objAPI: Implement CopyObject API. (#3487)

This is written so that to simplify our handler code
and provide a way to only update metadata instead of
the data when source and destination in CopyObject
request are same.

Fixes #3316

cmd/api-errors.go

@@ -62,6 +62,7 @@ const (
 	ErrInvalidPartNumberMarker
 	ErrInvalidRequestBody
 	ErrInvalidCopySource
+	ErrInvalidMetadataDirective
 	ErrInvalidCopyDest
 	ErrInvalidPolicyDocument
 	ErrInvalidObjectState
@@ -145,7 +146,7 @@ const (
 var errorCodeResponse = map[APIErrorCode]APIError{
 	ErrInvalidCopyDest: {
 		Code:           "InvalidRequest",
-		Description:    "This copy request is illegal because it is trying to copy an object to itself.",
+		Description:    "This copy request is illegal because it is trying to copy an object to itself without changing the object's metadata, storage class, website redirect location or encryption attributes.",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
 	ErrInvalidCopySource: {
@@ -153,6 +154,11 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "Copy Source must mention the source bucket and key: sourcebucket/sourcekey.",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
+	ErrInvalidMetadataDirective: {
+		Code:           "InvalidArgument",
+		Description:    "Unknown metadata directive.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	ErrInvalidRequestBody: {
 		Code:           "InvalidArgument",
 		Description:    "Body shouldn't be set for this request.",

cmd/fs-createfile.go

@@ -1,39 +0,0 @@
-/*
- * Minio Cloud Storage, (C) 2016 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 "io"
-
-func fsCreateFile(disk StorageAPI, reader io.Reader, buf []byte, tmpBucket, tempObj string) (int64, error) {
-	bytesWritten := int64(0)
-	// Read the buffer till io.EOF and append the read data to the temporary file.
-	for {
-		n, rErr := reader.Read(buf)
-		if rErr != nil && rErr != io.EOF {
-			return 0, traceError(rErr)
-		}
-		bytesWritten += int64(n)
-		wErr := disk.AppendFile(tmpBucket, tempObj, buf[0:n])
-		if wErr != nil {
-			return 0, traceError(wErr)
-		}
-		if rErr == io.EOF {
-			break
-		}
-	}
-	return bytesWritten, nil
-}

cmd/fs-helpers.go

@@ -0,0 +1,91 @@
+/*
+ * Minio Cloud Storage, (C) 2016 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 "io"
+
+// Reads from the requested local location uses a staging buffer. Restricts
+// reads upto requested range of length and offset. If successful staging
+// buffer is written to the incoming stream. Returns errors if any.
+func fsReadFile(disk StorageAPI, bucket, object string, writer io.Writer, totalLeft, startOffset int64, buf []byte) (err error) {
+	bufSize := int64(len(buf))
+	// Start the read loop until requested range.
+	for {
+		// Figure out the right size for the buffer.
+		curLeft := bufSize
+		if totalLeft < bufSize {
+			curLeft = totalLeft
+		}
+		// Reads the file at offset.
+		nr, er := disk.ReadFile(bucket, object, startOffset, buf[:curLeft])
+		if nr > 0 {
+			// Write to response writer.
+			nw, ew := writer.Write(buf[0:nr])
+			if nw > 0 {
+				// Decrement whats left to write.
+				totalLeft -= int64(nw)
+
+				// Progress the offset
+				startOffset += int64(nw)
+			}
+			if ew != nil {
+				err = traceError(ew)
+				break
+			}
+			if nr != int64(nw) {
+				err = traceError(io.ErrShortWrite)
+				break
+			}
+		}
+		if er == io.EOF || er == io.ErrUnexpectedEOF {
+			break
+		}
+		if er != nil {
+			err = traceError(er)
+			break
+		}
+		if totalLeft == 0 {
+			break
+		}
+	}
+	return err
+}
+
+// Reads from input stream until end of file, takes an input buffer for staging reads.
+// The staging buffer is then written to the disk. Returns for any error that occurs
+// while reading the stream or writing to disk. Caller should cleanup partial files.
+// Upon errors total data written will be 0 and returns error, on success returns
+// total data written to disk.
+func fsCreateFile(disk StorageAPI, reader io.Reader, buf []byte, bucket, object string) (int64, error) {
+	bytesWritten := int64(0)
+	// Read the buffer till io.EOF and appends data to path at bucket/object.
+	for {
+		n, rErr := reader.Read(buf)
+		if rErr != nil && rErr != io.EOF {
+			return 0, traceError(rErr)
+		}
+		bytesWritten += int64(n)
+		wErr := disk.AppendFile(bucket, object, buf[0:n])
+		if wErr != nil {
+			return 0, traceError(wErr)
+		}
+		if rErr == io.EOF {
+			break
+		}
+	}
+	return bytesWritten, nil
+}

cmd/fs-v1.go

@@ -217,7 +217,65 @@ func (fs fsObjects) DeleteBucket(bucket string) error {
 
 /// Object Operations
 
-// GetObject - get an object.
+// CopyObject - copy object source object to destination object.
+// if source object and destination object are same we only
+// update metadata.
+func (fs fsObjects) CopyObject(srcBucket, srcObject, dstBucket, dstObject string, metadata map[string]string) (ObjectInfo, error) {
+	// Stat the file to get file size.
+	fi, err := fs.storage.StatFile(srcBucket, srcObject)
+	if err != nil {
+		return ObjectInfo{}, toObjectErr(traceError(err), srcBucket, srcObject)
+	}
+
+	// Check if this request is only metadata update.
+	cpMetadataOnly := strings.EqualFold(pathJoin(srcBucket, srcObject), pathJoin(dstBucket, dstObject))
+	if cpMetadataOnly {
+		// Save objects' metadata in `fs.json`.
+		fsMeta := newFSMetaV1()
+		fsMeta.Meta = metadata
+
+		fsMetaPath := pathJoin(bucketMetaPrefix, dstBucket, dstObject, fsMetaJSONFile)
+		if err = writeFSMetadata(fs.storage, minioMetaBucket, fsMetaPath, fsMeta); err != nil {
+			return ObjectInfo{}, toObjectErr(err, dstBucket, dstObject)
+		}
+
+		// Get object info.
+		return fs.getObjectInfo(dstBucket, dstObject)
+	}
+
+	// Length of the file to read.
+	length := fi.Size
+
+	// Initialize pipe.
+	pipeReader, pipeWriter := io.Pipe()
+
+	go func() {
+		startOffset := int64(0) // Read the whole file.
+		if gerr := fs.GetObject(srcBucket, srcObject, startOffset, length, pipeWriter); gerr != nil {
+			errorIf(gerr, "Unable to read %s/%s.", srcBucket, srcObject)
+			pipeWriter.CloseWithError(gerr)
+			return
+		}
+		pipeWriter.Close() // Close writer explicitly signalling we wrote all data.
+	}()
+
+	objInfo, err := fs.PutObject(dstBucket, dstObject, length, pipeReader, metadata, "")
+	if err != nil {
+		return ObjectInfo{}, toObjectErr(err, dstBucket, dstObject)
+	}
+
+	// Explicitly close the reader.
+	pipeReader.Close()
+
+	return objInfo, nil
+}
+
+// GetObject - reads an object from the disk.
+// Supports additional parameters like offset and length
+// which are synonymous with HTTP Range requests.
+//
+// startOffset indicates the starting read location of the object.
+// length indicates the total length of the object.
 func (fs fsObjects) GetObject(bucket, object string, offset int64, length int64, writer io.Writer) (err error) {
 	if err = checkGetObjArgs(bucket, object); err != nil {
 		return err
@@ -254,50 +312,14 @@ func (fs fsObjects) GetObject(bucket, object string, offset int64, length int64,
 	}
 	// Allocate a staging buffer.
 	buf := make([]byte, int(bufSize))
-	for {
+	if err = fsReadFile(fs.storage, bucket, object, writer, totalLeft, offset, buf); err != nil {
-		// Figure out the right size for the buffer.
+		// Returns any error.
-		curLeft := bufSize
+		return toObjectErr(err, bucket, object)
-		if totalLeft < bufSize {
-			curLeft = totalLeft
-		}
-		// Reads the file at offset.
-		nr, er := fs.storage.ReadFile(bucket, object, offset, buf[:curLeft])
-		if nr > 0 {
-			// Write to response writer.
-			nw, ew := writer.Write(buf[0:nr])
-			if nw > 0 {
-				// Decrement whats left to write.
-				totalLeft -= int64(nw)
-
-				// Progress the offset
-				offset += int64(nw)
-			}
-			if ew != nil {
-				err = traceError(ew)
-				break
-			}
-			if nr != int64(nw) {
-				err = traceError(io.ErrShortWrite)
-				break
-			}
-		}
-		if er == io.EOF || er == io.ErrUnexpectedEOF {
-			break
-		}
-		if er != nil {
-			err = traceError(er)
-			break
-		}
-		if totalLeft == 0 {
-			break
-		}
 	}
-
+	return nil
-	// Returns any error.
-	return toObjectErr(err, bucket, object)
 }
 
-// getObjectInfo - get object info.
+// getObjectInfo - wrapper for reading object metadata and constructs ObjectInfo.
 func (fs fsObjects) getObjectInfo(bucket, object string) (ObjectInfo, error) {
 	fi, err := fs.storage.StatFile(bucket, object)
 	if err != nil {
@@ -342,7 +364,7 @@ func (fs fsObjects) getObjectInfo(bucket, object string) (ObjectInfo, error) {
 	return objInfo, nil
 }
 
-// GetObjectInfo - get object info.
+// GetObjectInfo - reads object metadata and replies back ObjectInfo.
 func (fs fsObjects) GetObjectInfo(bucket, object string) (ObjectInfo, error) {
 	if err := checkGetObjArgs(bucket, object); err != nil {
 		return ObjectInfo{}, err
@@ -350,7 +372,10 @@ func (fs fsObjects) GetObjectInfo(bucket, object string) (ObjectInfo, error) {
 	return fs.getObjectInfo(bucket, object)
 }
 
-// PutObject - create an object.
+// PutObject - creates an object upon reading from the input stream
+// until EOF, writes data directly to configured filesystem path.
+// Additionally writes `fs.json` which carries the necessary metadata
+// for future object operations.
 func (fs fsObjects) PutObject(bucket string, object string, size int64, data io.Reader, metadata map[string]string, sha256sum string) (objInfo ObjectInfo, err error) {
 	if err = checkPutObjectArgs(bucket, object, fs); err != nil {
 		return ObjectInfo{}, err

cmd/handler-utils.go

@@ -65,6 +65,45 @@ var supportedHeaders = []string{
 	// Add more supported headers here.
 }
 
+// isMetadataDirectiveValid - check if metadata-directive is valid.
+func isMetadataDirectiveValid(h http.Header) bool {
+	_, ok := h[http.CanonicalHeaderKey("X-Amz-Metadata-Directive")]
+	if ok {
+		// Check atleast set metadata-directive is valid.
+		return (isMetadataCopy(h) || isMetadataReplace(h))
+	}
+	// By default if x-amz-metadata-directive is not we
+	// treat it as 'COPY' this function returns true.
+	return true
+}
+
+// Check if the metadata COPY is requested.
+func isMetadataCopy(h http.Header) bool {
+	return h.Get("X-Amz-Metadata-Directive") == "COPY"
+}
+
+// Check if the metadata REPLACE is requested.
+func isMetadataReplace(h http.Header) bool {
+	return h.Get("X-Amz-Metadata-Directive") == "REPLACE"
+}
+
+// Splits an incoming path into bucket and object components.
+func path2BucketAndObject(path string) (bucket, object string) {
+	// Skip the first element if it is '/', split the rest.
+	path = strings.TrimPrefix(path, "/")
+	pathComponents := strings.SplitN(path, "/", 2)
+
+	// Save the bucket and object extracted from path.
+	switch len(pathComponents) {
+	case 1:
+		bucket = pathComponents[0]
+	case 2:
+		bucket = pathComponents[0]
+		object = pathComponents[1]
+	}
+	return bucket, object
+}
+
 // extractMetadataFromHeader extracts metadata from HTTP header.
 func extractMetadataFromHeader(header http.Header) map[string]string {
 	metadata := make(map[string]string)

cmd/object-api-interface.go

@@ -34,7 +34,8 @@ type ObjectLayer interface {
 	// Object operations.
 	GetObject(bucket, object string, startOffset int64, length int64, writer io.Writer) (err error)
 	GetObjectInfo(bucket, object string) (objInfo ObjectInfo, err error)
-	PutObject(bucket, object string, size int64, data io.Reader, metadata map[string]string, sha256sum string) (objInto ObjectInfo, err error)
+	PutObject(bucket, object string, size int64, data io.Reader, metadata map[string]string, sha256sum string) (objInfo ObjectInfo, err error)
+	CopyObject(srcBucket, srcObject, destBucket, destObject string, metadata map[string]string) (objInfo ObjectInfo, err error)
 	DeleteObject(bucket, object string) error
 
 	// Multipart operations.

cmd/object-handlers.go

@@ -19,7 +19,6 @@ package cmd
 import (
 	"encoding/hex"
 	"encoding/xml"
-	"io"
 	"io/ioutil"
 	"net/http"
 	"net/url"
@@ -228,14 +227,32 @@ func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Re
 	w.WriteHeader(http.StatusOK)
 }
 
+// Extract metadata relevant for an CopyObject operation based on conditional
+// header values specified in X-Amz-Metadata-Directive.
+func getCpObjMetadataFromHeader(header http.Header, defaultMeta map[string]string) map[string]string {
+	// if x-amz-metadata-directive says REPLACE then
+	// we extract metadata from the input headers.
+	if isMetadataReplace(header) {
+		return extractMetadataFromHeader(header)
+	}
+	// if x-amz-metadata-directive says COPY then we
+	// return the default metadata.
+	if isMetadataCopy(header) {
+		return defaultMeta
+	}
+	// Copy is default behavior if not x-amz-metadata-directive is set.
+	return defaultMeta
+}
+
 // CopyObjectHandler - Copy Object
 // ----------
 // This implementation of the PUT operation adds an object to a bucket
 // while reading the object from another source.
 func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
-	bucket := vars["bucket"]
+	dstBucket := vars["bucket"]
-	object := vars["object"]
+	dstObject := vars["object"]
+	cpDestPath := "/" + path.Join(dstBucket, dstObject)
 
 	objectAPI := api.ObjectAPI()
 	if objectAPI == nil {
@@ -243,51 +260,58 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
 		return
 	}
 
-	if s3Error := checkRequestAuthType(r, bucket, "s3:PutObject", serverConfig.GetRegion()); s3Error != ErrNone {
+	if s3Error := checkRequestAuthType(r, dstBucket, "s3:PutObject", serverConfig.GetRegion()); s3Error != ErrNone {
 		writeErrorResponse(w, r, s3Error, r.URL.Path)
 		return
 	}
 
 	// TODO: Reject requests where body/payload is present, for now we don't even read it.
 
-	// objectSource
+	// Copy source path.
-	objectSource, err := url.QueryUnescape(r.Header.Get("X-Amz-Copy-Source"))
+	cpSrcPath, err := url.QueryUnescape(r.Header.Get("X-Amz-Copy-Source"))
 	if err != nil {
 		// Save unescaped string as is.
-		objectSource = r.Header.Get("X-Amz-Copy-Source")
+		cpSrcPath = r.Header.Get("X-Amz-Copy-Source")
 	}
 
-	// Skip the first element if it is '/', split the rest.
+	srcBucket, srcObject := path2BucketAndObject(cpSrcPath)
-	objectSource = strings.TrimPrefix(objectSource, "/")
+	// If source object is empty or bucket is empty, reply back invalid copy source.
-	splits := strings.SplitN(objectSource, "/", 2)
+	if srcObject == "" || srcBucket == "" {
-
-	// Save sourceBucket and sourceObject extracted from url Path.
-	var sourceBucket, sourceObject string
-	if len(splits) == 2 {
-		sourceBucket = splits[0]
-		sourceObject = splits[1]
-	}
-	// If source object is empty, reply back error.
-	if sourceObject == "" {
 		writeErrorResponse(w, r, ErrInvalidCopySource, r.URL.Path)
 		return
 	}
 
-	// Source and destination objects cannot be same, reply back error.
+	// Check if metadata directive is valid.
-	if sourceObject == object && sourceBucket == bucket {
+	if !isMetadataDirectiveValid(r.Header) {
-		writeErrorResponse(w, r, ErrInvalidCopyDest, r.URL.Path)
+		writeErrorResponse(w, r, ErrInvalidMetadataDirective, r.URL.Path)
 		return
 	}
 
-	// Lock the object before reading.
+	cpSrcDstSame := cpSrcPath == cpDestPath
-	objectRLock := globalNSMutex.NewNSLock(sourceBucket, sourceObject)
+	// Hold write lock on destination since in both cases
-	objectRLock.RLock()
+	// - if source and destination are same
-	defer objectRLock.RUnlock()
+	// - if source and destination are different
+	// it is the sole mutating state.
+	objectDWLock := globalNSMutex.NewNSLock(dstBucket, dstObject)
+	objectDWLock.Lock()
+	defer objectDWLock.Unlock()
 
-	objInfo, err := objectAPI.GetObjectInfo(sourceBucket, sourceObject)
+	// if source and destination are different, we have to hold
+	// additional read lock as well to protect against writes on
+	// source.
+	if !cpSrcDstSame {
+		// Hold read locks on source object only if we are
+		// going to read data from source object.
+		objectSRLock := globalNSMutex.NewNSLock(srcBucket, srcObject)
+		objectSRLock.RLock()
+		defer objectSRLock.RUnlock()
+
+	}
+
+	objInfo, err := objectAPI.GetObjectInfo(srcBucket, srcObject)
 	if err != nil {
 		errorIf(err, "Unable to fetch object info.")
-		writeErrorResponse(w, r, toAPIErrorCode(err), objectSource)
+		writeErrorResponse(w, r, toAPIErrorCode(err), cpSrcPath)
 		return
 	}
 
@@ -298,50 +322,34 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
 
 	/// maximum Upload size for object in a single CopyObject operation.
 	if isMaxObjectSize(objInfo.Size) {
-		writeErrorResponse(w, r, ErrEntityTooLarge, objectSource)
+		writeErrorResponse(w, r, ErrEntityTooLarge, cpSrcPath)
 		return
 	}
 
-	// Size of object.
+	defaultMeta := objInfo.UserDefined
-	size := objInfo.Size
 
-	pipeReader, pipeWriter := io.Pipe()
+	// Make sure to remove saved md5sum, object might have been uploaded
-	go func() {
+	// as multipart which doesn't have a standard md5sum, we just let
-		startOffset := int64(0) // Read the whole file.
+	// CopyObject calculate a new one.
-		// Get the object.
+	delete(defaultMeta, "md5Sum")
-		gErr := objectAPI.GetObject(sourceBucket, sourceObject, startOffset, size, pipeWriter)
-		if gErr != nil {
-			errorIf(gErr, "Unable to read an object.")
-			pipeWriter.CloseWithError(gErr)
-			return
-		}
-		pipeWriter.Close() // Close.
-	}()
 
-	// Save other metadata if available.
+	newMetadata := getCpObjMetadataFromHeader(r.Header, defaultMeta)
-	metadata := objInfo.UserDefined
+	// Check if x-amz-metadata-directive was not set to REPLACE and source,
+	// desination are same objects.
+	if !isMetadataReplace(r.Header) && cpSrcDstSame {
+		// If x-amz-metadata-directive is not set to REPLACE then we need
+		// to error out if source and destination are same.
+		writeErrorResponse(w, r, ErrInvalidCopyDest, r.URL.Path)
+		return
+	}
 
-	// Remove the etag from source metadata because if it was uploaded as a multipart object
+	// Copy source object to destination, if source and destination
-	// then its ETag will not be MD5sum of the object.
+	// object is same then only metadata is updated.
-	delete(metadata, "md5Sum")
+	objInfo, err = objectAPI.CopyObject(srcBucket, srcObject, dstBucket, dstObject, newMetadata)
-
-	sha256sum := ""
-
-	objectWLock := globalNSMutex.NewNSLock(bucket, object)
-	objectWLock.Lock()
-	defer objectWLock.Unlock()
-
-	// Create the object.
-	objInfo, err = objectAPI.PutObject(bucket, object, size, pipeReader, metadata, sha256sum)
 	if err != nil {
-		// Close the this end of the pipe upon error in PutObject.
-		pipeReader.CloseWithError(err)
-		errorIf(err, "Unable to create an object.")
 		writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
 		return
 	}
-	// Explicitly close the reader, before fetching object info.
-	pipeReader.Close()
 
 	md5Sum := objInfo.MD5Sum
 	response := generateCopyObjectResponse(md5Sum, objInfo.ModTime)
@@ -354,7 +362,7 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
 	// Notify object created event.
 	eventNotify(eventData{
 		Type:    ObjectCreatedCopy,
-		Bucket:  bucket,
+		Bucket:  dstBucket,
 		ObjInfo: objInfo,
 		ReqParams: map[string]string{
 			"sourceIPAddress": r.RemoteAddr,

cmd/object-handlers_test.go

@@ -981,19 +981,25 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 		bucketName       string
 		newObjectName    string // name of the newly copied object.
 		copySourceHeader string // data for "X-Amz-Copy-Source" header. Contains the object to be copied in the URL.
+		metadataGarbage  bool
+		metadataReplace  bool
+		metadataCopy     bool
+		metadata         map[string]string
 		accessKey        string
 		secretKey        string
 		// expected output.
 		expectedRespStatus int
 	}{
-		// Test case - 1.
+		// Test case - 1, copy metadata from newObject1, ignore request headers.
 		{
 			bucketName:       bucketName,
 			newObjectName:    "newObject1",
 			copySourceHeader: url.QueryEscape("/" + bucketName + "/" + objectName),
 			accessKey:        credentials.AccessKey,
 			secretKey:        credentials.SecretKey,
-
+			metadata: map[string]string{
+				"Content-Type": "application/json",
+			},
 			expectedRespStatus: http.StatusOK,
 		},
 
@@ -1008,6 +1014,7 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 
 			expectedRespStatus: http.StatusBadRequest,
 		},
+
 		// Test case - 3.
 		// Test case with new object name is same as object to be copied.
 		{
@@ -1019,7 +1026,58 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 
 			expectedRespStatus: http.StatusBadRequest,
 		},
+
 		// Test case - 4.
+		// Test case with new object name is same as object to be copied
+		// but metadata is updated.
+		{
+			bucketName:       bucketName,
+			newObjectName:    objectName,
+			copySourceHeader: url.QueryEscape("/" + bucketName + "/" + objectName),
+			metadata: map[string]string{
+				"Content-Type": "application/json",
+			},
+			metadataReplace: true,
+			accessKey:       credentials.AccessKey,
+			secretKey:       credentials.SecretKey,
+
+			expectedRespStatus: http.StatusOK,
+		},
+
+		// Test case - 5.
+		// Test case with invalid metadata-directive.
+		{
+			bucketName:       bucketName,
+			newObjectName:    "newObject1",
+			copySourceHeader: url.QueryEscape("/" + bucketName + "/" + objectName),
+			metadata: map[string]string{
+				"Content-Type": "application/json",
+			},
+			metadataGarbage: true,
+			accessKey:       credentials.AccessKey,
+			secretKey:       credentials.SecretKey,
+
+			expectedRespStatus: http.StatusBadRequest,
+		},
+
+		// Test case - 6.
+		// Test case with new object name is same as object to be copied
+		// fail with BadRequest.
+		{
+			bucketName:       bucketName,
+			newObjectName:    objectName,
+			copySourceHeader: url.QueryEscape("/" + bucketName + "/" + objectName),
+			metadata: map[string]string{
+				"Content-Type": "application/json",
+			},
+			metadataCopy: true,
+			accessKey:    credentials.AccessKey,
+			secretKey:    credentials.SecretKey,
+
+			expectedRespStatus: http.StatusBadRequest,
+		},
+
+		// Test case - 7.
 		// Test case with non-existent source file.
 		// Case for the purpose of failing `api.ObjectAPI.GetObjectInfo`.
 		// Expecting the response status code to http.StatusNotFound (404).
@@ -1032,7 +1090,8 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 
 			expectedRespStatus: http.StatusNotFound,
 		},
-		// Test case - 5.
+
+		// Test case - 8.
 		// Test case with non-existent source file.
 		// Case for the purpose of failing `api.ObjectAPI.PutObject`.
 		// Expecting the response status code to http.StatusNotFound (404).
@@ -1045,7 +1104,8 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 
 			expectedRespStatus: http.StatusNotFound,
 		},
-		// Test case - 6.
+
+		// Test case - 9.
 		// Case with invalid AccessKey.
 		{
 			bucketName:       bucketName,
@@ -1059,7 +1119,8 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 	}
 
 	for i, testCase := range testCases {
-		var req, reqV2 *http.Request
+		var req *http.Request
+		var reqV2 *http.Request
 		// initialize HTTP NewRecorder, this records any mutations to response writer inside the handler.
 		rec := httptest.NewRecorder()
 		// construct HTTP request for copy object.
@@ -1073,6 +1134,19 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 		if testCase.copySourceHeader != "" {
 			req.Header.Set("X-Amz-Copy-Source", testCase.copySourceHeader)
 		}
+		// Add custom metadata.
+		for k, v := range testCase.metadata {
+			req.Header.Set(k, v)
+		}
+		if testCase.metadataReplace {
+			req.Header.Set("X-Amz-Metadata-Directive", "REPLACE")
+		}
+		if testCase.metadataCopy {
+			req.Header.Set("X-Amz-Metadata-Directive", "COPY")
+		}
+		if testCase.metadataGarbage {
+			req.Header.Set("X-Amz-Metadata-Directive", "Unknown")
+		}
 		// Since `apiRouter` satisfies `http.Handler` it has a ServeHTTP to execute the logic of the handler.
 		// Call the ServeHTTP to execute the handler, `func (api objectAPIHandlers) CopyObjectHandler` handles the request.
 		apiRouter.ServeHTTP(rec, req)
@@ -1106,6 +1180,20 @@ func testAPICopyObjectHandler(obj ObjectLayer, instanceType, bucketName string,
 			reqV2.Header.Set("X-Amz-Copy-Source", testCase.copySourceHeader)
 		}
 
+		// Add custom metadata.
+		for k, v := range testCase.metadata {
+			reqV2.Header.Set(k, v+"+x")
+		}
+		if testCase.metadataReplace {
+			reqV2.Header.Set("X-Amz-Metadata-Directive", "REPLACE")
+		}
+		if testCase.metadataCopy {
+			reqV2.Header.Set("X-Amz-Metadata-Directive", "COPY")
+		}
+		if testCase.metadataGarbage {
+			reqV2.Header.Set("X-Amz-Metadata-Directive", "Unknown")
+		}
+
 		err = signRequestV2(reqV2, testCase.accessKey, testCase.secretKey)
 
 		if err != nil {

cmd/xl-v1-metadata.go

@@ -311,6 +311,14 @@ func deleteAllXLMetadata(disks []StorageAPI, bucket, prefix string, errs []error
 	wg.Wait()
 }
 
+// Rename `xl.json` content to destination location for each disk in order.
+func renameXLMetadata(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, quorum int) error {
+	isDir := false
+	srcXLJSON := path.Join(srcEntry, xlMetaJSONFile)
+	dstXLJSON := path.Join(dstEntry, xlMetaJSONFile)
+	return rename(disks, srcBucket, srcXLJSON, dstBucket, dstXLJSON, isDir, quorum)
+}
+
 // writeUniqueXLMetadata - writes unique `xl.json` content for each disk in order.
 func writeUniqueXLMetadata(disks []StorageAPI, bucket, prefix string, xlMetas []xlMetaV1, quorum int) error {
 	var wg = &sync.WaitGroup{}

cmd/xl-v1-object.go

@@ -42,13 +42,105 @@ var objectOpIgnoredErrs = []error{
 
 /// Object Operations
 
+// CopyObject - copy object source object to destination object.
+// if source object and destination object are same we only
+// update metadata.
+func (xl xlObjects) CopyObject(srcBucket, srcObject, dstBucket, dstObject string, metadata map[string]string) (ObjectInfo, error) {
+	// Read metadata associated with the object from all disks.
+	metaArr, errs := readAllXLMetadata(xl.storageDisks, srcBucket, srcObject)
+	// Do we have read quorum?
+	if !isDiskQuorum(errs, xl.readQuorum) {
+		return ObjectInfo{}, traceError(InsufficientReadQuorum{}, errs...)
+	}
+
+	if reducedErr := reduceReadQuorumErrs(errs, objectOpIgnoredErrs, xl.readQuorum); reducedErr != nil {
+		return ObjectInfo{}, toObjectErr(reducedErr, srcBucket, srcObject)
+	}
+
+	// List all online disks.
+	onlineDisks, modTime := listOnlineDisks(xl.storageDisks, metaArr, errs)
+
+	// Pick latest valid metadata.
+	xlMeta, err := pickValidXLMeta(metaArr, modTime)
+	if err != nil {
+		return ObjectInfo{}, toObjectErr(err, srcBucket, srcObject)
+	}
+
+	// Reorder online disks based on erasure distribution order.
+	onlineDisks = getOrderedDisks(xlMeta.Erasure.Distribution, onlineDisks)
+
+	// Length of the file to read.
+	length := xlMeta.Stat.Size
+
+	// Check if this request is only metadata update.
+	cpMetadataOnly := strings.EqualFold(pathJoin(srcBucket, srcObject), pathJoin(dstBucket, dstObject))
+	if cpMetadataOnly {
+		xlMeta.Meta = metadata
+		partsMetadata := make([]xlMetaV1, len(xl.storageDisks))
+		// Update `xl.json` content on each disks.
+		for index := range partsMetadata {
+			partsMetadata[index] = xlMeta
+		}
+
+		tempObj := mustGetUUID()
+
+		// Write unique `xl.json` for each disk.
+		if err = writeUniqueXLMetadata(onlineDisks, minioMetaTmpBucket, tempObj, partsMetadata, xl.writeQuorum); err != nil {
+			return ObjectInfo{}, toObjectErr(err, srcBucket, srcObject)
+		}
+		// Rename atomically `xl.json` from tmp location to destination for each disk.
+		if err = renameXLMetadata(onlineDisks, minioMetaTmpBucket, tempObj, srcBucket, srcObject, xl.writeQuorum); err != nil {
+			return ObjectInfo{}, toObjectErr(err, srcBucket, srcObject)
+		}
+
+		objInfo := ObjectInfo{
+			IsDir:           false,
+			Bucket:          srcBucket,
+			Name:            srcObject,
+			Size:            xlMeta.Stat.Size,
+			ModTime:         xlMeta.Stat.ModTime,
+			MD5Sum:          xlMeta.Meta["md5Sum"],
+			ContentType:     xlMeta.Meta["content-type"],
+			ContentEncoding: xlMeta.Meta["content-encoding"],
+		}
+		// md5Sum has already been extracted into objInfo.MD5Sum.  We
+		// need to remove it from xlMetaMap to avoid it from appearing as
+		// part of response headers. e.g, X-Minio-* or X-Amz-*.
+		delete(xlMeta.Meta, "md5Sum")
+		objInfo.UserDefined = xlMeta.Meta
+		return objInfo, nil
+	}
+
+	// Initialize pipe.
+	pipeReader, pipeWriter := io.Pipe()
+
+	go func() {
+		startOffset := int64(0) // Read the whole file.
+		if gerr := xl.GetObject(srcBucket, srcObject, startOffset, length, pipeWriter); gerr != nil {
+			errorIf(gerr, "Unable to read %s of the object `%s/%s`.", srcBucket, srcObject)
+			pipeWriter.CloseWithError(toObjectErr(gerr, srcBucket, srcObject))
+			return
+		}
+		pipeWriter.Close() // Close writer explicitly signalling we wrote all data.
+	}()
+
+	objInfo, err := xl.PutObject(dstBucket, dstObject, length, pipeReader, metadata, "")
+	if err != nil {
+		return ObjectInfo{}, toObjectErr(err, dstBucket, dstObject)
+	}
+
+	// Explicitly close the reader.
+	pipeReader.Close()
+
+	return objInfo, nil
+}
+
 // GetObject - reads an object erasured coded across multiple
 // disks. Supports additional parameters like offset and length
-// which is synonymous with HTTP Range requests.
+// which are synonymous with HTTP Range requests.
 //
-// startOffset indicates the location at which the client requested
+// startOffset indicates the starting read location of the object.
-// object to be read at. length indicates the total length of the
+// length indicates the total length of the object.
-// object requested by client.
 func (xl xlObjects) GetObject(bucket, object string, startOffset int64, length int64, writer io.Writer) error {
 	if err := checkGetObjArgs(bucket, object); err != nil {
 		return err
@@ -255,13 +347,13 @@ func (xl xlObjects) getObjectInfo(bucket, object string) (objInfo ObjectInfo, er
 	return objInfo, nil
 }
 
-func undoRename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, isPart bool, errs []error) {
+func undoRename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, isDir bool, errs []error) {
 	var wg = &sync.WaitGroup{}
 	// Undo rename object on disks where RenameFile succeeded.
 
 	// If srcEntry/dstEntry are objects then add a trailing slash to copy
 	// over all the parts inside the object directory
-	if !isPart {
+	if isDir {
 		srcEntry = retainSlash(srcEntry)
 		dstEntry = retainSlash(dstEntry)
 	}
@@ -284,14 +376,14 @@ func undoRename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry str
 
 // rename - common function that renamePart and renameObject use to rename
 // the respective underlying storage layer representations.
-func rename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, isPart bool, quorum int) error {
+func rename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, isDir bool, quorum int) error {
 	// Initialize sync waitgroup.
 	var wg = &sync.WaitGroup{}
 
 	// Initialize list of errors.
 	var errs = make([]error, len(disks))
 
-	if !isPart {
+	if isDir {
 		dstEntry = retainSlash(dstEntry)
 		srcEntry = retainSlash(srcEntry)
 	}
@@ -319,7 +411,7 @@ func rename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string,
 	// otherwise return failure. Cleanup successful renames.
 	if !isDiskQuorum(errs, quorum) {
 		// Undo all the partial rename operations.
-		undoRename(disks, srcBucket, srcEntry, dstBucket, dstEntry, isPart, errs)
+		undoRename(disks, srcBucket, srcEntry, dstBucket, dstEntry, isDir, errs)
 		return traceError(errXLWriteQuorum)
 	}
 	return reduceWriteQuorumErrs(errs, objectOpIgnoredErrs, quorum)
@@ -330,8 +422,8 @@ func rename(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string,
 // not have a readQuorum partially renamed files are renamed back to
 // its proper location.
 func renamePart(disks []StorageAPI, srcBucket, srcPart, dstBucket, dstPart string, quorum int) error {
-	isPart := true
+	isDir := false
-	return rename(disks, srcBucket, srcPart, dstBucket, dstPart, isPart, quorum)
+	return rename(disks, srcBucket, srcPart, dstBucket, dstPart, isDir, quorum)
 }
 
 // renameObject - renames all source objects to destination object
@@ -339,8 +431,8 @@ func renamePart(disks []StorageAPI, srcBucket, srcPart, dstBucket, dstPart strin
 // not have a readQuorum partially renamed files are renamed back to
 // its proper location.
 func renameObject(disks []StorageAPI, srcBucket, srcObject, dstBucket, dstObject string, quorum int) error {
-	isPart := false
+	isDir := true
-	return rename(disks, srcBucket, srcObject, dstBucket, dstObject, isPart, quorum)
+	return rename(disks, srcBucket, srcObject, dstBucket, dstObject, isDir, quorum)
 }
 
 // PutObject - creates an object upon reading from the input stream