Send SMTP email in Go

email_smtp.go

package main

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

const (
	SMTP_SERVER = "smtp.gmail.com"
	SMTP_PORT   = 587
)

func send(from, pass, to, subject, body string) error {
	msg := fmt.Sprintf("From: %s\nTo: %s\nSubject: %s\n\n%s", from, to, subject, body)
	auth := smtp.PlainAuth("", from, pass, SMTP_SERVER)
	return smtp.SendMail(fmt.Sprintf("%s:%d", SMTP_SERVER, SMTP_PORT), auth, from, []string{to}, []byte(msg))
}

func main() {
	from := "[email protected]"
	pass := "secret_password"
	to := "[email protected]"
	subject := "Hi there"
	body := "This is body"

	if err := send(from, pass, to, subject, body); err != nil {
		log.Fatal(err)
	}
	log.Println("Done")
}