Update federation target to etcd/clientv3 (#6119)

With CoreDNS now supporting etcdv3 as the DNS backend, we
can update our federation target to etcdv3. Users will now be
able to use etcdv3 server as the federation backbone.

Minio will update bucket data to etcdv3 and CoreDNS can pick
that data up and serve it as bucket style DNS path.

vendor/google.golang.org/grpc/grpclog/logger.go

@@ -1,52 +1,26 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * 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
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 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 grpclog defines logging for grpc.
-*/
-package grpclog // import "google.golang.org/grpc/grpclog"
-
-import (
-	"log"
-	"os"
-)
-
-// Use golang's standard logger by default.
-// Access is not mutex-protected: do not modify except in init()
-// functions.
-var logger Logger = log.New(os.Stderr, "", log.LstdFlags)
+package grpclog
 
 // Logger mimics golang's standard Logger as an interface.
+//
+// Deprecated: use LoggerV2.
 type Logger interface {
 	Fatal(args ...interface{})
 	Fatalf(format string, args ...interface{})
@@ -58,36 +32,54 @@ type Logger interface {
 
 // SetLogger sets the logger that is used in grpc. Call only from
 // init() functions.
+//
+// Deprecated: use SetLoggerV2.
 func SetLogger(l Logger) {
-	logger = l
+	logger = &loggerWrapper{Logger: l}
 }
 
-// Fatal is equivalent to Print() followed by a call to os.Exit() with a non-zero exit code.
-func Fatal(args ...interface{}) {
-	logger.Fatal(args...)
+// loggerWrapper wraps Logger into a LoggerV2.
+type loggerWrapper struct {
+	Logger
 }
 
-// Fatalf is equivalent to Printf() followed by a call to os.Exit() with a non-zero exit code.
-func Fatalf(format string, args ...interface{}) {
-	logger.Fatalf(format, args...)
+func (g *loggerWrapper) Info(args ...interface{}) {
+	g.Logger.Print(args...)
 }
 
-// Fatalln is equivalent to Println() followed by a call to os.Exit()) with a non-zero exit code.
-func Fatalln(args ...interface{}) {
-	logger.Fatalln(args...)
+func (g *loggerWrapper) Infoln(args ...interface{}) {
+	g.Logger.Println(args...)
 }
 
-// Print prints to the logger. Arguments are handled in the manner of fmt.Print.
-func Print(args ...interface{}) {
-	logger.Print(args...)
+func (g *loggerWrapper) Infof(format string, args ...interface{}) {
+	g.Logger.Printf(format, args...)
 }
 
-// Printf prints to the logger. Arguments are handled in the manner of fmt.Printf.
-func Printf(format string, args ...interface{}) {
-	logger.Printf(format, args...)
+func (g *loggerWrapper) Warning(args ...interface{}) {
+	g.Logger.Print(args...)
 }
 
-// Println prints to the logger. Arguments are handled in the manner of fmt.Println.
-func Println(args ...interface{}) {
-	logger.Println(args...)
+func (g *loggerWrapper) Warningln(args ...interface{}) {
+	g.Logger.Println(args...)
+}
+
+func (g *loggerWrapper) Warningf(format string, args ...interface{}) {
+	g.Logger.Printf(format, args...)
+}
+
+func (g *loggerWrapper) Error(args ...interface{}) {
+	g.Logger.Print(args...)
+}
+
+func (g *loggerWrapper) Errorln(args ...interface{}) {
+	g.Logger.Println(args...)
+}
+
+func (g *loggerWrapper) Errorf(format string, args ...interface{}) {
+	g.Logger.Printf(format, args...)
+}
+
+func (g *loggerWrapper) V(l int) bool {
+	// Returns true for all verbose level.
+	return true
 }