diff --git a/logs/conn.go b/logs/conn.go
index a5bc75c5..eed9ae2f 100644
--- a/logs/conn.go
+++ b/logs/conn.go
@@ -7,6 +7,8 @@ import (
 	"net"
 )
 
+// ConnWriter implements LoggerInterface.
+// it writes messages in keep-live tcp connection.
 type ConnWriter struct {
 	lg             *log.Logger
 	innerWriter    io.WriteCloser
@@ -17,12 +19,15 @@ type ConnWriter struct {
 	Level          int    `json:"level"`
 }
 
+// create new ConnWrite returning as LoggerInterface.
 func NewConn() LoggerInterface {
 	conn := new(ConnWriter)
 	conn.Level = LevelTrace
 	return conn
 }
 
+// init connection writer with json config.
+// json config only need key "level".
 func (c *ConnWriter) Init(jsonconfig string) error {
 	err := json.Unmarshal([]byte(jsonconfig), c)
 	if err != nil {
@@ -31,6 +36,8 @@ func (c *ConnWriter) Init(jsonconfig string) error {
 	return nil
 }
 
+// write message in connection.
+// if connection is down, try to re-connect.
 func (c *ConnWriter) WriteMsg(msg string, level int) error {
 	if level < c.Level {
 		return nil
@@ -49,10 +56,12 @@ func (c *ConnWriter) WriteMsg(msg string, level int) error {
 	return nil
 }
 
+// implementing method. empty.
 func (c *ConnWriter) Flush() {
 
 }
 
+// destroy connection writer and close tcp listener.
 func (c *ConnWriter) Destroy() {
 	if c.innerWriter == nil {
 		return
diff --git a/logs/console.go b/logs/console.go
index 0c7fc1e9..c5fa2380 100644
--- a/logs/console.go
+++ b/logs/console.go
@@ -6,11 +6,13 @@ import (
 	"os"
 )
 
+// ConsoleWriter implements LoggerInterface and writes messages to terminal.
 type ConsoleWriter struct {
 	lg    *log.Logger
 	Level int `json:"level"`
 }
 
+// create ConsoleWriter returning as LoggerInterface.
 func NewConsole() LoggerInterface {
 	cw := new(ConsoleWriter)
 	cw.lg = log.New(os.Stdout, "", log.Ldate|log.Ltime)
@@ -18,6 +20,8 @@ func NewConsole() LoggerInterface {
 	return cw
 }
 
+// init console logger.
+// jsonconfig like '{"level":LevelTrace}'.
 func (c *ConsoleWriter) Init(jsonconfig string) error {
 	err := json.Unmarshal([]byte(jsonconfig), c)
 	if err != nil {
@@ -26,6 +30,7 @@ func (c *ConsoleWriter) Init(jsonconfig string) error {
 	return nil
 }
 
+// write message in console.
 func (c *ConsoleWriter) WriteMsg(msg string, level int) error {
 	if level < c.Level {
 		return nil
@@ -34,10 +39,12 @@ func (c *ConsoleWriter) WriteMsg(msg string, level int) error {
 	return nil
 }
 
+// implementing method. empty.
 func (c *ConsoleWriter) Destroy() {
 
 }
 
+// implementing method. empty.
 func (c *ConsoleWriter) Flush() {
 
 }
diff --git a/logs/file.go b/logs/file.go
index e19c6c7f..d0512e26 100644
--- a/logs/file.go
+++ b/logs/file.go
@@ -13,6 +13,8 @@ import (
 	"time"
 )
 
+// FileLogWriter implements LoggerInterface.
+// It writes messages by lines limit, file size limit, or time frequency.
 type FileLogWriter struct {
 	*log.Logger
 	mw *MuxWriter
@@ -38,17 +40,20 @@ type FileLogWriter struct {
 	Level int `json:"level"`
 }
 
+// an *os.File writer with locker.
 type MuxWriter struct {
 	sync.Mutex
 	fd *os.File
 }
 
+// write to os.File.
 func (l *MuxWriter) Write(b []byte) (int, error) {
 	l.Lock()
 	defer l.Unlock()
 	return l.fd.Write(b)
 }
 
+// set os.File in writer.
 func (l *MuxWriter) SetFd(fd *os.File) {
 	if l.fd != nil {
 		l.fd.Close()
@@ -56,6 +61,7 @@ func (l *MuxWriter) SetFd(fd *os.File) {
 	l.fd = fd
 }
 
+// create a FileLogWriter returning as LoggerInterface.
 func NewFileWriter() LoggerInterface {
 	w := &FileLogWriter{
 		Filename: "",
@@ -73,15 +79,16 @@ func NewFileWriter() LoggerInterface {
 	return w
 }
 
-// jsonconfig like this
-//{
+// Init file logger with json config.
+// jsonconfig like:
+//	{
 //	"filename":"logs/beego.log",
 //	"maxlines":10000,
 //	"maxsize":1<<30,
 //	"daily":true,
 //	"maxdays":15,
 //	"rotate":true
-//}
+//	}
 func (w *FileLogWriter) Init(jsonconfig string) error {
 	err := json.Unmarshal([]byte(jsonconfig), w)
 	if err != nil {
@@ -94,6 +101,7 @@ func (w *FileLogWriter) Init(jsonconfig string) error {
 	return err
 }
 
+// start file logger. create log file and set to locker-inside file writer.
 func (w *FileLogWriter) StartLogger() error {
 	fd, err := w.createLogFile()
 	if err != nil {
@@ -122,6 +130,7 @@ func (w *FileLogWriter) docheck(size int) {
 	w.maxsize_cursize += size
 }
 
+// write logger message into file.
 func (w *FileLogWriter) WriteMsg(msg string, level int) error {
 	if level < w.Level {
 		return nil
@@ -158,6 +167,8 @@ func (w *FileLogWriter) initFd() error {
 	return nil
 }
 
+// DoRotate means it need to write file in new file.
+// new file name like xx.log.2013-01-01.2
 func (w *FileLogWriter) DoRotate() error {
 	_, err := os.Lstat(w.Filename)
 	if err == nil { // file exists
@@ -211,10 +222,14 @@ func (w *FileLogWriter) deleteOldLog() {
 	})
 }
 
+// destroy file logger, close file writer.
 func (w *FileLogWriter) Destroy() {
 	w.mw.fd.Close()
 }
 
+// flush file logger.
+// there are no buffering messages in file logger in memory.
+// flush file means sync file from disk.
 func (w *FileLogWriter) Flush() {
 	w.mw.fd.Sync()
 }
diff --git a/logs/log.go b/logs/log.go
index a9254aaa..b65414cb 100644
--- a/logs/log.go
+++ b/logs/log.go
@@ -6,6 +6,7 @@ import (
 )
 
 const (
+	// log message levels
 	LevelTrace = iota
 	LevelDebug
 	LevelInfo
@@ -16,6 +17,7 @@ const (
 
 type loggerType func() LoggerInterface
 
+// LoggerInterface defines the behavior of a log provider.
 type LoggerInterface interface {
 	Init(config string) error
 	WriteMsg(msg string, level int) error
@@ -38,6 +40,8 @@ func Register(name string, log loggerType) {
 	adapters[name] = log
 }
 
+// BeeLogger is default logger in beego application.
+// it can contain several providers and log message into all providers.
 type BeeLogger struct {
 	lock    sync.Mutex
 	level   int
@@ -50,7 +54,9 @@ type logMsg struct {
 	msg   string
 }
 
-// config need to be correct JSON as string: {"interval":360}
+// NewLogger returns a new BeeLogger.
+// channellen means the number of messages in chan.
+// if the buffering chan is full, logger adapters write to file or other way.
 func NewLogger(channellen int64) *BeeLogger {
 	bl := new(BeeLogger)
 	bl.msg = make(chan *logMsg, channellen)
@@ -60,6 +66,8 @@ func NewLogger(channellen int64) *BeeLogger {
 	return bl
 }
 
+// SetLogger provides a given logger adapter into BeeLogger with config string.
+// config need to be correct JSON as string: {"interval":360}.
 func (bl *BeeLogger) SetLogger(adaptername string, config string) error {
 	bl.lock.Lock()
 	defer bl.lock.Unlock()
@@ -73,6 +81,7 @@ func (bl *BeeLogger) SetLogger(adaptername string, config string) error {
 	}
 }
 
+// remove a logger adapter in BeeLogger.
 func (bl *BeeLogger) DelLogger(adaptername string) error {
 	bl.lock.Lock()
 	defer bl.lock.Unlock()
@@ -96,10 +105,14 @@ func (bl *BeeLogger) writerMsg(loglevel int, msg string) error {
 	return nil
 }
 
+// set log message level.
+// if message level (such as LevelTrace) is less than logger level (such as LevelWarn), ignore message.
 func (bl *BeeLogger) SetLevel(l int) {
 	bl.level = l
 }
 
+// start logger chan reading.
+// when chan is full, write logs.
 func (bl *BeeLogger) StartLogger() {
 	for {
 		select {
@@ -111,43 +124,50 @@ func (bl *BeeLogger) StartLogger() {
 	}
 }
 
+// log trace level message.
 func (bl *BeeLogger) Trace(format string, v ...interface{}) {
 	msg := fmt.Sprintf("[T] "+format, v...)
 	bl.writerMsg(LevelTrace, msg)
 }
 
+// log debug level message.
 func (bl *BeeLogger) Debug(format string, v ...interface{}) {
 	msg := fmt.Sprintf("[D] "+format, v...)
 	bl.writerMsg(LevelDebug, msg)
 }
 
+// log info level message.
 func (bl *BeeLogger) Info(format string, v ...interface{}) {
 	msg := fmt.Sprintf("[I] "+format, v...)
 	bl.writerMsg(LevelInfo, msg)
 }
 
+// log warn level message.
 func (bl *BeeLogger) Warn(format string, v ...interface{}) {
 	msg := fmt.Sprintf("[W] "+format, v...)
 	bl.writerMsg(LevelWarn, msg)
 }
 
+// log error level message.
 func (bl *BeeLogger) Error(format string, v ...interface{}) {
 	msg := fmt.Sprintf("[E] "+format, v...)
 	bl.writerMsg(LevelError, msg)
 }
 
+// log critical level message.
 func (bl *BeeLogger) Critical(format string, v ...interface{}) {
 	msg := fmt.Sprintf("[C] "+format, v...)
 	bl.writerMsg(LevelCritical, msg)
 }
 
-//flush all chan data
+// flush all chan data.
 func (bl *BeeLogger) Flush() {
 	for _, l := range bl.outputs {
 		l.Flush()
 	}
 }
 
+// close logger, flush all chan data and destroy all adapters in BeeLogger.
 func (bl *BeeLogger) Close() {
 	for {
 		if len(bl.msg) > 0 {
diff --git a/logs/smtp.go b/logs/smtp.go
index 228977bb..19296887 100644
--- a/logs/smtp.go
+++ b/logs/smtp.go
@@ -12,7 +12,7 @@ const (
 	subjectPhrase = "Diagnostic message from server"
 )
 
-// smtpWriter is used to send emails via given SMTP-server.
+// smtpWriter implements LoggerInterface and is used to send emails via given SMTP-server.
 type SmtpWriter struct {
 	Username           string   `json:"Username"`
 	Password           string   `json:"password"`
@@ -22,10 +22,21 @@ type SmtpWriter struct {
 	Level              int      `json:"level"`
 }
 
+// create smtp writer.
 func NewSmtpWriter() LoggerInterface {
 	return &SmtpWriter{Level: LevelTrace}
 }
 
+// init smtp writer with json config.
+// config like:
+//	{
+//		"Username":"example@gmail.com",
+//		"password:"password",
+//		"host":"smtp.gmail.com:465",
+//		"subject":"email title",
+//		"sendTos":["email1","email2"],
+//		"level":LevelError
+//	}
 func (s *SmtpWriter) Init(jsonconfig string) error {
 	err := json.Unmarshal([]byte(jsonconfig), s)
 	if err != nil {
@@ -34,6 +45,8 @@ func (s *SmtpWriter) Init(jsonconfig string) error {
 	return nil
 }
 
+// write message in smtp writer.
+// it will send an email with subject and only this message.
 func (s *SmtpWriter) WriteMsg(msg string, level int) error {
 	if level < s.Level {
 		return nil
@@ -65,9 +78,12 @@ func (s *SmtpWriter) WriteMsg(msg string, level int) error {
 	return err
 }
 
+// implementing method. empty.
 func (s *SmtpWriter) Flush() {
 	return
 }
+
+// implementing method. empty.
 func (s *SmtpWriter) Destroy() {
 	return
 }