improve handler feature for package glog

.example/os/glog/glog_CtxKeys.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"context"
+	"github.com/gogf/gf/frame/g"
+)
+
+func main() {
+	g.Log().SetCtxKeys("TraceId", "SpanId", "Test")
+	ctx := context.WithValue(context.Background(), "TraceId", "1234567890")
+	ctx = context.WithValue(ctx, "SpanId", "abcdefg")
+
+	g.Log().Ctx(ctx).Print(1, 2, 3)
+}

.example/os/glog/glog_SetConfigWithMap.go

@@ -6,7 +6,7 @@ import (
 )
 
 func main() {
-	err := glog.SetConfigWithMap(g.Map{
+	err := g.Log().SetConfigWithMap(g.Map{
 		"prefix": "[TEST]",
 	})
 	if err != nil {

.example/os/glog/glog_async_chaining.go

@@ -1,14 +1,13 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"time"
-
-	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
 	for i := 0; i < 10; i++ {
-		glog.Async().Print("async log", i)
+		g.Log().Async().Print("async log", i)
 	}
 	time.Sleep(time.Second)
 }

.example/os/glog/glog_async_configure.go

@@ -1,15 +1,14 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"time"
-
-	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
-	glog.SetAsync(true)
+	g.Log().SetAsync(true)
 	for i := 0; i < 10; i++ {
-		glog.Async().Print("async log", i)
+		g.Log().Print("async log", i)
 	}
 	time.Sleep(time.Second)
 }

.example/os/glog/glog_category.go

@@ -3,13 +3,12 @@ package main
 import (
 	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/os/gfile"
-	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
 	path := "/tmp/glog-cat"
-	glog.SetPath(path)
-	glog.Stdout(false).Cat("cat1").Cat("cat2").Println("test")
+	g.Log().SetPath(path)
+	g.Log().Stdout(false).Cat("cat1").Cat("cat2").Println("test")
 	list, err := gfile.ScanDir(path, "*", true)
 	g.Dump(err)
 	g.Dump(list)

.example/os/glog/glog_ctx.go

@@ -1,14 +0,0 @@
-package main
-
-import (
-	"context"
-	"github.com/gogf/gf/os/glog"
-)
-
-func main() {
-	glog.SetCtxKeys("Trace-Id", "Span-Id", "Test")
-	ctx := context.WithValue(context.Background(), "Trace-Id", "1234567890")
-	ctx = context.WithValue(ctx, "Span-Id", "abcdefg")
-
-	glog.Ctx(ctx).Print(1, 2, 3)
-}

.example/os/glog/glog_debug.go

@@ -1,19 +1,19 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"time"
 
-	"github.com/gogf/gf/os/glog"
 	"github.com/gogf/gf/os/gtime"
 	"github.com/gogf/gf/os/gtimer"
 )
 
 func main() {
 	gtimer.SetTimeout(3*time.Second, func() {
-		glog.SetDebug(false)
+		g.Log().SetDebug(false)
 	})
 	for {
-		glog.Debug(gtime.Datetime())
+		g.Log().Debug(gtime.Datetime())
 		time.Sleep(time.Second)
 	}
 }

.example/os/glog/glog_file.go

@@ -3,24 +3,25 @@ package main
 import (
 	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/os/gfile"
-	"github.com/gogf/gf/os/glog"
 )
 
 // 设置日志等级
 func main() {
-	l := glog.New()
 	path := "/tmp/glog"
-	l.SetPath(path)
-	l.SetStdoutPrint(false)
+	g.Log().SetPath(path)
+	g.Log().SetStdoutPrint(false)
+
 	// 使用默认文件名称格式
-	l.Println("标准文件名称格式，使用当前时间时期")
+	g.Log().Println("标准文件名称格式，使用当前时间时期")
+
 	// 通过SetFile设置文件名称格式
-	l.SetFile("stdout.log")
-	l.Println("设置日志输出文件名称格式为同一个文件")
+	g.Log().SetFile("stdout.log")
+	g.Log().Println("设置日志输出文件名称格式为同一个文件")
+
 	// 链式操作设置文件名称格式
-	l.File("stderr.log").Println("支持链式操作")
-	l.File("error-{Ymd}.log").Println("文件名称支持带gtime日期格式")
-	l.File("access-{Ymd}.log").Println("文件名称支持带gtime日期格式")
+	g.Log().File("stderr.log").Println("支持链式操作")
+	g.Log().File("error-{Ymd}.log").Println("文件名称支持带gtime日期格式")
+	g.Log().File("access-{Ymd}.log").Println("文件名称支持带gtime日期格式")
 
 	list, err := gfile.ScanDir(path, "*")
 	g.Dump(err)

.example/os/glog/glog_flags.go

@@ -1,15 +1,15 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
-	l := glog.New()
-	l.SetFlags(glog.F_TIME_TIME | glog.F_FILE_SHORT)
-	l.Println("time and short line number")
-	l.SetFlags(glog.F_TIME_MILLI | glog.F_FILE_LONG)
-	l.Println("time with millisecond and long line number")
-	l.SetFlags(glog.F_TIME_STD | glog.F_FILE_LONG)
-	l.Println("standard time format and long line number")
+	g.Log().SetFlags(glog.F_TIME_TIME | glog.F_FILE_SHORT)
+	g.Log().Println("time and short line number")
+	g.Log().SetFlags(glog.F_TIME_MILLI | glog.F_FILE_LONG)
+	g.Log().Println("time with millisecond and long line number")
+	g.Log().SetFlags(glog.F_TIME_STD | glog.F_FILE_LONG)
+	g.Log().Println("standard time format and long line number")
 }

.example/os/glog/glog_gerror.go

@@ -2,9 +2,9 @@ package main
 
 import (
 	"errors"
+	"github.com/gogf/gf/frame/g"
 
 	"github.com/gogf/gf/errors/gerror"
-	"github.com/gogf/gf/os/glog"
 )
 
 func MakeError() error {
@@ -18,8 +18,8 @@ func MakeGError() error {
 func TestGError() {
 	err1 := MakeError()
 	err2 := MakeGError()
-	glog.Error(err1)
-	glog.Error(err2)
+	g.Log().Error(err1)
+	g.Log().Error(err2)
 }
 
 func main() {

.example/os/glog/glog_json.go

@@ -2,15 +2,14 @@ package main
 
 import (
 	"github.com/gogf/gf/frame/g"
-	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
-	glog.Debug(g.Map{"uid": 100, "name": "john"})
+	g.Log().Debug(g.Map{"uid": 100, "name": "john"})
 
 	type User struct {
 		Uid  int    `json:"uid"`
 		Name string `json:"name"`
 	}
-	glog.Debug(User{100, "john"})
+	g.Log().Debug(User{100, "john"})
 }

.example/os/glog/glog_level.go

@@ -1,13 +1,13 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/os/glog"
 )
 
 // 设置日志等级，过滤掉Info日志信息
 func main() {
-	l := glog.New()
-	l.Info("info1")
-	l.SetLevel(glog.LEVEL_ALL ^ glog.LEVEL_INFO)
-	l.Info("info2")
+	g.Log().Info("info1")
+	g.Log().SetLevel(glog.LEVEL_ALL ^ glog.LEVEL_INFO)
+	g.Log().Info("info2")
 }

.example/os/glog/glog_level_prefix.go

@@ -1,11 +1,11 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
-	l := glog.New()
-	l.SetLevelPrefix(glog.LEVEL_DEBU, "debug")
-	l.Debug("test")
+	g.Log().SetLevelPrefix(glog.LEVEL_DEBU, "debug")
+	g.Log().Debug("test")
 }

.example/os/glog/glog_line.go

@@ -1,10 +1,10 @@
 package main
 
 import (
-	"github.com/gogf/gf/os/glog"
+	"github.com/gogf/gf/frame/g"
 )
 
 func main() {
-	glog.Line().Debug("this is the short file name with its line number")
-	glog.Line(true).Debug("lone file name with line number")
+	g.Log().Line().Debug("this is the short file name with its line number")
+	g.Log().Line(true).Debug("lone file name with line number")
 }

.example/os/glog/glog_line2.go

@@ -1,12 +1,12 @@
 package main
 
 import (
-	"github.com/gogf/gf/os/glog"
+	"github.com/gogf/gf/frame/g"
 )
 
 func PrintLog(content string) {
-	glog.Skip(0).Line().Println("line number with skip:", content)
-	glog.Line(true).Println("line number without skip:", content)
+	g.Log().Skip(0).Line().Println("line number with skip:", content)
+	g.Log().Line(true).Println("line number without skip:", content)
 }
 
 func main() {

.example/os/glog/glog_path.go

@@ -3,14 +3,13 @@ package main
 import (
 	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/os/gfile"
-	"github.com/gogf/gf/os/glog"
 )
 
 // 设置日志输出路径
 func main() {
 	path := "/tmp/glog"
-	glog.SetPath(path)
-	glog.Println("日志内容")
+	g.Log().SetPath(path)
+	g.Log().Println("日志内容")
 	list, err := gfile.ScanDir(path, "*")
 	g.Dump(err)
 	g.Dump(list)

.example/os/glog/glog_pool.go

@@ -1,18 +1,18 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"time"
 
-	"github.com/gogf/gf/os/glog"
 	"github.com/gogf/gf/os/gtime"
 )
 
 // 测试删除日志文件是否会重建日志文件
 func main() {
 	path := "/Users/john/Temp/test"
-	glog.SetPath(path)
+	g.Log().SetPath(path)
 	for {
-		glog.Println(gtime.Now().String())
+		g.Log().Println(gtime.Now().String())
 		time.Sleep(time.Second)
 	}
 }

.example/os/glog/glog_prefix.go

@@ -1,12 +1,11 @@
 package main
 
 import (
-	"github.com/gogf/gf/os/glog"
+	"github.com/gogf/gf/frame/g"
 )
 
 func main() {
-	l := glog.New()
-	l.SetPrefix("[API]")
-	l.Println("hello world")
-	l.Error("error occurred")
+	g.Log().SetPrefix("[API]")
+	g.Log().Println("hello world")
+	g.Log().Error("error occurred")
 }

.example/os/glog/glog_stack.go

@@ -2,15 +2,11 @@ package main
 
 import (
 	"fmt"
-
-	"github.com/gogf/gf/os/glog"
+	"github.com/gogf/gf/frame/g"
 )
 
 func main() {
+	g.Log().PrintStack()
 
-	glog.PrintStack()
-	glog.New().PrintStack()
-
-	fmt.Println(glog.GetStack())
-	fmt.Println(glog.New().GetStack())
+	fmt.Println(g.Log().GetStack())
 }

.example/os/glog/glog_stdout.go

@@ -1,22 +1,23 @@
 package main
 
 import (
+	"github.com/gogf/gf/frame/g"
 	"sync"
-
-	"github.com/gogf/gf/os/glog"
 )
 
 func main() {
-	wg := sync.WaitGroup{}
-	c := make(chan struct{})
+	var (
+		wg = sync.WaitGroup{}
+		ch = make(chan struct{})
+	)
 	wg.Add(3000)
 	for i := 0; i < 3000; i++ {
 		go func() {
-			<-c
-			glog.Println("abcdefghijklmnopqrstuvwxyz1234567890")
+			<-ch
+			g.Log().Println("abcdefghijklmnopqrstuvwxyz1234567890")
 			wg.Done()
 		}()
 	}
-	close(c)
+	close(ch)
 	wg.Wait()
 }

.example/os/glog/glog_writer_hook.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"fmt"
+	"github.com/gogf/gf/frame/g"
 
-	"github.com/gogf/gf/net/ghttp"
 	"github.com/gogf/gf/os/glog"
 	"github.com/gogf/gf/text/gregex"
 )
@@ -16,7 +16,7 @@ func (w *MyWriter) Write(p []byte) (n int, err error) {
 	s := string(p)
 	if gregex.IsMatchString(`\[(PANI|FATA)\]`, s) {
 		fmt.Println("SERIOUS ISSUE OCCURRED!! I'd better tell monitor in first time!")
-		ghttp.PostContent("http://monitor.mydomain.com", s)
+		g.Client().PostContent("http://monitor.mydomain.com", s)
 	}
 	return w.logger.Write(p)
 }

.example/os/glog/handler/glog_handler_json.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"context"
+	"github.com/gogf/gf/frame/g"
+	"github.com/gogf/gf/internal/json"
+	"github.com/gogf/gf/os/glog"
+	"github.com/gogf/gf/text/gstr"
+	"os"
+)
+
+// JsonOutputsForLogger is for JSON marshaling in sequence.
+type JsonOutputsForLogger struct {
+	Time    string `json:"time"`
+	Level   string `json:"level"`
+	Content string `json:"content"`
+}
+
+// LoggingJsonHandler is a example handler for logging JSON format content.
+var LoggingJsonHandler glog.Handler = func(ctx context.Context, in *glog.HandlerInput) {
+	jsonForLogger := JsonOutputsForLogger{
+		Time:    in.TimeFormat,
+		Level:   in.LevelFormat,
+		Content: gstr.Trim(in.String()),
+	}
+	jsonBytes, err := json.Marshal(jsonForLogger)
+	if err != nil {
+		_, _ = os.Stderr.WriteString(err.Error())
+		return
+	}
+	in.Buffer.Write(jsonBytes)
+	in.Buffer.WriteString("\n")
+	in.Next()
+}
+
+func main() {
+	g.Log().SetHandlers(LoggingJsonHandler)
+
+	g.Log().Debug("Debugging...")
+	g.Log().Warning("It is warning info")
+	g.Log().Error("Error occurs, please have a check")
+}

.example/os/gmlock/1.lock&unlock.go

@@ -10,8 +10,10 @@ import (
 
 // 内存锁基本使用
 func main() {
-	key := "lock"
-	wg := sync.WaitGroup{}
+	var (
+		key = "lock"
+		wg  = sync.WaitGroup{}
+	)
 	for i := 0; i < 10; i++ {
 		wg.Add(1)
 		go func(i int) {

.example/os/gmlock/4.test_deadlock.go

@@ -11,12 +11,13 @@ import (
 
 // 测试Locker是否会产生死锁
 func main() {
-	l := gmlock.New()
-	wg := sync.WaitGroup{}
-	key := "test"
-	event := make(chan int)
-	number := 100000
-
+	var (
+		l      = gmlock.New()
+		wg     = sync.WaitGroup{}
+		key    = "test"
+		event  = make(chan int)
+		number = 100000
+	)
 	for i := 0; i < number; i++ {
 		wg.Add(1)
 		go func() {

.example/os/gmlock/locker2.go

@@ -1,23 +0,0 @@
-package main
-
-import (
-	"sync"
-
-	"github.com/gogf/gf/os/glog"
-	"github.com/gogf/gf/os/gmlock"
-)
-
-// 内存锁 - 给定过期时间
-func main() {
-	key := "lock"
-	wg := sync.WaitGroup{}
-	for i := 0; i < 10; i++ {
-		wg.Add(1)
-		go func(i int) {
-			gmlock.Lock(key, 1000)
-			glog.Println(i)
-			wg.Done()
-		}(i)
-	}
-	wg.Wait()
-}

.example/os/gmlock/test_mutex.go

@@ -1,95 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"math/rand"
-	"sync"
-	"time"
-
-	"github.com/gogf/gf/os/gmlock"
-)
-
-// 测试是否会产生死锁
-func main() {
-	mu := gmlock.NewMutex()
-	wg := sync.WaitGroup{}
-	event := make(chan int)
-	number := 100000
-
-	for i := 0; i < number; i++ {
-		wg.Add(1)
-		go func() {
-			<-event
-			mu.Lock()
-			//fmt.Println("get lock")
-			mu.Unlock()
-			wg.Done()
-		}()
-	}
-
-	for i := 0; i < number; i++ {
-		wg.Add(1)
-		go func() {
-			<-event
-			mu.RLock()
-			//fmt.Println("get rlock")
-			mu.RUnlock()
-			wg.Done()
-		}()
-	}
-
-	for i := 0; i < number; i++ {
-		wg.Add(1)
-		go func() {
-			<-event
-			if mu.TryLock() {
-				//fmt.Println("get lock")
-				mu.Unlock()
-			}
-			wg.Done()
-		}()
-	}
-
-	for i := 0; i < number; i++ {
-		wg.Add(1)
-		go func() {
-			<-event
-			if mu.TryRLock() {
-				//fmt.Println("get rlock")
-				mu.RUnlock()
-			}
-			wg.Done()
-		}()
-	}
-
-	for i := 0; i < number; i++ {
-		wg.Add(1)
-		go func() {
-			<-event
-			if mu.TryLock() {
-				// 模拟业务逻辑的随机处理间隔
-				time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
-				mu.Unlock()
-			}
-			wg.Done()
-		}()
-	}
-
-	for i := 0; i < number; i++ {
-		wg.Add(1)
-		go func() {
-			<-event
-			if mu.TryRLock() {
-				// 模拟业务逻辑的随机处理间隔
-				time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
-				mu.RUnlock()
-			}
-			wg.Done()
-		}()
-	}
-	// 使用chan作为事件发送测试指令，让所有的goroutine同时执行
-	close(event)
-	wg.Wait()
-
-	fmt.Println("done!")
-}

os/glog/glog_logger.go

@@ -7,6 +7,7 @@
 package glog
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"github.com/fatih/color"
@@ -77,11 +78,11 @@ func NewWithWriter(writer io.Writer) *Logger {
 // Clone returns a new logger, which is the clone the current logger.
 // It's commonly used for chaining operations.
 func (l *Logger) Clone() *Logger {
-	logger := New()
-	logger.ctx = l.ctx
-	logger.config = l.config
-	logger.parent = l
-	return logger
+	newLogger := New()
+	newLogger.ctx = l.ctx
+	newLogger.config = l.config
+	newLogger.parent = l
+	return newLogger
 }
 
 // getFilePath returns the logging file path.
@@ -115,12 +116,13 @@ func (l *Logger) print(ctx context.Context, level int, values ...interface{}) {
 	var (
 		now   = time.Now()
 		input = &HandlerInput{
-			logger: l,
-			index:  -1,
-			Ctx:    ctx,
-			Time:   now,
-			Color:  defaultLevelColor[level],
-			Level:  level,
+			Logger:       l,
+			Buffer:       bytes.NewBuffer(nil),
+			Ctx:          ctx,
+			Time:         now,
+			Color:        defaultLevelColor[level],
+			Level:        level,
+			handlerIndex: -1,
 		}
 	)
 	if l.config.HeaderPrint {
@@ -224,8 +226,8 @@ func (l *Logger) print(ctx context.Context, level int, values ...interface{}) {
 	}
 }
 
-// doPrint outputs the logging content according configuration.
-func (l *Logger) doPrint(ctx context.Context, input *HandlerInput) {
+// doDefaultPrint outputs the logging content according configuration.
+func (l *Logger) doDefaultPrint(ctx context.Context, input *HandlerInput) {
 	if l.config.Writer == nil {
 		// Output content to disk file.
 		if l.config.Path != "" {
@@ -245,7 +247,7 @@ func (l *Logger) doPrint(ctx context.Context, input *HandlerInput) {
 func (l *Logger) printToWriter(ctx context.Context, input *HandlerInput) {
 	if l.config.Writer != nil {
 		var (
-			buffer = input.getBuffer(l.config.WriterColorEnable)
+			buffer = input.getRealBuffer(l.config.WriterColorEnable)
 		)
 		if _, err := l.config.Writer.Write(buffer.Bytes()); err != nil {
 			intlog.Error(ctx, err)
@@ -257,18 +259,18 @@ func (l *Logger) printToWriter(ctx context.Context, input *HandlerInput) {
 func (l *Logger) printToStdout(ctx context.Context, input *HandlerInput) {
 	if l.config.StdoutPrint {
 		// This will lose color in Windows os system.
-		// if _, err := os.Stdout.Write(input.getBuffer(true).Bytes()); err != nil {
+		// if _, err := os.Stdout.Write(input.getRealBuffer(true).Bytes()); err != nil {
 		// This will print color in Windows os system.
-		if _, err := fmt.Fprintf(color.Output, input.getBuffer(true).String()); err != nil {
+		if _, err := fmt.Fprintf(color.Output, input.getRealBuffer(true).String()); err != nil {
 			intlog.Error(ctx, err)
 		}
 	}
 }
 
 // printToFile outputs logging content to disk file.
-func (l *Logger) printToFile(ctx context.Context, t time.Time, input *HandlerInput) {
+func (l *Logger) printToFile(ctx context.Context, t time.Time, in *HandlerInput) {
 	var (
-		buffer        = input.getBuffer(l.config.WriterColorEnable)
+		buffer        = in.getRealBuffer(l.config.WriterColorEnable)
 		logFilePath   = l.getFilePath(t)
 		memoryLockKey = memoryLockPrefixForPrintingToFile + logFilePath
 	)
@@ -362,3 +364,8 @@ func (l *Logger) GetStack(skip ...int) string {
 	}
 	return gdebug.StackWithFilters(filters, stackSkip)
 }
+
+// GetConfig returns the configuration of current Logger.
+func (l *Logger) GetConfig() Config {
+	return l.config
+}

os/glog/glog_logger_config.go

@@ -24,10 +24,10 @@ type Config struct {
 	Writer               io.Writer      `json:"-"`                    // Customized io.Writer.
 	Flags                int            `json:"flags"`                // Extra flags for logging output features.
 	Path                 string         `json:"path"`                 // Logging directory path.
-	File                 string         `json:"file"`                 // Format for logging file.
+	File                 string         `json:"file"`                 // Format pattern for logging file.
 	Level                int            `json:"level"`                // Output level.
 	Prefix               string         `json:"prefix"`               // Prefix string for every logging content.
-	StSkip               int            `json:"stSkip"`               // Skip count for stack.
+	StSkip               int            `json:"stSkip"`               // Skipping count for stack.
 	StStatus             int            `json:"stStatus"`             // Stack status(1: enabled - default; 0: disabled)
 	StFilter             string         `json:"stFilter"`             // Stack string filter.
 	CtxKeys              []interface{}  `json:"ctxKeys"`              // Context keys for logging, which is used for value retrieving from context.

os/glog/glog_logger_handler.go

@@ -15,51 +15,53 @@ import (
 // Handler is function handler for custom logging content outputs.
 type Handler func(ctx context.Context, in *HandlerInput)
 
+// HandlerInput is the input parameter struct for logging Handler.
 type HandlerInput struct {
-	logger      *Logger         // Logger.
-	index       int             // Middleware handling index for internal usage.
-	Ctx         context.Context // Context.
-	Time        time.Time       // Logging time, which is the time that logging triggers.
-	TimeFormat  string          // Formatted time string, like "2016-01-09 12:00:00".
-	Color       int             // Using color, like COLOR_RED, COLOR_BLUE, etc.
-	Level       int             // Using level, like LEVEL_INFO, LEVEL_ERRO, etc.
-	LevelFormat string          // Formatted level string, like "DEBU", "ERRO", etc.
-	CallerFunc  string          // The source function name that calls logging.
-	CallerPath  string          // The source file path and its line number that calls logging.
-	CtxStr      string          // The retrieved context value string from context.
-	Prefix      string          // Custom prefix string for logging content.
-	Content     string          // Content is the main logging content that passed by you.
-	IsAsync     bool            // IsAsync marks it is in asynchronous logging.
+	Logger       *Logger         // Logger.
+	Ctx          context.Context // Context.
+	Buffer       *bytes.Buffer   // Buffer for logging content outputs.
+	Time         time.Time       // Logging time, which is the time that logging triggers.
+	TimeFormat   string          // Formatted time string, like "2016-01-09 12:00:00".
+	Color        int             // Using color, like COLOR_RED, COLOR_BLUE, etc.
+	Level        int             // Using level, like LEVEL_INFO, LEVEL_ERRO, etc.
+	LevelFormat  string          // Formatted level string, like "DEBU", "ERRO", etc.
+	CallerFunc   string          // The source function name that calls logging.
+	CallerPath   string          // The source file path and its line number that calls logging.
+	CtxStr       string          // The retrieved context value string from context.
+	Prefix       string          // Custom prefix string for logging content.
+	Content      string          // Content is the main logging content that passed by you.
+	IsAsync      bool            // IsAsync marks it is in asynchronous logging.
+	handlerIndex int             // Middleware handling index for internal usage.
 }
 
-// defaultHandler is the default handler for logger.
-func defaultHandler(ctx context.Context, in *HandlerInput) {
-	in.logger.doPrint(ctx, in)
-}
-
-func (i *HandlerInput) addStringToBuffer(buffer *bytes.Buffer, strings ...string) {
-	for _, s := range strings {
-		if buffer.Len() > 0 {
-			buffer.WriteByte(' ')
-		}
-		buffer.WriteString(s)
+// Next calls the next logging handler in middleware way.
+func (i *HandlerInput) Next() {
+	if len(i.Logger.config.Handlers)-1 > i.handlerIndex {
+		i.handlerIndex++
+		i.Logger.config.Handlers[i.handlerIndex](i.Ctx, i)
+	} else {
+		defaultHandler(i.Ctx, i)
 	}
 }
 
-// Buffer creates and returns a buffer that handled by default logging content handler.
-func (i *HandlerInput) Buffer() *bytes.Buffer {
-	return i.getBuffer(false)
+// String returns the logging content formatted by default logging handler.
+func (i *HandlerInput) String(withColor ...bool) string {
+	formatWithColor := false
+	if len(withColor) > 0 {
+		formatWithColor = withColor[0]
+	}
+	return i.getDefaultBuffer(formatWithColor).String()
 }
 
-func (i *HandlerInput) getBuffer(withColor bool) *bytes.Buffer {
+func (i *HandlerInput) getDefaultBuffer(withColor bool) *bytes.Buffer {
 	buffer := bytes.NewBuffer(nil)
 	if i.TimeFormat != "" {
 		buffer.WriteString(i.TimeFormat)
 	}
 	if i.LevelFormat != "" {
 		if withColor {
-			i.addStringToBuffer(buffer, i.logger.getColoredStr(
-				i.logger.getColorByLevel(i.Level), i.LevelFormat,
+			i.addStringToBuffer(buffer, i.Logger.getColoredStr(
+				i.Logger.getColorByLevel(i.Level), i.LevelFormat,
 			))
 		} else {
 			i.addStringToBuffer(buffer, i.LevelFormat)
@@ -84,18 +86,23 @@ func (i *HandlerInput) getBuffer(withColor bool) *bytes.Buffer {
 	return buffer
 }
 
-// String retrieves and returns the logging content handled by default handler.
-func (i *HandlerInput) String() string {
-	return i.Buffer().String()
+func (i *HandlerInput) getRealBuffer(withColor bool) *bytes.Buffer {
+	if i.Buffer.Len() > 0 {
+		return i.Buffer
+	}
+	return i.getDefaultBuffer(withColor)
 }
 
-// Next calls the next logging handler in middleware way.
-func (i *HandlerInput) Next() {
-	if len(i.logger.config.Handlers)-1 > i.index {
-		i.index++
-		i.logger.config.Handlers[i.index](i.Ctx, i)
-	} else {
-		// The last handler is the default handler.
-		defaultHandler(i.Ctx, i)
+// defaultHandler is the default handler for logger.
+func defaultHandler(ctx context.Context, in *HandlerInput) {
+	in.Logger.doDefaultPrint(ctx, in)
+}
+
+func (i *HandlerInput) addStringToBuffer(buffer *bytes.Buffer, strings ...string) {
+	for _, s := range strings {
+		if buffer.Len() > 0 {
+			buffer.WriteByte(' ')
+		}
+		buffer.WriteString(s)
 	}
 }

os/glog/glog_z_unit_handler_test.go

@@ -19,7 +19,7 @@ import (
 var arrayForHandlerTest1 = garray.NewStrArray()
 
 func customHandler1(ctx context.Context, input *glog.HandlerInput) {
-	arrayForHandlerTest1.Append(input.String())
+	arrayForHandlerTest1.Append(input.String(false))
 	input.Next()
 }
 
@@ -51,7 +51,7 @@ func TestLogger_SetHandlers1(t *testing.T) {
 var arrayForHandlerTest2 = garray.NewStrArray()
 
 func customHandler2(ctx context.Context, input *glog.HandlerInput) {
-	arrayForHandlerTest2.Append(input.String())
+	arrayForHandlerTest2.Append(input.String(false))
 }
 
 func TestLogger_SetHandlers2(t *testing.T) {