Bring back original NewZapCoreLoggerBuilder api. (#12973)

The funcion signature has been changed in:
eafbc8c57efc716644c328f63677ca7eadeebdfe .
Instead we should have added new method `NewZapLoggerBuilder()`.

CHANGELOG-3.5.md

@@ -71,8 +71,10 @@ See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0...v3.5.0) and
 - [ETCD_CLIENT_DEBUG env](https://github.com/etcd-io/etcd/pull/12786): Now supports log levels (debug, info, warn, error, dpanic, panic, fatal). Only when set, overrides application-wide grpc logging settings.
 - [Embed Etcd.Close()](https://github.com/etcd-io/etcd/pull/12828) needs to called exactly once and closes Etcd.Err() stream.
 - [Embed Etcd does not override global/grpc logger](https://github.com/etcd-io/etcd/pull/12861) be default any longer. If desired, please call `embed.Config::SetupGlobalLoggers()` explicitly. 
+- [Embed Etcd custom logger should be configured using simpler builder `NewZapLoggerBuilder`](https://github.com/etcd-io/etcd/pull/12973).
 - Client errors of `context cancelled` or `context deadline exceeded` are exposed as `codes.Canceled` and `codes.DeadlineExceeded`, instead of `codes.Unknown`.
 
+
 ### Storage format changes
 - [WAL log's snapshots persists raftpb.ConfState](https://github.com/etcd-io/etcd/pull/12735)
 - [Backend persists raftpb.ConfState](https://github.com/etcd-io/etcd/pull/12962) in the `meta` bucket `confState` key.

server/embed/config_logging.go

@@ -103,16 +103,11 @@ func (cfg *Config) setupLogging() error {
 			copied = logutil.MergeOutputPaths(copied)
 			copied.Level = zap.NewAtomicLevelAt(logutil.ConvertToZapLevel(cfg.LogLevel))
 			if cfg.ZapLoggerBuilder == nil {
-				cfg.ZapLoggerBuilder = func(c *Config) error {
+				lg, err := copied.Build()
-					c.loggerMu.Lock()
-					defer c.loggerMu.Unlock()
-					var err error
-					c.logger, err = copied.Build()
 				if err != nil {
 					return err
 				}
-					return nil
+				cfg.ZapLoggerBuilder = NewZapLoggerBuilder(lg)
-				}
 			}
 		} else {
 			if len(cfg.LogOutputs) > 1 {
@@ -139,12 +134,7 @@ func (cfg *Config) setupLogging() error {
 				lvl,
 			)
 			if cfg.ZapLoggerBuilder == nil {
-				cfg.ZapLoggerBuilder = func(c *Config) error {
+				cfg.ZapLoggerBuilder = NewZapLoggerBuilder(zap.New(cr, zap.AddCaller(), zap.ErrorOutput(syncer)))
-					c.loggerMu.Lock()
-					defer c.loggerMu.Unlock()
-					c.logger = zap.New(cr, zap.AddCaller(), zap.ErrorOutput(syncer))
-					return nil
-				}
 			}
 		}
 
@@ -190,8 +180,9 @@ func (cfg *Config) setupLogging() error {
 	return nil
 }
 
-// NewZapCoreLoggerBuilder generates a zap core logger builder.
+// NewZapLoggerBuilder generates a zap logger builder that sets given loger
-func NewZapCoreLoggerBuilder(lg *zap.Logger) func(*Config) error {
+// for embedded etcd.
+func NewZapLoggerBuilder(lg *zap.Logger) func(*Config) error {
 	return func(cfg *Config) error {
 		cfg.loggerMu.Lock()
 		defer cfg.loggerMu.Unlock()
@@ -200,6 +191,12 @@ func NewZapCoreLoggerBuilder(lg *zap.Logger) func(*Config) error {
 	}
 }
 
+// NewZapCoreLoggerBuilder - is a deprecated setter for the logger.
+// Deprecated: Use simpler NewZapLoggerBuilder. To be removed in etcd-3.6.
+func NewZapCoreLoggerBuilder(lg *zap.Logger, _ zapcore.Core, _ zapcore.WriteSyncer) func(*Config) error {
+	return NewZapLoggerBuilder(lg)
+}
+
 // SetupGlobalLoggers configures 'global' loggers (grpc, zapGlobal) based on the cfg.
 //
 // The method is not executed by embed server by default (since 3.5) to

tests/integration/testing.go

@@ -67,7 +67,7 @@ func NewEmbedConfig(t testing.TB, name string) *embed.Config {
 	cfg := embed.NewConfig()
 	cfg.Name = name
 	lg := zaptest.NewLogger(t, zaptest.Level(zapcore.InfoLevel)).Named(cfg.Name)
-	cfg.ZapLoggerBuilder = embed.NewZapCoreLoggerBuilder(lg)
+	cfg.ZapLoggerBuilder = embed.NewZapLoggerBuilder(lg)
 	cfg.Dir = t.TempDir()
 	return cfg
 }