server: Use default logging configuration instead of zap production one

This fixes problem where logs json changes format of timestamp.

tests/functional/cmd/etcd-agent/main.go

@@ -18,6 +18,7 @@ package main
 import (
 	"flag"
 
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
 	"go.etcd.io/etcd/tests/v3/functional/agent"
 
 	"go.uber.org/zap"
@@ -27,7 +28,7 @@ var logger *zap.Logger
 
 func init() {
 	var err error
-	logger, err = zap.NewProduction()
+	logger, err = logutil.CreateDefaultZapLogger(zap.InfoLevel)
 	if err != nil {
 		panic(err)
 	}

tests/functional/cmd/etcd-proxy/main.go

@@ -28,6 +28,7 @@ import (
 	"syscall"
 	"time"
 
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
 	"go.etcd.io/etcd/pkg/v3/proxy"
 
 	"go.uber.org/zap"
@@ -76,7 +77,11 @@ $ ./bin/etcdctl --endpoints localhost:23790 put foo bar`)
 		To:   url.URL{Scheme: "tcp", Host: to},
 	}
 	if verbose {
-		cfg.Logger = zap.NewExample()
+		var err error
+		cfg.Logger, err = logutil.CreateDefaultZapLogger(zap.InfoLevel)
+		if err != nil {
+			panic(err)
+		}
 	}
 	p := proxy.NewServer(cfg)
 	<-p.Ready()

tests/functional/cmd/etcd-tester/main.go

@@ -19,6 +19,7 @@ import (
 	"flag"
 
 	_ "github.com/etcd-io/gofail/runtime"
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
 	"go.etcd.io/etcd/tests/v3/functional/tester"
 	"go.uber.org/zap"
 )
@@ -27,7 +28,7 @@ var logger *zap.Logger
 
 func init() {
 	var err error
-	logger, err = zap.NewProduction()
+	logger, err = logutil.CreateDefaultZapLogger(zap.InfoLevel)
 	if err != nil {
 		panic(err)
 	}

tests/functional/tester/cluster_test.go

@@ -19,6 +19,7 @@ import (
 	"sort"
 	"testing"
 
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
 	"go.etcd.io/etcd/tests/v3/functional/rpcpb"
 
 	"go.uber.org/zap"
@@ -256,7 +257,7 @@ func Test_read(t *testing.T) {
 		},
 	}
 
-	logger, err := zap.NewProduction()
+	logger, err := logutil.CreateDefaultZapLogger(zap.InfoLevel)
 	if err != nil {
 		t.Fatal(err)
 	}