Golang gmail smtp authentication

app.go

package main

import (
	"log"
	"net/smtp"
	"strconv"
	"crypto/tls"
	

)

func ValidateSMTPServer(port int, serverHost, securityType, username, password string) error  {

	// Connect to server
	serverAddress := serverHost + ":" + strconv.Itoa(port)
	log.Println(serverAddress)
	smtpClient, err := smtp.Dial(serverAddress)
	if err != nil {
		return err
	}
	defer smtpClient.Close()
	log.Println("Dialed")
	if ok, _ := smtpClient.Extension("STARTTLS"); ok {
		config := &tls.Config{ServerName: serverHost}
		if err = smtpClient.StartTLS(config); err != nil {
			return err
		}
	}
	log.Println("STARTTL Done")
	auth := smtp.PlainAuth("", username, password, serverHost)
	if err = smtpClient.Auth(auth); err != nil {
				return err
	}
	
	return nil
}

func main() {
	log.Println("starting smtp authentication")
	err := ValidateSMTPServer(587, "smtp.gmail.com", "SSL", "example@gmail.com", "password");	
	log.Println(err)
}