refactor: enhance logger module

logger/encoder.go

@@ -25,9 +25,9 @@ func getGid() uint64 {
 
 // getCaller calculate relative source path of caller.
 func getCaller(ec zapcore.EntryCaller, verbose bool) string {
-	file, err := filepath.Rel(logHandle.path, ec.File)
+	file, err := filepath.Rel(project, ec.File)
 	if err != nil {
-		return "undefined"
+		return "unknown"
 	}
 	if verbose {
 		return file + ":" + strconv.Itoa(ec.Line)
@@ -46,24 +46,23 @@ func timeEncoder(t time.Time, enc zapcore.PrimitiveArrayEncoder) {
 func timeColoredEncoder(t time.Time, enc zapcore.PrimitiveArrayEncoder) {
 	enc.AppendString(fmt.Sprintf(
 		"%s %s",
-		color.Cyan.Render(logHandle.prefix), // colored prefix
+		color.Cyan.Render(logger.prefix), // colored prefix
 		color.Gray.Render(t.Format("2006-01-02 15:04:05.000")),
 	))
 }
 
 // callerEncoder formats caller in square brackets.
 func callerEncoder(ec zapcore.EntryCaller, enc zapcore.PrimitiveArrayEncoder) {
-	if !logHandle.verbose {
+	if !logger.verbose {
 		enc.AppendString("[" + getCaller(ec, false) + "]")
 		return
 	}
 	enc.AppendString(fmt.Sprintf("[%d] [%s]", getGid(), getCaller(ec, true)))
 }
 
-// callerColoredEncoder formats caller in square brackets with
-// magenta color.
+// callerColoredEncoder formats caller in square brackets with magenta color.
 func callerColoredEncoder(ec zapcore.EntryCaller, enc zapcore.PrimitiveArrayEncoder) {
-	if !logHandle.verbose {
+	if !logger.verbose {
 		enc.AppendString(color.Magenta.Render("[" + getCaller(ec, false) + "]"))
 		return
 	}
@@ -79,8 +78,8 @@ func levelEncoder(level zapcore.Level, enc zapcore.PrimitiveArrayEncoder) {
 	enc.AppendString("[" + level.CapitalString() + "]")
 }
 
-// levelColoredEncoder formats log level using square brackets
-// and uses different colors.
+// levelColoredEncoder formats log level using square brackets and uses
+// different colors.
 func levelColoredEncoder(level zapcore.Level, enc zapcore.PrimitiveArrayEncoder) {
 	levelStr := "[" + level.CapitalString() + "]"
 	switch level {

logger/interface.go

@@ -14,46 +14,50 @@ const (
 )
 
 func Debugf(template string, args ...interface{}) {
-	logHandle.sugar.Debugf(template, args...)
+	logger.entry.Debugf(template, args...)
 }
 
 func Infof(template string, args ...interface{}) {
-	logHandle.sugar.Infof(template, args...)
+	logger.entry.Infof(template, args...)
 }
 
 func Warnf(template string, args ...interface{}) {
-	logHandle.sugar.Warnf(template, args...)
+	logger.entry.Warnf(template, args...)
 }
 
 func Errorf(template string, args ...interface{}) {
-	logHandle.sugar.Errorf(template, args...)
+	logger.entry.Errorf(template, args...)
 }
 
 func Panicf(template string, args ...interface{}) {
-	logHandle.sugar.Panicf(template, args...)
+	logger.entry.Panicf(template, args...)
 }
 
 // GetLevel return the current logger level.
 func GetLevel() zapcore.Level {
-	return logHandle.level.Level()
+	return logger.level.Level()
 }
 
-// SetLevel configure logger output level. Note that debug level
-// will output more information and reduce performance.
+// SetLevel configure logger output level. Note that debug level will output
+// more information and reduce performance.
 func SetLevel(level zapcore.Level) {
-	logHandle.level.SetLevel(level)
+	logger.level.SetLevel(level)
 	if level == DebugLevel {
-		logHandle.verbose = true
+		logger.verbose = true
 	} else {
-		logHandle.verbose = false
+		logger.verbose = false
 	}
 }
 
-// AddOutputs adds more plain output channel to the logger module.
-func AddOutputs(outputs ...io.Writer) {
-	var writers []zapcore.WriteSyncer
-	for _, output := range outputs {
-		writers = append(writers, zapcore.AddSync(output))
+// AddWriters add more writers to target log channel.
+func AddWriters(colored bool, writers ...io.Writer) {
+	var syncWriters []zapcore.WriteSyncer
+	for _, writer := range writers {
+		syncWriters = append(syncWriters, zapcore.AddSync(writer))
+	}
+	if !colored {
+		logger.addPlainWrites(syncWriters...)
+	} else {
+		logger.addColoredWrites(syncWriters...)
 	}
-	addWrites(writers...)
 }

logger/logger.go

@@ -8,21 +8,44 @@ import (
 	"runtime"
 )
 
-type logger struct {
-	logger  *zap.Logger
-	level   *zap.AtomicLevel
-	sugar   *zap.SugaredLogger
+var project string  // project absolute path
+var logger *logCore // singleton logger handle
+
+// logChannel handle multiple writers with unified format.
+type logChannel struct {
+	encoder zapcore.Encoder
 	writers []zapcore.WriteSyncer
-	stderr  zapcore.Core // fixed stderr output
-	prefix  string       // custom output prefix
-	path    string       // project absolute path
-	verbose bool         // show goroutine id and caller line
 }
 
-var logHandle *logger // singleton logger handle
+// logCore manage log level, channels and other interfaces.
+type logCore struct {
+	prefix  string // custom output prefix
+	verbose bool   // show verbose information
+
+	plain   logChannel // log channel with plain text
+	colored logChannel // log channel with colored text
+
+	level *zap.AtomicLevel   // zap log level pointer
+	entry *zap.SugaredLogger // zap sugared logger entry
+}
+
+func init() {
+	_, src, _, _ := runtime.Caller(0) // absolute path of current code
+	project = path.Join(path.Dir(src), "../")
 
-// logConfig generates log config for XProxy.
-func logConfig(colored bool) zapcore.EncoderConfig {
+	zapLevel := zap.NewAtomicLevelAt(InfoLevel) // using info level in default
+	logger = &logCore{
+		verbose: false,
+		level:   &zapLevel,
+		prefix:  "[XProxy]",
+		plain:   buildChannel(false),
+		colored: buildChannel(true),
+	}
+	logger.addColoredWrites(os.Stderr) // output into stderr in default
+}
+
+// buildChannel generate logChannel with `colored` option.
+func buildChannel(colored bool) logChannel {
 	config := zapcore.EncoderConfig{
 		ConsoleSeparator: " ",
 		MessageKey:       "msg",
@@ -33,46 +56,40 @@ func logConfig(colored bool) zapcore.EncoderConfig {
 		EncodeLevel:      levelEncoder,
 		EncodeCaller:     callerEncoder,
 	}
-	if colored {
+	if colored { // using colored version
 		config.EncodeTime = timeColoredEncoder
 		config.EncodeLevel = levelColoredEncoder
 		config.EncodeCaller = callerColoredEncoder
 	}
-	return config
+	return logChannel{
+		encoder: zapcore.NewConsoleEncoder(config),
+		writers: []zapcore.WriteSyncer{}, // without any writer
+	}
 }
 
-func init() {
-	zapLevel := zap.NewAtomicLevelAt(InfoLevel) // using info level in default
-	zapCore := zapcore.NewCore(
-		zapcore.NewConsoleEncoder(logConfig(true)), // colorful output
-		zapcore.Lock(os.Stderr),
-		zapLevel,
-	)
-	zapLogger := zap.New(zapCore, zap.AddCaller(), zap.AddCallerSkip(1))
-	_, src, _, _ := runtime.Caller(0) // absolute path of current code
-	logHandle = &logger{
-		logger:  zapLogger,
-		level:   &zapLevel,
-		stderr:  zapCore,
-		sugar:   zapLogger.Sugar(),
-		writers: []zapcore.WriteSyncer{},
-		path:    path.Join(path.Dir(src), "../"),
-		prefix:  "[XProxy]",
-		verbose: false,
+// update refreshes the binding of the log core to the writers.
+func (handle *logCore) update() {
+	buildCore := func(channel *logChannel) zapcore.Core { // build zap core from logChannel
+		return zapcore.NewCore(
+			channel.encoder,
+			zap.CombineWriteSyncers(channel.writers...),
+			handle.level,
+		)
 	}
+	handle.entry = zap.New(
+		zapcore.NewTee(buildCore(&handle.plain), buildCore(&handle.colored)),
+		zap.AddCaller(), zap.AddCallerSkip(1),
+	).Sugar()
 }
 
-// addWrites adds more plain log writers.
-func addWrites(writers ...zapcore.WriteSyncer) {
-	logHandle.writers = append(logHandle.writers, writers...)
-	plainCore := zapcore.NewCore(
-		zapcore.NewConsoleEncoder(logConfig(false)), // without colored
-		zap.CombineWriteSyncers(logHandle.writers...),
-		logHandle.level,
-	)
-	logHandle.logger = zap.New(
-		zapcore.NewTee(logHandle.stderr, plainCore),
-		zap.AddCaller(), zap.AddCallerSkip(1),
-	)
-	logHandle.sugar = logHandle.logger.Sugar()
+// addPlainWrites adds plain text writers to the logCore.
+func (handle *logCore) addPlainWrites(writers ...zapcore.WriteSyncer) {
+	handle.plain.writers = append(handle.plain.writers, writers...)
+	handle.update()
+}
+
+// addColoredWrites adds colored text writers to the logCore.
+func (handle *logCore) addColoredWrites(writers ...zapcore.WriteSyncer) {
+	handle.colored.writers = append(handle.colored.writers, writers...)
+	handle.update()
 }

main.go

@@ -6,6 +6,8 @@ import (
 )
 
 func main() {
+	//logger.SetLevel(zap.DebugLevel)
+
 	//logger.Debugf("here is %s level", "debug")
 	//logger.Infof("here is %s level", "info")
 	//logger.Warnf("here is %s level", "warn")
@@ -19,13 +21,13 @@ func main() {
 	logger.Debugf("output msg 1 at debug")
 	logger.Infof("output msg 1 at info")
 	logger.Warnf("output msg 1 at warn")
-	logger.AddOutputs(fp1, fp2)
+	logger.AddWriters(false, fp1, fp2)
 	logger.SetLevel(logger.InfoLevel)
 	logger.Debugf("output msg 2 at debug")
 	logger.Infof("output msg 2 at info")
 	logger.Warnf("output msg 2 at warn")
 	logger.SetLevel(logger.WarnLevel)
-	logger.AddOutputs(fp3)
+	logger.AddWriters(true, fp3)
 	logger.Debugf("output msg 3 at debug")
 	logger.Infof("output msg 3 at info")
 	logger.Warnf("output msg 3 at warn")