bug & feat: replace the global default logger with custom logger

Fixes #467

client_unix.go

@@ -37,27 +37,28 @@ import (
 
 // Client of gnet.
 type Client struct {
-	opts     *Options
-	el       *eventloop
-	logFlush func() error
+	opts *Options
+	el   *eventloop
 }
 
 // NewClient creates an instance of Client.
 func NewClient(eh EventHandler, opts ...Option) (cli *Client, err error) {
 	options := loadOptions(opts...)
 	cli = new(Client)
 	cli.opts = options
-	var logger logging.Logger
-	if options.LogPath != "" {
-		if logger, cli.logFlush, err = logging.CreateLoggerAsLocalFile(options.LogPath, options.LogLevel); err != nil {
-			return
-		}
-	} else {
-		logger = logging.GetDefaultLogger()
-	}
+
+	logger, logFlusher := logging.GetDefaultLogger(), logging.GetDefaultFlusher()
 	if options.Logger == nil {
+		if options.LogPath != "" {
+			logger, logFlusher, _ = logging.CreateLoggerAsLocalFile(options.LogPath, options.LogLevel)
+		}
 		options.Logger = logger
+	} else {
+		logger = options.Logger
+		logFlusher = nil
 	}
+	logging.SetDefaultLoggerAndFlusher(logger, logFlusher)
+
 	var p *netpoll.Poller
 	if p, err = netpoll.OpenPoller(); err != nil {
 		return
@@ -130,9 +131,6 @@ func (cli *Client) Stop() (err error) {
 	_ = cli.el.engine.workerPool.Wait()
 	logging.Error(cli.el.poller.Close())
 	cli.el.eventHandler.OnShutdown(Engine{})
-	if cli.logFlush != nil {
-		err = cli.logFlush()
-	}
 	logging.Cleanup()
 	return
 }

gnet.go

@@ -429,28 +429,21 @@ var MaxStreamBufferCap = 64 * 1024 // 64KB
 func Run(eventHandler EventHandler, protoAddr string, opts ...Option) (err error) {
 	options := loadOptions(opts...)
 
-	logging.Debugf("default logging level is %s", logging.LogLevel())
-
-	var (
-		logger logging.Logger
-		flush  func() error
-	)
-	if options.LogPath != "" {
-		if logger, flush, err = logging.CreateLoggerAsLocalFile(options.LogPath, options.LogLevel); err != nil {
-			return
-		}
-	} else {
-		logger = logging.GetDefaultLogger()
-	}
+	logger, logFlusher := logging.GetDefaultLogger(), logging.GetDefaultFlusher()
 	if options.Logger == nil {
+		if options.LogPath != "" {
+			logger, logFlusher, _ = logging.CreateLoggerAsLocalFile(options.LogPath, options.LogLevel)
+		}
 		options.Logger = logger
+	} else {
+		logger = options.Logger
+		logFlusher = nil
 	}
-	defer func() {
-		if flush != nil {
-			_ = flush()
-		}
-		logging.Cleanup()
-	}()
+	logging.SetDefaultLoggerAndFlusher(logger, logFlusher)
+
+	defer logging.Cleanup()
+
+	logging.Debugf("default logging level is %s", logging.LogLevel())
 
 	// The maximum number of operating system threads that the Go program can use is initially set to 10000,
 	// which should also be the maximum amount of I/O event-loops locked to OS threads that users can start up.

pkg/logging/logger.go

@@ -50,17 +50,20 @@ import (
 	"errors"
 	"os"
 	"strconv"
+	"sync"
 
 	"go.uber.org/zap"
 	"go.uber.org/zap/buffer"
 	"go.uber.org/zap/zapcore"
 	"gopkg.in/natefinch/lumberjack.v2"
 )
 
+type Flusher = func() error
+
 var (
-	flushLogs           func() error
 	defaultLogger       Logger
 	defaultLoggingLevel Level
+	defaultFlusher      Flusher
 )
 
 // Level is the alias of zapcore.Level.
@@ -101,7 +104,7 @@ func init() {
 	fileName := os.Getenv("GNET_LOGGING_FILE")
 	if len(fileName) > 0 {
 		var err error
-		defaultLogger, flushLogs, err = CreateLoggerAsLocalFile(fileName, defaultLoggingLevel)
+		defaultLogger, defaultFlusher, err = CreateLoggerAsLocalFile(fileName, defaultLoggingLevel)
 		if err != nil {
 			panic("invalid GNET_LOGGING_FILE, " + err.Error())
 		}
@@ -169,6 +172,24 @@ func GetDefaultLogger() Logger {
 	return defaultLogger
 }
 
+// GetDefaultFlusher returns the default flusher.
+func GetDefaultFlusher() Flusher {
+	return defaultFlusher
+}
+
+var setupOnce sync.Once
+
+// SetDefaultLoggerAndFlusher sets the default logger and its flusher.
+//
+// Note that this function should only be called once at the
+// start of the program and not thereafter for the entire runtime,
+// otherwise it will only keep the first setup.
+func SetDefaultLoggerAndFlusher(logger Logger, flusher Flusher) {
+	setupOnce.Do(func() {
+		defaultLogger, defaultFlusher = logger, flusher
+	})
+}
+
 // LogLevel tells what the default logging level is.
 func LogLevel() string {
 	return defaultLoggingLevel.String()
@@ -204,8 +225,8 @@ func CreateLoggerAsLocalFile(localFilePath string, logLevel Level) (logger Logge
 
 // Cleanup does something windup for logger, like closing, flushing, etc.
 func Cleanup() {
-	if flushLogs != nil {
-		_ = flushLogs()
+	if defaultFlusher != nil {
+		_ = defaultFlusher()
 	}
 }