fix: change SetRemoteTarget API to allow editing remote target granularly (#12175)

Currently, only credentials could be updated with
`mc admin bucket remote edit`. 

Allow updating synchronous replication flag, path, 
bandwidth and healthcheck duration on buckets, and
a flag to disable proxying in active-active replication.

cmd/admin-bucket-handlers.go

@@ -165,14 +165,44 @@ func (a adminAPIHandlers) SetRemoteTargetHandler(w http.ResponseWriter, r *http.
 	}
 
 	target.SourceBucket = bucket
-	if !update {
+	var ops []madmin.TargetUpdateType
+	if update {
+		ops = madmin.GetTargetUpdateOps(r.URL.Query())
+	} else {
 		target.Arn = globalBucketTargetSys.getRemoteARN(bucket, &target)
 	}
 	if target.Arn == "" {
 		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErrWithErr(ErrAdminConfigBadJSON, err), r.URL)
 		return
 	}
-
+	if update {
+		// overlay the updates on existing target
+		tgt := globalBucketTargetSys.GetRemoteBucketTargetByArn(ctx, bucket, target.Arn)
+		if tgt.Empty() {
+			writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErrWithErr(ErrRemoteTargetNotFoundError, err), r.URL)
+			return
+		}
+		for _, op := range ops {
+			switch op {
+			case madmin.CredentialsUpdateType:
+				tgt.Credentials = target.Credentials
+				tgt.TargetBucket = target.TargetBucket
+				tgt.Secure = target.Secure
+				tgt.Endpoint = target.Endpoint
+			case madmin.SyncUpdateType:
+				tgt.ReplicationSync = target.ReplicationSync
+			case madmin.ProxyUpdateType:
+				tgt.DisableProxy = target.DisableProxy
+			case madmin.PathUpdateType:
+				tgt.Path = target.Path
+			case madmin.BandwidthLimitUpdateType:
+				tgt.BandwidthLimit = target.BandwidthLimit
+			case madmin.HealthCheckDurationUpdateType:
+				tgt.HealthCheckDuration = target.HealthCheckDuration
+			}
+		}
+		target = tgt
+	}
 	if err = globalBucketTargetSys.SetTarget(ctx, bucket, &target, update); err != nil {
 		switch err.(type) {
 		case BucketRemoteConnectionErr:

cmd/bucket-replication.go

@@ -1049,7 +1049,10 @@ func proxyHeadToRepTarget(ctx context.Context, bucket, object string, opts Objec
 	if tgt == nil || tgt.isOffline() {
 		return nil, oi, false, fmt.Errorf("target is offline or not configured")
 	}
-
+	// if proxying explicitly disabled on remote target
+	if tgt.disableProxy {
+		return nil, oi, false, nil
+	}
 	gopts := miniogo.GetObjectOptions{
 		VersionID:            opts.VersionID,
 		ServerSideEncryption: opts.ServerSideEncryption,

cmd/bucket-targets.go

@@ -204,6 +204,21 @@ func (sys *BucketTargetSys) GetRemoteTargetClient(ctx context.Context, arn strin
 	return sys.arnRemotesMap[arn]
 }
 
+// GetRemoteBucketTargetByArn returns BucketTarget for a ARN
+func (sys *BucketTargetSys) GetRemoteBucketTargetByArn(ctx context.Context, bucket, arn string) madmin.BucketTarget {
+	sys.RLock()
+	defer sys.RUnlock()
+	var tgt madmin.BucketTarget
+	for _, t := range sys.targetsMap[bucket] {
+		if t.Arn == arn {
+			tgt = t.Clone()
+			tgt.Credentials = t.Credentials
+			return tgt
+		}
+	}
+	return tgt
+}
+
 // NewBucketTargetSys - creates new replication system.
 func NewBucketTargetSys() *BucketTargetSys {
 	return &BucketTargetSys{
@@ -315,6 +330,7 @@ func (sys *BucketTargetSys) getRemoteTargetClient(tcfg *madmin.BucketTarget) (*T
 		replicateSync:       tcfg.ReplicationSync,
 		Bucket:              tcfg.TargetBucket,
 		StorageClass:        tcfg.StorageClass,
+		disableProxy:        tcfg.DisableProxy,
 	}
 	go tc.healthCheck()
 	return tc, nil
@@ -393,6 +409,7 @@ type TargetClient struct {
 	Bucket              string // remote bucket target
 	replicateSync       bool
 	StorageClass        string // storage class on remote
+	disableProxy        bool
 }
 
 func (tc *TargetClient) isOffline() bool {