Send email with Go

sendmail.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net/smtp"
)

func main() {
	username := flag.String("username", "", "Username in the smtp server")
	password := flag.String("password", "", "Password in the smtp server")
	smtpHost := flag.String("host", "", "SMTP server host")
	smtpPort := flag.Int("port", 587, "SMTP server port")

	toAddr := flag.String("to", "", "Receiver address")
	from := flag.String("from", "", "Sender address")
	subject := flag.String("subject", "", "Email subject")
	messageText := flag.String("message", "", "Email content")
	flag.Parse()

	msg := []byte("From: " + *from + "\r\n" +
		"To: " + *toAddr + "\r\n" +
		"Subject: " + *subject + "\r\n\r\n" +
		*messageText + "\r\n")

	auth := smtp.PlainAuth(*from, *username, *password, *smtpHost)

	err := smtp.SendMail(
		fmt.Sprintf("%s:%d", *smtpHost, *smtpPort), auth, *from, []string{*toAddr}, msg)
	if err != nil {
		log.Fatal(err)
	}
}