Added description in README.md

README.md

@@ -43,6 +43,74 @@ MailDirGroup | string | User of Maildir (used on `chown`) | Account restore
 
 Returns: server struct instance `srv`
 
+## Logging
+
+Problem statement
+
+To implement logging using a module (like logrus) the functions must be implemented either in main.go or in dovecot using exactly the choosen module.
+Using an other module later would be a huge effort for refactoring
+Solution
+To be able to use any logging api you want logging is implemented as callbacks including seperate functions for
+
+- Info
+- Error
+- Warn
+- Fatal
+
+A struct containing the callbacks for above log-levels is created as `godovecot.Logger`. This is allocated at server-creation in the followimg way
+
+````golang
+f, err := os.OpenFile("testlogrus.log", os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
+if err != nil {
+    fmt.Printf("error opening file: %v", err)
+}
+
+logger := logrus.New()
+logger.SetOutput(f)
+
+log := log.Default()
+
+	sl := dovecot.Logger{
+
+		LogError: func(e ...interface{}) {
+			//log.Println(e)
+			logger.Error(e)
+		},
+		LogInfo: func(i ...interface{}) {
+			//log.Println(i)
+			logger.Info(i)
+		},
+		LogWarn: func(w ...interface{}) {
+			//log.Println(w)
+			logger.Warn(w)
+		},
+	}
+
+	ds := dovecot.MailServer{
+		ApiConfig: &dovecot.ApiConfig{
+			ApiHost:  "https://plesk.ververis.eu",
+			ApiUser:  "admin",
+			Password: "Sektor@mailD2312",
+		},
+		SSHConfig: &dovecot.SSHConfig{
+			SSHHost:             "89.22.111.212",
+			SSHPort:             "22",
+			SSHUser:             "root",
+			LocalPrivateKeyPath: "/Users/mandi/.ssh/id_rsa",
+			LocalKnownHostPath:  "/Users/mandi/.ssh/known_hosts",
+		},
+		MaildirPath:        "/var/qmail/mailnames/ververis.eu",
+		BakupMailsPath:     "sync",
+		BackupAccountsPath: "sync/accounts",
+		MailDirOwner:       "popuser",
+		MailDirGroup:       "popuser",
+
+		Logger: &sl,
+	}
+````
+Above example shows implementation using `sirupsen/logrus`
+https://github.com/sirupsen/logrus
+
 ### RestoreMail(a ...IPacket)
 
 `ResroreMail(a ...IPacket)` is implemented as variadic to be able to pass parameters as different types implementing the `IPacket` interface: