Restruct logger order

Signed-off-by: Asai Neko <sugar@sne.moe>

logger/logrus.go

@@ -1,36 +1,46 @@
 package logger
 
 import (
+	"io"
 	"os"
 
 	"github.com/gin-gonic/gin"
-	log "github.com/sirupsen/logrus"
-	"github.com/spf13/viper"
+	"github.com/sirupsen/logrus"
 )
 
 func Init() {
-	FileLogger := viper.GetBool("server.file_logger")
-	DebugMode := viper.GetBool("server.debug_mode")
-
-	if FileLogger == true {
-		gin.DisableConsoleColor()
-		file, err := os.OpenFile("app.log", os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
-		if err != nil {
-			log.Panicln("Error opening log file: ", err)
-		}
-		log.SetFormatter(&log.JSONFormatter{})
-		log.SetOutput(file)
-		log.SetLevel(log.DebugLevel)
-	} else {
-		log.SetFormatter(&log.JSONFormatter{})
-		log.SetOutput(os.Stdout)
-		log.SetLevel(log.WarnLevel)
+	levelStr := os.Getenv("LOG_LEVEL")
+	level, err := logrus.ParseLevel(levelStr)
+	if err != nil {
+		level = logrus.InfoLevel
 	}
+	logrus.SetLevel(level)
 
-	if DebugMode == true {
+	if level == logrus.DebugLevel {
 		gin.SetMode(gin.DebugMode)
-		log.SetLevel(log.DebugLevel)
 	} else {
 		gin.SetMode(gin.ReleaseMode)
+		gin.DisableConsoleColor()
 	}
+
+	logrus.SetFormatter(&logrus.JSONFormatter{
+		TimestampFormat: "2006-01-02 15:04:05",
+	})
+
+	logrus.SetReportCaller(true)
+
+	file, err := os.OpenFile("app.log", os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
+	if err != nil {
+		logrus.SetOutput(os.Stdout)
+		logrus.Errorf("Error to create log file: %v", err)
+	} else {
+		logrus.SetOutput(io.MultiWriter(os.Stdout, file))
+	}
+
+	logrus.RegisterExitHandler(func() {
+		if file != nil {
+			file.Sync()
+			file.Close()
+		}
+	})
 }