Add errorIf for all API handlers to print call trace upon errors

server-api-bucket-handlers.go

@@ -30,6 +30,7 @@ func (api MinioAPI) isValidOp(w http.ResponseWriter, req *http.Request, acceptsC
 
 	bucketMetadata, err := api.Donut.GetBucketMetadata(bucket, nil)
 	if err != nil {
+		errorIf(err.Trace(), "GetBucketMetadata failed.", nil)
 		switch err.ToGoError().(type) {
 		case donut.BucketNotFound:
 			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
@@ -38,7 +39,6 @@ func (api MinioAPI) isValidOp(w http.ResponseWriter, req *http.Request, acceptsC
 			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
 			return false
 		default:
-			// log.Error.Println(err.Trace())
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return false
 		}
@@ -100,31 +100,32 @@ func (api MinioAPI) ListMultipartUploadsHandler(w http.ResponseWriter, req *http
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	resources, err := api.Donut.ListMultipartUploads(bucket, resources, signature)
-	if err == nil {
+	if err != nil {
-		// generate response
+		errorIf(err.Trace(), "ListMultipartUploads failed.", nil)
-		response := generateListMultipartUploadsResponse(bucket, resources)
+		switch err.ToGoError().(type) {
-		encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
+		case donut.SignatureDoesNotMatch:
-		// write headers
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-		setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
+		case donut.BucketNotFound:
-		// write body
+			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
-		w.Write(encodedSuccessResponse)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	// generate response
-	case donut.SignatureDoesNotMatch:
+	response := generateListMultipartUploadsResponse(bucket, resources)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+	encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
-	case donut.BucketNotFound:
+	// write headers
-		writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
+	setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
-	default:
+	// write body
-		// log.Error.Println(err.Trace())
+	w.Write(encodedSuccessResponse)
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // ListObjectsHandler - GET Bucket (List Objects)
@@ -171,6 +172,7 @@ func (api MinioAPI) ListObjectsHandler(w http.ResponseWriter, req *http.Request)
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
@@ -199,7 +201,7 @@ func (api MinioAPI) ListObjectsHandler(w http.ResponseWriter, req *http.Request)
 	case donut.ObjectNameInvalid:
 		writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
 	default:
-		// log.Error.Println(err.Trace())
+		errorIf(err.Trace(), "ListObjects failed.", nil)
 		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 	}
 }
@@ -232,6 +234,7 @@ func (api MinioAPI) ListBucketsHandler(w http.ResponseWriter, req *http.Request)
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
@@ -252,7 +255,7 @@ func (api MinioAPI) ListBucketsHandler(w http.ResponseWriter, req *http.Request)
 	case donut.SignatureDoesNotMatch:
 		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
 	default:
-		// log.Error.Println(err.Trace())
+		errorIf(err.Trace(), "ListBuckets failed.", nil)
 		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 	}
 }
@@ -298,6 +301,7 @@ func (api MinioAPI) PutBucketHandler(w http.ResponseWriter, req *http.Request) {
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
@@ -314,25 +318,25 @@ func (api MinioAPI) PutBucketHandler(w http.ResponseWriter, req *http.Request) {
 	}
 
 	err := api.Donut.MakeBucket(bucket, getACLTypeString(aclType), req.Body, signature)
-	if err == nil {
+	if err != nil {
-		// Make sure to add Location information here only for bucket
+		errorIf(err.Trace(), "MakeBucket failed.", nil)
-		w.Header().Set("Location", "/"+bucket)
+		switch err.ToGoError().(type) {
-		writeSuccessResponse(w, acceptsContentType)
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.TooManyBuckets:
+			writeErrorResponse(w, req, TooManyBuckets, acceptsContentType, req.URL.Path)
+		case donut.BucketNameInvalid:
+			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
+		case donut.BucketExists:
+			writeErrorResponse(w, req, BucketAlreadyExists, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	// Make sure to add Location information here only for bucket
-	case donut.SignatureDoesNotMatch:
+	w.Header().Set("Location", "/"+bucket)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+	writeSuccessResponse(w, acceptsContentType)
-	case donut.TooManyBuckets:
-		writeErrorResponse(w, req, TooManyBuckets, acceptsContentType, req.URL.Path)
-	case donut.BucketNameInvalid:
-		writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
-	case donut.BucketExists:
-		writeErrorResponse(w, req, BucketAlreadyExists, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // PutBucketACLHandler - PUT Bucket ACL
@@ -366,27 +370,28 @@ func (api MinioAPI) PutBucketACLHandler(w http.ResponseWriter, req *http.Request
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	err := api.Donut.SetBucketMetadata(bucket, map[string]string{"acl": getACLTypeString(aclType)}, signature)
-	if err == nil {
+	if err != nil {
-		writeSuccessResponse(w, acceptsContentType)
+		errorIf(err.Trace(), "PutBucketACL failed.", nil)
+		switch err.ToGoError().(type) {
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.BucketNameInvalid:
+			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
+		case donut.BucketNotFound:
+			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	writeSuccessResponse(w, acceptsContentType)
-	case donut.SignatureDoesNotMatch:
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.BucketNameInvalid:
-		writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
-	case donut.BucketNotFound:
-		writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // HeadBucketHandler - HEAD Bucket
@@ -416,25 +421,26 @@ func (api MinioAPI) HeadBucketHandler(w http.ResponseWriter, req *http.Request)
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	_, err := api.Donut.GetBucketMetadata(bucket, signature)
-	if err == nil {
+	if err != nil {
-		writeSuccessResponse(w, acceptsContentType)
+		errorIf(err.Trace(), "GetBucketMetadata failed.", nil)
+		switch err.ToGoError().(type) {
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.BucketNotFound:
+			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
+		case donut.BucketNameInvalid:
+			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	writeSuccessResponse(w, acceptsContentType)
-	case donut.SignatureDoesNotMatch:
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.BucketNotFound:
-		writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
-	case donut.BucketNameInvalid:
-		writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }

server-api-object-handlers.go

@@ -59,41 +59,41 @@ func (api MinioAPI) GetObjectHandler(w http.ResponseWriter, req *http.Request) {
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	metadata, err := api.Donut.GetObjectMetadata(bucket, object, signature)
-	if err == nil {
+	if err != nil {
-		var hrange *httpRange
+		errorIf(err.Trace(), "GetObject failed.", nil)
-		hrange, err = getRequestedRange(req.Header.Get("Range"), metadata.Size)
+		switch err.ToGoError().(type) {
-		if err != nil {
+		case donut.SignatureDoesNotMatch:
-			writeErrorResponse(w, req, InvalidRange, acceptsContentType, req.URL.Path)
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-			return
+		case donut.BucketNameInvalid:
-		}
+			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
-		setObjectHeaders(w, metadata, hrange)
+		case donut.BucketNotFound:
-		if _, err = api.Donut.GetObject(w, bucket, object, hrange.start, hrange.length); err != nil {
+			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
-			// unable to write headers, we've already printed data. Just close the connection.
+		case donut.ObjectNotFound:
-			// log.Error.Println(err.Trace())
+			writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
-			return
+		case donut.ObjectNameInvalid:
+			writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	var hrange *httpRange
-	case donut.SignatureDoesNotMatch:
+	hrange, err = getRequestedRange(req.Header.Get("Range"), metadata.Size)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+	if err != nil {
-	case donut.BucketNameInvalid:
+		writeErrorResponse(w, req, InvalidRange, acceptsContentType, req.URL.Path)
-		writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
+		return
-	case donut.BucketNotFound:
+	}
-		writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
+	setObjectHeaders(w, metadata, hrange)
-	case donut.ObjectNotFound:
+	if _, err = api.Donut.GetObject(w, bucket, object, hrange.start, hrange.length); err != nil {
-		writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
+		errorIf(err.Trace(), "GetObject failed.", nil)
-	case donut.ObjectNameInvalid:
+		return
-		writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 	}
 }
 
@@ -126,32 +126,33 @@ func (api MinioAPI) HeadObjectHandler(w http.ResponseWriter, req *http.Request)
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	metadata, err := api.Donut.GetObjectMetadata(bucket, object, signature)
-	if err == nil {
+	if err != nil {
-		setObjectHeaders(w, metadata, nil)
+		errorIf(err.Trace(), "GetObjectMetadata failed.", nil)
-		w.WriteHeader(http.StatusOK)
+		switch err.ToGoError().(type) {
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.BucketNameInvalid:
+			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
+		case donut.BucketNotFound:
+			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
+		case donut.ObjectNotFound:
+			writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
+		case donut.ObjectNameInvalid:
+			writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	setObjectHeaders(w, metadata, nil)
-	case donut.SignatureDoesNotMatch:
+	w.WriteHeader(http.StatusOK)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.BucketNameInvalid:
-		writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
-	case donut.BucketNotFound:
-		writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
-	case donut.ObjectNotFound:
-		writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
-	case donut.ObjectNameInvalid:
-		writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // PutObjectHandler - PUT Object
@@ -220,40 +221,41 @@ func (api MinioAPI) PutObjectHandler(w http.ResponseWriter, req *http.Request) {
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	metadata, err := api.Donut.CreateObject(bucket, object, md5, sizeInt64, req.Body, nil, signature)
-	if err == nil {
+	if err != nil {
-		w.Header().Set("ETag", metadata.MD5Sum)
+		errorIf(err.Trace(), "CreateObject failed.", nil)
-		writeSuccessResponse(w, acceptsContentType)
+		switch err.ToGoError().(type) {
+		case donut.BucketNotFound:
+			writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
+		case donut.BucketNameInvalid:
+			writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
+		case donut.ObjectExists:
+			writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
+		case donut.BadDigest:
+			writeErrorResponse(w, req, BadDigest, acceptsContentType, req.URL.Path)
+		case donut.MissingDateHeader:
+			writeErrorResponse(w, req, RequestTimeTooSkewed, acceptsContentType, req.URL.Path)
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.IncompleteBody:
+			writeErrorResponse(w, req, IncompleteBody, acceptsContentType, req.URL.Path)
+		case donut.EntityTooLarge:
+			writeErrorResponse(w, req, EntityTooLarge, acceptsContentType, req.URL.Path)
+		case donut.InvalidDigest:
+			writeErrorResponse(w, req, InvalidDigest, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	w.Header().Set("ETag", metadata.MD5Sum)
-	case donut.BucketNotFound:
+	writeSuccessResponse(w, acceptsContentType)
-		writeErrorResponse(w, req, NoSuchBucket, acceptsContentType, req.URL.Path)
-	case donut.BucketNameInvalid:
-		writeErrorResponse(w, req, InvalidBucketName, acceptsContentType, req.URL.Path)
-	case donut.ObjectExists:
-		writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
-	case donut.BadDigest:
-		writeErrorResponse(w, req, BadDigest, acceptsContentType, req.URL.Path)
-	case donut.MissingDateHeader:
-		writeErrorResponse(w, req, RequestTimeTooSkewed, acceptsContentType, req.URL.Path)
-	case donut.SignatureDoesNotMatch:
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.IncompleteBody:
-		writeErrorResponse(w, req, IncompleteBody, acceptsContentType, req.URL.Path)
-	case donut.EntityTooLarge:
-		writeErrorResponse(w, req, EntityTooLarge, acceptsContentType, req.URL.Path)
-	case donut.InvalidDigest:
-		writeErrorResponse(w, req, InvalidDigest, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 /// Multipart API
@@ -290,30 +292,32 @@ func (api MinioAPI) NewMultipartUploadHandler(w http.ResponseWriter, req *http.R
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	uploadID, err := api.Donut.NewMultipartUpload(bucket, object, req.Header.Get("Content-Type"), signature)
-	if err == nil {
+	if err != nil {
-		response := generateInitiateMultipartUploadResponse(bucket, object, uploadID)
+		errorIf(err.Trace(), "NewMultipartUpload failed.", nil)
-		encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
+		switch err.ToGoError().(type) {
-		// write headers
+		case donut.SignatureDoesNotMatch:
-		setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-		// write body
+		case donut.ObjectExists:
-		w.Write(encodedSuccessResponse)
+			writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+
-	case donut.SignatureDoesNotMatch:
+	response := generateInitiateMultipartUploadResponse(bucket, object, uploadID)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+	encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
-	case donut.ObjectExists:
+	// write headers
-		writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
+	setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
-	default:
+	// write body
-		// log.Error.Println(err.Trace())
+	w.Write(encodedSuccessResponse)
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // PutObjectPartHandler - Upload part
@@ -375,6 +379,7 @@ func (api MinioAPI) PutObjectPartHandler(w http.ResponseWriter, req *http.Reques
 		partID, err = strconv.Atoi(partIDString)
 		if err != nil {
 			writeErrorResponse(w, req, InvalidPart, acceptsContentType, req.URL.Path)
+			return
 		}
 	}
 
@@ -384,36 +389,37 @@ func (api MinioAPI) PutObjectPartHandler(w http.ResponseWriter, req *http.Reques
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	calculatedMD5, err := api.Donut.CreateObjectPart(bucket, object, uploadID, partID, "", md5, sizeInt64, req.Body, signature)
-	if err == nil {
+	if err != nil {
-		w.Header().Set("ETag", calculatedMD5)
+		errorIf(err.Trace(), "CreateObjectPart failed.", nil)
-		writeSuccessResponse(w, acceptsContentType)
+		switch err.ToGoError().(type) {
+		case donut.InvalidUploadID:
+			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+		case donut.ObjectExists:
+			writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
+		case donut.BadDigest:
+			writeErrorResponse(w, req, BadDigest, acceptsContentType, req.URL.Path)
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.IncompleteBody:
+			writeErrorResponse(w, req, IncompleteBody, acceptsContentType, req.URL.Path)
+		case donut.EntityTooLarge:
+			writeErrorResponse(w, req, EntityTooLarge, acceptsContentType, req.URL.Path)
+		case donut.InvalidDigest:
+			writeErrorResponse(w, req, InvalidDigest, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	w.Header().Set("ETag", calculatedMD5)
-	case donut.InvalidUploadID:
+	writeSuccessResponse(w, acceptsContentType)
-		writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
-	case donut.ObjectExists:
-		writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
-	case donut.BadDigest:
-		writeErrorResponse(w, req, BadDigest, acceptsContentType, req.URL.Path)
-	case donut.SignatureDoesNotMatch:
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.IncompleteBody:
-		writeErrorResponse(w, req, IncompleteBody, acceptsContentType, req.URL.Path)
-	case donut.EntityTooLarge:
-		writeErrorResponse(w, req, EntityTooLarge, acceptsContentType, req.URL.Path)
-	case donut.InvalidDigest:
-		writeErrorResponse(w, req, InvalidDigest, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // AbortMultipartUploadHandler - Abort multipart upload
@@ -444,26 +450,27 @@ func (api MinioAPI) AbortMultipartUploadHandler(w http.ResponseWriter, req *http
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	err := api.Donut.AbortMultipartUpload(bucket, object, objectResourcesMetadata.UploadID, signature)
-	if err == nil {
+	if err != nil {
-		setCommonHeaders(w, getContentTypeString(acceptsContentType), 0)
+		errorIf(err.Trace(), "AbortMutlipartUpload failed.", nil)
-		w.WriteHeader(http.StatusNoContent)
+		switch err.ToGoError().(type) {
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.InvalidUploadID:
+			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	setCommonHeaders(w, getContentTypeString(acceptsContentType), 0)
-	case donut.SignatureDoesNotMatch:
+	w.WriteHeader(http.StatusNoContent)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.InvalidUploadID:
-		writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // ListObjectPartsHandler - List object parts
@@ -505,30 +512,31 @@ func (api MinioAPI) ListObjectPartsHandler(w http.ResponseWriter, req *http.Requ
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 
 	objectResourcesMetadata, err := api.Donut.ListObjectParts(bucket, object, objectResourcesMetadata, signature)
-	if err == nil {
+	if err != nil {
-		response := generateListPartsResponse(objectResourcesMetadata)
+		errorIf(err.Trace(), "ListObjectParts failed.", nil)
-		encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
+		switch err.ToGoError().(type) {
-		// write headers
+		case donut.SignatureDoesNotMatch:
-		setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-		// write body
+		case donut.InvalidUploadID:
-		w.Write(encodedSuccessResponse)
+			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	response := generateListPartsResponse(objectResourcesMetadata)
-	case donut.SignatureDoesNotMatch:
+	encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+	// write headers
-	case donut.InvalidUploadID:
+	setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
-		writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+	// write body
-	default:
+	w.Write(encodedSuccessResponse)
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 // CompleteMultipartUploadHandler - Complete multipart upload
@@ -559,39 +567,40 @@ func (api MinioAPI) CompleteMultipartUploadHandler(w http.ResponseWriter, req *h
 		var err *probe.Error
 		signature, err = initSignatureV4(req)
 		if err != nil {
+			errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 			return
 		}
 	}
 	metadata, err := api.Donut.CompleteMultipartUpload(bucket, object, objectResourcesMetadata.UploadID, req.Body, signature)
-	if err == nil {
+	if err != nil {
-		response := generateCompleteMultpartUploadResponse(bucket, object, "", metadata.MD5Sum)
+		errorIf(err.Trace(), "CompleteMultipartUpload failed.", nil)
-		encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
+		switch err.ToGoError().(type) {
-		// write headers
+		case donut.InvalidUploadID:
-		setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
+			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
-		// write body
+		case donut.InvalidPart:
-		w.Write(encodedSuccessResponse)
+			writeErrorResponse(w, req, InvalidPart, acceptsContentType, req.URL.Path)
+		case donut.InvalidPartOrder:
+			writeErrorResponse(w, req, InvalidPartOrder, acceptsContentType, req.URL.Path)
+		case donut.MissingDateHeader:
+			writeErrorResponse(w, req, RequestTimeTooSkewed, acceptsContentType, req.URL.Path)
+		case donut.SignatureDoesNotMatch:
+			writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
+		case donut.IncompleteBody:
+			writeErrorResponse(w, req, IncompleteBody, acceptsContentType, req.URL.Path)
+		case donut.MalformedXML:
+			writeErrorResponse(w, req, MalformedXML, acceptsContentType, req.URL.Path)
+		default:
+			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+		}
 		return
 	}
-	switch err.ToGoError().(type) {
+	response := generateCompleteMultpartUploadResponse(bucket, object, "", metadata.MD5Sum)
-	case donut.InvalidUploadID:
+	encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
-		writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+	// write headers
-	case donut.InvalidPart:
+	setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
-		writeErrorResponse(w, req, InvalidPart, acceptsContentType, req.URL.Path)
+	// write body
-	case donut.InvalidPartOrder:
+	w.Write(encodedSuccessResponse)
-		writeErrorResponse(w, req, InvalidPartOrder, acceptsContentType, req.URL.Path)
-	case donut.MissingDateHeader:
-		writeErrorResponse(w, req, RequestTimeTooSkewed, acceptsContentType, req.URL.Path)
-	case donut.SignatureDoesNotMatch:
-		writeErrorResponse(w, req, SignatureDoesNotMatch, acceptsContentType, req.URL.Path)
-	case donut.IncompleteBody:
-		writeErrorResponse(w, req, IncompleteBody, acceptsContentType, req.URL.Path)
-	case donut.MalformedXML:
-		writeErrorResponse(w, req, MalformedXML, acceptsContentType, req.URL.Path)
-	default:
-		// log.Error.Println(err.Trace())
-		writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
-	}
 }
 
 /// Delete API