+// The expected transition or restore time is always a midnight time following the the object
+// modification time plus the number of transition/restore days.
+//   e.g. If the object modtime is `Thu May 21 13:42:50 GMT 2020` and the object should
+//       transition in 1 day, then the expected transition time is `Fri, 23 May 2020 00:00:00 GMT`
+func ExpectedExpiryTime(modTime time.Time, days int) time.Time {
+	t := modTime.UTC().Add(time.Duration(days+1) * 24 * time.Hour)
+	return t.Truncate(24 * time.Hour)
+}
+
+// PredictExpiryTime returns the expiry date/time of a given object
+// after evaluating the current lifecycle document.
+func (lc Lifecycle) PredictExpiryTime(obj ObjectOpts) (string, time.Time) {
+	if obj.DeleteMarker {
+		// We don't need to send any x-amz-expiration for delete marker.
+		return "", time.Time{}
+	}
+
+	var finalExpiryDate time.Time
+	var finalExpiryRuleID string
+
+	// Iterate over all actionable rules and find the earliest
+	// expiration date and its associated rule ID.
+	for _, rule := range lc.FilterActionableRules(obj) {
+		if !rule.NoncurrentVersionExpiration.IsDaysNull() && !obj.IsLatest && obj.VersionID != "" {
+			return rule.ID, ExpectedExpiryTime(obj.SuccessorModTime, int(rule.NoncurrentVersionExpiration.NoncurrentDays))
+		}
+
+		if !rule.Expiration.IsDateNull() {
+			if finalExpiryDate.IsZero() || finalExpiryDate.After(rule.Expiration.Date.Time) {
+				finalExpiryRuleID = rule.ID
+				finalExpiryDate = rule.Expiration.Date.Time
+			}
+		}
+		if !rule.Expiration.IsDaysNull() {
+			expectedExpiry := ExpectedExpiryTime(obj.ModTime, int(rule.Expiration.Days))
+			if finalExpiryDate.IsZero() || finalExpiryDate.After(expectedExpiry) {
+				finalExpiryRuleID = rule.ID
+				finalExpiryDate = expectedExpiry
+			}
+		}
+	}
+	return finalExpiryRuleID, finalExpiryDate
+}
+
+// PredictTransitionTime returns the transition date/time of a given object
+// after evaluating the current lifecycle document.
+func (lc Lifecycle) PredictTransitionTime(obj ObjectOpts) (string, time.Time) {
+	if obj.DeleteMarker {
+		// We don't need to send any x-minio-transition for delete marker.
+		return "", time.Time{}
+	}
+
+	if obj.TransitionStatus == TransitionComplete {
+		return "", time.Time{}
+	}
+
+	var finalTransitionDate time.Time
+	var finalTransitionRuleID string
+
+	// Iterate over all actionable rules and find the earliest
+	// transition date and its associated rule ID.
+	for _, rule := range lc.FilterActionableRules(obj) {
+		switch {
+		case !rule.Transition.IsDateNull():
+			if finalTransitionDate.IsZero() || finalTransitionDate.After(rule.Transition.Date.Time) {
+				finalTransitionRuleID = rule.ID
+				finalTransitionDate = rule.Transition.Date.Time
+			}
+		case !rule.Transition.IsDaysNull():
+			expectedTransition := ExpectedExpiryTime(obj.ModTime, int(rule.Expiration.Days))
+			if finalTransitionDate.IsZero() || finalTransitionDate.After(expectedTransition) {
+				finalTransitionRuleID = rule.ID
+				finalTransitionDate = expectedTransition
+			}
+		}
+	}
+	return finalTransitionRuleID, finalTransitionDate
+}

internal/bucket/lifecycle/lifecycle_test.go

@@ -0,0 +1,431 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestParseAndValidateLifecycleConfig(t *testing.T) {
+	testCases := []struct {
+		inputConfig           string
+		expectedParsingErr    error
+		expectedValidationErr error
+	}{
+		{ // Valid lifecycle config
+			inputConfig: `<LifecycleConfiguration>
+								  <Rule>
+								  <ID>testRule1</ID>
+		                          <Filter>
+		                             <Prefix>prefix</Prefix>
+		                          </Filter>
+		                          <Status>Enabled</Status>
+		                          <Expiration><Days>3</Days></Expiration>
+		                          </Rule>
+		                              <Rule>
+								  <ID>testRule2</ID>
+		                          <Filter>
+		                             <Prefix>another-prefix</Prefix>
+		                          </Filter>
+		                          <Status>Enabled</Status>
+		                          <Expiration><Days>3</Days></Expiration>
+		                          </Rule>
+		                          </LifecycleConfiguration>`,
+			expectedParsingErr:    nil,
+			expectedValidationErr: nil,
+		},
+		{ // Valid lifecycle config
+			inputConfig: `<LifecycleConfiguration>
+					  <Rule>
+					  <Filter>
+					  <And><Tag><Key>key1</Key><Value>val1</Value><Key>key2</Key><Value>val2</Value></Tag></And>
+		                          </Filter>
+		                          <Expiration><Days>3</Days></Expiration>
+		                          </Rule>
+		                          </LifecycleConfiguration>`,
+			expectedParsingErr:    errDuplicatedXMLTag,
+			expectedValidationErr: nil,
+		},
+		{ // lifecycle config with no rules
+			inputConfig: `<LifecycleConfiguration>
+		                          </LifecycleConfiguration>`,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errLifecycleNoRule,
+		},
+		{ // lifecycle config with rules having overlapping prefix
+			inputConfig:           `<LifecycleConfiguration><Rule><ID>rule1</ID><Status>Enabled</Status><Filter><Prefix>/a/b</Prefix></Filter><Expiration><Days>3</Days></Expiration></Rule><Rule><ID>rule2</ID><Status>Enabled</Status><Filter><And><Prefix>/a/b/c</Prefix><Tag><Key>key1</Key><Value>val1</Value></Tag></And></Filter><Expiration><Days>3</Days></Expiration></Rule></LifecycleConfiguration> `,
+			expectedParsingErr:    nil,
+			expectedValidationErr: nil,
+		},
+		{ // lifecycle config with rules having duplicate ID
+			inputConfig:           `<LifecycleConfiguration><Rule><ID>duplicateID</ID><Status>Enabled</Status><Filter><Prefix>/a/b</Prefix></Filter><Expiration><Days>3</Days></Expiration></Rule><Rule><ID>duplicateID</ID><Status>Enabled</Status><Filter><And><Prefix>/x/z</Prefix><Tag><Key>key1</Key><Value>val1</Value></Tag></And></Filter><Expiration><Days>4</Days></Expiration></Rule></LifecycleConfiguration>`,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errLifecycleDuplicateID,
+		},
+		// Missing <Tag> in <And>
+		{
+			inputConfig:           `<LifecycleConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ID>sample-rule-2</ID><Filter><And><Prefix>/a/b/c</Prefix></And></Filter><Status>Enabled</Status><Expiration><Days>1</Days></Expiration></Rule></LifecycleConfiguration>`,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errXMLNotWellFormed,
+		},
+		// Lifecycle with the deprecated Prefix tag
+		{
+			inputConfig:           `<LifecycleConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ID>rule</ID><Prefix /><Status>Enabled</Status><Expiration><Days>1</Days></Expiration></Rule></LifecycleConfiguration>`,
+			expectedParsingErr:    nil,
+			expectedValidationErr: nil,
+		},
+		// Lifecycle with empty Filter tag
+		{
+			inputConfig:           `<LifecycleConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ID>rule</ID><Filter></Filter><Status>Enabled</Status><Expiration><Days>1</Days></Expiration></Rule></LifecycleConfiguration>`,
+			expectedParsingErr:    nil,
+			expectedValidationErr: nil,
+		},
+	}
+
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			lc, err := ParseLifecycleConfig(bytes.NewReader([]byte(tc.inputConfig)))
+			if err != tc.expectedParsingErr {
+				t.Fatalf("%d: Expected %v during parsing but got %v", i+1, tc.expectedParsingErr, err)
+			}
+			if tc.expectedParsingErr != nil {
+				// We already expect a parsing error,
+				// no need to continue this test.
+				return
+			}
+			err = lc.Validate()
+			if err != tc.expectedValidationErr {
+				t.Fatalf("%d: Expected %v during parsing but got %v", i+1, tc.expectedValidationErr, err)
+			}
+		})
+	}
+}
+
+// TestMarshalLifecycleConfig checks if lifecycleconfig xml
+// marshaling/unmarshaling can handle output from each other
+func TestMarshalLifecycleConfig(t *testing.T) {
+	// Time at midnight UTC
+	midnightTS := ExpirationDate{time.Date(2019, time.April, 20, 0, 0, 0, 0, time.UTC)}
+	lc := Lifecycle{
+		Rules: []Rule{
+			{
+				Status:     "Enabled",
+				Filter:     Filter{Prefix: Prefix{string: "prefix-1", set: true}},
+				Expiration: Expiration{Days: ExpirationDays(3)},
+			},
+			{
+				Status:     "Enabled",
+				Filter:     Filter{Prefix: Prefix{string: "prefix-1", set: true}},
+				Expiration: Expiration{Date: midnightTS},
+			},
+			{
+				Status:                      "Enabled",
+				Filter:                      Filter{Prefix: Prefix{string: "prefix-1", set: true}},
+				Expiration:                  Expiration{Date: midnightTS},
+				NoncurrentVersionTransition: NoncurrentVersionTransition{NoncurrentDays: 2, StorageClass: "TEST"},
+			},
+		},
+	}
+	b, err := xml.MarshalIndent(&lc, "", "\t")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var lc1 Lifecycle
+	err = xml.Unmarshal(b, &lc1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ruleSet := make(map[string]struct{})
+	for _, rule := range lc.Rules {
+		ruleBytes, err := xml.Marshal(rule)
+		if err != nil {
+			t.Fatal(err)
+		}
+		ruleSet[string(ruleBytes)] = struct{}{}
+	}
+	for _, rule := range lc1.Rules {
+		ruleBytes, err := xml.Marshal(rule)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if _, ok := ruleSet[string(ruleBytes)]; !ok {
+			t.Fatalf("Expected %v to be equal to %v, %v missing", lc, lc1, rule)
+		}
+	}
+}
+
+func TestExpectedExpiryTime(t *testing.T) {
+	testCases := []struct {
+		modTime  time.Time
+		days     ExpirationDays
+		expected time.Time
+	}{
+		{
+			time.Date(2020, time.March, 15, 10, 10, 10, 0, time.UTC),
+			4,
+			time.Date(2020, time.March, 20, 0, 0, 0, 0, time.UTC),
+		},
+		{
+			time.Date(2020, time.March, 15, 0, 0, 0, 0, time.UTC),
+			1,
+			time.Date(2020, time.March, 17, 0, 0, 0, 0, time.UTC),
+		},
+	}
+
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			got := ExpectedExpiryTime(tc.modTime, int(tc.days))
+			if !got.Equal(tc.expected) {
+				t.Fatalf("Expected %v to be equal to %v", got, tc.expected)
+			}
+		})
+	}
+
+}
+
+func TestComputeActions(t *testing.T) {
+	testCases := []struct {
+		inputConfig    string
+		objectName     string
+		objectTags     string
+		objectModTime  time.Time
+		expectedAction Action
+	}{
+		// Empty object name (unexpected case) should always return NoneAction
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>prefix</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			expectedAction: NoneAction,
+		},
+		// Disabled should always return NoneAction
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Disabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-10 * 24 * time.Hour), // Created 10 days ago
+			expectedAction: NoneAction,
+		},
+		// No modTime, should be none-action
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			expectedAction: NoneAction,
+		},
+		// Prefix not matched
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-10 * 24 * time.Hour), // Created 10 days ago
+			expectedAction: NoneAction,
+		},
+		// Test rule with empty prefix e.g. for whole bucket
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix></Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject/foo.txt",
+			objectModTime:  time.Now().UTC().Add(-10 * 24 * time.Hour), // Created 10 days ago
+			expectedAction: DeleteAction,
+		},
+		// Too early to remove (test Days)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-10 * 24 * time.Hour), // Created 10 days ago
+			expectedAction: NoneAction,
+		},
+		// Should remove (test Days)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-6 * 24 * time.Hour), // Created 6 days ago
+			expectedAction: DeleteAction,
+		},
+		// Too early to remove (test Date)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().UTC().Truncate(24*time.Hour).Add(24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: NoneAction,
+		},
+		// Should remove (test Days)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().UTC().Truncate(24*time.Hour).Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should remove (Tags match)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Prefix>foodir/</Prefix><Tag><Key>tag1</Key><Value>value1</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().UTC().Truncate(24*time.Hour).Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectTags:     "tag1=value1&tag2=value2",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should remove (Multiple Rules, Tags match)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Prefix>foodir/</Prefix><Tag><Key>tag1</Key><Value>value1</Value></Tag><Tag><Key>tag2</Key><Value>value2</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule><Rule><Filter><And><Prefix>abc/</Prefix><Tag><Key>tag2</Key><Value>value</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectTags:     "tag1=value1&tag2=value2",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should remove (Tags match)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Prefix>foodir/</Prefix><Tag><Key>tag1</Key><Value>value1</Value></Tag><Tag><Key>tag2</Key><Value>value2</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectTags:     "tag1=value1&tag2=value2",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should remove (Tags match with inverted order)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Tag><Key>factory</Key><Value>true</Value></Tag><Tag><Key>storeforever</Key><Value>false</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "fooobject",
+			objectTags:     "storeforever=false&factory=true",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+
+		// Should not remove (Tags don't match)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Prefix>foodir/</Prefix><Tag><Key>tag</Key><Value>value1</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().UTC().Truncate(24*time.Hour).Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectTags:     "tag1=value1",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: NoneAction,
+		},
+		// Should not remove (Tags match, but prefix doesn't match)
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Prefix>foodir/</Prefix><Tag><Key>tag1</Key><Value>value1</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject",
+			objectTags:     "tag1=value1",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: NoneAction,
+		},
+		// Should remove - empty prefix, tags match, date expiration kicked in
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Tag><Key>tag1</Key><Value>value1</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject",
+			objectTags:     "tag1=value1",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should remove - empty prefix, tags match, object is expired based on specified Days
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><And><Prefix></Prefix><Tag><Key>tag1</Key><Value>value1</Value></Tag></And></Filter><Status>Enabled</Status><Expiration><Days>1</Days></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject",
+			objectTags:     "tag1=value1",
+			objectModTime:  time.Now().UTC().Add(-48 * time.Hour), // Created 2 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should remove, the second rule has expiration kicked in
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule><Rule><Filter><Prefix>foxdir/</Prefix></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></LifecycleConfiguration>`,
+			objectName:     "foxdir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+		// Should accept BucketLifecycleConfiguration root tag
+		{
+			inputConfig:    `<BucketLifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Date>` + time.Now().Truncate(24*time.Hour).UTC().Add(-24*time.Hour).Format(time.RFC3339) + `</Date></Expiration></Rule></BucketLifecycleConfiguration>`,
+			objectName:     "foodir/fooobject",
+			objectModTime:  time.Now().UTC().Add(-24 * time.Hour), // Created 1 day ago
+			expectedAction: DeleteAction,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run("", func(t *testing.T) {
+			lc, err := ParseLifecycleConfig(bytes.NewReader([]byte(tc.inputConfig)))
+			if err != nil {
+				t.Fatalf("Got unexpected error: %v", err)
+			}
+			if resultAction := lc.ComputeAction(ObjectOpts{
+				Name:     tc.objectName,
+				UserTags: tc.objectTags,
+				ModTime:  tc.objectModTime,
+				IsLatest: true,
+			}); resultAction != tc.expectedAction {
+				t.Fatalf("Expected action: `%v`, got: `%v`", tc.expectedAction, resultAction)
+			}
+		})
+
+	}
+}
+
+func TestHasActiveRules(t *testing.T) {
+	testCases := []struct {
+		inputConfig    string
+		prefix         string
+		expectedNonRec bool
+		expectedRec    bool
+	}{
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			prefix:         "foodir/foobject",
+			expectedNonRec: true, expectedRec: true,
+		},
+		{ // empty prefix
+			inputConfig:    `<LifecycleConfiguration><Rule><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			prefix:         "foodir/foobject/foo.txt",
+			expectedNonRec: true, expectedRec: true,
+		},
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			prefix:         "zdir/foobject",
+			expectedNonRec: false, expectedRec: false,
+		},
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/zdir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			prefix:         "foodir/",
+			expectedNonRec: false, expectedRec: true,
+		},
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix></Prefix></Filter><Status>Disabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,
+			prefix:         "foodir/",
+			expectedNonRec: false, expectedRec: false,
+		},
+		{
+			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Date>2999-01-01T00:00:00.000Z</Date></Expiration></Rule></LifecycleConfiguration>`,
+			prefix:         "foodir/foobject",
+			expectedNonRec: false, expectedRec: false,
+		},
+	}
+
+	for i, tc := range testCases {
+		tc := tc
+		t.Run(fmt.Sprintf("Test_%d", i+1), func(t *testing.T) {
+			lc, err := ParseLifecycleConfig(bytes.NewReader([]byte(tc.inputConfig)))
+			if err != nil {
+				t.Fatalf("Got unexpected error: %v", err)
+			}
+			if got := lc.HasActiveRules(tc.prefix, false); got != tc.expectedNonRec {
+				t.Fatalf("Expected result with recursive set to false: `%v`, got: `%v`", tc.expectedNonRec, got)
+			}
+			if got := lc.HasActiveRules(tc.prefix, true); got != tc.expectedRec {
+				t.Fatalf("Expected result with recursive set to true: `%v`, got: `%v`", tc.expectedRec, got)
+			}
+
+		})
+
+	}
+}

internal/bucket/lifecycle/noncurrentversion.go

@@ -0,0 +1,114 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+)
+
+// NoncurrentVersionExpiration - an action for lifecycle configuration rule.
+type NoncurrentVersionExpiration struct {
+	XMLName        xml.Name       `xml:"NoncurrentVersionExpiration"`
+	NoncurrentDays ExpirationDays `xml:"NoncurrentDays,omitempty"`
+	set            bool
+}
+
+// MarshalXML if non-current days not set to non zero value
+func (n NoncurrentVersionExpiration) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if n.IsDaysNull() {
+		return nil
+	}
+	type noncurrentVersionExpirationWrapper NoncurrentVersionExpiration
+	return e.EncodeElement(noncurrentVersionExpirationWrapper(n), start)
+}
+
+// UnmarshalXML decodes NoncurrentVersionExpiration
+func (n *NoncurrentVersionExpiration) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	type noncurrentVersionExpirationWrapper NoncurrentVersionExpiration
+	var val noncurrentVersionExpirationWrapper
+	err := d.DecodeElement(&val, &startElement)
+	if err != nil {
+		return err
+	}
+	*n = NoncurrentVersionExpiration(val)
+	n.set = true
+	return nil
+}
+
+// IsDaysNull returns true if days field is null
+func (n NoncurrentVersionExpiration) IsDaysNull() bool {
+	return n.NoncurrentDays == ExpirationDays(0)
+}
+
+// Validate returns an error with wrong value
+func (n NoncurrentVersionExpiration) Validate() error {
+	if !n.set {
+		return nil
+	}
+	val := int(n.NoncurrentDays)
+	if val <= 0 {
+		return errXMLNotWellFormed
+	}
+	return nil
+}
+
+// NoncurrentVersionTransition - an action for lifecycle configuration rule.
+type NoncurrentVersionTransition struct {
+	NoncurrentDays ExpirationDays `xml:"NoncurrentDays"`
+	StorageClass   string         `xml:"StorageClass"`
+	set            bool
+}
+
+// MarshalXML is extended to leave out
+// <NoncurrentVersionTransition></NoncurrentVersionTransition> tags
+func (n NoncurrentVersionTransition) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if n.NoncurrentDays == ExpirationDays(0) {
+		return nil
+	}
+	type noncurrentVersionTransitionWrapper NoncurrentVersionTransition
+	return e.EncodeElement(noncurrentVersionTransitionWrapper(n), start)
+}
+
+// IsDaysNull returns true if days field is null
+func (n NoncurrentVersionTransition) IsDaysNull() bool {
+	return n.NoncurrentDays == ExpirationDays(0)
+}
+
+// UnmarshalXML decodes NoncurrentVersionExpiration
+func (n *NoncurrentVersionTransition) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	type noncurrentVersionTransitionWrapper NoncurrentVersionTransition
+	var val noncurrentVersionTransitionWrapper
+	err := d.DecodeElement(&val, &startElement)
+	if err != nil {
+		return err
+	}
+	*n = NoncurrentVersionTransition(val)
+	n.set = true
+	return nil
+}
+
+// Validate returns an error with wrong value
+func (n NoncurrentVersionTransition) Validate() error {
+	if !n.set {
+		return nil
+	}
+	if int(n.NoncurrentDays) <= 0 || n.StorageClass == "" {
+		return errXMLNotWellFormed
+	}
+	return nil
+}

internal/bucket/lifecycle/prefix.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+)
+
+// Prefix holds the prefix xml tag in <Rule> and <Filter>
+type Prefix struct {
+	string
+	set bool
+}
+
+// UnmarshalXML - decodes XML data.
+func (p *Prefix) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
+	var s string
+	if err = d.DecodeElement(&s, &start); err != nil {
+		return err
+	}
+	*p = Prefix{string: s, set: true}
+	return nil
+}
+
+// MarshalXML - decodes XML data.
+func (p Prefix) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if !p.set {
+		return nil
+	}
+	return e.EncodeElement(p.string, startElement)
+}
+
+// String returns the prefix string
+func (p Prefix) String() string {
+	return p.string
+}

internal/bucket/lifecycle/rule.go

@@ -0,0 +1,186 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"bytes"
+	"encoding/xml"
+
+	"github.com/google/uuid"
+)
+
+// Status represents lifecycle configuration status
+type Status string
+
+// Supported status types
+const (
+	Enabled  Status = "Enabled"
+	Disabled Status = "Disabled"
+)
+
+// Rule - a rule for lifecycle configuration.
+type Rule struct {
+	XMLName    xml.Name   `xml:"Rule"`
+	ID         string     `xml:"ID,omitempty"`
+	Status     Status     `xml:"Status"`
+	Filter     Filter     `xml:"Filter,omitempty"`
+	Prefix     Prefix     `xml:"Prefix,omitempty"`
+	Expiration Expiration `xml:"Expiration,omitempty"`
+	Transition Transition `xml:"Transition,omitempty"`
+	// FIXME: add a type to catch unsupported AbortIncompleteMultipartUpload AbortIncompleteMultipartUpload `xml:"AbortIncompleteMultipartUpload,omitempty"`
+	NoncurrentVersionExpiration NoncurrentVersionExpiration `xml:"NoncurrentVersionExpiration,omitempty"`
+	NoncurrentVersionTransition NoncurrentVersionTransition `xml:"NoncurrentVersionTransition,omitempty"`
+}
+
+var (
+	errInvalidRuleID     = Errorf("ID length is limited to 255 characters")
+	errEmptyRuleStatus   = Errorf("Status should not be empty")
+	errInvalidRuleStatus = Errorf("Status must be set to either Enabled or Disabled")
+)
+
+// generates random UUID
+func getNewUUID() (string, error) {
+	u, err := uuid.NewRandom()
+	if err != nil {
+		return "", err
+	}
+
+	return u.String(), nil
+}
+
+// validateID - checks if ID is valid or not.
+func (r Rule) validateID() error {
+	IDLen := len(r.ID)
+	// generate new ID when not provided
+	// cannot be longer than 255 characters
+	if IDLen == 0 {
+		if newID, err := getNewUUID(); err == nil {
+			r.ID = newID
+		} else {
+			return err
+		}
+	} else if IDLen > 255 {
+		return errInvalidRuleID
+	}
+	return nil
+}
+
+// validateStatus - checks if status is valid or not.
+func (r Rule) validateStatus() error {
+	// Status can't be empty
+	if len(r.Status) == 0 {
+		return errEmptyRuleStatus
+	}
+
+	// Status must be one of Enabled or Disabled
+	if r.Status != Enabled && r.Status != Disabled {
+		return errInvalidRuleStatus
+	}
+	return nil
+}
+
+func (r Rule) validateExpiration() error {
+	return r.Expiration.Validate()
+}
+
+func (r Rule) validateNoncurrentExpiration() error {
+	return r.NoncurrentVersionExpiration.Validate()
+}
+
+func (r Rule) validatePrefixAndFilter() error {
+	if !r.Prefix.set && r.Filter.IsEmpty() || r.Prefix.set && !r.Filter.IsEmpty() {
+		return errXMLNotWellFormed
+	}
+	if !r.Prefix.set {
+		return r.Filter.Validate()
+	}
+	return nil
+}
+
+func (r Rule) validateTransition() error {
+	return r.Transition.Validate()
+}
+
+func (r Rule) validateNoncurrentTransition() error {
+	return r.NoncurrentVersionTransition.Validate()
+}
+
+// GetPrefix - a rule can either have prefix under <rule></rule>, <filter></filter>
+// or under <filter><and></and></filter>. This method returns the prefix from the
+// location where it is available.
+func (r Rule) GetPrefix() string {
+	if p := r.Prefix.String(); p != "" {
+		return p
+	}
+	if p := r.Filter.Prefix.String(); p != "" {
+		return p
+	}
+	if p := r.Filter.And.Prefix.String(); p != "" {
+		return p
+	}
+	return ""
+}
+
+// Tags - a rule can either have tag under <filter></filter> or under
+// <filter><and></and></filter>. This method returns all the tags from the
+// rule in the format tag1=value1&tag2=value2
+func (r Rule) Tags() string {
+	if !r.Filter.Tag.IsEmpty() {
+		return r.Filter.Tag.String()
+	}
+	if len(r.Filter.And.Tags) != 0 {
+		var buf bytes.Buffer
+		for _, t := range r.Filter.And.Tags {
+			if buf.Len() > 0 {
+				buf.WriteString("&")
+			}
+			buf.WriteString(t.String())
+		}
+		return buf.String()
+	}
+	return ""
+}
+
+// Validate - validates the rule element
+func (r Rule) Validate() error {
+	if err := r.validateID(); err != nil {
+		return err
+	}
+	if err := r.validateStatus(); err != nil {
+		return err
+	}
+	if err := r.validateExpiration(); err != nil {
+		return err
+	}
+	if err := r.validateNoncurrentExpiration(); err != nil {
+		return err
+	}
+	if err := r.validatePrefixAndFilter(); err != nil {
+		return err
+	}
+	if err := r.validateTransition(); err != nil {
+		return err
+	}
+	if err := r.validateNoncurrentTransition(); err != nil {
+		return err
+	}
+	if !r.Expiration.set && !r.Transition.set && !r.NoncurrentVersionExpiration.set && !r.NoncurrentVersionTransition.set {
+		return errXMLNotWellFormed
+	}
+	return nil
+}

internal/bucket/lifecycle/rule_test.go

@@ -0,0 +1,79 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"fmt"
+	"testing"
+)
+
+// TestInvalidRules checks if Rule xml with invalid elements returns
+// appropriate errors on validation
+func TestInvalidRules(t *testing.T) {
+	invalidTestCases := []struct {
+		inputXML    string
+		expectedErr error
+	}{
+		{ // Rule with ID longer than 255 characters
+			inputXML: ` <Rule>
+	                    <ID> babababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababababab </ID>
+	                    </Rule>`,
+			expectedErr: errInvalidRuleID,
+		},
+		{ // Rule with empty ID
+			inputXML: `<Rule>
+							<ID></ID>
+							<Filter><Prefix></Prefix></Filter>
+							<Expiration>
+								<Days>365</Days>
+							</Expiration>
+                            <Status>Enabled</Status>
+	                    </Rule>`,
+			expectedErr: nil,
+		},
+		{ // Rule with empty status
+			inputXML: ` <Rule>
+			                  <ID>rule with empty status</ID>
+                              <Status></Status>
+	                    </Rule>`,
+			expectedErr: errEmptyRuleStatus,
+		},
+		{ // Rule with invalid status
+			inputXML: ` <Rule>
+			                  <ID>rule with invalid status</ID>
+                              <Status>OK</Status>
+	                    </Rule>`,
+			expectedErr: errInvalidRuleStatus,
+		},
+	}
+
+	for i, tc := range invalidTestCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			var rule Rule
+			err := xml.Unmarshal([]byte(tc.inputXML), &rule)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if err := rule.Validate(); err != tc.expectedErr {
+				t.Fatalf("%d: Expected %v but got %v", i+1, tc.expectedErr, err)
+			}
+		})
+	}
+}

internal/bucket/lifecycle/tag.go

@@ -0,0 +1,102 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"io"
+	"unicode/utf8"
+)
+
+// Tag - a tag for a lifecycle configuration Rule filter.
+type Tag struct {
+	XMLName xml.Name `xml:"Tag"`
+	Key     string   `xml:"Key,omitempty"`
+	Value   string   `xml:"Value,omitempty"`
+}
+
+var (
+	errInvalidTagKey   = Errorf("The TagKey you have provided is invalid")
+	errInvalidTagValue = Errorf("The TagValue you have provided is invalid")
+
+	errDuplicatedXMLTag = Errorf("duplicated XML Tag")
+	errUnknownXMLTag    = Errorf("unknown XML Tag")
+)
+
+// UnmarshalXML - decodes XML data.
+func (tag *Tag) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
+	var keyAlreadyParsed, valueAlreadyParsed bool
+	for {
+		// Read tokens from the XML document in a stream.
+		t, err := d.Token()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		switch se := t.(type) {
+		case xml.StartElement:
+			var s string
+			if err = d.DecodeElement(&s, &se); err != nil {
+				return err
+			}
+			switch se.Name.Local {
+			case "Key":
+				if keyAlreadyParsed {
+					return errDuplicatedXMLTag
+				}
+				tag.Key = s
+				keyAlreadyParsed = true
+			case "Value":
+				if valueAlreadyParsed {
+					return errDuplicatedXMLTag
+				}
+				tag.Value = s
+				valueAlreadyParsed = true
+			default:
+				return errUnknownXMLTag
+			}
+		}
+	}
+
+	return nil
+}
+
+func (tag Tag) String() string {
+	return tag.Key + "=" + tag.Value
+}
+
+// IsEmpty returns whether this tag is empty or not.
+func (tag Tag) IsEmpty() bool {
+	return tag.Key == ""
+}
+
+// Validate checks this tag.
+func (tag Tag) Validate() error {
+	if len(tag.Key) == 0 || utf8.RuneCountInString(tag.Key) > 128 {
+		return errInvalidTagKey
+	}
+
+	if utf8.RuneCountInString(tag.Value) > 256 {
+		return errInvalidTagValue
+	}
+
+	return nil
+}

internal/bucket/lifecycle/transition.go

@@ -0,0 +1,165 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lifecycle
+
+import (
+	"encoding/xml"
+	"time"
+)
+
+var (
+	errTransitionInvalidDays     = Errorf("Days must be 0 or greater when used with Transition")
+	errTransitionInvalidDate     = Errorf("Date must be provided in ISO 8601 format")
+	errTransitionInvalid         = Errorf("Exactly one of Days (0 or greater) or Date (positive ISO 8601 format) should be present inside Expiration.")
+	errTransitionDateNotMidnight = Errorf("'Date' must be at midnight GMT")
+)
+
+// TransitionDate is a embedded type containing time.Time to unmarshal
+// Date in Transition
+type TransitionDate struct {
+	time.Time
+}
+
+// UnmarshalXML parses date from Transition and validates date format
+func (tDate *TransitionDate) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	var dateStr string
+	err := d.DecodeElement(&dateStr, &startElement)
+	if err != nil {
+		return err
+	}
+	// While AWS documentation mentions that the date specified
+	// must be present in ISO 8601 format, in reality they allow
+	// users to provide RFC 3339 compliant dates.
+	trnDate, err := time.Parse(time.RFC3339, dateStr)
+	if err != nil {
+		return errTransitionInvalidDate
+	}
+	// Allow only date timestamp specifying midnight GMT
+	hr, min, sec := trnDate.Clock()
+	nsec := trnDate.Nanosecond()
+	loc := trnDate.Location()
+	if !(hr == 0 && min == 0 && sec == 0 && nsec == 0 && loc.String() == time.UTC.String()) {
+		return errTransitionDateNotMidnight
+	}
+
+	*tDate = TransitionDate{trnDate}
+	return nil
+}
+
+// MarshalXML encodes expiration date if it is non-zero and encodes
+// empty string otherwise
+func (tDate TransitionDate) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if tDate.Time.IsZero() {
+		return nil
+	}
+	return e.EncodeElement(tDate.Format(time.RFC3339), startElement)
+}
+
+// TransitionDays is a type alias to unmarshal Days in Transition
+type TransitionDays int
+
+// UnmarshalXML parses number of days from Transition and validates if
+// >= 0
+func (tDays *TransitionDays) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	var numDays int
+	err := d.DecodeElement(&numDays, &startElement)
+	if err != nil {
+		return err
+	}
+	if numDays < 0 {
+		return errTransitionInvalidDays
+	}
+	*tDays = TransitionDays(numDays)
+	return nil
+}
+
+// MarshalXML encodes number of days to expire if it is non-zero and
+// encodes empty string otherwise
+func (tDays TransitionDays) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if tDays == 0 {
+		return nil
+	}
+	return e.EncodeElement(int(tDays), startElement)
+}
+
+// Transition - transition actions for a rule in lifecycle configuration.
+type Transition struct {
+	XMLName      xml.Name       `xml:"Transition"`
+	Days         TransitionDays `xml:"Days,omitempty"`
+	Date         TransitionDate `xml:"Date,omitempty"`
+	StorageClass string         `xml:"StorageClass,omitempty"`
+
+	set bool
+}
+
+// MarshalXML encodes transition field into an XML form.
+func (t Transition) MarshalXML(enc *xml.Encoder, start xml.StartElement) error {
+	if !t.set {
+		return nil
+	}
+	type transitionWrapper Transition
+	return enc.EncodeElement(transitionWrapper(t), start)
+}
+
+// UnmarshalXML decodes transition field from the XML form.
+func (t *Transition) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	type transitionWrapper Transition
+	var trw transitionWrapper
+	err := d.DecodeElement(&trw, &startElement)
+	if err != nil {
+		return err
+	}
+	*t = Transition(trw)
+	t.set = true
+	return nil
+}
+
+// Validate - validates the "Transition" element
+func (t Transition) Validate() error {
+	if !t.set {
+		return nil
+	}
+
+	if t.IsDaysNull() && t.IsDateNull() {
+		return errXMLNotWellFormed
+	}
+
+	// Both transition days and date are specified
+	if !t.IsDaysNull() && !t.IsDateNull() {
+		return errTransitionInvalid
+	}
+	if t.StorageClass == "" {
+		return errXMLNotWellFormed
+	}
+	return nil
+}
+
+// IsDaysNull returns true if days field is null
+func (t Transition) IsDaysNull() bool {
+	return t.Days == TransitionDays(0)
+}
+
+// IsDateNull returns true if date field is null
+func (t Transition) IsDateNull() bool {
+	return t.Date.Time.IsZero()
+}
+
+// IsNull returns true if both date and days fields are null
+func (t Transition) IsNull() bool {
+	return t.IsDaysNull() && t.IsDateNull()
+}

internal/bucket/object/lock/lock.go

@@ -0,0 +1,576 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lock
+
+import (
+	"context"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/beevik/ntp"
+	"github.com/minio/minio/internal/logger"
+	"github.com/minio/pkg/env"
+)
+
+// RetMode - object retention mode.
+type RetMode string
+
+const (
+	// RetGovernance - governance mode.
+	RetGovernance RetMode = "GOVERNANCE"
+
+	// RetCompliance - compliance mode.
+	RetCompliance RetMode = "COMPLIANCE"
+)
+
+// Valid - returns if retention mode is valid
+func (r RetMode) Valid() bool {
+	switch r {
+	case RetGovernance, RetCompliance:
+		return true
+	}
+	return false
+}
+
+func parseRetMode(modeStr string) (mode RetMode) {
+	switch strings.ToUpper(modeStr) {
+	case "GOVERNANCE":
+		mode = RetGovernance
+	case "COMPLIANCE":
+		mode = RetCompliance
+	}
+	return mode
+}
+
+// LegalHoldStatus - object legal hold status.
+type LegalHoldStatus string
+
+const (
+	// LegalHoldOn - legal hold is on.
+	LegalHoldOn LegalHoldStatus = "ON"
+
+	// LegalHoldOff - legal hold is off.
+	LegalHoldOff LegalHoldStatus = "OFF"
+)
+
+// Valid - returns true if legal hold status has valid values
+func (l LegalHoldStatus) Valid() bool {
+	switch l {
+	case LegalHoldOn, LegalHoldOff:
+		return true
+	}
+	return false
+}
+
+func parseLegalHoldStatus(holdStr string) (st LegalHoldStatus) {
+	switch strings.ToUpper(holdStr) {
+	case "ON":
+		st = LegalHoldOn
+	case "OFF":
+		st = LegalHoldOff
+	}
+	return st
+}
+
+// Bypass retention governance header.
+const (
+	AmzObjectLockBypassRetGovernance = "X-Amz-Bypass-Governance-Retention"
+	AmzObjectLockRetainUntilDate     = "X-Amz-Object-Lock-Retain-Until-Date"
+	AmzObjectLockMode                = "X-Amz-Object-Lock-Mode"
+	AmzObjectLockLegalHold           = "X-Amz-Object-Lock-Legal-Hold"
+)
+
+var (
+	// ErrMalformedBucketObjectConfig -indicates that the bucket object lock config is malformed
+	ErrMalformedBucketObjectConfig = errors.New("invalid bucket object lock config")
+	// ErrInvalidRetentionDate - indicates that retention date needs to be in ISO 8601 format
+	ErrInvalidRetentionDate = errors.New("date must be provided in ISO 8601 format")
+	// ErrPastObjectLockRetainDate - indicates that retention date must be in the future
+	ErrPastObjectLockRetainDate = errors.New("the retain until date must be in the future")
+	// ErrUnknownWORMModeDirective - indicates that the retention mode is invalid
+	ErrUnknownWORMModeDirective = errors.New("unknown WORM mode directive")
+	// ErrObjectLockMissingContentMD5 - indicates missing Content-MD5 header for put object requests with locking
+	ErrObjectLockMissingContentMD5 = errors.New("content-MD5 HTTP header is required for Put Object requests with Object Lock parameters")
+	// ErrObjectLockInvalidHeaders indicates that object lock headers are missing
+	ErrObjectLockInvalidHeaders = errors.New("x-amz-object-lock-retain-until-date and x-amz-object-lock-mode must both be supplied")
+	// ErrMalformedXML - generic error indicating malformed XML
+	ErrMalformedXML = errors.New("the XML you provided was not well-formed or did not validate against our published schema")
+)
+
+const (
+	ntpServerEnv = "MINIO_NTP_SERVER"
+)
+
+var (
+	ntpServer = env.Get(ntpServerEnv, "")
+)
+
+// UTCNowNTP - is similar in functionality to UTCNow()
+// but only used when we do not wish to rely on system
+// time.
+func UTCNowNTP() (time.Time, error) {
+	// ntp server is disabled
+	if ntpServer == "" {
+		return time.Now().UTC(), nil
+	}
+	return ntp.Time(ntpServer)
+}
+
+// Retention - bucket level retention configuration.
+type Retention struct {
+	Mode        RetMode
+	Validity    time.Duration
+	LockEnabled bool
+}
+
+// Retain - check whether given date is retainable by validity time.
+func (r Retention) Retain(created time.Time) bool {
+	t, err := UTCNowNTP()
+	if err != nil {
+		logger.LogIf(context.Background(), err)
+		// Retain
+		return true
+	}
+	return created.Add(r.Validity).After(t)
+}
+
+// DefaultRetention - default retention configuration.
+type DefaultRetention struct {
+	XMLName xml.Name `xml:"DefaultRetention"`
+	Mode    RetMode  `xml:"Mode"`
+	Days    *uint64  `xml:"Days"`
+	Years   *uint64  `xml:"Years"`
+}
+
+// Maximum support retention days and years supported by AWS S3.
+const (
+	// This tested by using `mc lock` command
+	maximumRetentionDays  = 36500
+	maximumRetentionYears = 100
+)
+
+// UnmarshalXML - decodes XML data.
+func (dr *DefaultRetention) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type defaultRetention DefaultRetention
+	retention := defaultRetention{}
+
+	if err := d.DecodeElement(&retention, &start); err != nil {
+		return err
+	}
+
+	switch retention.Mode {
+	case RetGovernance, RetCompliance:
+	default:
+		return fmt.Errorf("unknown retention mode %v", retention.Mode)
+	}
+
+	if retention.Days == nil && retention.Years == nil {
+		return fmt.Errorf("either Days or Years must be specified")
+	}
+
+	if retention.Days != nil && retention.Years != nil {
+		return fmt.Errorf("either Days or Years must be specified, not both")
+	}
+
+	if retention.Days != nil {
+		if *retention.Days == 0 {
+			return fmt.Errorf("Default retention period must be a positive integer value for 'Days'")
+		}
+		if *retention.Days > maximumRetentionDays {
+			return fmt.Errorf("Default retention period too large for 'Days' %d", *retention.Days)
+		}
+	} else if *retention.Years == 0 {
+		return fmt.Errorf("Default retention period must be a positive integer value for 'Years'")
+	} else if *retention.Years > maximumRetentionYears {
+		return fmt.Errorf("Default retention period too large for 'Years' %d", *retention.Years)
+	}
+
+	*dr = DefaultRetention(retention)
+
+	return nil
+}
+
+// Config - object lock configuration specified in
+// https://docs.aws.amazon.com/AmazonS3/latest/API/Type_API_ObjectLockConfiguration.html
+type Config struct {
+	XMLNS             string   `xml:"xmlns,attr,omitempty"`
+	XMLName           xml.Name `xml:"ObjectLockConfiguration"`
+	ObjectLockEnabled string   `xml:"ObjectLockEnabled"`
+	Rule              *struct {
+		DefaultRetention DefaultRetention `xml:"DefaultRetention"`
+	} `xml:"Rule,omitempty"`
+}
+
+// UnmarshalXML - decodes XML data.
+func (config *Config) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type objectLockConfig Config
+	parsedConfig := objectLockConfig{}
+
+	if err := d.DecodeElement(&parsedConfig, &start); err != nil {
+		return err
+	}
+
+	if parsedConfig.ObjectLockEnabled != "Enabled" {
+		return fmt.Errorf("only 'Enabled' value is allowed to ObjectLockEnabled element")
+	}
+
+	*config = Config(parsedConfig)
+	return nil
+}
+
+// ToRetention - convert to Retention type.
+func (config *Config) ToRetention() Retention {
+	r := Retention{
+		LockEnabled: config.ObjectLockEnabled == "Enabled",
+	}
+	if config.Rule != nil {
+		r.Mode = config.Rule.DefaultRetention.Mode
+
+		t, err := UTCNowNTP()
+		if err != nil {
+			logger.LogIf(context.Background(), err)
+			// Do not change any configuration
+			// upon NTP failure.
+			return r
+		}
+
+		if config.Rule.DefaultRetention.Days != nil {
+			r.Validity = t.AddDate(0, 0, int(*config.Rule.DefaultRetention.Days)).Sub(t)
+		} else {
+			r.Validity = t.AddDate(int(*config.Rule.DefaultRetention.Years), 0, 0).Sub(t)
+		}
+	}
+
+	return r
+}
+
+// Maximum 4KiB size per object lock config.
+const maxObjectLockConfigSize = 1 << 12
+
+// ParseObjectLockConfig parses ObjectLockConfig from xml
+func ParseObjectLockConfig(reader io.Reader) (*Config, error) {
+	config := Config{}
+	if err := xml.NewDecoder(io.LimitReader(reader, maxObjectLockConfigSize)).Decode(&config); err != nil {
+		return nil, err
+	}
+
+	return &config, nil
+}
+
+// NewObjectLockConfig returns a initialized lock.Config struct
+func NewObjectLockConfig() *Config {
+	return &Config{
+		ObjectLockEnabled: "Enabled",
+	}
+}
+
+// RetentionDate is a embedded type containing time.Time to unmarshal
+// Date in Retention
+type RetentionDate struct {
+	time.Time
+}
+
+// UnmarshalXML parses date from Retention and validates date format
+func (rDate *RetentionDate) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
+	var dateStr string
+	err := d.DecodeElement(&dateStr, &startElement)
+	if err != nil {
+		return err
+	}
+	// While AWS documentation mentions that the date specified
+	// must be present in ISO 8601 format, in reality they allow
+	// users to provide RFC 3339 compliant dates.
+	retDate, err := time.Parse(time.RFC3339, dateStr)
+	if err != nil {
+		return ErrInvalidRetentionDate
+	}
+
+	*rDate = RetentionDate{retDate}
+	return nil
+}
+
+// MarshalXML encodes expiration date if it is non-zero and encodes
+// empty string otherwise
+func (rDate *RetentionDate) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
+	if *rDate == (RetentionDate{time.Time{}}) {
+		return nil
+	}
+	return e.EncodeElement(rDate.Format(time.RFC3339), startElement)
+}
+
+// ObjectRetention specified in
+// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutObjectRetention.html
+type ObjectRetention struct {
+	XMLNS           string        `xml:"xmlns,attr,omitempty"`
+	XMLName         xml.Name      `xml:"Retention"`
+	Mode            RetMode       `xml:"Mode,omitempty"`
+	RetainUntilDate RetentionDate `xml:"RetainUntilDate,omitempty"`
+}
+
+// Maximum 4KiB size per object retention config.
+const maxObjectRetentionSize = 1 << 12
+
+// ParseObjectRetention constructs ObjectRetention struct from xml input
+func ParseObjectRetention(reader io.Reader) (*ObjectRetention, error) {
+	ret := ObjectRetention{}
+	if err := xml.NewDecoder(io.LimitReader(reader, maxObjectRetentionSize)).Decode(&ret); err != nil {
+		return nil, err
+	}
+	if ret.Mode != "" && !ret.Mode.Valid() {
+		return &ret, ErrUnknownWORMModeDirective
+	}
+
+	if ret.Mode.Valid() && ret.RetainUntilDate.IsZero() {
+		return &ret, ErrMalformedXML
+	}
+
+	if !ret.Mode.Valid() && !ret.RetainUntilDate.IsZero() {
+		return &ret, ErrMalformedXML
+	}
+
+	t, err := UTCNowNTP()
+	if err != nil {
+		logger.LogIf(context.Background(), err)
+		return &ret, ErrPastObjectLockRetainDate
+	}
+
+	if !ret.RetainUntilDate.IsZero() && ret.RetainUntilDate.Before(t) {
+		return &ret, ErrPastObjectLockRetainDate
+	}
+
+	return &ret, nil
+}
+
+// IsObjectLockRetentionRequested returns true if object lock retention headers are set.
+func IsObjectLockRetentionRequested(h http.Header) bool {
+	if _, ok := h[AmzObjectLockMode]; ok {
+		return true
+	}
+	if _, ok := h[AmzObjectLockRetainUntilDate]; ok {
+		return true
+	}
+	return false
+}
+
+// IsObjectLockLegalHoldRequested returns true if object lock legal hold header is set.
+func IsObjectLockLegalHoldRequested(h http.Header) bool {
+	_, ok := h[AmzObjectLockLegalHold]
+	return ok
+}
+
+// IsObjectLockGovernanceBypassSet returns true if object lock governance bypass header is set.
+func IsObjectLockGovernanceBypassSet(h http.Header) bool {
+	return strings.ToLower(h.Get(AmzObjectLockBypassRetGovernance)) == "true"
+}
+
+// IsObjectLockRequested returns true if legal hold or object lock retention headers are requested.
+func IsObjectLockRequested(h http.Header) bool {
+	return IsObjectLockLegalHoldRequested(h) || IsObjectLockRetentionRequested(h)
+}
+
+// ParseObjectLockRetentionHeaders parses http headers to extract retention mode and retention date
+func ParseObjectLockRetentionHeaders(h http.Header) (rmode RetMode, r RetentionDate, err error) {
+	retMode := h.Get(AmzObjectLockMode)
+	dateStr := h.Get(AmzObjectLockRetainUntilDate)
+	if len(retMode) == 0 || len(dateStr) == 0 {
+		return rmode, r, ErrObjectLockInvalidHeaders
+	}
+
+	rmode = parseRetMode(retMode)
+	if !rmode.Valid() {
+		return rmode, r, ErrUnknownWORMModeDirective
+	}
+
+	var retDate time.Time
+	// While AWS documentation mentions that the date specified
+	// must be present in ISO 8601 format, in reality they allow
+	// users to provide RFC 3339 compliant dates.
+	retDate, err = time.Parse(time.RFC3339, dateStr)
+	if err != nil {
+		return rmode, r, ErrInvalidRetentionDate
+	}
+
+	t, err := UTCNowNTP()
+	if err != nil {
+		logger.LogIf(context.Background(), err)
+		return rmode, r, ErrPastObjectLockRetainDate
+	}
+
+	if retDate.Before(t) {
+		return rmode, r, ErrPastObjectLockRetainDate
+	}
+
+	return rmode, RetentionDate{retDate}, nil
+
+}
+
+// GetObjectRetentionMeta constructs ObjectRetention from metadata
+func GetObjectRetentionMeta(meta map[string]string) ObjectRetention {
+	var mode RetMode
+	var retainTill RetentionDate
+
+	var modeStr, tillStr string
+	ok := false
+
+	modeStr, ok = meta[strings.ToLower(AmzObjectLockMode)]
+	if !ok {
+		modeStr, ok = meta[AmzObjectLockMode]
+	}
+	if ok {
+		mode = parseRetMode(modeStr)
+	} else {
+		return ObjectRetention{}
+	}
+
+	tillStr, ok = meta[strings.ToLower(AmzObjectLockRetainUntilDate)]
+	if !ok {
+		tillStr, ok = meta[AmzObjectLockRetainUntilDate]
+	}
+	if ok {
+		if t, e := time.Parse(time.RFC3339, tillStr); e == nil {
+			retainTill = RetentionDate{t.UTC()}
+		}
+	}
+	return ObjectRetention{XMLNS: "http://s3.amazonaws.com/doc/2006-03-01/", Mode: mode, RetainUntilDate: retainTill}
+}
+
+// GetObjectLegalHoldMeta constructs ObjectLegalHold from metadata
+func GetObjectLegalHoldMeta(meta map[string]string) ObjectLegalHold {
+	holdStr, ok := meta[strings.ToLower(AmzObjectLockLegalHold)]
+	if !ok {
+		holdStr, ok = meta[AmzObjectLockLegalHold]
+	}
+	if ok {
+		return ObjectLegalHold{XMLNS: "http://s3.amazonaws.com/doc/2006-03-01/", Status: parseLegalHoldStatus(holdStr)}
+	}
+	return ObjectLegalHold{}
+}
+
+// ParseObjectLockLegalHoldHeaders parses request headers to construct ObjectLegalHold
+func ParseObjectLockLegalHoldHeaders(h http.Header) (lhold ObjectLegalHold, err error) {
+	holdStatus, ok := h[AmzObjectLockLegalHold]
+	if ok {
+		lh := parseLegalHoldStatus(holdStatus[0])
+		if !lh.Valid() {
+			return lhold, ErrUnknownWORMModeDirective
+		}
+		lhold = ObjectLegalHold{XMLNS: "http://s3.amazonaws.com/doc/2006-03-01/", Status: lh}
+	}
+	return lhold, nil
+
+}
+
+// ObjectLegalHold specified in
+// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutObjectLegalHold.html
+type ObjectLegalHold struct {
+	XMLNS   string          `xml:"xmlns,attr,omitempty"`
+	XMLName xml.Name        `xml:"LegalHold"`
+	Status  LegalHoldStatus `xml:"Status,omitempty"`
+}
+
+// UnmarshalXML - decodes XML data.
+func (l *ObjectLegalHold) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
+	switch start.Name.Local {
+	case "LegalHold", "ObjectLockLegalHold":
+	default:
+		return xml.UnmarshalError(fmt.Sprintf("expected element type <LegalHold>/<ObjectLockLegalHold> but have <%s>",
+			start.Name.Local))
+	}
+	for {
+		// Read tokens from the XML document in a stream.
+		t, err := d.Token()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		switch se := t.(type) {
+		case xml.StartElement:
+			switch se.Name.Local {
+			case "Status":
+				var st LegalHoldStatus
+				if err = d.DecodeElement(&st, &se); err != nil {
+					return err
+				}
+				l.Status = st
+			default:
+				return xml.UnmarshalError(fmt.Sprintf("expected element type <Status> but have <%s>", se.Name.Local))
+			}
+		}
+	}
+	return nil
+}
+
+// IsEmpty returns true if struct is empty
+func (l *ObjectLegalHold) IsEmpty() bool {
+	return !l.Status.Valid()
+}
+
+// ParseObjectLegalHold decodes the XML into ObjectLegalHold
+func ParseObjectLegalHold(reader io.Reader) (hold *ObjectLegalHold, err error) {
+	hold = &ObjectLegalHold{}
+	if err = xml.NewDecoder(reader).Decode(hold); err != nil {
+		return
+	}
+
+	if !hold.Status.Valid() {
+		return nil, ErrMalformedXML
+	}
+	return
+}
+
+// FilterObjectLockMetadata filters object lock metadata if s3:GetObjectRetention permission is denied or if isCopy flag set.
+func FilterObjectLockMetadata(metadata map[string]string, filterRetention, filterLegalHold bool) map[string]string {
+	// Copy on write
+	dst := metadata
+	var copied bool
+	delKey := func(key string) {
+		if _, ok := metadata[key]; !ok {
+			return
+		}
+		if !copied {
+			dst = make(map[string]string, len(metadata))
+			for k, v := range metadata {
+				dst[k] = v
+			}
+			copied = true
+		}
+		delete(dst, key)
+	}
+	legalHold := GetObjectLegalHoldMeta(metadata)
+	if !legalHold.Status.Valid() || filterLegalHold {
+		delKey(AmzObjectLockLegalHold)
+	}
+
+	ret := GetObjectRetentionMeta(metadata)
+	if !ret.Mode.Valid() || filterRetention {
+		delKey(AmzObjectLockMode)
+		delKey(AmzObjectLockRetainUntilDate)
+		return dst
+	}
+	return dst
+}

internal/bucket/object/lock/lock_test.go

@@ -0,0 +1,586 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package lock
+
+import (
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"net/http"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	xhttp "github.com/minio/minio/internal/http"
+)
+
+func TestParseMode(t *testing.T) {
+	testCases := []struct {
+		value        string
+		expectedMode RetMode
+	}{
+		{
+			value:        "governance",
+			expectedMode: RetGovernance,
+		},
+		{
+			value:        "complIAnce",
+			expectedMode: RetCompliance,
+		},
+		{
+			value:        "gce",
+			expectedMode: "",
+		},
+	}
+
+	for _, tc := range testCases {
+		if parseRetMode(tc.value) != tc.expectedMode {
+			t.Errorf("Expected Mode %s, got %s", tc.expectedMode, parseRetMode(tc.value))
+		}
+	}
+}
+func TestParseLegalHoldStatus(t *testing.T) {
+	tests := []struct {
+		value          string
+		expectedStatus LegalHoldStatus
+	}{
+		{
+			value:          "ON",
+			expectedStatus: LegalHoldOn,
+		},
+		{
+			value:          "Off",
+			expectedStatus: LegalHoldOff,
+		},
+		{
+			value:          "x",
+			expectedStatus: "",
+		},
+	}
+
+	for _, tt := range tests {
+		actualStatus := parseLegalHoldStatus(tt.value)
+		if actualStatus != tt.expectedStatus {
+			t.Errorf("Expected legal hold status %s, got %s", tt.expectedStatus, actualStatus)
+		}
+	}
+}
+
+// TestUnmarshalDefaultRetention checks if default retention
+// marshaling and unmarshaling work as expected
+func TestUnmarshalDefaultRetention(t *testing.T) {
+	days := uint64(4)
+	years := uint64(1)
+	zerodays := uint64(0)
+	invalidDays := uint64(maximumRetentionDays + 1)
+	tests := []struct {
+		value       DefaultRetention
+		expectedErr error
+		expectErr   bool
+	}{
+		{
+			value:       DefaultRetention{Mode: "retain"},
+			expectedErr: fmt.Errorf("unknown retention mode retain"),
+			expectErr:   true,
+		},
+		{
+			value:       DefaultRetention{Mode: RetGovernance},
+			expectedErr: fmt.Errorf("either Days or Years must be specified"),
+			expectErr:   true,
+		},
+		{
+			value:       DefaultRetention{Mode: RetGovernance, Days: &days},
+			expectedErr: nil,
+			expectErr:   false,
+		},
+		{
+			value:       DefaultRetention{Mode: RetGovernance, Years: &years},
+			expectedErr: nil,
+			expectErr:   false,
+		},
+		{
+			value:       DefaultRetention{Mode: RetGovernance, Days: &days, Years: &years},
+			expectedErr: fmt.Errorf("either Days or Years must be specified, not both"),
+			expectErr:   true,
+		},
+		{
+			value:       DefaultRetention{Mode: RetGovernance, Days: &zerodays},
+			expectedErr: fmt.Errorf("Default retention period must be a positive integer value for 'Days'"),
+			expectErr:   true,
+		},
+		{
+			value:       DefaultRetention{Mode: RetGovernance, Days: &invalidDays},
+			expectedErr: fmt.Errorf("Default retention period too large for 'Days' %d", invalidDays),
+			expectErr:   true,
+		},
+	}
+	for _, tt := range tests {
+		d, err := xml.MarshalIndent(&tt.value, "", "\t")
+		if err != nil {
+			t.Fatal(err)
+		}
+		var dr DefaultRetention
+		err = xml.Unmarshal(d, &dr)
+		if tt.expectedErr == nil {
+			if err != nil {
+				t.Fatalf("error: expected = <nil>, got = %v", err)
+			}
+		} else if err == nil {
+			t.Fatalf("error: expected = %v, got = <nil>", tt.expectedErr)
+		} else if tt.expectedErr.Error() != err.Error() {
+			t.Fatalf("error: expected = %v, got = %v", tt.expectedErr, err)
+		}
+	}
+}
+
+func TestParseObjectLockConfig(t *testing.T) {
+	tests := []struct {
+		value       string
+		expectedErr error
+		expectErr   bool
+	}{
+		{
+			value:       `<ObjectLockConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><ObjectLockEnabled>yes</ObjectLockEnabled></ObjectLockConfiguration>`,
+			expectedErr: fmt.Errorf("only 'Enabled' value is allowed to ObjectLockEnabled element"),
+			expectErr:   true,
+		},
+		{
+			value:       `<ObjectLockConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><ObjectLockEnabled>Enabled</ObjectLockEnabled><Rule><DefaultRetention><Mode>COMPLIANCE</Mode><Days>0</Days></DefaultRetention></Rule></ObjectLockConfiguration>`,
+			expectedErr: fmt.Errorf("Default retention period must be a positive integer value for 'Days'"),
+			expectErr:   true,
+		},
+		{
+			value:       `<ObjectLockConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><ObjectLockEnabled>Enabled</ObjectLockEnabled><Rule><DefaultRetention><Mode>COMPLIANCE</Mode><Days>30</Days></DefaultRetention></Rule></ObjectLockConfiguration>`,
+			expectedErr: nil,
+			expectErr:   false,
+		},
+	}
+	for _, tt := range tests {
+		_, err := ParseObjectLockConfig(strings.NewReader(tt.value))
+		if tt.expectedErr == nil {
+			if err != nil {
+				t.Fatalf("error: expected = <nil>, got = %v", err)
+			}
+		} else if err == nil {
+			t.Fatalf("error: expected = %v, got = <nil>", tt.expectedErr)
+		} else if tt.expectedErr.Error() != err.Error() {
+			t.Fatalf("error: expected = %v, got = %v", tt.expectedErr, err)
+		}
+	}
+}
+
+func TestParseObjectRetention(t *testing.T) {
+	tests := []struct {
+		value       string
+		expectedErr error
+		expectErr   bool
+	}{
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><Retention xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Mode>string</Mode><RetainUntilDate>2020-01-02T15:04:05Z</RetainUntilDate></Retention>`,
+			expectedErr: ErrUnknownWORMModeDirective,
+			expectErr:   true,
+		},
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><Retention xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Mode>COMPLIANCE</Mode><RetainUntilDate>2017-01-02T15:04:05Z</RetainUntilDate></Retention>`,
+			expectedErr: ErrPastObjectLockRetainDate,
+			expectErr:   true,
+		},
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><Retention xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Mode>GOVERNANCE</Mode><RetainUntilDate>2057-01-02T15:04:05Z</RetainUntilDate></Retention>`,
+			expectedErr: nil,
+			expectErr:   false,
+		},
+	}
+	for _, tt := range tests {
+		_, err := ParseObjectRetention(strings.NewReader(tt.value))
+		if tt.expectedErr == nil {
+			if err != nil {
+				t.Fatalf("error: expected = <nil>, got = %v", err)
+			}
+		} else if err == nil {
+			t.Fatalf("error: expected = %v, got = <nil>", tt.expectedErr)
+		} else if tt.expectedErr.Error() != err.Error() {
+			t.Fatalf("error: expected = %v, got = %v", tt.expectedErr, err)
+		}
+	}
+}
+
+func TestIsObjectLockRequested(t *testing.T) {
+	tests := []struct {
+		header      http.Header
+		expectedVal bool
+	}{
+		{
+			header: http.Header{
+				"Authorization":        []string{"AWS4-HMAC-SHA256 <cred_string>"},
+				"X-Amz-Content-Sha256": []string{""},
+				"Content-Encoding":     []string{""},
+			},
+			expectedVal: false,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockLegalHold: []string{""},
+			},
+			expectedVal: true,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockRetainUntilDate: []string{""},
+				AmzObjectLockMode:            []string{""},
+			},
+			expectedVal: true,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockBypassRetGovernance: []string{""},
+			},
+			expectedVal: false,
+		},
+	}
+	for _, tt := range tests {
+		actualVal := IsObjectLockRequested(tt.header)
+		if actualVal != tt.expectedVal {
+			t.Fatalf("error: expected %v, actual %v", tt.expectedVal, actualVal)
+		}
+	}
+}
+
+func TestIsObjectLockGovernanceBypassSet(t *testing.T) {
+	tests := []struct {
+		header      http.Header
+		expectedVal bool
+	}{
+		{
+			header: http.Header{
+				"Authorization":        []string{"AWS4-HMAC-SHA256 <cred_string>"},
+				"X-Amz-Content-Sha256": []string{""},
+				"Content-Encoding":     []string{""},
+			},
+			expectedVal: false,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockLegalHold: []string{""},
+			},
+			expectedVal: false,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockRetainUntilDate: []string{""},
+				AmzObjectLockMode:            []string{""},
+			},
+			expectedVal: false,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockBypassRetGovernance: []string{""},
+			},
+			expectedVal: false,
+		},
+		{
+			header: http.Header{
+				AmzObjectLockBypassRetGovernance: []string{"true"},
+			},
+			expectedVal: true,
+		},
+	}
+	for _, tt := range tests {
+		actualVal := IsObjectLockGovernanceBypassSet(tt.header)
+		if actualVal != tt.expectedVal {
+			t.Fatalf("error: expected %v, actual %v", tt.expectedVal, actualVal)
+		}
+	}
+}
+
+func TestParseObjectLockRetentionHeaders(t *testing.T) {
+	tests := []struct {
+		header      http.Header
+		expectedErr error
+	}{
+		{
+			header: http.Header{
+				"Authorization":        []string{"AWS4-HMAC-SHA256 <cred_string>"},
+				"X-Amz-Content-Sha256": []string{""},
+				"Content-Encoding":     []string{""},
+			},
+			expectedErr: ErrObjectLockInvalidHeaders,
+		},
+		{
+			header: http.Header{
+				xhttp.AmzObjectLockMode:            []string{"lock"},
+				xhttp.AmzObjectLockRetainUntilDate: []string{"2017-01-02"},
+			},
+			expectedErr: ErrUnknownWORMModeDirective,
+		},
+		{
+			header: http.Header{
+				xhttp.AmzObjectLockMode: []string{"governance"},
+			},
+			expectedErr: ErrObjectLockInvalidHeaders,
+		},
+		{
+			header: http.Header{
+				xhttp.AmzObjectLockRetainUntilDate: []string{"2017-01-02"},
+				xhttp.AmzObjectLockMode:            []string{"governance"},
+			},
+			expectedErr: ErrInvalidRetentionDate,
+		},
+		{
+			header: http.Header{
+				xhttp.AmzObjectLockRetainUntilDate: []string{"2017-01-02T15:04:05Z"},
+				xhttp.AmzObjectLockMode:            []string{"governance"},
+			},
+			expectedErr: ErrPastObjectLockRetainDate,
+		},
+		{
+			header: http.Header{
+				xhttp.AmzObjectLockMode:            []string{"governance"},
+				xhttp.AmzObjectLockRetainUntilDate: []string{"2017-01-02T15:04:05Z"},
+			},
+			expectedErr: ErrPastObjectLockRetainDate,
+		},
+		{
+			header: http.Header{
+				xhttp.AmzObjectLockMode:            []string{"governance"},
+				xhttp.AmzObjectLockRetainUntilDate: []string{"2087-01-02T15:04:05Z"},
+			},
+			expectedErr: nil,
+		},
+	}
+
+	for i, tt := range tests {
+		_, _, err := ParseObjectLockRetentionHeaders(tt.header)
+		if tt.expectedErr == nil {
+			if err != nil {
+				t.Fatalf("Case %d error: expected = <nil>, got = %v", i, err)
+			}
+		} else if err == nil {
+			t.Fatalf("Case %d error: expected = %v, got = <nil>", i, tt.expectedErr)
+		} else if tt.expectedErr.Error() != err.Error() {
+			t.Fatalf("Case %d error: expected = %v, got = %v", i, tt.expectedErr, err)
+		}
+	}
+}
+
+func TestGetObjectRetentionMeta(t *testing.T) {
+	tests := []struct {
+		metadata map[string]string
+		expected ObjectRetention
+	}{
+		{
+			metadata: map[string]string{
+				"Authorization":        "AWS4-HMAC-SHA256 <cred_string>",
+				"X-Amz-Content-Sha256": "",
+				"Content-Encoding":     "",
+			},
+			expected: ObjectRetention{},
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-mode": "governance",
+			},
+			expected: ObjectRetention{Mode: RetGovernance},
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-retain-until-date": "2020-02-01",
+			},
+			expected: ObjectRetention{RetainUntilDate: RetentionDate{time.Date(2020, 2, 1, 12, 0, 0, 0, time.UTC)}},
+		},
+	}
+
+	for i, tt := range tests {
+		o := GetObjectRetentionMeta(tt.metadata)
+		if o.Mode != tt.expected.Mode {
+			t.Fatalf("Case %d expected %v, got %v", i, tt.expected.Mode, o.Mode)
+		}
+	}
+}
+
+func TestGetObjectLegalHoldMeta(t *testing.T) {
+	tests := []struct {
+		metadata map[string]string
+		expected ObjectLegalHold
+	}{
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-mode": "governance",
+			},
+			expected: ObjectLegalHold{},
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold": "on",
+			},
+			expected: ObjectLegalHold{Status: LegalHoldOn},
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold": "off",
+			},
+			expected: ObjectLegalHold{Status: LegalHoldOff},
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold": "X",
+			},
+			expected: ObjectLegalHold{Status: ""},
+		},
+	}
+
+	for i, tt := range tests {
+		o := GetObjectLegalHoldMeta(tt.metadata)
+		if o.Status != tt.expected.Status {
+			t.Fatalf("Case %d expected %v, got %v", i, tt.expected.Status, o.Status)
+		}
+	}
+}
+
+func TestParseObjectLegalHold(t *testing.T) {
+	tests := []struct {
+		value       string
+		expectedErr error
+		expectErr   bool
+	}{
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><LegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>string</Status></LegalHold>`,
+			expectedErr: ErrMalformedXML,
+			expectErr:   true,
+		},
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><LegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>ON</Status></LegalHold>`,
+			expectedErr: nil,
+			expectErr:   false,
+		},
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><ObjectLockLegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>ON</Status></ObjectLockLegalHold>`,
+			expectedErr: nil,
+			expectErr:   false,
+		},
+		// invalid Status key
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><ObjectLockLegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><MyStatus>ON</MyStatus></ObjectLockLegalHold>`,
+			expectedErr: errors.New("expected element type <Status> but have <MyStatus>"),
+			expectErr:   true,
+		},
+		// invalid XML attr
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><UnknownLegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>ON</Status></UnknownLegalHold>`,
+			expectedErr: errors.New("expected element type <LegalHold>/<ObjectLockLegalHold> but have <UnknownLegalHold>"),
+			expectErr:   true,
+		},
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><LegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>On</Status></LegalHold>`,
+			expectedErr: ErrMalformedXML,
+			expectErr:   true,
+		},
+	}
+	for i, tt := range tests {
+		_, err := ParseObjectLegalHold(strings.NewReader(tt.value))
+		if tt.expectedErr == nil {
+			if err != nil {
+				t.Fatalf("Case %d error: expected = <nil>, got = %v", i, err)
+			}
+		} else if err == nil {
+			t.Fatalf("Case %d error: expected = %v, got = <nil>", i, tt.expectedErr)
+		} else if tt.expectedErr.Error() != err.Error() {
+			t.Fatalf("Case %d error: expected = %v, got = %v", i, tt.expectedErr, err)
+		}
+	}
+}
+func TestFilterObjectLockMetadata(t *testing.T) {
+	tests := []struct {
+		metadata        map[string]string
+		filterRetention bool
+		filterLegalHold bool
+		expected        map[string]string
+	}{
+		{
+			metadata: map[string]string{
+				"Authorization":        "AWS4-HMAC-SHA256 <cred_string>",
+				"X-Amz-Content-Sha256": "",
+				"Content-Encoding":     "",
+			},
+			expected: map[string]string{
+				"Authorization":        "AWS4-HMAC-SHA256 <cred_string>",
+				"X-Amz-Content-Sha256": "",
+				"Content-Encoding":     "",
+			},
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-mode": "governance",
+			},
+			expected: map[string]string{
+				"x-amz-object-lock-mode": "governance",
+			},
+			filterRetention: false,
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-mode":              "governance",
+				"x-amz-object-lock-retain-until-date": "2020-02-01",
+			},
+			expected:        map[string]string{},
+			filterRetention: true,
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold": "off",
+			},
+			expected:        map[string]string{},
+			filterLegalHold: true,
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold": "on",
+			},
+			expected:        map[string]string{"x-amz-object-lock-legal-hold": "on"},
+			filterLegalHold: false,
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold":        "on",
+				"x-amz-object-lock-mode":              "governance",
+				"x-amz-object-lock-retain-until-date": "2020-02-01",
+			},
+			expected:        map[string]string{},
+			filterRetention: true,
+			filterLegalHold: true,
+		},
+		{
+			metadata: map[string]string{
+				"x-amz-object-lock-legal-hold":        "on",
+				"x-amz-object-lock-mode":              "governance",
+				"x-amz-object-lock-retain-until-date": "2020-02-01",
+			},
+			expected: map[string]string{"x-amz-object-lock-legal-hold": "on",
+				"x-amz-object-lock-mode":              "governance",
+				"x-amz-object-lock-retain-until-date": "2020-02-01"},
+		},
+	}
+
+	for i, tt := range tests {
+		o := FilterObjectLockMetadata(tt.metadata, tt.filterRetention, tt.filterLegalHold)
+		if !reflect.DeepEqual(o, tt.metadata) {
+			t.Fatalf("Case %d expected %v, got %v", i, tt.metadata, o)
+		}
+	}
+}

internal/bucket/replication/and.go

@@ -0,0 +1,63 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"encoding/xml"
+)
+
+// And - a tag to combine a prefix and multiple tags for replication configuration rule.
+type And struct {
+	XMLName xml.Name `xml:"And" json:"And"`
+	Prefix  string   `xml:"Prefix,omitempty" json:"Prefix,omitempty"`
+	Tags    []Tag    `xml:"Tag,omitempty" json:"Tag,omitempty"`
+}
+
+var errDuplicateTagKey = Errorf("Duplicate Tag Keys are not allowed")
+
+// isEmpty returns true if Tags field is null
+func (a And) isEmpty() bool {
+	return len(a.Tags) == 0 && a.Prefix == ""
+}
+
+// Validate - validates the And field
+func (a And) Validate() error {
+	if a.ContainsDuplicateTag() {
+		return errDuplicateTagKey
+	}
+	for _, t := range a.Tags {
+		if err := t.Validate(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// ContainsDuplicateTag - returns true if duplicate keys are present in And
+func (a And) ContainsDuplicateTag() bool {
+	x := make(map[string]struct{}, len(a.Tags))
+
+	for _, t := range a.Tags {
+		if _, has := x[t.Key]; has {
+			return true
+		}
+		x[t.Key] = struct{}{}
+	}
+
+	return false
+}

internal/bucket/replication/destination.go

@@ -0,0 +1,119 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"encoding/xml"
+	"fmt"
+	"strings"
+
+	"github.com/minio/pkg/wildcard"
+)
+
+// DestinationARNPrefix - destination ARN prefix as per AWS S3 specification.
+const DestinationARNPrefix = "arn:aws:s3:::"
+
+// Destination - destination in ReplicationConfiguration.
+type Destination struct {
+	XMLName      xml.Name `xml:"Destination" json:"Destination"`
+	Bucket       string   `xml:"Bucket" json:"Bucket"`
+	StorageClass string   `xml:"StorageClass" json:"StorageClass"`
+	//EncryptionConfiguration TODO: not needed for MinIO
+}
+
+func (d Destination) isValidStorageClass() bool {
+	if d.StorageClass == "" {
+		return true
+	}
+	return d.StorageClass == "STANDARD" || d.StorageClass == "REDUCED_REDUNDANCY"
+}
+
+// IsValid - checks whether Destination is valid or not.
+func (d Destination) IsValid() bool {
+	return d.Bucket != "" || !d.isValidStorageClass()
+}
+
+func (d Destination) String() string {
+	return DestinationARNPrefix + d.Bucket
+}
+
+// MarshalXML - encodes to XML data.
+func (d Destination) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if err := e.EncodeToken(start); err != nil {
+		return err
+	}
+	if err := e.EncodeElement(d.String(), xml.StartElement{Name: xml.Name{Local: "Bucket"}}); err != nil {
+		return err
+	}
+	if d.StorageClass != "" {
+		if err := e.EncodeElement(d.StorageClass, xml.StartElement{Name: xml.Name{Local: "StorageClass"}}); err != nil {
+			return err
+		}
+	}
+	return e.EncodeToken(xml.EndElement{Name: start.Name})
+}
+
+// UnmarshalXML - decodes XML data.
+func (d *Destination) UnmarshalXML(dec *xml.Decoder, start xml.StartElement) (err error) {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type destination Destination
+	dest := destination{}
+
+	if err := dec.DecodeElement(&dest, &start); err != nil {
+		return err
+	}
+	parsedDest, err := parseDestination(dest.Bucket)
+	if err != nil {
+		return err
+	}
+	if dest.StorageClass != "" {
+		switch dest.StorageClass {
+		case "STANDARD", "REDUCED_REDUNDANCY":
+		default:
+			return fmt.Errorf("unknown storage class %s", dest.StorageClass)
+		}
+	}
+	parsedDest.StorageClass = dest.StorageClass
+	*d = parsedDest
+	return nil
+}
+
+// Validate - validates Resource is for given bucket or not.
+func (d Destination) Validate(bucketName string) error {
+	if !d.IsValid() {
+		return Errorf("invalid destination")
+	}
+
+	if !wildcard.Match(d.Bucket, bucketName) {
+		return Errorf("bucket name does not match")
+	}
+	return nil
+}
+
+// parseDestination - parses string to Destination.
+func parseDestination(s string) (Destination, error) {
+	if !strings.HasPrefix(s, DestinationARNPrefix) {
+		return Destination{}, Errorf("invalid destination '%s'", s)
+	}
+
+	bucketName := strings.TrimPrefix(s, DestinationARNPrefix)
+
+	return Destination{
+		Bucket: bucketName,
+	}, nil
+}

internal/bucket/replication/error.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"fmt"
+)
+
+// Error is the generic type for any error happening during tag
+// parsing.
+type Error struct {
+	err error
+}
+
+// Errorf - formats according to a format specifier and returns
+// the string as a value that satisfies error of type tagging.Error
+func Errorf(format string, a ...interface{}) error {
+	return Error{err: fmt.Errorf(format, a...)}
+}
+
+// Unwrap the internal error.
+func (e Error) Unwrap() error { return e.err }
+
+// Error 'error' compatible method.
+func (e Error) Error() string {
+	if e.err == nil {
+		return "replication: cause <nil>"
+	}
+	return e.err.Error()
+}

internal/bucket/replication/filter.go

@@ -0,0 +1,121 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"encoding/xml"
+)
+
+var (
+	errInvalidFilter = Errorf("Filter must have exactly one of Prefix, Tag, or And specified")
+)
+
+// Filter - a filter for a replication configuration Rule.
+type Filter struct {
+	XMLName xml.Name `xml:"Filter" json:"Filter"`
+	Prefix  string
+	And     And
+	Tag     Tag
+	// Caching tags, only once
+	cachedTags map[string]struct{}
+}
+
+// IsEmpty returns true if filter is not set
+func (f Filter) IsEmpty() bool {
+	return f.And.isEmpty() && f.Tag.IsEmpty() && f.Prefix == ""
+}
+
+// MarshalXML - produces the xml representation of the Filter struct
+// only one of Prefix, And and Tag should be present in the output.
+func (f Filter) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if err := e.EncodeToken(start); err != nil {
+		return err
+	}
+
+	switch {
+	case !f.And.isEmpty():
+		if err := e.EncodeElement(f.And, xml.StartElement{Name: xml.Name{Local: "And"}}); err != nil {
+			return err
+		}
+	case !f.Tag.IsEmpty():
+		if err := e.EncodeElement(f.Tag, xml.StartElement{Name: xml.Name{Local: "Tag"}}); err != nil {
+			return err
+		}
+	default:
+		// Always print Prefix field when both And & Tag are empty
+		if err := e.EncodeElement(f.Prefix, xml.StartElement{Name: xml.Name{Local: "Prefix"}}); err != nil {
+			return err
+		}
+	}
+
+	return e.EncodeToken(xml.EndElement{Name: start.Name})
+}
+
+// Validate - validates the filter element
+func (f Filter) Validate() error {
+	// A Filter must have exactly one of Prefix, Tag, or And specified.
+	if !f.And.isEmpty() {
+		if f.Prefix != "" {
+			return errInvalidFilter
+		}
+		if !f.Tag.IsEmpty() {
+			return errInvalidFilter
+		}
+		if err := f.And.Validate(); err != nil {
+			return err
+		}
+	}
+	if f.Prefix != "" {
+		if !f.Tag.IsEmpty() {
+			return errInvalidFilter
+		}
+	}
+	if !f.Tag.IsEmpty() {
+		if err := f.Tag.Validate(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// TestTags tests if the object tags satisfy the Filter tags requirement,
+// it returns true if there is no tags in the underlying Filter.
+func (f *Filter) TestTags(ttags []string) bool {
+	if f.cachedTags == nil {
+		tags := make(map[string]struct{})
+		for _, t := range append(f.And.Tags, f.Tag) {
+			if !t.IsEmpty() {
+				tags[t.String()] = struct{}{}
+			}
+		}
+		f.cachedTags = tags
+	}
+	for ct := range f.cachedTags {
+		foundTag := false
+		for _, t := range ttags {
+			if ct == t {
+				foundTag = true
+				break
+			}
+		}
+		if !foundTag {
+			return false
+		}
+	}
+	return true
+}

internal/bucket/replication/replication.go

@@ -0,0 +1,234 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"encoding/xml"
+	"io"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// StatusType of Replication for x-amz-replication-status header
+type StatusType string
+
+const (
+	// Pending - replication is pending.
+	Pending StatusType = "PENDING"
+
+	// Completed - replication completed ok.
+	Completed StatusType = "COMPLETED"
+
+	// Failed - replication failed.
+	Failed StatusType = "FAILED"
+
+	// Replica - this is a replica.
+	Replica StatusType = "REPLICA"
+)
+
+// String returns string representation of status
+func (s StatusType) String() string {
+	return string(s)
+}
+
+// Empty returns true if this status is not set
+func (s StatusType) Empty() bool {
+	return string(s) == ""
+}
+
+var (
+	errReplicationTooManyRules        = Errorf("Replication configuration allows a maximum of 1000 rules")
+	errReplicationNoRule              = Errorf("Replication configuration should have at least one rule")
+	errReplicationUniquePriority      = Errorf("Replication configuration has duplicate priority")
+	errReplicationDestinationMismatch = Errorf("The destination bucket must be same for all rules")
+	errRoleArnMissing                 = Errorf("Missing required parameter `Role` in ReplicationConfiguration")
+	errInvalidSourceSelectionCriteria = Errorf("Invalid ReplicaModification status")
+)
+
+// Config - replication configuration specified in
+// https://docs.aws.amazon.com/AmazonS3/latest/dev/replication-add-config.html
+type Config struct {
+	XMLName xml.Name `xml:"ReplicationConfiguration" json:"-"`
+	Rules   []Rule   `xml:"Rule" json:"Rules"`
+	// RoleArn is being reused for MinIO replication ARN
+	RoleArn string `xml:"Role" json:"Role"`
+}
+
+// Maximum 2MiB size per replication config.
+const maxReplicationConfigSize = 2 << 20
+
+// ParseConfig parses ReplicationConfiguration from xml
+func ParseConfig(reader io.Reader) (*Config, error) {
+	config := Config{}
+	if err := xml.NewDecoder(io.LimitReader(reader, maxReplicationConfigSize)).Decode(&config); err != nil {
+		return nil, err
+	}
+	// By default, set replica modification to enabled if unset.
+	for i := range config.Rules {
+		if len(config.Rules[i].SourceSelectionCriteria.ReplicaModifications.Status) == 0 {
+			config.Rules[i].SourceSelectionCriteria = SourceSelectionCriteria{
+				ReplicaModifications: ReplicaModifications{
+					Status: Enabled,
+				},
+			}
+		}
+	}
+	return &config, nil
+}
+
+// Validate - validates the replication configuration
+func (c Config) Validate(bucket string, sameTarget bool) error {
+	// replication config can't have more than 1000 rules
+	if len(c.Rules) > 1000 {
+		return errReplicationTooManyRules
+	}
+	// replication config should have at least one rule
+	if len(c.Rules) == 0 {
+		return errReplicationNoRule
+	}
+	if c.RoleArn == "" {
+		return errRoleArnMissing
+	}
+	// Validate all the rules in the replication config
+	targetMap := make(map[string]struct{})
+	priorityMap := make(map[string]struct{})
+	for _, r := range c.Rules {
+		if len(targetMap) == 0 {
+			targetMap[r.Destination.Bucket] = struct{}{}
+		}
+		if _, ok := targetMap[r.Destination.Bucket]; !ok {
+			return errReplicationDestinationMismatch
+		}
+		if err := r.Validate(bucket, sameTarget); err != nil {
+			return err
+		}
+		if _, ok := priorityMap[strconv.Itoa(r.Priority)]; ok {
+			return errReplicationUniquePriority
+		}
+		priorityMap[strconv.Itoa(r.Priority)] = struct{}{}
+	}
+	return nil
+}
+
+// Type - replication type enum
+type Type int
+
+// Types of replication
+const (
+	ObjectReplicationType Type = 1 + iota
+	DeleteReplicationType
+	MetadataReplicationType
+	HealReplicationType
+)
+
+// ObjectOpts provides information to deduce whether replication
+// can be triggered on the resultant object.
+type ObjectOpts struct {
+	Name         string
+	UserTags     string
+	VersionID    string
+	IsLatest     bool
+	DeleteMarker bool
+	SSEC         bool
+	OpType       Type
+	Replica      bool
+}
+
+// FilterActionableRules returns the rules actions that need to be executed
+// after evaluating prefix/tag filtering
+func (c Config) FilterActionableRules(obj ObjectOpts) []Rule {
+	if obj.Name == "" {
+		return nil
+	}
+	var rules []Rule
+	for _, rule := range c.Rules {
+		if rule.Status == Disabled {
+			continue
+		}
+		if !strings.HasPrefix(obj.Name, rule.Prefix()) {
+			continue
+		}
+		if rule.Filter.TestTags(strings.Split(obj.UserTags, "&")) {
+			rules = append(rules, rule)
+		}
+	}
+	sort.Slice(rules[:], func(i, j int) bool {
+		return rules[i].Priority > rules[j].Priority
+	})
+	return rules
+}
+
+// GetDestination returns destination bucket and storage class.
+func (c Config) GetDestination() Destination {
+	if len(c.Rules) > 0 {
+		return c.Rules[0].Destination
+	}
+	return Destination{}
+}
+
+// Replicate returns true if the object should be replicated.
+func (c Config) Replicate(obj ObjectOpts) bool {
+	if obj.SSEC {
+		return false
+	}
+	for _, rule := range c.FilterActionableRules(obj) {
+		if rule.Status == Disabled {
+			continue
+		}
+		if obj.OpType == DeleteReplicationType {
+			switch {
+			case obj.VersionID != "":
+				// // check MinIO extension for versioned deletes
+				return rule.DeleteReplication.Status == Enabled
+			default:
+				return rule.DeleteMarkerReplication.Status == Enabled
+			}
+		} // regular object/metadata replication
+		return rule.MetadataReplicate(obj)
+	}
+	return false
+}
+
+// HasActiveRules - returns whether replication policy has active rules
+// Optionally a prefix can be supplied.
+// If recursive is specified the function will also return true if any level below the
+// prefix has active rules. If no prefix is specified recursive is effectively true.
+func (c Config) HasActiveRules(prefix string, recursive bool) bool {
+	if len(c.Rules) == 0 {
+		return false
+	}
+	for _, rule := range c.Rules {
+		if rule.Status == Disabled {
+			continue
+		}
+		if len(prefix) > 0 && len(rule.Filter.Prefix) > 0 {
+			// incoming prefix must be in rule prefix
+			if !recursive && !strings.HasPrefix(prefix, rule.Filter.Prefix) {
+				continue
+			}
+			// If recursive, we can skip this rule if it doesn't match the tested prefix or level below prefix
+			// does not match
+			if recursive && !strings.HasPrefix(rule.Prefix(), prefix) && !strings.HasPrefix(prefix, rule.Prefix()) {
+				continue
+			}
+		}
+		return true
+	}
+	return false
+}

internal/bucket/replication/replication_test.go

@@ -0,0 +1,335 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
+
+func TestParseAndValidateReplicationConfig(t *testing.T) {
+	testCases := []struct {
+		inputConfig           string
+		expectedParsingErr    error
+		expectedValidationErr error
+		destBucket            string
+		sameTarget            bool
+	}{
+		{ //1 Invalid delete marker status in replication config
+			inputConfig:           `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>string</Status></DeleteMarkerReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errInvalidDeleteMarkerReplicationStatus,
+		},
+		//2 Invalid delete replication status in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errDeleteReplicationMissing,
+		},
+		//3 valid replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: nil,
+		},
+		//4 missing role in config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			// destination bucket in config different from bucket specified
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errRoleArnMissing,
+		},
+		//5 replication destination in different rules not identical
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule><Rule><Status>Enabled</Status><Priority>3</Priority><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket2</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errReplicationDestinationMismatch,
+		},
+		//6 missing rule status in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errEmptyRuleStatus,
+		},
+		//7 invalid rule status in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enssabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errInvalidRuleStatus,
+		},
+		//8 invalid rule id exceeds length allowed in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><ID>vsUVERgOc8zZYagLSzSa5lE8qeI6nh1lyLNS4R9W052yfecrhhepGboswSWMMNO8CPcXM4GM3nKyQ72EadlMzzZBFoYWKn7ju5GoE5w9c57a0piHR1vexpdd9FrMquiruvAJ0MTGVupm0EegMVxoIOdjx7VgZhGrmi2XDvpVEFT7WmYMA9fSK297XkTHWyECaNHBySJ1Qp4vwX8tPNauKpfHx4kzUpnKe1PZbptGMWbY5qTcwlNuMhVSmgFffShq</ID><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errInvalidRuleID,
+		},
+		//9 invalid priority status in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errReplicationUniquePriority,
+		},
+		//10 no rule in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    nil,
+			expectedValidationErr: errReplicationNoRule,
+		},
+		//11 no destination in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    Errorf("invalid destination '%v'", ""),
+			expectedValidationErr: nil,
+		},
+		//12 destination not matching ARN in replication config
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>destinationbucket2</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			destBucket:            "destinationbucket",
+			sameTarget:            false,
+			expectedParsingErr:    fmt.Errorf("invalid destination '%v'", "destinationbucket2"),
+			expectedValidationErr: nil,
+		},
+	}
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
+			cfg, err := ParseConfig(bytes.NewReader([]byte(tc.inputConfig)))
+			if err != nil && tc.expectedParsingErr != nil && err.Error() != tc.expectedParsingErr.Error() {
+				t.Fatalf("%d: Expected '%v' during parsing but got '%v'", i+1, tc.expectedParsingErr, err)
+			}
+			if err == nil && tc.expectedParsingErr != nil {
+				t.Fatalf("%d: Expected '%v' during parsing but got '%v'", i+1, tc.expectedParsingErr, err)
+			}
+			if tc.expectedParsingErr != nil {
+				// We already expect a parsing error,
+				// no need to continue this test.
+				return
+			}
+			err = cfg.Validate(tc.destBucket, tc.sameTarget)
+			if err != tc.expectedValidationErr {
+				t.Fatalf("%d: Expected %v during parsing but got %v", i+1, tc.expectedValidationErr, err)
+			}
+		})
+	}
+}
+func TestReplicate(t *testing.T) {
+	cfgs := []Config{
+		{ // Config0 - Replication config has no filters, all replication enabled
+			Rules: []Rule{
+				{
+					Status:                  Enabled,
+					Priority:                3,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Enabled},
+					DeleteReplication:       DeleteReplication{Status: Enabled},
+					Filter:                  Filter{},
+				},
+			},
+		},
+		{ // Config1 - Replication config has no filters, delete,delete-marker replication disabled
+			Rules: []Rule{
+				{
+					Status:                  Enabled,
+					Priority:                3,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Disabled},
+					DeleteReplication:       DeleteReplication{Status: Disabled},
+					Filter:                  Filter{},
+				},
+			},
+		},
+		{ // Config2 - Replication config has filters and more than 1 matching rule, delete,delete-marker replication disabled
+			Rules: []Rule{
+				{
+					Status:                  Enabled,
+					Priority:                2,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Disabled},
+					DeleteReplication:       DeleteReplication{Status: Enabled},
+					Filter:                  Filter{Prefix: "xy", And: And{}, Tag: Tag{Key: "k1", Value: "v1"}},
+				},
+				{
+					Status:                  Enabled,
+					Priority:                1,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Enabled},
+					DeleteReplication:       DeleteReplication{Status: Disabled},
+					Filter:                  Filter{Prefix: "xyz"},
+				},
+			},
+		},
+		{ // Config3 - Replication config has filters and no overlapping rules
+			Rules: []Rule{
+				{
+					Status:                  Enabled,
+					Priority:                2,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Disabled},
+					DeleteReplication:       DeleteReplication{Status: Enabled},
+					Filter:                  Filter{Prefix: "xy", And: And{}, Tag: Tag{Key: "k1", Value: "v1"}},
+				},
+				{
+					Status:                  Enabled,
+					Priority:                1,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Enabled},
+					DeleteReplication:       DeleteReplication{Status: Disabled},
+					Filter:                  Filter{Prefix: "abc"},
+				},
+			},
+		},
+		{ // Config4 - Replication config has filters and SourceSelectionCriteria Disabled
+			Rules: []Rule{
+				{
+					Status:                  Enabled,
+					Priority:                2,
+					DeleteMarkerReplication: DeleteMarkerReplication{Status: Enabled},
+					DeleteReplication:       DeleteReplication{Status: Enabled},
+					SourceSelectionCriteria: SourceSelectionCriteria{ReplicaModifications: ReplicaModifications{Status: Disabled}},
+				},
+			},
+		},
+	}
+	testCases := []struct {
+		opts           ObjectOpts
+		c              Config
+		expectedResult bool
+	}{
+		// using config 1 - no filters, all replication enabled
+		{ObjectOpts{}, cfgs[0], false},                                //1. invalid ObjectOpts missing object name
+		{ObjectOpts{Name: "c1test"}, cfgs[0], true},                   //2. valid ObjectOpts passing empty Filter
+		{ObjectOpts{Name: "c1test", VersionID: "vid"}, cfgs[0], true}, //3. valid ObjectOpts passing empty Filter
+
+		{ObjectOpts{Name: "c1test", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[0], true},                                //4. DeleteMarker version replication valid case - matches DeleteMarkerReplication status
+		{ObjectOpts{Name: "c1test", VersionID: "vid", OpType: DeleteReplicationType}, cfgs[0], true},                                  //5. permanent delete of version, matches DeleteReplication status - valid case
+		{ObjectOpts{Name: "c1test", VersionID: "vid", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[0], true},              //6. permanent delete of version, matches DeleteReplication status
+		{ObjectOpts{Name: "c1test", VersionID: "vid", DeleteMarker: true, SSEC: true, OpType: DeleteReplicationType}, cfgs[0], false}, //7. permanent delete of version, disqualified by SSE-C
+		{ObjectOpts{Name: "c1test", DeleteMarker: true, SSEC: true, OpType: DeleteReplicationType}, cfgs[0], false},                   //8. setting DeleteMarker on SSE-C encrypted object, disqualified by SSE-C
+		{ObjectOpts{Name: "c1test", SSEC: true}, cfgs[0], false},                                                                      //9. replication of SSE-C encrypted object, disqualified
+
+		//  using config 2 - no filters, only replication of object, metadata enabled
+		{ObjectOpts{Name: "c2test"}, cfgs[1], true},                                                                                   //10. valid ObjectOpts passing empty Filter
+		{ObjectOpts{Name: "c2test", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[1], false},                               //11. DeleteMarker version replication  not allowed due to DeleteMarkerReplication status
+		{ObjectOpts{Name: "c2test", VersionID: "vid", OpType: DeleteReplicationType}, cfgs[1], false},                                 //12. permanent delete of version, disallowed by DeleteReplication status
+		{ObjectOpts{Name: "c2test", VersionID: "vid", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[1], false},             //13. permanent delete of DeleteMarker version, disallowed by DeleteReplication status
+		{ObjectOpts{Name: "c2test", VersionID: "vid", DeleteMarker: true, SSEC: true, OpType: DeleteReplicationType}, cfgs[1], false}, //14. permanent delete of version, disqualified by SSE-C & DeleteReplication status
+		{ObjectOpts{Name: "c2test", DeleteMarker: true, SSEC: true, OpType: DeleteReplicationType}, cfgs[1], false},                   //15. setting DeleteMarker on SSE-C encrypted object, disqualified by SSE-C & DeleteMarkerReplication status
+		{ObjectOpts{Name: "c2test", SSEC: true}, cfgs[1], false},                                                                      //16. replication of SSE-C encrypted object, disqualified by default
+		// using config 2 - has more than one rule with overlapping prefixes
+		{ObjectOpts{Name: "xy/c3test", UserTags: "k1=v1"}, cfgs[2], true},                                                                       //17. matches rule 1 for replication of content/metadata
+		{ObjectOpts{Name: "xyz/c3test", UserTags: "k1=v1"}, cfgs[2], true},                                                                      //18. matches rule 1 for replication of content/metadata
+		{ObjectOpts{Name: "xyz/c3test", UserTags: "k1=v1", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[2], false},                  //19. matches rule 1 - DeleteMarker replication disallowed by rule
+		{ObjectOpts{Name: "xyz/c3test", UserTags: "k1=v1", DeleteMarker: true, VersionID: "vid", OpType: DeleteReplicationType}, cfgs[2], true}, //20. matches rule 1 - DeleteReplication allowed by rule for permanent delete of DeleteMarker
+		{ObjectOpts{Name: "xyz/c3test", UserTags: "k1=v1", VersionID: "vid", OpType: DeleteReplicationType}, cfgs[2], true},                     //21. matches rule 1 - DeleteReplication allowed by rule for permanent delete of version
+		{ObjectOpts{Name: "xyz/c3test"}, cfgs[2], true},                                                                                         //22. matches rule 2 for replication of content/metadata
+		{ObjectOpts{Name: "xy/c3test", UserTags: "k1=v2"}, cfgs[2], false},                                                                      //23. does not match rule1 because tag value does not pass filter
+		{ObjectOpts{Name: "xyz/c3test", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[2], true},                                      //24. matches rule 2 - DeleteMarker replication allowed by rule
+		{ObjectOpts{Name: "xyz/c3test", DeleteMarker: true, VersionID: "vid", OpType: DeleteReplicationType}, cfgs[2], false},                   //25. matches rule 2 - DeleteReplication disallowed by rule for permanent delete of DeleteMarker
+		{ObjectOpts{Name: "xyz/c3test", VersionID: "vid", OpType: DeleteReplicationType}, cfgs[2], false},                                       //26. matches rule 1 - DeleteReplication disallowed by rule for permanent delete of version
+		{ObjectOpts{Name: "abc/c3test"}, cfgs[2], false},                                                                                        //27. matches no rule because object prefix does not match
+
+		// using config 3 - has no overlapping rules
+		{ObjectOpts{Name: "xy/c4test", UserTags: "k1=v1"}, cfgs[3], true},                                                                       //28. matches rule 1 for replication of content/metadata
+		{ObjectOpts{Name: "xa/c4test", UserTags: "k1=v1"}, cfgs[3], false},                                                                      //29. no rule match object prefix not in rules
+		{ObjectOpts{Name: "xyz/c4test", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[3], false},                                     //30. rule 1 not matched because of tags filter
+		{ObjectOpts{Name: "xyz/c4test", UserTags: "k1=v1", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[3], false},                  //31. matches rule 1 - DeleteMarker replication disallowed by rule
+		{ObjectOpts{Name: "xyz/c4test", UserTags: "k1=v1", DeleteMarker: true, VersionID: "vid", OpType: DeleteReplicationType}, cfgs[3], true}, //32. matches rule 1 - DeleteReplication allowed by rule for permanent delete of DeleteMarker
+		{ObjectOpts{Name: "xyz/c4test", UserTags: "k1=v1", VersionID: "vid", OpType: DeleteReplicationType}, cfgs[3], true},                     //33. matches rule 1 - DeleteReplication allowed by rule for permanent delete of version
+		{ObjectOpts{Name: "abc/c4test"}, cfgs[3], true},                                                                                         //34. matches rule 2 for replication of content/metadata
+		{ObjectOpts{Name: "abc/c4test", UserTags: "k1=v2"}, cfgs[3], true},                                                                      //35. matches rule 2 for replication of content/metadata
+		{ObjectOpts{Name: "abc/c4test", DeleteMarker: true, OpType: DeleteReplicationType}, cfgs[3], true},                                      //36. matches rule 2 - DeleteMarker replication allowed by rule
+		{ObjectOpts{Name: "abc/c4test", DeleteMarker: true, VersionID: "vid", OpType: DeleteReplicationType}, cfgs[3], false},                   //37. matches rule 2 - DeleteReplication disallowed by rule for permanent delete of DeleteMarker
+		{ObjectOpts{Name: "abc/c4test", VersionID: "vid", OpType: DeleteReplicationType}, cfgs[3], false},                                       //38. matches rule 2 - DeleteReplication disallowed by rule for permanent delete of version
+		//  using config 4 - with replica modification sync disabled.
+		{ObjectOpts{Name: "xy/c5test", UserTags: "k1=v1", Replica: true}, cfgs[4], false}, //39. replica syncing disabled, this object is a replica
+		{ObjectOpts{Name: "xa/c5test", UserTags: "k1=v1", Replica: false}, cfgs[4], true}, //40. replica syncing disabled, this object is NOT a replica
+	}
+
+	for i, testCase := range testCases {
+		result := testCase.c.Replicate(testCase.opts)
+
+		if result != testCase.expectedResult {
+			t.Fatalf("case %v: expected: %v, got: %v", i+1, testCase.expectedResult, result)
+		}
+	}
+}
+
+func TestHasActiveRules(t *testing.T) {
+	testCases := []struct {
+		inputConfig    string
+		prefix         string
+		expectedNonRec bool
+		expectedRec    bool
+	}{
+
+		// case 1 - only one rule which is in Disabled status
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Disabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			prefix:         "miss/prefix",
+			expectedNonRec: false,
+			expectedRec:    false,
+		},
+		// case 2 - only one rule which matches prefix filter
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Filter><Prefix>key/prefix</Prefix></Filter><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			prefix:         "key/prefix1",
+			expectedNonRec: true,
+			expectedRec:    true,
+		},
+		// case 3 - empty prefix
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			prefix:         "key-prefix",
+			expectedNonRec: true,
+			expectedRec:    true,
+		},
+		// case 4 - has Filter based on prefix
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Filter><Prefix>testdir/dir1/</Prefix></Filter><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			prefix:         "testdir/",
+			expectedNonRec: false,
+			expectedRec:    true,
+		},
+		//case 5 - has filter with prefix and tags, here we are not matching on tags
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Filter>
+		<And><Prefix>key-prefix</Prefix><Tag><Key>key1</Key><Value>value1</Value></Tag><Tag><Key>key2</Key><Value>value2</Value></Tag></And></Filter><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination></Rule></ReplicationConfiguration>`,
+			prefix:         "testdir/",
+			expectedNonRec: true,
+			expectedRec:    true,
+		},
+	}
+
+	for i, tc := range testCases {
+		tc := tc
+		t.Run(fmt.Sprintf("Test_%d", i+1), func(t *testing.T) {
+			cfg, err := ParseConfig(bytes.NewReader([]byte(tc.inputConfig)))
+			if err != nil {
+				t.Fatalf("Got unexpected error: %v", err)
+			}
+			if got := cfg.HasActiveRules(tc.prefix, false); got != tc.expectedNonRec {
+				t.Fatalf("Expected result with recursive set to false: `%v`, got: `%v`", tc.expectedNonRec, got)
+			}
+			if got := cfg.HasActiveRules(tc.prefix, true); got != tc.expectedRec {
+				t.Fatalf("Expected result with recursive set to true: `%v`, got: `%v`", tc.expectedRec, got)
+			}
+
+		})
+
+	}
+}

internal/bucket/replication/rule.go

@@ -0,0 +1,213 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"bytes"
+	"encoding/xml"
+)
+
+// Status represents Enabled/Disabled status
+type Status string
+
+// Supported status types
+const (
+	Enabled  Status = "Enabled"
+	Disabled Status = "Disabled"
+)
+
+// DeleteMarkerReplication - whether delete markers are replicated - https://docs.aws.amazon.com/AmazonS3/latest/dev/replication-add-config.html
+type DeleteMarkerReplication struct {
+	Status Status `xml:"Status"` // should be set to "Disabled" by default
+}
+
+// IsEmpty returns true if DeleteMarkerReplication is not set
+func (d DeleteMarkerReplication) IsEmpty() bool {
+	return len(d.Status) == 0
+}
+
+// Validate validates whether the status is disabled.
+func (d DeleteMarkerReplication) Validate() error {
+	if d.IsEmpty() {
+		return errDeleteMarkerReplicationMissing
+	}
+	if d.Status != Disabled && d.Status != Enabled {
+		return errInvalidDeleteMarkerReplicationStatus
+	}
+	return nil
+}
+
+// DeleteReplication - whether versioned deletes are replicated - this is a MinIO only
+// extension.
+type DeleteReplication struct {
+	Status Status `xml:"Status"` // should be set to "Disabled" by default
+}
+
+// IsEmpty returns true if DeleteReplication is not set
+func (d DeleteReplication) IsEmpty() bool {
+	return len(d.Status) == 0
+}
+
+// Validate validates whether the status is disabled.
+func (d DeleteReplication) Validate() error {
+	if d.IsEmpty() {
+		return errDeleteReplicationMissing
+	}
+	if d.Status != Disabled && d.Status != Enabled {
+		return errInvalidDeleteReplicationStatus
+	}
+	return nil
+}
+
+// UnmarshalXML - decodes XML data.
+func (d *DeleteReplication) UnmarshalXML(dec *xml.Decoder, start xml.StartElement) (err error) {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type deleteReplication DeleteReplication
+	drep := deleteReplication{}
+
+	if err := dec.DecodeElement(&drep, &start); err != nil {
+		return err
+	}
+	if len(drep.Status) == 0 {
+		drep.Status = Disabled
+	}
+	d.Status = drep.Status
+	return nil
+}
+
+// Rule - a rule for replication configuration.
+type Rule struct {
+	XMLName                 xml.Name                `xml:"Rule" json:"Rule"`
+	ID                      string                  `xml:"ID,omitempty" json:"ID,omitempty"`
+	Status                  Status                  `xml:"Status" json:"Status"`
+	Priority                int                     `xml:"Priority" json:"Priority"`
+	DeleteMarkerReplication DeleteMarkerReplication `xml:"DeleteMarkerReplication" json:"DeleteMarkerReplication"`
+	// MinIO extension to replicate versioned deletes
+	DeleteReplication       DeleteReplication       `xml:"DeleteReplication" json:"DeleteReplication"`
+	Destination             Destination             `xml:"Destination" json:"Destination"`
+	SourceSelectionCriteria SourceSelectionCriteria `xml:"SourceSelectionCriteria" json:"SourceSelectionCriteria"`
+	Filter                  Filter                  `xml:"Filter" json:"Filter"`
+}
+
+var (
+	errInvalidRuleID                        = Errorf("ID must be less than 255 characters")
+	errEmptyRuleStatus                      = Errorf("Status should not be empty")
+	errInvalidRuleStatus                    = Errorf("Status must be set to either Enabled or Disabled")
+	errDeleteMarkerReplicationMissing       = Errorf("DeleteMarkerReplication must be specified")
+	errPriorityMissing                      = Errorf("Priority must be specified")
+	errInvalidDeleteMarkerReplicationStatus = Errorf("Delete marker replication status is invalid")
+	errDestinationSourceIdentical           = Errorf("Destination bucket cannot be the same as the source bucket.")
+	errDeleteReplicationMissing             = Errorf("Delete replication must be specified")
+	errInvalidDeleteReplicationStatus       = Errorf("Delete replication is either enable|disable")
+)
+
+// validateID - checks if ID is valid or not.
+func (r Rule) validateID() error {
+	// cannot be longer than 255 characters
+	if len(r.ID) > 255 {
+		return errInvalidRuleID
+	}
+	return nil
+}
+
+// validateStatus - checks if status is valid or not.
+func (r Rule) validateStatus() error {
+	// Status can't be empty
+	if len(r.Status) == 0 {
+		return errEmptyRuleStatus
+	}
+
+	// Status must be one of Enabled or Disabled
+	if r.Status != Enabled && r.Status != Disabled {
+		return errInvalidRuleStatus
+	}
+	return nil
+}
+
+func (r Rule) validateFilter() error {
+	return r.Filter.Validate()
+}
+
+// Prefix - a rule can either have prefix under <filter></filter> or under
+// <filter><and></and></filter>. This method returns the prefix from the
+// location where it is available
+func (r Rule) Prefix() string {
+	if r.Filter.Prefix != "" {
+		return r.Filter.Prefix
+	}
+	return r.Filter.And.Prefix
+}
+
+// Tags - a rule can either have tag under <filter></filter> or under
+// <filter><and></and></filter>. This method returns all the tags from the
+// rule in the format tag1=value1&tag2=value2
+func (r Rule) Tags() string {
+	if !r.Filter.Tag.IsEmpty() {
+		return r.Filter.Tag.String()
+	}
+	if len(r.Filter.And.Tags) != 0 {
+		var buf bytes.Buffer
+		for _, t := range r.Filter.And.Tags {
+			if buf.Len() > 0 {
+				buf.WriteString("&")
+			}
+			buf.WriteString(t.String())
+		}
+		return buf.String()
+	}
+	return ""
+}
+
+// Validate - validates the rule element
+func (r Rule) Validate(bucket string, sameTarget bool) error {
+	if err := r.validateID(); err != nil {
+		return err
+	}
+	if err := r.validateStatus(); err != nil {
+		return err
+	}
+	if err := r.validateFilter(); err != nil {
+		return err
+	}
+	if err := r.DeleteMarkerReplication.Validate(); err != nil {
+		return err
+	}
+	if err := r.DeleteReplication.Validate(); err != nil {
+		return err
+	}
+	if err := r.SourceSelectionCriteria.Validate(); err != nil {
+		return err
+	}
+
+	if r.Priority < 0 {
+		return errPriorityMissing
+	}
+	if r.Destination.Bucket == bucket && sameTarget {
+		return errDestinationSourceIdentical
+	}
+	return nil
+}
+
+// MetadataReplicate  returns true if object is not a replica or in the case of replicas,
+// replica modification sync is enabled.
+func (r Rule) MetadataReplicate(obj ObjectOpts) bool {
+	if !obj.Replica {
+		return true
+	}
+	return obj.Replica && r.SourceSelectionCriteria.ReplicaModifications.Status == Enabled
+}

internal/bucket/replication/rule_test.go

@@ -0,0 +1,68 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
+
+func TestMetadataReplicate(t *testing.T) {
+	testCases := []struct {
+		inputConfig    string
+		opts           ObjectOpts
+		expectedResult bool
+	}{
+		// case 1 - rule with replica modification enabled; not a replica
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination><SourceSelectionCriteria><ReplicaModifications><Status>Enabled</Status></ReplicaModifications></SourceSelectionCriteria></Rule></ReplicationConfiguration>`,
+			opts:           ObjectOpts{Name: "c1test", DeleteMarker: false, OpType: ObjectReplicationType, Replica: false}, //1. Replica mod sync enabled; not a replica
+			expectedResult: true,
+		},
+		// case 2 - rule with replica modification disabled; a replica
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination><SourceSelectionCriteria><ReplicaModifications><Status>Disabled</Status></ReplicaModifications></SourceSelectionCriteria></Rule></ReplicationConfiguration>`,
+			opts:           ObjectOpts{Name: "c2test", DeleteMarker: false, OpType: ObjectReplicationType, Replica: true}, //1. Replica mod sync enabled; a replica
+			expectedResult: false,
+		},
+		// case 3 - rule with replica modification disabled; not a replica
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination><SourceSelectionCriteria><ReplicaModifications><Status>Disabled</Status></ReplicaModifications></SourceSelectionCriteria></Rule></ReplicationConfiguration>`,
+			opts:           ObjectOpts{Name: "c2test", DeleteMarker: false, OpType: ObjectReplicationType, Replica: false}, //1. Replica mod sync disabled; not a replica
+			expectedResult: true,
+		},
+
+		// case 4 - rule with replica modification enabled; a replica
+		{inputConfig: `<ReplicationConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Role>arn:aws:iam::AcctID:role/role-name</Role><Rule><Status>Enabled</Status><DeleteMarkerReplication><Status>Disabled</Status></DeleteMarkerReplication><DeleteReplication><Status>Disabled</Status></DeleteReplication><Prefix>key-prefix</Prefix><Destination><Bucket>arn:aws:s3:::destinationbucket</Bucket></Destination><SourceSelectionCriteria><ReplicaModifications><Status>Enabled</Status></ReplicaModifications></SourceSelectionCriteria></Rule></ReplicationConfiguration>`,
+			opts:           ObjectOpts{Name: "c2test", DeleteMarker: false, OpType: MetadataReplicationType, Replica: true}, //1. Replica mod sync enabled;  a replica
+			expectedResult: true,
+		},
+	}
+
+	for i, tc := range testCases {
+		tc := tc
+		t.Run(fmt.Sprintf("Test_%d", i+1), func(t *testing.T) {
+			cfg, err := ParseConfig(bytes.NewReader([]byte(tc.inputConfig)))
+			if err != nil {
+				t.Fatalf("Got unexpected error: %v", err)
+			}
+			if got := cfg.Rules[0].MetadataReplicate(tc.opts); got != tc.expectedResult {
+				t.Fatalf("Expected result with recursive set to false: `%v`, got: `%v`", tc.expectedResult, got)
+			}
+		})
+
+	}
+}

internal/bucket/replication/sourceselectioncriteria.go

@@ -0,0 +1,76 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"encoding/xml"
+)
+
+// ReplicaModifications specifies if replica modification sync is enabled
+type ReplicaModifications struct {
+	Status Status `xml:"Status" json:"Status"`
+}
+
+// SourceSelectionCriteria - specifies additional source selection criteria in ReplicationConfiguration.
+type SourceSelectionCriteria struct {
+	ReplicaModifications ReplicaModifications `xml:"ReplicaModifications" json:"ReplicaModifications"`
+}
+
+// IsValid - checks whether SourceSelectionCriteria is valid or not.
+func (s SourceSelectionCriteria) IsValid() bool {
+	return s.ReplicaModifications.Status == Enabled || s.ReplicaModifications.Status == Disabled
+}
+
+// Validate source selection criteria
+func (s SourceSelectionCriteria) Validate() error {
+	if (s == SourceSelectionCriteria{}) {
+		return nil
+	}
+	if !s.IsValid() {
+		return errInvalidSourceSelectionCriteria
+	}
+	return nil
+}
+
+// UnmarshalXML - decodes XML data.
+func (s *SourceSelectionCriteria) UnmarshalXML(dec *xml.Decoder, start xml.StartElement) (err error) {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type sourceSelectionCriteria SourceSelectionCriteria
+	ssc := sourceSelectionCriteria{}
+	if err := dec.DecodeElement(&ssc, &start); err != nil {
+		return err
+	}
+	if len(ssc.ReplicaModifications.Status) == 0 {
+		ssc.ReplicaModifications.Status = Enabled
+	}
+	*s = SourceSelectionCriteria(ssc)
+	return nil
+}
+
+// MarshalXML - encodes to XML data.
+func (s SourceSelectionCriteria) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	if err := e.EncodeToken(start); err != nil {
+		return err
+	}
+	if s.IsValid() {
+		if err := e.EncodeElement(s.ReplicaModifications, xml.StartElement{Name: xml.Name{Local: "ReplicaModifications"}}); err != nil {
+			return err
+		}
+	}
+	return e.EncodeToken(xml.EndElement{Name: start.Name})
+}

internal/bucket/replication/tag.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package replication
+
+import (
+	"encoding/xml"
+	"unicode/utf8"
+)
+
+// Tag - a tag for a replication configuration Rule filter.
+type Tag struct {
+	XMLName xml.Name `xml:"Tag" json:"Tag"`
+	Key     string   `xml:"Key,omitempty" json:"Key,omitempty"`
+	Value   string   `xml:"Value,omitempty" json:"Value,omitempty"`
+}
+
+var (
+	errInvalidTagKey   = Errorf("The TagKey you have provided is invalid")
+	errInvalidTagValue = Errorf("The TagValue you have provided is invalid")
+)
+
+func (tag Tag) String() string {
+	return tag.Key + "=" + tag.Value
+}
+
+// IsEmpty returns whether this tag is empty or not.
+func (tag Tag) IsEmpty() bool {
+	return tag.Key == ""
+}
+
+// Validate checks this tag.
+func (tag Tag) Validate() error {
+	if len(tag.Key) == 0 || utf8.RuneCountInString(tag.Key) > 128 {
+		return errInvalidTagKey
+	}
+
+	if utf8.RuneCountInString(tag.Value) > 256 {
+		return errInvalidTagValue
+	}
+
+	return nil
+}

internal/bucket/versioning/error.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package versioning
+
+import (
+	"fmt"
+)
+
+// Error is the generic type for any error happening during tag
+// parsing.
+type Error struct {
+	err error
+}
+
+// Errorf - formats according to a format specifier and returns
+// the string as a value that satisfies error of type tagging.Error
+func Errorf(format string, a ...interface{}) error {
+	return Error{err: fmt.Errorf(format, a...)}
+}
+
+// Unwrap the internal error.
+func (e Error) Unwrap() error { return e.err }
+
+// Error 'error' compatible method.
+func (e Error) Error() string {
+	if e.err == nil {
+		return "versioning: cause <nil>"
+	}
+	return e.err.Error()
+}

internal/bucket/versioning/versioning.go

@@ -0,0 +1,80 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package versioning
+
+import (
+	"encoding/xml"
+	"io"
+)
+
+// State - enabled/disabled/suspended states
+// for multifactor and status of versioning.
+type State string
+
+// Various supported states
+const (
+	Enabled State = "Enabled"
+	// Disabled  State = "Disabled" only used by MFA Delete not supported yet.
+	Suspended State = "Suspended"
+)
+
+// Versioning - Configuration for bucket versioning.
+type Versioning struct {
+	XMLNS   string   `xml:"xmlns,attr,omitempty"`
+	XMLName xml.Name `xml:"VersioningConfiguration"`
+	// MFADelete State    `xml:"MFADelete,omitempty"` // not supported yet.
+	Status State `xml:"Status,omitempty"`
+}
+
+// Validate - validates the versioning configuration
+func (v Versioning) Validate() error {
+	// Not supported yet
+	// switch v.MFADelete {
+	// case Enabled, Disabled:
+	// default:
+	// 	return Errorf("unsupported MFADelete state %s", v.MFADelete)
+	// }
+	switch v.Status {
+	case Enabled, Suspended:
+	default:
+		return Errorf("unsupported Versioning status %s", v.Status)
+	}
+	return nil
+}
+
+// Enabled - returns true if versioning is enabled
+func (v Versioning) Enabled() bool {
+	return v.Status == Enabled
+}
+
+// Suspended - returns true if versioning is suspended
+func (v Versioning) Suspended() bool {
+	return v.Status == Suspended
+}
+
+// ParseConfig - parses data in given reader to VersioningConfiguration.
+func ParseConfig(reader io.Reader) (*Versioning, error) {
+	var v Versioning
+	if err := xml.NewDecoder(reader).Decode(&v); err != nil {
+		return nil, err
+	}
+	if err := v.Validate(); err != nil {
+		return nil, err
+	}
+	return &v, nil
+}