Add basic bandwidth monitoring for replication. (#10501)

This change tracks bandwidth for a bucket and object

- [x] Add Admin API
- [x] Add Peer API
- [x] Add BW throttling
- [x] Admin APIs to set replication limit
- [x] Admin APIs for fetch bandwidth

pkg/bucket/bandwidth/measurement.go

@@ -0,0 +1,87 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+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
+}

pkg/bucket/bandwidth/monitor.go

@@ -0,0 +1,175 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package bandwidth
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"github.com/minio/minio/pkg/bandwidth"
+	"github.com/minio/minio/pkg/pubsub"
+)
+
+// throttleBandwidth gets the throttle for bucket with the configured value
+func (m *Monitor) throttleBandwidth(ctx context.Context, bucket string, bandwidthBytesPerSecond int64) *throttle {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	throttle, ok := m.bucketThrottle[bucket]
+	if !ok {
+		throttle = newThrottle(ctx, bandwidthBytesPerSecond)
+		m.bucketThrottle[bucket] = throttle
+		return throttle
+	}
+	throttle.SetBandwidth(bandwidthBytesPerSecond)
+	return throttle
+}
+
+// SubscribeToBuckets subscribes to buckets. Empty array for monitoring all buckets.
+func (m *Monitor) SubscribeToBuckets(subCh chan interface{}, doneCh <-chan struct{}, buckets []string) {
+	m.pubsub.Subscribe(subCh, doneCh, func(f interface{}) bool {
+		if buckets != nil || len(buckets) == 0 {
+			return true
+		}
+		report, ok := f.(*bandwidth.Report)
+		if !ok {
+			return false
+		}
+		for _, b := range buckets {
+			_, ok := report.BucketStats[b]
+			if ok {
+				return true
+			}
+		}
+		return false
+	})
+}
+
+// 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
+
+	pubsub *pubsub.PubSub // PubSub for reporting bandwidths.
+
+	bucketThrottle map[string]*throttle
+
+	startProcessing sync.Once
+
+	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(1 * time.Second),
+		pubsub:                pubsub.New(),
+		bucketThrottle:        make(map[string]*throttle),
+		doneCh:                doneCh,
+	}
+	return m
+}
+
+// SelectionFunction for buckets
+type SelectionFunction func(bucket string) bool
+
+// SelectAllBuckets will select all buckets
+func SelectAllBuckets() SelectionFunction {
+	return func(bucket string) bool {
+		return true
+	}
+}
+
+// SelectBuckets will select all the buckets passed in.
+func SelectBuckets(buckets ...string) SelectionFunction {
+	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) *bandwidth.Report {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	return m.getReport(selectBucket)
+}
+
+func (m *Monitor) getReport(selectBucket SelectionFunction) *bandwidth.Report {
+	report := &bandwidth.Report{
+		BucketStats: make(map[string]bandwidth.Details),
+	}
+	for bucket, bucketMeasurement := range m.activeBuckets {
+		if !selectBucket(bucket) {
+			continue
+		}
+		report.BucketStats[bucket] = bandwidth.Details{
+			LimitInBytesPerSecond:            m.bucketThrottle[bucket].bytesPerSecond,
+			CurrentBandwidthInBytesPerSecond: bucketMeasurement.getExpMovingAvgBytesPerSecond(),
+		}
+	}
+	return report
+}
+
+func (m *Monitor) process(doneCh <-chan struct{}) {
+	for {
+		select {
+		case <-m.bucketMovingAvgTicker.C:
+			m.processAvg()
+		case <-doneCh:
+			return
+		default:
+		}
+	}
+}
+
+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) processAvg() {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	for _, bucketMeasurement := range m.activeBuckets {
+		bucketMeasurement.updateExponentialMovingAverage(time.Now())
+	}
+	m.pubsub.Publish(m.getReport(SelectAllBuckets()))
+}
+
+// track returns the measurement object for bucket and object
+func (m *Monitor) track(bucket string, object string, timeNow time.Time) *bucketMeasurement {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	m.startProcessing.Do(func() {
+		go m.process(m.doneCh)
+	})
+	b := m.getBucketMeasurement(bucket, timeNow)
+	return b
+}

pkg/bucket/bandwidth/monitor_test.go

@@ -0,0 +1,157 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package bandwidth
+
+import (
+	"context"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/minio/minio/pkg/bandwidth"
+)
+
+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)
+	t2 := newThrottle(context.Background(), 200)
+	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); 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   *bandwidth.Report
+		want2  *bandwidth.Report
+	}{
+		{
+			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: &bandwidth.Report{
+				BucketStats: map[string]bandwidth.Details{"bucket": {LimitInBytesPerSecond: 1024 * 1024, CurrentBandwidthInBytesPerSecond: 0}},
+			},
+			want2: &bandwidth.Report{
+				BucketStats: map[string]bandwidth.Details{"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: &bandwidth.Report{
+				BucketStats: map[string]bandwidth.Details{"bucket": {LimitInBytesPerSecond: 1024 * 1024, CurrentBandwidthInBytesPerSecond: float64(oneMiB)}},
+			},
+			want2: &bandwidth.Report{
+				BucketStats: map[string]bandwidth.Details{"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,
+			}
+			m := &Monitor{
+				activeBuckets:  tt.fields.activeBuckets,
+				bucketThrottle: map[string]*throttle{"bucket": &thr},
+			}
+			m.activeBuckets["bucket"].updateExponentialMovingAverage(tt.fields.endTime)
+			got := m.GetReport(SelectAllBuckets())
+			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(SelectAllBuckets())
+			if !reflect.DeepEqual(got, tt.want2) {
+				t.Errorf("GetReport() = %v, want %v", got, tt.want2)
+			}
+		})
+	}
+}

pkg/bucket/bandwidth/reader.go

@@ -0,0 +1,86 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package bandwidth
+
+import (
+	"context"
+	"io"
+	"time"
+)
+
+// MonitoredReader monitors the bandwidth
+type MonitoredReader struct {
+	bucket            string             // Token to track bucket
+	bucketMeasurement *bucketMeasurement // bucket measurement object
+	object            string             // Token to track object
+	reader            io.Reader          // Reader to wrap
+	lastStop          time.Time          // Last timestamp for a measurement
+	headerSize        int                // Size of the header not captured by reader
+	throttle          *throttle          // throttle the rate at which replication occur
+	monitor           *Monitor           // Monitor reference
+	closed            bool               // Reader is closed
+}
+
+// NewMonitoredReader returns a io.ReadCloser that reports bandwidth details
+func NewMonitoredReader(ctx context.Context, monitor *Monitor, bucket string, object string, reader io.Reader, headerSize int, bandwidthBytesPerSecond int64) *MonitoredReader {
+	timeNow := time.Now()
+	b := monitor.track(bucket, object, timeNow)
+	return &MonitoredReader{
+		bucket:            bucket,
+		object:            object,
+		bucketMeasurement: b,
+		reader:            reader,
+		lastStop:          timeNow,
+		headerSize:        headerSize,
+		throttle:          monitor.throttleBandwidth(ctx, bucket, bandwidthBytesPerSecond),
+		monitor:           monitor,
+	}
+}
+
+// Read wraps the read reader
+func (m *MonitoredReader) Read(p []byte) (n int, err error) {
+	if m.closed {
+		err = io.ErrClosedPipe
+		return
+	}
+	p = p[:m.throttle.GetLimitForBytes(int64(len(p)))]
+
+	n, err = m.reader.Read(p)
+	stop := time.Now()
+	update := uint64(n + m.headerSize)
+
+	m.bucketMeasurement.incrementBytes(update)
+	m.lastStop = stop
+	unused := len(p) - (n + m.headerSize)
+	m.headerSize = 0 // Set to 0 post first read
+
+	if unused > 0 {
+		m.throttle.ReleaseUnusedBandwidth(int64(unused))
+	}
+	return
+}
+
+// Close stops tracking the io
+func (m *MonitoredReader) Close() error {
+	rc, ok := m.reader.(io.ReadCloser)
+	m.closed = true
+	if ok {
+		return rc.Close()
+	}
+	return nil
+}

pkg/bucket/bandwidth/throttle.go

@@ -0,0 +1,107 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+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
+	cond             *sync.Cond   // Used to notify waiting threads for bandwidth availability
+}
+
+// newThrottle returns a new bandwidth throttle. Set bytesPerSecond to 0 for no limit
+func newThrottle(ctx context.Context, bytesPerSecond int64) *throttle {
+	if bytesPerSecond == 0 {
+		return &throttle{}
+	}
+	t := &throttle{
+		bytesPerSecond: bytesPerSecond,
+		generateTicker: time.NewTicker(throttleInternal),
+	}
+
+	t.cond = sync.NewCond(&sync.Mutex{})
+	t.SetBandwidth(bytesPerSecond)
+	t.freeBytes = t.bytesPerInterval
+	go t.generateBandwidth(ctx)
+	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)
+		return send
+	}
+}
+
+// SetBandwidth sets a new bandwidth limit in bytes per second.
+func (t *throttle) SetBandwidth(bandwidthBiPS 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:
+			// 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
+		default:
+		}
+	}
+}