Feature: Experimental Unix socket support for HTTPD & SMTPD (#373)

sendmail/cmd/cmd.go

@@ -18,15 +18,15 @@ import (
 	"fmt"
 	"io"
 	"net/mail"
-	"net/smtp"
 	"os"
 	"os/user"
+	"path"
 	"regexp"
 	"strings"
 
 	"github.com/axllent/mailpit/config"
 	"github.com/axllent/mailpit/internal/logger"
-	"github.com/reiver/go-telnet"
+	"github.com/mneis/go-telnet"
 	flag "github.com/spf13/pflag"
 )
 
@@ -113,14 +113,23 @@ func Run() {
 		os.Exit(1)
 	}
 
+	socketAddr, isSocket := socketAddress(SMTPAddr)
+
 	// handles `sendmail -bs`
+	// telnet directly to SMTP
 	if UseB && UseS {
 		var caller telnet.Caller = telnet.StandardCaller
 
-		// telnet directly to SMTP
-		if err := telnet.DialToAndCall(SMTPAddr, caller); err != nil {
-			fmt.Println(err)
-			os.Exit(1)
+		if isSocket {
+			if err := telnet.DialToAndCallUnix(socketAddr, caller); err != nil {
+				fmt.Println(err)
+				os.Exit(1)
+			}
+		} else {
+			if err := telnet.DialToAndCall(SMTPAddr, caller); err != nil {
+				fmt.Println(err)
+				os.Exit(1)
+			}
 		}
 
 		return
@@ -167,8 +176,7 @@ func Run() {
 		os.Exit(11)
 	}
 
-	err = smtp.SendMail(SMTPAddr, nil, from.Address, addresses, body)
-	if err != nil {
+	if err := Send(SMTPAddr, from.Address, addresses, body); err != nil {
 		fmt.Fprintln(os.Stderr, "error sending mail")
 		logger.Log().Fatal(err)
 	}
@@ -192,3 +200,17 @@ Flags:
   -v          Ignored
 `, config.Version, strings.Join(args, " "), FromAddr)
 }
+
+// SocketAddress returns a path and a FileMode if the address is in
+// the format of unix:<path>
+func socketAddress(address string) (string, bool) {
+	re := regexp.MustCompile(`^unix:(.*)$`)
+
+	if !re.MatchString(address) {
+		return "", false
+	}
+
+	m := re.FindAllStringSubmatch(address, 1)
+
+	return path.Clean(m[0][1]), true
+}

sendmail/cmd/smtp.go

@@ -0,0 +1,71 @@
+// Package cmd is a wrapper library to send mail
+package cmd
+
+import (
+	"fmt"
+	"net"
+	"net/mail"
+	"net/smtp"
+	"os"
+
+	"github.com/axllent/mailpit/internal/logger"
+)
+
+// Send is a wrapper for smtp.SendMail() which also supports sending via unix sockets.
+// Unix sockets must be set as unix:/path/to/socket
+// It does not support authentication.
+func Send(addr string, from string, to []string, msg []byte) error {
+	socketPath, isSocket := socketAddress(addr)
+
+	fromAddress, err := mail.ParseAddress(from)
+	if err != nil {
+		return fmt.Errorf("invalid from address: %s", from)
+	}
+
+	if len(to) == 0 {
+		return fmt.Errorf("no To addresses specified")
+	}
+
+	if !isSocket {
+		return smtp.SendMail(addr, nil, fromAddress.Address, to, msg)
+	}
+
+	conn, err := net.Dial("unix", socketPath)
+	if err != nil {
+		return fmt.Errorf("error connecting to %s", addr)
+	}
+
+	client, err := smtp.NewClient(conn, "")
+	if err != nil {
+		return err
+	}
+
+	// Set the sender
+	if err := client.Mail(fromAddress.Address); err != nil {
+		fmt.Fprintln(os.Stderr, "error sending mail")
+		logger.Log().Fatal(err)
+	}
+
+	// Set the recipient
+	for _, a := range to {
+		if err := client.Rcpt(a); err != nil {
+			return err
+		}
+	}
+
+	wc, err := client.Data()
+	if err != nil {
+		return err
+	}
+
+	_, err = wc.Write(msg)
+	if err != nil {
+		return err
+	}
+	err = wc.Close()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}