smtpd

lavab/smtpd

smtpd is a simple library for implementing SMTP servers in Golang. Supports STARTTLS, middleware chains for event handling and configurable limits, proxy protocol for servers listening behind HAProxy of Amazon ELB load balancers.

Example

package main

import (
	"log"

	"github.com/getsentry/raven-go"
	"github.com/lavab/smtpd"
)

func main() {
	// Connect to raven for sentry logging
	rc, err := raven.NewClient("some raven dsn", nil)
	if err != nil {
		log.Fatal(err)
	}

	// Create a new SMTPD server
	server := &smtpd.Server{
		WelcomeMessage: "Hello world!",

		WrapperChain: []smtpd.Wrapper{
			smtpd.Wrapper(func(next smtpd.Wrapped) smtpd.Wrapped {
				return smtpd.Wrapped(func() {
					rc.CapturePanic(next, nil)
				})
			}),
		},
		DeliveryChain: []smtpd.Middleware{
			smtpd.Middleware(func(next smtpd.Handler) smtpd.Handler {
				return smtpd.Handler(func(conn *smtpd.Connection) {
					log.Printf("Sender: %s", conn.Envelope.Sender)
					log.Printf("Recipients: %s", strings.Join(conn.Envelope.Recipients, ", "))
					log.Printf("Body:\n%s", string(conn.Envelope.Body))
					
					next(conn)
				})
			}),
		},
	}

	// Bind it to an address
	if err := server.ListenAndServe(":25"); err != nil {
		log.Fatal(err)
	}
}