Format notification server log and redirect stderr to log (#707)

* Format notification server log and redirect stderr to log

* Set http server error log

* Delete unused file

* Modify pkg name

---------

Co-authored-by: 杨赫然 <heran.yang@seafile.com>

notification-server/logger.go

@@ -1,18 +1,36 @@
 package main
 
 import (
+	"fmt"
+	"strings"
+
 	log "github.com/sirupsen/logrus"
 )
 
 const (
-	timestampFormat = "2006/01/02 15:04:05 "
+	timestampFormat = "[2006-01-02 15:04:05] "
 )
 
 type LogFormatter struct{}
 
 func (f *LogFormatter) Format(entry *log.Entry) ([]byte, error) {
-	buf := make([]byte, 0, len(timestampFormat)+len(entry.Message)+1)
+	levelStr := entry.Level.String()
+	if levelStr == "fatal" {
+		levelStr = "ERROR"
+	} else {
+		levelStr = strings.ToUpper(levelStr)
+	}
+	level := fmt.Sprintf("[%s] ", levelStr)
+	appName := ""
+	if logToStdout {
+		appName = "[notification-server] "
+	}
+	buf := make([]byte, 0, len(appName)+len(timestampFormat)+len(level)+len(entry.Message)+1)
+	if logToStdout {
+		buf = append(buf, appName...)
+	}
 	buf = entry.Time.AppendFormat(buf, timestampFormat)
+	buf = append(buf, level...)
 	buf = append(buf, entry.Message...)
 	buf = append(buf, '\n')
 	return buf, nil