Refactor replication target management. (#10154)

Generalize replication target management so
that remote targets for a bucket can be
managed with ARNs. `mc admin bucket remote`
command will be used to manage targets.

cmd/bucket-targets.go

@@ -0,0 +1,242 @@
+/*
+ * 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"
+	"fmt"
+	"net/http"
+	"sync"
+
+	miniogo "github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+	"github.com/minio/minio/pkg/bucket/versioning"
+	"github.com/minio/minio/pkg/madmin"
+)
+
+// BucketTargetSys represents bucket targets subsystem
+type BucketTargetSys struct {
+	sync.RWMutex
+	arnRemotesMap map[string]*miniogo.Core
+	targetsMap    map[string][]madmin.BucketTarget
+	clientsCache  map[string]*miniogo.Core
+}
+
+// ListTargets - gets list of bucket targets for this bucket.
+func (sys *BucketTargetSys) ListTargets(ctx context.Context, bucket string) (*madmin.BucketTargets, error) {
+	if globalIsGateway {
+		return nil, nil
+	}
+	tgts, ok := sys.targetsMap[bucket]
+	if ok {
+		return &madmin.BucketTargets{Targets: tgts}, nil
+	}
+	return nil, fmt.Errorf("No remote targets exist for bucket %s", bucket)
+}
+
+// SetTarget - sets a new minio-go client target for this bucket.
+func (sys *BucketTargetSys) SetTarget(ctx context.Context, bucket string, tgt *madmin.BucketTarget) error {
+	if globalIsGateway {
+		return nil
+	}
+	if !tgt.Type.IsValid() {
+		return BucketRemoteArnTypeInvalid{Bucket: bucket}
+	}
+	clnt, err := sys.getRemoteTargetClient(tgt)
+	if err != nil {
+		return BucketRemoteTargetNotFound{Bucket: tgt.TargetBucket}
+	}
+
+	if tgt.Type == madmin.ReplicationArn {
+		vcfg, err := clnt.GetBucketVersioning(ctx, tgt.TargetBucket)
+		if err != nil || vcfg.Status != string(versioning.Enabled) {
+			if isErrBucketNotFound(err) {
+				return BucketRemoteTargetNotFound{Bucket: tgt.TargetBucket}
+			}
+			return BucketReplicationTargetNotVersioned{Bucket: tgt.TargetBucket}
+		}
+	}
+
+	sys.Lock()
+	defer sys.Unlock()
+
+	tgts := sys.targetsMap[bucket]
+	newtgts := make([]madmin.BucketTarget, len(tgts))
+	found := false
+	for idx, t := range tgts {
+		if t.Type == tgt.Type {
+			if t.Arn == tgt.Arn {
+				return BucketRemoteAlreadyExists{Bucket: t.TargetBucket}
+			}
+			newtgts[idx] = *tgt
+			found = true
+			continue
+		}
+		newtgts[idx] = t
+	}
+	if !found {
+		newtgts = append(newtgts, *tgt)
+	}
+
+	sys.targetsMap[bucket] = newtgts
+	sys.arnRemotesMap[tgt.Arn] = clnt
+	if _, ok := sys.clientsCache[clnt.EndpointURL().String()]; !ok {
+		sys.clientsCache[clnt.EndpointURL().String()] = clnt
+	}
+	return nil
+}
+
+// RemoveTarget - removes a remote bucket target for this source bucket.
+func (sys *BucketTargetSys) RemoveTarget(ctx context.Context, bucket, arnStr string) error {
+	if globalIsGateway {
+		return nil
+	}
+	if arnStr == "" {
+		return BucketRemoteArnInvalid{Bucket: bucket}
+	}
+	arn, err := madmin.ParseARN(arnStr)
+	if err != nil {
+		return BucketRemoteArnInvalid{Bucket: bucket}
+	}
+	if arn.Type == madmin.ReplicationArn {
+		// reject removal of remote target if replication configuration is present
+		rcfg, err := getReplicationConfig(ctx, bucket)
+		if err == nil && rcfg.ReplicationArn == arnStr {
+			if _, ok := sys.arnRemotesMap[arnStr]; ok {
+				return BucketRemoteRemoveDisallowed{Bucket: bucket}
+			}
+		}
+	}
+	// delete ARN type from list of matching targets
+	sys.Lock()
+	defer sys.Unlock()
+	targets := make([]madmin.BucketTarget, 0)
+	tgts := sys.targetsMap[bucket]
+	for _, tgt := range tgts {
+		if tgt.Arn != arnStr {
+			targets = append(targets, tgt)
+		}
+	}
+	sys.targetsMap[bucket] = targets
+	delete(sys.arnRemotesMap, arnStr)
+	return nil
+}
+
+// GetReplicationTargetClient returns minio-go client for replication target instance
+func (sys *BucketTargetSys) GetReplicationTargetClient(ctx context.Context, arn string) *miniogo.Core {
+	sys.RLock()
+	defer sys.RUnlock()
+	return sys.arnRemotesMap[arn]
+}
+
+// NewBucketTargetSys - creates new replication system.
+func NewBucketTargetSys() *BucketTargetSys {
+	return &BucketTargetSys{
+		arnRemotesMap: make(map[string]*miniogo.Core),
+		targetsMap:    make(map[string][]madmin.BucketTarget),
+		clientsCache:  make(map[string]*miniogo.Core),
+	}
+}
+
+// Init initializes the bucket targets subsystem for buckets which have targets configured.
+func (sys *BucketTargetSys) Init(ctx context.Context, buckets []BucketInfo, objAPI ObjectLayer) error {
+	if objAPI == nil {
+		return errServerNotInitialized
+	}
+
+	// In gateway mode, bucket targets is not supported.
+	if globalIsGateway {
+		return nil
+	}
+
+	// Load bucket targets once during boot.
+	sys.load(ctx, buckets, objAPI)
+	return nil
+}
+
+// create minio-go clients for buckets having remote targets
+func (sys *BucketTargetSys) load(ctx context.Context, buckets []BucketInfo, objAPI ObjectLayer) {
+	for _, bucket := range buckets {
+		cfg, err := globalBucketMetadataSys.GetBucketTargetsConfig(bucket.Name)
+		if err != nil {
+			continue
+		}
+		if cfg == nil || cfg.Empty() {
+			continue
+		}
+		if len(cfg.Targets) > 0 {
+			sys.targetsMap[bucket.Name] = cfg.Targets
+		}
+		for _, tgt := range cfg.Targets {
+			tgtClient, err := sys.getRemoteTargetClient(&tgt)
+			if err != nil {
+				continue
+			}
+			sys.arnRemotesMap[tgt.Arn] = tgtClient
+			if _, ok := sys.clientsCache[tgtClient.EndpointURL().String()]; !ok {
+				sys.clientsCache[tgtClient.EndpointURL().String()] = tgtClient
+			}
+		}
+		sys.targetsMap[bucket.Name] = cfg.Targets
+	}
+}
+
+// getRemoteTargetInstanceTransport contains a singleton roundtripper.
+var getRemoteTargetInstanceTransport http.RoundTripper
+var getRemoteTargetInstanceTransportOnce sync.Once
+
+// Returns a minio-go Client configured to access remote host described in replication target config.
+func (sys *BucketTargetSys) getRemoteTargetClient(tcfg *madmin.BucketTarget) (*miniogo.Core, error) {
+	if clnt, ok := sys.clientsCache[tcfg.Endpoint]; ok {
+		return clnt, nil
+	}
+	config := tcfg.Credentials
+	creds := credentials.NewStaticV4(config.AccessKey, config.SecretKey, "")
+
+	getRemoteTargetInstanceTransportOnce.Do(func() {
+		getRemoteTargetInstanceTransport = NewGatewayHTTPTransport()
+	})
+	core, err := miniogo.NewCore(tcfg.Endpoint, &miniogo.Options{
+		Creds:     creds,
+		Secure:    tcfg.Secure,
+		Transport: getRemoteTargetInstanceTransport,
+	})
+	return core, err
+}
+
+// getRemoteARN gets existing ARN for an endpoint or generates a new one.
+func (sys *BucketTargetSys) getRemoteARN(bucket string, target *madmin.BucketTarget) string {
+	if target == nil {
+		return ""
+	}
+	tgts := sys.targetsMap[bucket]
+	for _, tgt := range tgts {
+		if tgt.Type == target.Type && tgt.TargetBucket == target.TargetBucket && target.URL() == tgt.URL() {
+			return tgt.Arn
+		}
+	}
+	if !madmin.ArnType(target.Type).IsValid() {
+		return ""
+	}
+	arn := madmin.ARN{
+		Type:   target.Type,
+		ID:     mustGetUUID(),
+		Region: target.Region,
+		Bucket: target.TargetBucket,
+	}
+	return arn.String()
+}