From 4a09f90bf1a9038527493be82be6be024e526530 Mon Sep 17 00:00:00 2001
From: Oleg Lobanov <oleg@lobanov.me>
Date: Sun, 31 Jan 2016 11:51:12 +0400
Subject: [PATCH] Replace real object logger with interface.

---
 echo.go                   | 39 +++++++++++++++++++++++----------------
 middleware/logger_test.go |  7 +++++--
 2 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/echo.go b/echo.go
index 6859bab5..9654a6ff 100644
--- a/echo.go
+++ b/echo.go
@@ -66,10 +66,28 @@ type (
 		debug                   bool
 		hook                    http.HandlerFunc
 		autoIndex               bool
-		logger                  *log.Logger
+		logger                  Logger
 		router                  *Router
 	}
 
+	// Logger is the interface that declares echo's logging system.
+	Logger interface {
+		Debug(...interface{})
+		Debugf(string, ...interface{})
+
+		Info(...interface{})
+		Infof(string, ...interface{})
+
+		Warn(...interface{})
+		Warnf(string, ...interface{})
+
+		Error(...interface{})
+		Errorf(string, ...interface{})
+
+		Fatal(...interface{})
+		Fatalf(string, ...interface{})
+	}
+
 	// Route contains a handler and information for matching against requests.
 	Route struct {
 		Method  string
@@ -254,7 +272,6 @@ func New() (e *Echo) {
 
 	// Logger
 	e.logger = log.New("echo")
-	e.logger.SetLevel(log.INFO)
 
 	return
 }
@@ -264,23 +281,13 @@ func (e *Echo) Router() *Router {
 	return e.router
 }
 
-// SetLogPrefix sets the prefix for the logger. Default value is `echo`.
-func (e *Echo) SetLogPrefix(prefix string) {
-	e.logger.SetPrefix(prefix)
-}
-
-// SetLogOutput sets the output destination for the logger. Default value is `os.Stdout`
-func (e *Echo) SetLogOutput(w io.Writer) {
-	e.logger.SetOutput(w)
-}
-
-// SetLogLevel sets the log level for the logger. Default value is `log.INFO`.
-func (e *Echo) SetLogLevel(l log.Level) {
-	e.logger.SetLevel(l)
+// SetLogger sets the logger instance.
+func (e *Echo) SetLogger(logger Logger) {
+	e.logger = logger
 }
 
 // Logger returns the logger instance.
-func (e *Echo) Logger() *log.Logger {
+func (e *Echo) Logger() Logger {
 	return e.logger
 }
 
diff --git a/middleware/logger_test.go b/middleware/logger_test.go
index 298154b4..3ae4970b 100644
--- a/middleware/logger_test.go
+++ b/middleware/logger_test.go
@@ -8,6 +8,7 @@ import (
 	"testing"
 
 	"github.com/labstack/echo"
+	"github.com/labstack/gommon/log"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -52,11 +53,13 @@ func TestLogger(t *testing.T) {
 
 func TestLoggerIPAddress(t *testing.T) {
 	e := echo.New()
+	l := log.New("echo")
+	buf := new(bytes.Buffer)
+	l.SetOutput(buf)
+	e.SetLogger(l)
 	req, _ := http.NewRequest(echo.GET, "/", nil)
 	rec := httptest.NewRecorder()
 	c := echo.NewContext(req, echo.NewResponse(rec, e), e)
-	buf := new(bytes.Buffer)
-	e.Logger().SetOutput(buf)
 	ip := "127.0.0.1"
 	h := func(c *echo.Context) error {
 		return c.String(http.StatusOK, "test")