diff --git a/log/default_logger.go b/log/default_logger.go
new file mode 100644
index 0000000..da9eaff
--- /dev/null
+++ b/log/default_logger.go
@@ -0,0 +1,71 @@
+package log
+
+import (
+	"github.com/weloe/token-go/model"
+	"log"
+)
+
+var _ Logger = (*DefaultLogger)(nil)
+
+type DefaultLogger struct {
+	enable bool
+}
+
+func (d *DefaultLogger) Enable(bool bool) {
+	d.enable = bool
+}
+
+func (d *DefaultLogger) IsEnabled() bool {
+	return d.enable
+}
+
+func (d *DefaultLogger) Login(loginType string, id interface{}, tokenValue string, loginModel *model.Login) {
+	if !d.enable {
+		return
+	}
+	log.Printf("LoginByModel: loginId = %v, loginType = %v, tokenValue = %v, "+
+		"loginMode = %v", id, loginType, tokenValue, loginModel)
+
+}
+
+func (d *DefaultLogger) Logout(loginType string, id interface{}, tokenValue string) {
+	if !d.enable {
+		return
+	}
+	log.Printf("Logout: loginId = %v, loginType = %v, tokenValue = %v", id, loginType, tokenValue)
+}
+
+func (d *DefaultLogger) Kickout(loginType string, id interface{}, tokenValue string) {
+	if !d.enable {
+		return
+	}
+	log.Printf("Kickout: loginId = %v, loginType = %v, tokenValue = %v", id, loginType, tokenValue)
+}
+
+func (d *DefaultLogger) Replace(loginType string, id interface{}, tokenValue string) {
+	if !d.enable {
+		return
+	}
+	log.Printf("Replaced: loginId = %v, loginType = %v, tokenValue = %v", id, loginType, tokenValue)
+}
+
+func (d *DefaultLogger) Ban(loginType string, id interface{}, service string) {
+	if !d.enable {
+		return
+	}
+	log.Printf("Banned: loginId = %v, loginType = %v, service = %v", id, loginType, service)
+}
+
+func (d *DefaultLogger) UnBan(loginType string, id interface{}, service string) {
+	if !d.enable {
+		return
+	}
+	log.Printf("UnBanned: loginId = %v, loginType = %v, service = %v", id, loginType, service)
+}
+
+func (d *DefaultLogger) RefreshToken(tokenValue string, id interface{}, timeout int64) {
+	if !d.enable {
+		return
+	}
+	log.Printf("RefreshToken: loginId = %v, tokenValue = %v, timeout = %v", id, tokenValue, timeout)
+}
diff --git a/log/logger.go b/log/logger.go
new file mode 100644
index 0000000..9a2dfc3
--- /dev/null
+++ b/log/logger.go
@@ -0,0 +1,13 @@
+package log
+
+import "github.com/weloe/token-go/persist"
+
+type Logger interface {
+	persist.Watcher
+
+	// Enable turn on or off
+	Enable(bool bool)
+
+	// IsEnabled return if logger is enabled
+	IsEnabled() bool
+}
diff --git a/model/login.go b/model/login.go
new file mode 100644
index 0000000..431ad0d
--- /dev/null
+++ b/model/login.go
@@ -0,0 +1,21 @@
+package model
+
+type Login struct {
+	Device          string
+	IsLastingCookie bool
+	Timeout         int64
+	JwtData         map[string]interface{}
+	Token           string
+	IsWriteHeader   bool
+}
+
+func DefaultLoginModel() *Login {
+	return &Login{
+		Device:          "default",
+		IsLastingCookie: true,
+		Timeout:         60 * 60 * 24 * 30,
+		JwtData:         nil,
+		Token:           "",
+		IsWriteHeader:   true,
+	}
+}
diff --git a/persist/watcher.go b/persist/watcher.go
new file mode 100644
index 0000000..02beb67
--- /dev/null
+++ b/persist/watcher.go
@@ -0,0 +1,21 @@
+package persist
+
+import "github.com/weloe/token-go/model"
+
+// Watcher event watcher
+type Watcher interface {
+	// Login called after login
+	Login(loginType string, id interface{}, tokenValue string, loginModel *model.Login)
+	// Logout called after logout
+	Logout(loginType string, id interface{}, tokenValue string)
+	// Kickout called when being kicked out of the server
+	Kickout(loginType string, id interface{}, tokenValue string)
+	// Replace called when Someone else has taken over your account
+	Replace(loginType string, id interface{}, tokenValue string)
+	// Ban called when account banned
+	Ban(loginType string, id interface{}, service string)
+	// UnBan called when account has been unbanned.
+	UnBan(loginType string, id interface{}, service string)
+	// RefreshToken called when renew token timeout
+	RefreshToken(tokenValue string, id interface{}, timeout int64)
+}