Allow CopyObjectPart to work in federated setups (#8066)

Fixes #8065

cmd/object-handlers.go

@@ -601,8 +601,21 @@ var getRemoteInstanceClient = func(r *http.Request, host string) (*miniogo.Core,
 	return core, nil
 }
 
+// Check if the destination bucket is on a remote site, this code only gets executed
+// when federation is enabled, ie when globalDNSConfig is non 'nil'.
+//
+// This function is similar to isRemoteCallRequired but specifically for COPY object API
+// if destination and source are same we do not need to check for destnation bucket
+// to exist locally.
+func isRemoteCopyRequired(ctx context.Context, srcBucket, dstBucket string, objAPI ObjectLayer) bool {
+	if srcBucket == dstBucket {
+		return false
+	}
+	return isRemoteCallRequired(ctx, dstBucket, objAPI)
+}
+
 // Check if the bucket is on a remote site, this code only gets executed when federation is enabled.
-var isRemoteCallRequired = func(ctx context.Context, bucket string, objAPI ObjectLayer) bool {
+func isRemoteCallRequired(ctx context.Context, bucket string, objAPI ObjectLayer) bool {
 	if globalDNSConfig == nil {
 		return false
 	}
@@ -787,23 +800,6 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
 		length = actualSize
 	}
 
-	// Check if the destination bucket is on a remote site, this code only gets executed
-	// when federation is enabled, ie when globalDNSConfig is non 'nil'.
-	//
-	// This function is similar to isRemoteCallRequired but specifically for COPY object API
-	// if destination and source are same we do not need to check for destnation bucket
-	// to exist locally.
-	var isRemoteCopyRequired = func(ctx context.Context, srcBucket, dstBucket string, objAPI ObjectLayer) bool {
-		if globalDNSConfig == nil {
-			return false
-		}
-		if srcBucket == dstBucket {
-			return false
-		}
-		_, err := objAPI.GetBucketInfo(ctx, dstBucket)
-		return err == toObjectErr(errVolumeNotFound, dstBucket)
-	}
-
 	var compressMetadata map[string]string
 	// No need to compress for remote etcd calls
 	// Pass the decompressed stream to such calls.
@@ -1591,6 +1587,36 @@ func (api objectAPIHandlers) CopyObjectPartHandler(w http.ResponseWriter, r *htt
 		return
 	}
 
+	if isRemoteCopyRequired(ctx, srcBucket, dstBucket, objectAPI) {
+		var dstRecords []dns.SrvRecord
+		dstRecords, err = globalDNSConfig.Get(dstBucket)
+		if err != nil {
+			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
+			return
+		}
+
+		// Send PutObject request to appropriate instance (in federated deployment)
+		client, rerr := getRemoteInstanceClient(r, getHostFromSrv(dstRecords))
+		if rerr != nil {
+			writeErrorResponse(ctx, w, toAPIError(ctx, rerr), r.URL, guessIsBrowserReq(r))
+			return
+		}
+
+		partInfo, err := client.PutObjectPart(dstBucket, dstObject, uploadID, partID,
+			srcInfo.Reader, srcInfo.Size, "", "", dstOpts.ServerSideEncryption)
+		if err != nil {
+			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
+			return
+		}
+
+		response := generateCopyObjectPartResponse(partInfo.ETag, partInfo.LastModified)
+		encodedSuccessResponse := encodeResponse(response)
+
+		// Write success response.
+		writeSuccessResponseXML(w, encodedSuccessResponse)
+		return
+	}
+
 	actualPartSize = length
 	var reader io.Reader