migrate all bucket metadata into a single file (#9586)

this is a major overhaul by migrating off all
bucket metadata related configs into a single
object '.metadata.bin' this allows us for faster
bootups across 1000's of buckets and as well
as keeps the code simple enough for future
work and additions.

Additionally also fixes #9396, #9394

cmd/bucket-metadata.go

@@ -0,0 +1,221 @@
+/*
+ * 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 cmd
+
+import (
+	"context"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"path"
+	"time"
+
+	"github.com/minio/minio/cmd/logger"
+)
+
+const (
+	legacyBucketObjectLockEnabledConfigFile = "object-lock-enabled.json"
+	legacyBucketObjectLockEnabledConfig     = `{"x-amz-bucket-object-lock-enabled":true}`
+
+	bucketMetadataFile    = ".metadata.bin"
+	bucketMetadataFormat  = 1
+	bucketMetadataVersion = 1
+)
+
+var (
+	defaultBucketObjectLockConfig = []byte(`<ObjectLockConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><ObjectLockEnabled>Enabled</ObjectLockEnabled></ObjectLockConfiguration>`)
+)
+
+//go:generate msgp -file $GOFILE
+
+// BucketMetadata contains bucket metadata.
+// When adding/removing fields, regenerate the marshal code using the go generate above.
+// Only changing meaning of fields requires a version bump.
+// bucketMetadataFormat refers to the format.
+// bucketMetadataVersion can be used to track a rolling upgrade of a field.
+type BucketMetadata struct {
+	Name                       string
+	Created                    time.Time
+	LockEnabled                bool // legacy not used anymore.
+	PolicyConfigJSON           []byte
+	NotificationXML            []byte
+	LifecycleConfigXML         []byte
+	ObjectLockConfigurationXML []byte
+	EncryptionConfigXML        []byte
+	TaggingConfigXML           []byte
+	QuotaConfigJSON            []byte
+}
+
+// newBucketMetadata creates BucketMetadata with the supplied name and Created to Now.
+func newBucketMetadata(name string) BucketMetadata {
+	return BucketMetadata{
+		Name:    name,
+		Created: UTCNow(),
+	}
+}
+
+// Load - loads the metadata of bucket by name from ObjectLayer api.
+// If an error is returned the returned metadata will be default initialized.
+func (b *BucketMetadata) Load(ctx context.Context, api ObjectLayer, name string) error {
+	configFile := path.Join(bucketConfigPrefix, name, bucketMetadataFile)
+	data, err := readConfig(ctx, api, configFile)
+	if err != nil {
+		return err
+	}
+	if len(data) <= 4 {
+		return fmt.Errorf("loadBucketMetadata: no data")
+	}
+	// Read header
+	switch binary.LittleEndian.Uint16(data[0:2]) {
+	case bucketMetadataFormat:
+	default:
+		return fmt.Errorf("loadBucketMetadata: unknown format: %d", binary.LittleEndian.Uint16(data[0:2]))
+	}
+	switch binary.LittleEndian.Uint16(data[2:4]) {
+	case bucketMetadataVersion:
+	default:
+		return fmt.Errorf("loadBucketMetadata: unknown version: %d", binary.LittleEndian.Uint16(data[2:4]))
+	}
+
+	// OK, parse data.
+	_, err = b.UnmarshalMsg(data[4:])
+	return err
+}
+
+// loadBucketMetadata loads and migrates to bucket metadata.
+func loadBucketMetadata(ctx context.Context, objectAPI ObjectLayer, bucket string) (BucketMetadata, error) {
+	b := newBucketMetadata(bucket)
+	err := b.Load(ctx, objectAPI, bucket)
+	if err == nil {
+		return b, b.convertLegacyConfigs(ctx, objectAPI)
+	}
+
+	if err != errConfigNotFound {
+		return b, err
+	}
+
+	// Old bucket without bucket metadata. Hence we migrate existing settings.
+	return b, b.convertLegacyConfigs(ctx, objectAPI)
+}
+
+func (b *BucketMetadata) convertLegacyConfigs(ctx context.Context, objectAPI ObjectLayer) error {
+	legacyConfigs := []string{
+		legacyBucketObjectLockEnabledConfigFile,
+		bucketPolicyConfig,
+		bucketNotificationConfig,
+		bucketLifecycleConfig,
+		bucketQuotaConfigFile,
+		bucketSSEConfig,
+		bucketTaggingConfigFile,
+		objectLockConfig,
+	}
+
+	configs := make(map[string][]byte)
+
+	// Handle migration from lockEnabled to newer format.
+	if b.LockEnabled {
+		configs[objectLockConfig] = defaultBucketObjectLockConfig
+		b.LockEnabled = false // legacy value unset it
+		// we are only interested in b.ObjectLockConfigurationXML or objectLockConfig value
+	}
+
+	for _, legacyFile := range legacyConfigs {
+		configFile := path.Join(bucketConfigPrefix, b.Name, legacyFile)
+
+		configData, err := readConfig(ctx, objectAPI, configFile)
+		if err != nil {
+			if errors.Is(err, errConfigNotFound) {
+				// legacy file config not found, proceed to look for new metadata.
+				continue
+			}
+
+			return err
+		}
+		configs[legacyFile] = configData
+	}
+
+	if len(configs) == 0 {
+		// nothing to update, return right away.
+		return nil
+	}
+
+	for legacyFile, configData := range configs {
+		switch legacyFile {
+		case legacyBucketObjectLockEnabledConfigFile:
+			if string(configData) == legacyBucketObjectLockEnabledConfig {
+				b.ObjectLockConfigurationXML = defaultBucketObjectLockConfig
+				b.LockEnabled = false // legacy value unset it
+				// we are only interested in b.ObjectLockConfigurationXML
+			}
+		case bucketPolicyConfig:
+			b.PolicyConfigJSON = configData
+		case bucketNotificationConfig:
+			b.NotificationXML = configData
+		case bucketLifecycleConfig:
+			b.LifecycleConfigXML = configData
+		case bucketSSEConfig:
+			b.EncryptionConfigXML = configData
+		case bucketTaggingConfigFile:
+			b.TaggingConfigXML = configData
+		case objectLockConfig:
+			b.ObjectLockConfigurationXML = configData
+		case bucketQuotaConfigFile:
+			b.QuotaConfigJSON = configData
+		}
+	}
+
+	if err := b.Save(ctx, objectAPI); err != nil {
+		return err
+	}
+
+	for legacyFile := range configs {
+		configFile := path.Join(bucketConfigPrefix, b.Name, legacyFile)
+		if err := deleteConfig(ctx, objectAPI, configFile); err != nil && !errors.Is(err, errConfigNotFound) {
+			logger.LogIf(ctx, err)
+		}
+	}
+
+	return nil
+}
+
+// Save config to supplied ObjectLayer api.
+func (b *BucketMetadata) Save(ctx context.Context, api ObjectLayer) error {
+	data := make([]byte, 4, b.Msgsize()+4)
+
+	// Initialize the header.
+	binary.LittleEndian.PutUint16(data[0:2], bucketMetadataFormat)
+	binary.LittleEndian.PutUint16(data[2:4], bucketMetadataVersion)
+
+	// Marshal the bucket metadata
+	data, err := b.MarshalMsg(data)
+	if err != nil {
+		return err
+	}
+
+	configFile := path.Join(bucketConfigPrefix, b.Name, bucketMetadataFile)
+	return saveConfig(ctx, api, configFile, data)
+}
+
+// deleteBucketMetadata deletes bucket metadata
+// If config does not exist no error is returned.
+func deleteBucketMetadata(ctx context.Context, obj ObjectLayer, bucket string) error {
+	configFile := path.Join(bucketConfigPrefix, bucket, bucketMetadataFile)
+	if err := deleteConfig(ctx, obj, configFile); err != nil && err != errConfigNotFound {
+		return err
+	}
+	return nil
+}