diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/discard_logger.go b/vendor/github.com/coreos/etcd/pkg/logutil/discard_logger.go
new file mode 100644
index 0000000..81b0a9d
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/discard_logger.go
@@ -0,0 +1,46 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"log"
+
+	"google.golang.org/grpc/grpclog"
+)
+
+// assert that "discardLogger" satisfy "Logger" interface
+var _ Logger = &discardLogger{}
+
+// NewDiscardLogger returns a new Logger that discards everything except "fatal".
+func NewDiscardLogger() Logger { return &discardLogger{} }
+
+type discardLogger struct{}
+
+func (l *discardLogger) Info(args ...interface{})                    {}
+func (l *discardLogger) Infoln(args ...interface{})                  {}
+func (l *discardLogger) Infof(format string, args ...interface{})    {}
+func (l *discardLogger) Warning(args ...interface{})                 {}
+func (l *discardLogger) Warningln(args ...interface{})               {}
+func (l *discardLogger) Warningf(format string, args ...interface{}) {}
+func (l *discardLogger) Error(args ...interface{})                   {}
+func (l *discardLogger) Errorln(args ...interface{})                 {}
+func (l *discardLogger) Errorf(format string, args ...interface{})   {}
+func (l *discardLogger) Fatal(args ...interface{})                   { log.Fatal(args...) }
+func (l *discardLogger) Fatalln(args ...interface{})                 { log.Fatalln(args...) }
+func (l *discardLogger) Fatalf(format string, args ...interface{})   { log.Fatalf(format, args...) }
+func (l *discardLogger) V(lvl int) bool {
+	return false
+}
+func (l *discardLogger) Lvl(lvl int) grpclog.LoggerV2 { return l }
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/doc.go b/vendor/github.com/coreos/etcd/pkg/logutil/doc.go
new file mode 100644
index 0000000..e919f24
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 logutil includes utilities to facilitate logging.
+package logutil
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/log_level.go b/vendor/github.com/coreos/etcd/pkg/logutil/log_level.go
new file mode 100644
index 0000000..d57e173
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/log_level.go
@@ -0,0 +1,70 @@
+// Copyright 2019 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"fmt"
+
+	"github.com/coreos/pkg/capnslog"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+var DefaultLogLevel = "info"
+
+// ConvertToZapLevel converts log level string to zapcore.Level.
+func ConvertToZapLevel(lvl string) zapcore.Level {
+	switch lvl {
+	case "debug":
+		return zap.DebugLevel
+	case "info":
+		return zap.InfoLevel
+	case "warn":
+		return zap.WarnLevel
+	case "error":
+		return zap.ErrorLevel
+	case "dpanic":
+		return zap.DPanicLevel
+	case "panic":
+		return zap.PanicLevel
+	case "fatal":
+		return zap.FatalLevel
+	default:
+		panic(fmt.Sprintf("unknown level %q", lvl))
+	}
+}
+
+// ConvertToCapnslogLogLevel convert log level string to capnslog.LogLevel.
+// TODO: deprecate this in 3.5
+func ConvertToCapnslogLogLevel(lvl string) capnslog.LogLevel {
+	switch lvl {
+	case "debug":
+		return capnslog.DEBUG
+	case "info":
+		return capnslog.INFO
+	case "warn":
+		return capnslog.WARNING
+	case "error":
+		return capnslog.ERROR
+	case "dpanic":
+		return capnslog.CRITICAL
+	case "panic":
+		return capnslog.CRITICAL
+	case "fatal":
+		return capnslog.CRITICAL
+	default:
+		panic(fmt.Sprintf("unknown level %q", lvl))
+	}
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/logger.go b/vendor/github.com/coreos/etcd/pkg/logutil/logger.go
new file mode 100644
index 0000000..e7da80e
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/logger.go
@@ -0,0 +1,64 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 logutil
+
+import "google.golang.org/grpc/grpclog"
+
+// Logger defines logging interface.
+// TODO: deprecate in v3.5.
+type Logger interface {
+	grpclog.LoggerV2
+
+	// Lvl returns logger if logger's verbosity level >= "lvl".
+	// Otherwise, logger that discards everything.
+	Lvl(lvl int) grpclog.LoggerV2
+}
+
+// assert that "defaultLogger" satisfy "Logger" interface
+var _ Logger = &defaultLogger{}
+
+// NewLogger wraps "grpclog.LoggerV2" that implements "Logger" interface.
+//
+// For example:
+//
+//  var defaultLogger Logger
+//  g := grpclog.NewLoggerV2WithVerbosity(os.Stderr, os.Stderr, os.Stderr, 4)
+//  defaultLogger = NewLogger(g)
+//
+func NewLogger(g grpclog.LoggerV2) Logger { return &defaultLogger{g: g} }
+
+type defaultLogger struct {
+	g grpclog.LoggerV2
+}
+
+func (l *defaultLogger) Info(args ...interface{})                    { l.g.Info(args...) }
+func (l *defaultLogger) Infoln(args ...interface{})                  { l.g.Info(args...) }
+func (l *defaultLogger) Infof(format string, args ...interface{})    { l.g.Infof(format, args...) }
+func (l *defaultLogger) Warning(args ...interface{})                 { l.g.Warning(args...) }
+func (l *defaultLogger) Warningln(args ...interface{})               { l.g.Warning(args...) }
+func (l *defaultLogger) Warningf(format string, args ...interface{}) { l.g.Warningf(format, args...) }
+func (l *defaultLogger) Error(args ...interface{})                   { l.g.Error(args...) }
+func (l *defaultLogger) Errorln(args ...interface{})                 { l.g.Error(args...) }
+func (l *defaultLogger) Errorf(format string, args ...interface{})   { l.g.Errorf(format, args...) }
+func (l *defaultLogger) Fatal(args ...interface{})                   { l.g.Fatal(args...) }
+func (l *defaultLogger) Fatalln(args ...interface{})                 { l.g.Fatal(args...) }
+func (l *defaultLogger) Fatalf(format string, args ...interface{})   { l.g.Fatalf(format, args...) }
+func (l *defaultLogger) V(lvl int) bool                              { return l.g.V(lvl) }
+func (l *defaultLogger) Lvl(lvl int) grpclog.LoggerV2 {
+	if l.g.V(lvl) {
+		return l
+	}
+	return &discardLogger{}
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/merge_logger.go b/vendor/github.com/coreos/etcd/pkg/logutil/merge_logger.go
new file mode 100644
index 0000000..866b6f7
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/merge_logger.go
@@ -0,0 +1,194 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/coreos/pkg/capnslog"
+)
+
+var (
+	defaultMergePeriod     = time.Second
+	defaultTimeOutputScale = 10 * time.Millisecond
+
+	outputInterval = time.Second
+)
+
+// line represents a log line that can be printed out
+// through capnslog.PackageLogger.
+type line struct {
+	level capnslog.LogLevel
+	str   string
+}
+
+func (l line) append(s string) line {
+	return line{
+		level: l.level,
+		str:   l.str + " " + s,
+	}
+}
+
+// status represents the merge status of a line.
+type status struct {
+	period time.Duration
+
+	start time.Time // start time of latest merge period
+	count int       // number of merged lines from starting
+}
+
+func (s *status) isInMergePeriod(now time.Time) bool {
+	return s.period == 0 || s.start.Add(s.period).After(now)
+}
+
+func (s *status) isEmpty() bool { return s.count == 0 }
+
+func (s *status) summary(now time.Time) string {
+	ts := s.start.Round(defaultTimeOutputScale)
+	took := now.Round(defaultTimeOutputScale).Sub(ts)
+	return fmt.Sprintf("[merged %d repeated lines in %s]", s.count, took)
+}
+
+func (s *status) reset(now time.Time) {
+	s.start = now
+	s.count = 0
+}
+
+// MergeLogger supports merge logging, which merges repeated log lines
+// and prints summary log lines instead.
+//
+// For merge logging, MergeLogger prints out the line when the line appears
+// at the first time. MergeLogger holds the same log line printed within
+// defaultMergePeriod, and prints out summary log line at the end of defaultMergePeriod.
+// It stops merging when the line doesn't appear within the
+// defaultMergePeriod.
+type MergeLogger struct {
+	*capnslog.PackageLogger
+
+	mu      sync.Mutex // protect statusm
+	statusm map[line]*status
+}
+
+func NewMergeLogger(logger *capnslog.PackageLogger) *MergeLogger {
+	l := &MergeLogger{
+		PackageLogger: logger,
+		statusm:       make(map[line]*status),
+	}
+	go l.outputLoop()
+	return l
+}
+
+func (l *MergeLogger) MergeInfo(entries ...interface{}) {
+	l.merge(line{
+		level: capnslog.INFO,
+		str:   fmt.Sprint(entries...),
+	})
+}
+
+func (l *MergeLogger) MergeInfof(format string, args ...interface{}) {
+	l.merge(line{
+		level: capnslog.INFO,
+		str:   fmt.Sprintf(format, args...),
+	})
+}
+
+func (l *MergeLogger) MergeNotice(entries ...interface{}) {
+	l.merge(line{
+		level: capnslog.NOTICE,
+		str:   fmt.Sprint(entries...),
+	})
+}
+
+func (l *MergeLogger) MergeNoticef(format string, args ...interface{}) {
+	l.merge(line{
+		level: capnslog.NOTICE,
+		str:   fmt.Sprintf(format, args...),
+	})
+}
+
+func (l *MergeLogger) MergeWarning(entries ...interface{}) {
+	l.merge(line{
+		level: capnslog.WARNING,
+		str:   fmt.Sprint(entries...),
+	})
+}
+
+func (l *MergeLogger) MergeWarningf(format string, args ...interface{}) {
+	l.merge(line{
+		level: capnslog.WARNING,
+		str:   fmt.Sprintf(format, args...),
+	})
+}
+
+func (l *MergeLogger) MergeError(entries ...interface{}) {
+	l.merge(line{
+		level: capnslog.ERROR,
+		str:   fmt.Sprint(entries...),
+	})
+}
+
+func (l *MergeLogger) MergeErrorf(format string, args ...interface{}) {
+	l.merge(line{
+		level: capnslog.ERROR,
+		str:   fmt.Sprintf(format, args...),
+	})
+}
+
+func (l *MergeLogger) merge(ln line) {
+	l.mu.Lock()
+
+	// increase count if the logger is merging the line
+	if status, ok := l.statusm[ln]; ok {
+		status.count++
+		l.mu.Unlock()
+		return
+	}
+
+	// initialize status of the line
+	l.statusm[ln] = &status{
+		period: defaultMergePeriod,
+		start:  time.Now(),
+	}
+	// release the lock before IO operation
+	l.mu.Unlock()
+	// print out the line at its first time
+	l.PackageLogger.Logf(ln.level, ln.str)
+}
+
+func (l *MergeLogger) outputLoop() {
+	for now := range time.Tick(outputInterval) {
+		var outputs []line
+
+		l.mu.Lock()
+		for ln, status := range l.statusm {
+			if status.isInMergePeriod(now) {
+				continue
+			}
+			if status.isEmpty() {
+				delete(l.statusm, ln)
+				continue
+			}
+			outputs = append(outputs, ln.append(status.summary(now)))
+			status.reset(now)
+		}
+		l.mu.Unlock()
+
+		for _, o := range outputs {
+			l.PackageLogger.Logf(o.level, o.str)
+		}
+	}
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/package_logger.go b/vendor/github.com/coreos/etcd/pkg/logutil/package_logger.go
new file mode 100644
index 0000000..378bee0
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/package_logger.go
@@ -0,0 +1,60 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"github.com/coreos/pkg/capnslog"
+	"google.golang.org/grpc/grpclog"
+)
+
+// assert that "packageLogger" satisfy "Logger" interface
+var _ Logger = &packageLogger{}
+
+// NewPackageLogger wraps "*capnslog.PackageLogger" that implements "Logger" interface.
+//
+// For example:
+//
+//  var defaultLogger Logger
+//  defaultLogger = NewPackageLogger("github.com/coreos/etcd", "snapshot")
+//
+func NewPackageLogger(repo, pkg string) Logger {
+	return &packageLogger{p: capnslog.NewPackageLogger(repo, pkg)}
+}
+
+type packageLogger struct {
+	p *capnslog.PackageLogger
+}
+
+func (l *packageLogger) Info(args ...interface{})                    { l.p.Info(args...) }
+func (l *packageLogger) Infoln(args ...interface{})                  { l.p.Info(args...) }
+func (l *packageLogger) Infof(format string, args ...interface{})    { l.p.Infof(format, args...) }
+func (l *packageLogger) Warning(args ...interface{})                 { l.p.Warning(args...) }
+func (l *packageLogger) Warningln(args ...interface{})               { l.p.Warning(args...) }
+func (l *packageLogger) Warningf(format string, args ...interface{}) { l.p.Warningf(format, args...) }
+func (l *packageLogger) Error(args ...interface{})                   { l.p.Error(args...) }
+func (l *packageLogger) Errorln(args ...interface{})                 { l.p.Error(args...) }
+func (l *packageLogger) Errorf(format string, args ...interface{})   { l.p.Errorf(format, args...) }
+func (l *packageLogger) Fatal(args ...interface{})                   { l.p.Fatal(args...) }
+func (l *packageLogger) Fatalln(args ...interface{})                 { l.p.Fatal(args...) }
+func (l *packageLogger) Fatalf(format string, args ...interface{})   { l.p.Fatalf(format, args...) }
+func (l *packageLogger) V(lvl int) bool {
+	return l.p.LevelAt(capnslog.LogLevel(lvl))
+}
+func (l *packageLogger) Lvl(lvl int) grpclog.LoggerV2 {
+	if l.p.LevelAt(capnslog.LogLevel(lvl)) {
+		return l
+	}
+	return &discardLogger{}
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/zap.go b/vendor/github.com/coreos/etcd/pkg/logutil/zap.go
new file mode 100644
index 0000000..2f69223
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/zap.go
@@ -0,0 +1,97 @@
+// Copyright 2019 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"sort"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+// DefaultZapLoggerConfig defines default zap logger configuration.
+var DefaultZapLoggerConfig = zap.Config{
+	Level: zap.NewAtomicLevelAt(ConvertToZapLevel(DefaultLogLevel)),
+
+	Development: false,
+	Sampling: &zap.SamplingConfig{
+		Initial:    100,
+		Thereafter: 100,
+	},
+
+	Encoding: "json",
+
+	// copied from "zap.NewProductionEncoderConfig" with some updates
+	EncoderConfig: zapcore.EncoderConfig{
+		TimeKey:        "ts",
+		LevelKey:       "level",
+		NameKey:        "logger",
+		CallerKey:      "caller",
+		MessageKey:     "msg",
+		StacktraceKey:  "stacktrace",
+		LineEnding:     zapcore.DefaultLineEnding,
+		EncodeLevel:    zapcore.LowercaseLevelEncoder,
+		EncodeTime:     zapcore.ISO8601TimeEncoder,
+		EncodeDuration: zapcore.StringDurationEncoder,
+		EncodeCaller:   zapcore.ShortCallerEncoder,
+	},
+
+	// Use "/dev/null" to discard all
+	OutputPaths:      []string{"stderr"},
+	ErrorOutputPaths: []string{"stderr"},
+}
+
+// AddOutputPaths adds output paths to the existing output paths, resolving conflicts.
+func AddOutputPaths(cfg zap.Config, outputPaths, errorOutputPaths []string) zap.Config {
+	outputs := make(map[string]struct{})
+	for _, v := range cfg.OutputPaths {
+		outputs[v] = struct{}{}
+	}
+	for _, v := range outputPaths {
+		outputs[v] = struct{}{}
+	}
+	outputSlice := make([]string, 0)
+	if _, ok := outputs["/dev/null"]; ok {
+		// "/dev/null" to discard all
+		outputSlice = []string{"/dev/null"}
+	} else {
+		for k := range outputs {
+			outputSlice = append(outputSlice, k)
+		}
+	}
+	cfg.OutputPaths = outputSlice
+	sort.Strings(cfg.OutputPaths)
+
+	errOutputs := make(map[string]struct{})
+	for _, v := range cfg.ErrorOutputPaths {
+		errOutputs[v] = struct{}{}
+	}
+	for _, v := range errorOutputPaths {
+		errOutputs[v] = struct{}{}
+	}
+	errOutputSlice := make([]string, 0)
+	if _, ok := errOutputs["/dev/null"]; ok {
+		// "/dev/null" to discard all
+		errOutputSlice = []string{"/dev/null"}
+	} else {
+		for k := range errOutputs {
+			errOutputSlice = append(errOutputSlice, k)
+		}
+	}
+	cfg.ErrorOutputPaths = errOutputSlice
+	sort.Strings(cfg.ErrorOutputPaths)
+
+	return cfg
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/zap_grpc.go b/vendor/github.com/coreos/etcd/pkg/logutil/zap_grpc.go
new file mode 100644
index 0000000..3f48d81
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/zap_grpc.go
@@ -0,0 +1,111 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"google.golang.org/grpc/grpclog"
+)
+
+// NewGRPCLoggerV2 converts "*zap.Logger" to "grpclog.LoggerV2".
+// It discards all INFO level logging in gRPC, if debug level
+// is not enabled in "*zap.Logger".
+func NewGRPCLoggerV2(lcfg zap.Config) (grpclog.LoggerV2, error) {
+	lg, err := lcfg.Build(zap.AddCallerSkip(1)) // to annotate caller outside of "logutil"
+	if err != nil {
+		return nil, err
+	}
+	return &zapGRPCLogger{lg: lg, sugar: lg.Sugar()}, nil
+}
+
+// NewGRPCLoggerV2FromZapCore creates "grpclog.LoggerV2" from "zap.Core"
+// and "zapcore.WriteSyncer". It discards all INFO level logging in gRPC,
+// if debug level is not enabled in "*zap.Logger".
+func NewGRPCLoggerV2FromZapCore(cr zapcore.Core, syncer zapcore.WriteSyncer) grpclog.LoggerV2 {
+	// "AddCallerSkip" to annotate caller outside of "logutil"
+	lg := zap.New(cr, zap.AddCaller(), zap.AddCallerSkip(1), zap.ErrorOutput(syncer))
+	return &zapGRPCLogger{lg: lg, sugar: lg.Sugar()}
+}
+
+type zapGRPCLogger struct {
+	lg    *zap.Logger
+	sugar *zap.SugaredLogger
+}
+
+func (zl *zapGRPCLogger) Info(args ...interface{}) {
+	if !zl.lg.Core().Enabled(zapcore.DebugLevel) {
+		return
+	}
+	zl.sugar.Info(args...)
+}
+
+func (zl *zapGRPCLogger) Infoln(args ...interface{}) {
+	if !zl.lg.Core().Enabled(zapcore.DebugLevel) {
+		return
+	}
+	zl.sugar.Info(args...)
+}
+
+func (zl *zapGRPCLogger) Infof(format string, args ...interface{}) {
+	if !zl.lg.Core().Enabled(zapcore.DebugLevel) {
+		return
+	}
+	zl.sugar.Infof(format, args...)
+}
+
+func (zl *zapGRPCLogger) Warning(args ...interface{}) {
+	zl.sugar.Warn(args...)
+}
+
+func (zl *zapGRPCLogger) Warningln(args ...interface{}) {
+	zl.sugar.Warn(args...)
+}
+
+func (zl *zapGRPCLogger) Warningf(format string, args ...interface{}) {
+	zl.sugar.Warnf(format, args...)
+}
+
+func (zl *zapGRPCLogger) Error(args ...interface{}) {
+	zl.sugar.Error(args...)
+}
+
+func (zl *zapGRPCLogger) Errorln(args ...interface{}) {
+	zl.sugar.Error(args...)
+}
+
+func (zl *zapGRPCLogger) Errorf(format string, args ...interface{}) {
+	zl.sugar.Errorf(format, args...)
+}
+
+func (zl *zapGRPCLogger) Fatal(args ...interface{}) {
+	zl.sugar.Fatal(args...)
+}
+
+func (zl *zapGRPCLogger) Fatalln(args ...interface{}) {
+	zl.sugar.Fatal(args...)
+}
+
+func (zl *zapGRPCLogger) Fatalf(format string, args ...interface{}) {
+	zl.sugar.Fatalf(format, args...)
+}
+
+func (zl *zapGRPCLogger) V(l int) bool {
+	// infoLog == 0
+	if l <= 0 { // debug level, then we ignore info level in gRPC
+		return !zl.lg.Core().Enabled(zapcore.DebugLevel)
+	}
+	return true
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/zap_journal.go b/vendor/github.com/coreos/etcd/pkg/logutil/zap_journal.go
new file mode 100644
index 0000000..b1788bc
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/zap_journal.go
@@ -0,0 +1,92 @@
+// Copyright 2018 The etcd Authors
+//
+// 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.
+
+// +build !windows
+
+package logutil
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/coreos/etcd/pkg/systemd"
+
+	"github.com/coreos/go-systemd/journal"
+	"go.uber.org/zap/zapcore"
+)
+
+// NewJournalWriter wraps "io.Writer" to redirect log output
+// to the local systemd journal. If journald send fails, it fails
+// back to writing to the original writer.
+// The decode overhead is only <30µs per write.
+// Reference: https://github.com/coreos/pkg/blob/master/capnslog/journald_formatter.go
+func NewJournalWriter(wr io.Writer) (io.Writer, error) {
+	return &journalWriter{Writer: wr}, systemd.DialJournal()
+}
+
+type journalWriter struct {
+	io.Writer
+}
+
+// WARN: assume that etcd uses default field names in zap encoder config
+// make sure to keep this up-to-date!
+type logLine struct {
+	Level  string `json:"level"`
+	Caller string `json:"caller"`
+}
+
+func (w *journalWriter) Write(p []byte) (int, error) {
+	line := &logLine{}
+	if err := json.NewDecoder(bytes.NewReader(p)).Decode(line); err != nil {
+		return 0, err
+	}
+
+	var pri journal.Priority
+	switch line.Level {
+	case zapcore.DebugLevel.String():
+		pri = journal.PriDebug
+	case zapcore.InfoLevel.String():
+		pri = journal.PriInfo
+
+	case zapcore.WarnLevel.String():
+		pri = journal.PriWarning
+	case zapcore.ErrorLevel.String():
+		pri = journal.PriErr
+
+	case zapcore.DPanicLevel.String():
+		pri = journal.PriCrit
+	case zapcore.PanicLevel.String():
+		pri = journal.PriCrit
+	case zapcore.FatalLevel.String():
+		pri = journal.PriCrit
+
+	default:
+		panic(fmt.Errorf("unknown log level: %q", line.Level))
+	}
+
+	err := journal.Send(string(p), pri, map[string]string{
+		"PACKAGE":           filepath.Dir(line.Caller),
+		"SYSLOG_IDENTIFIER": filepath.Base(os.Args[0]),
+	})
+	if err != nil {
+		// "journal" also falls back to stderr
+		// "fmt.Fprintln(os.Stderr, s)"
+		return w.Writer.Write(p)
+	}
+	return 0, nil
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/logutil/zap_raft.go b/vendor/github.com/coreos/etcd/pkg/logutil/zap_raft.go
new file mode 100644
index 0000000..012d688
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/logutil/zap_raft.go
@@ -0,0 +1,102 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 logutil
+
+import (
+	"errors"
+
+	"github.com/coreos/etcd/raft"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+// NewRaftLogger builds "raft.Logger" from "*zap.Config".
+func NewRaftLogger(lcfg *zap.Config) (raft.Logger, error) {
+	if lcfg == nil {
+		return nil, errors.New("nil zap.Config")
+	}
+	lg, err := lcfg.Build(zap.AddCallerSkip(1)) // to annotate caller outside of "logutil"
+	if err != nil {
+		return nil, err
+	}
+	return &zapRaftLogger{lg: lg, sugar: lg.Sugar()}, nil
+}
+
+// NewRaftLoggerZap converts "*zap.Logger" to "raft.Logger".
+func NewRaftLoggerZap(lg *zap.Logger) raft.Logger {
+	return &zapRaftLogger{lg: lg, sugar: lg.Sugar()}
+}
+
+// NewRaftLoggerFromZapCore creates "raft.Logger" from "zap.Core"
+// and "zapcore.WriteSyncer".
+func NewRaftLoggerFromZapCore(cr zapcore.Core, syncer zapcore.WriteSyncer) raft.Logger {
+	// "AddCallerSkip" to annotate caller outside of "logutil"
+	lg := zap.New(cr, zap.AddCaller(), zap.AddCallerSkip(1), zap.ErrorOutput(syncer))
+	return &zapRaftLogger{lg: lg, sugar: lg.Sugar()}
+}
+
+type zapRaftLogger struct {
+	lg    *zap.Logger
+	sugar *zap.SugaredLogger
+}
+
+func (zl *zapRaftLogger) Debug(args ...interface{}) {
+	zl.sugar.Debug(args...)
+}
+
+func (zl *zapRaftLogger) Debugf(format string, args ...interface{}) {
+	zl.sugar.Debugf(format, args...)
+}
+
+func (zl *zapRaftLogger) Error(args ...interface{}) {
+	zl.sugar.Error(args...)
+}
+
+func (zl *zapRaftLogger) Errorf(format string, args ...interface{}) {
+	zl.sugar.Errorf(format, args...)
+}
+
+func (zl *zapRaftLogger) Info(args ...interface{}) {
+	zl.sugar.Info(args...)
+}
+
+func (zl *zapRaftLogger) Infof(format string, args ...interface{}) {
+	zl.sugar.Infof(format, args...)
+}
+
+func (zl *zapRaftLogger) Warning(args ...interface{}) {
+	zl.sugar.Warn(args...)
+}
+
+func (zl *zapRaftLogger) Warningf(format string, args ...interface{}) {
+	zl.sugar.Warnf(format, args...)
+}
+
+func (zl *zapRaftLogger) Fatal(args ...interface{}) {
+	zl.sugar.Fatal(args...)
+}
+
+func (zl *zapRaftLogger) Fatalf(format string, args ...interface{}) {
+	zl.sugar.Fatalf(format, args...)
+}
+
+func (zl *zapRaftLogger) Panic(args ...interface{}) {
+	zl.sugar.Panic(args...)
+}
+
+func (zl *zapRaftLogger) Panicf(format string, args ...interface{}) {
+	zl.sugar.Panicf(format, args...)
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/systemd/doc.go b/vendor/github.com/coreos/etcd/pkg/systemd/doc.go
new file mode 100644
index 0000000..30e77ce
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/systemd/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 systemd provides utility functions for systemd.
+package systemd
diff --git a/vendor/github.com/coreos/etcd/pkg/systemd/journal.go b/vendor/github.com/coreos/etcd/pkg/systemd/journal.go
new file mode 100644
index 0000000..b861c69
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/systemd/journal.go
@@ -0,0 +1,29 @@
+// Copyright 2018 The etcd Authors
+//
+// 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 systemd
+
+import "net"
+
+// DialJournal returns no error if the process can dial journal socket.
+// Returns an error if dial failed, whichi indicates journald is not available
+// (e.g. run embedded etcd as docker daemon).
+// Reference: https://github.com/coreos/go-systemd/blob/master/journal/journal.go.
+func DialJournal() error {
+	conn, err := net.Dial("unixgram", "/run/systemd/journal/socket")
+	if conn != nil {
+		defer conn.Close()
+	}
+	return err
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/types/doc.go b/vendor/github.com/coreos/etcd/pkg/types/doc.go
new file mode 100644
index 0000000..de8ef0b
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/types/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 types declares various data types and implements type-checking
+// functions.
+package types
diff --git a/vendor/github.com/coreos/etcd/pkg/types/id.go b/vendor/github.com/coreos/etcd/pkg/types/id.go
new file mode 100644
index 0000000..1b042d9
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/types/id.go
@@ -0,0 +1,41 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 types
+
+import (
+	"strconv"
+)
+
+// ID represents a generic identifier which is canonically
+// stored as a uint64 but is typically represented as a
+// base-16 string for input/output
+type ID uint64
+
+func (i ID) String() string {
+	return strconv.FormatUint(uint64(i), 16)
+}
+
+// IDFromString attempts to create an ID from a base-16 string.
+func IDFromString(s string) (ID, error) {
+	i, err := strconv.ParseUint(s, 16, 64)
+	return ID(i), err
+}
+
+// IDSlice implements the sort interface
+type IDSlice []ID
+
+func (p IDSlice) Len() int           { return len(p) }
+func (p IDSlice) Less(i, j int) bool { return uint64(p[i]) < uint64(p[j]) }
+func (p IDSlice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
diff --git a/vendor/github.com/coreos/etcd/pkg/types/set.go b/vendor/github.com/coreos/etcd/pkg/types/set.go
new file mode 100644
index 0000000..c111b0c
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/types/set.go
@@ -0,0 +1,178 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 types
+
+import (
+	"reflect"
+	"sort"
+	"sync"
+)
+
+type Set interface {
+	Add(string)
+	Remove(string)
+	Contains(string) bool
+	Equals(Set) bool
+	Length() int
+	Values() []string
+	Copy() Set
+	Sub(Set) Set
+}
+
+func NewUnsafeSet(values ...string) *unsafeSet {
+	set := &unsafeSet{make(map[string]struct{})}
+	for _, v := range values {
+		set.Add(v)
+	}
+	return set
+}
+
+func NewThreadsafeSet(values ...string) *tsafeSet {
+	us := NewUnsafeSet(values...)
+	return &tsafeSet{us, sync.RWMutex{}}
+}
+
+type unsafeSet struct {
+	d map[string]struct{}
+}
+
+// Add adds a new value to the set (no-op if the value is already present)
+func (us *unsafeSet) Add(value string) {
+	us.d[value] = struct{}{}
+}
+
+// Remove removes the given value from the set
+func (us *unsafeSet) Remove(value string) {
+	delete(us.d, value)
+}
+
+// Contains returns whether the set contains the given value
+func (us *unsafeSet) Contains(value string) (exists bool) {
+	_, exists = us.d[value]
+	return exists
+}
+
+// ContainsAll returns whether the set contains all given values
+func (us *unsafeSet) ContainsAll(values []string) bool {
+	for _, s := range values {
+		if !us.Contains(s) {
+			return false
+		}
+	}
+	return true
+}
+
+// Equals returns whether the contents of two sets are identical
+func (us *unsafeSet) Equals(other Set) bool {
+	v1 := sort.StringSlice(us.Values())
+	v2 := sort.StringSlice(other.Values())
+	v1.Sort()
+	v2.Sort()
+	return reflect.DeepEqual(v1, v2)
+}
+
+// Length returns the number of elements in the set
+func (us *unsafeSet) Length() int {
+	return len(us.d)
+}
+
+// Values returns the values of the Set in an unspecified order.
+func (us *unsafeSet) Values() (values []string) {
+	values = make([]string, 0)
+	for val := range us.d {
+		values = append(values, val)
+	}
+	return values
+}
+
+// Copy creates a new Set containing the values of the first
+func (us *unsafeSet) Copy() Set {
+	cp := NewUnsafeSet()
+	for val := range us.d {
+		cp.Add(val)
+	}
+
+	return cp
+}
+
+// Sub removes all elements in other from the set
+func (us *unsafeSet) Sub(other Set) Set {
+	oValues := other.Values()
+	result := us.Copy().(*unsafeSet)
+
+	for _, val := range oValues {
+		if _, ok := result.d[val]; !ok {
+			continue
+		}
+		delete(result.d, val)
+	}
+
+	return result
+}
+
+type tsafeSet struct {
+	us *unsafeSet
+	m  sync.RWMutex
+}
+
+func (ts *tsafeSet) Add(value string) {
+	ts.m.Lock()
+	defer ts.m.Unlock()
+	ts.us.Add(value)
+}
+
+func (ts *tsafeSet) Remove(value string) {
+	ts.m.Lock()
+	defer ts.m.Unlock()
+	ts.us.Remove(value)
+}
+
+func (ts *tsafeSet) Contains(value string) (exists bool) {
+	ts.m.RLock()
+	defer ts.m.RUnlock()
+	return ts.us.Contains(value)
+}
+
+func (ts *tsafeSet) Equals(other Set) bool {
+	ts.m.RLock()
+	defer ts.m.RUnlock()
+	return ts.us.Equals(other)
+}
+
+func (ts *tsafeSet) Length() int {
+	ts.m.RLock()
+	defer ts.m.RUnlock()
+	return ts.us.Length()
+}
+
+func (ts *tsafeSet) Values() (values []string) {
+	ts.m.RLock()
+	defer ts.m.RUnlock()
+	return ts.us.Values()
+}
+
+func (ts *tsafeSet) Copy() Set {
+	ts.m.RLock()
+	defer ts.m.RUnlock()
+	usResult := ts.us.Copy().(*unsafeSet)
+	return &tsafeSet{usResult, sync.RWMutex{}}
+}
+
+func (ts *tsafeSet) Sub(other Set) Set {
+	ts.m.RLock()
+	defer ts.m.RUnlock()
+	usResult := ts.us.Sub(other).(*unsafeSet)
+	return &tsafeSet{usResult, sync.RWMutex{}}
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/types/slice.go b/vendor/github.com/coreos/etcd/pkg/types/slice.go
new file mode 100644
index 0000000..0dd9ca7
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/types/slice.go
@@ -0,0 +1,22 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 types
+
+// Uint64Slice implements sort interface
+type Uint64Slice []uint64
+
+func (p Uint64Slice) Len() int           { return len(p) }
+func (p Uint64Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p Uint64Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
diff --git a/vendor/github.com/coreos/etcd/pkg/types/urls.go b/vendor/github.com/coreos/etcd/pkg/types/urls.go
new file mode 100644
index 0000000..9e5d03f
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/types/urls.go
@@ -0,0 +1,82 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 types
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/url"
+	"sort"
+	"strings"
+)
+
+type URLs []url.URL
+
+func NewURLs(strs []string) (URLs, error) {
+	all := make([]url.URL, len(strs))
+	if len(all) == 0 {
+		return nil, errors.New("no valid URLs given")
+	}
+	for i, in := range strs {
+		in = strings.TrimSpace(in)
+		u, err := url.Parse(in)
+		if err != nil {
+			return nil, err
+		}
+		if u.Scheme != "http" && u.Scheme != "https" && u.Scheme != "unix" && u.Scheme != "unixs" {
+			return nil, fmt.Errorf("URL scheme must be http, https, unix, or unixs: %s", in)
+		}
+		if _, _, err := net.SplitHostPort(u.Host); err != nil {
+			return nil, fmt.Errorf(`URL address does not have the form "host:port": %s`, in)
+		}
+		if u.Path != "" {
+			return nil, fmt.Errorf("URL must not contain a path: %s", in)
+		}
+		all[i] = *u
+	}
+	us := URLs(all)
+	us.Sort()
+
+	return us, nil
+}
+
+func MustNewURLs(strs []string) URLs {
+	urls, err := NewURLs(strs)
+	if err != nil {
+		panic(err)
+	}
+	return urls
+}
+
+func (us URLs) String() string {
+	return strings.Join(us.StringSlice(), ",")
+}
+
+func (us *URLs) Sort() {
+	sort.Sort(us)
+}
+func (us URLs) Len() int           { return len(us) }
+func (us URLs) Less(i, j int) bool { return us[i].String() < us[j].String() }
+func (us URLs) Swap(i, j int)      { us[i], us[j] = us[j], us[i] }
+
+func (us URLs) StringSlice() []string {
+	out := make([]string, len(us))
+	for i := range us {
+		out[i] = us[i].String()
+	}
+
+	return out
+}
diff --git a/vendor/github.com/coreos/etcd/pkg/types/urlsmap.go b/vendor/github.com/coreos/etcd/pkg/types/urlsmap.go
new file mode 100644
index 0000000..47690cc
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/types/urlsmap.go
@@ -0,0 +1,107 @@
+// Copyright 2015 The etcd Authors
+//
+// 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 types
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// URLsMap is a map from a name to its URLs.
+type URLsMap map[string]URLs
+
+// NewURLsMap returns a URLsMap instantiated from the given string,
+// which consists of discovery-formatted names-to-URLs, like:
+// mach0=http://1.1.1.1:2380,mach0=http://2.2.2.2::2380,mach1=http://3.3.3.3:2380,mach2=http://4.4.4.4:2380
+func NewURLsMap(s string) (URLsMap, error) {
+	m := parse(s)
+
+	cl := URLsMap{}
+	for name, urls := range m {
+		us, err := NewURLs(urls)
+		if err != nil {
+			return nil, err
+		}
+		cl[name] = us
+	}
+	return cl, nil
+}
+
+// NewURLsMapFromStringMap takes a map of strings and returns a URLsMap. The
+// string values in the map can be multiple values separated by the sep string.
+func NewURLsMapFromStringMap(m map[string]string, sep string) (URLsMap, error) {
+	var err error
+	um := URLsMap{}
+	for k, v := range m {
+		um[k], err = NewURLs(strings.Split(v, sep))
+		if err != nil {
+			return nil, err
+		}
+	}
+	return um, nil
+}
+
+// String turns URLsMap into discovery-formatted name-to-URLs sorted by name.
+func (c URLsMap) String() string {
+	var pairs []string
+	for name, urls := range c {
+		for _, url := range urls {
+			pairs = append(pairs, fmt.Sprintf("%s=%s", name, url.String()))
+		}
+	}
+	sort.Strings(pairs)
+	return strings.Join(pairs, ",")
+}
+
+// URLs returns a list of all URLs.
+// The returned list is sorted in ascending lexicographical order.
+func (c URLsMap) URLs() []string {
+	var urls []string
+	for _, us := range c {
+		for _, u := range us {
+			urls = append(urls, u.String())
+		}
+	}
+	sort.Strings(urls)
+	return urls
+}
+
+// Len returns the size of URLsMap.
+func (c URLsMap) Len() int {
+	return len(c)
+}
+
+// parse parses the given string and returns a map listing the values specified for each key.
+func parse(s string) map[string][]string {
+	m := make(map[string][]string)
+	for s != "" {
+		key := s
+		if i := strings.IndexAny(key, ","); i >= 0 {
+			key, s = key[:i], key[i+1:]
+		} else {
+			s = ""
+		}
+		if key == "" {
+			continue
+		}
+		value := ""
+		if i := strings.Index(key, "="); i >= 0 {
+			key, value = key[:i], key[i+1:]
+		}
+		m[key] = append(m[key], value)
+	}
+	return m
+}