use apache log format

logger.go

@@ -3,12 +3,21 @@ package ginlogrus
 import (
 	"fmt"
 	"math"
+	"os"
 	"time"
 
 	"github.com/Sirupsen/logrus"
 	"github.com/gin-gonic/gin"
 )
 
+// 2016-09-27 09:38:21.541541811 +0200 CEST
+// 127.0.0.1 - frank [10/Oct/2000:13:55:36 -0700]
+// "GET /apache_pb.gif HTTP/1.0" 200 2326
+// "http://www.example.com/start.html"
+// "Mozilla/4.08 [en] (Win98; I ;Nav)"
+
+var timeFormat = "02/Jan/2006:15:04:05 -0700"
+
 // Logger is the logrus logger handler
 func Logger(log *logrus.Logger) gin.HandlerFunc {
 	return func(c *gin.Context) {
@@ -17,9 +26,19 @@ func Logger(log *logrus.Logger) gin.HandlerFunc {
 		start := time.Now()
 		c.Next()
 		stop := time.Since(start)
-		statusCode := c.Writer.Status()
 		latency := int(math.Ceil(float64(stop.Nanoseconds()) / 1000.0))
+		statusCode := c.Writer.Status()
 		clientIP := c.ClientIP()
+		clientUserAgent := c.Request.UserAgent()
+		referer := c.Request.Referer()
+		hostname, err := os.Hostname()
+		if err != nil {
+			hostname = "unknow"
+		}
+		dataLength := c.Writer.Size()
+		if dataLength < 0 {
+			dataLength = 0
+		}
 
 		entry := logrus.NewEntry(log).WithFields(logrus.Fields{
 			"statusCode": statusCode,
@@ -27,13 +46,15 @@ func Logger(log *logrus.Logger) gin.HandlerFunc {
 			"clientIP":   clientIP,
 			"method":     c.Request.Method,
 			"path":       path,
+			"referer":    referer,
+			"dataLength": dataLength,
+			"userAgent":  clientUserAgent,
 		})
 
 		if len(c.Errors) > 0 {
 			entry.Error(c.Errors.ByType(gin.ErrorTypePrivate).String())
 		} else {
-			msg := fmt.Sprintf("%s - %s %s %d (%dms)", clientIP, c.Request.Method, path, statusCode, latency)
-
+			msg := fmt.Sprintf("%s - %s [%s] \"%s %s\" %d %d \"%s\" \"%s\" (%dms)", clientIP, hostname, time.Now().Format(timeFormat), c.Request.Method, path, statusCode, dataLength, referer, clientUserAgent, latency)
 			if statusCode > 499 {
 				entry.Error(msg)
 			} else if statusCode > 399 {