Can send mail through a smtp relay

ldap.go

@@ -19,6 +19,10 @@ type LDAP struct {
 	BaseDN          string
 	ServiceDN       string
 	ServicePassword string
+	MailHost        string
+	MailPort        int
+	MailUser        string
+	MailPassword    string
 }
 
 func (l LDAP) Connect() (*LDAPConn, error) {

lost.go

@@ -116,33 +116,44 @@ func lostPassword(w http.ResponseWriter, r *http.Request) {
 	m.SetHeader("Subject", "SSO nemunai.re: password recovery")
 	m.SetBody("text/plain", "Hello "+cn+"!\n\nSomeone, and we hope it's you, requested to reset your account password. \nIn order to continue, go to:\nhttps://ldap.nemunai.re/reset?l="+r.PostFormValue("login")+"&t="+token+"\n\nBest regards,\n-- \nnemunai.re SSO")
 
-	// Using local sendmail: delegate to the local admin sys the responsability to transport the mail
-	s := gomail.SendFunc(func(from string, to []string, msg io.WriterTo) error {
-		cmd := exec.Command("sendmail", "-t")
-		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
-
-		pw, err := cmd.StdinPipe()
+	var s gomail.Sender
+	if myLDAP.MailHost != "" {
+		d := gomail.NewDialer(myLDAP.MailHost, myLDAP.MailPort, myLDAP.MailUser, myLDAP.MailPassword)
+		s, err = d.Dial()
 		if err != nil {
-			return err
+			log.Println("Unable to connect to email server: " + err.Error())
+			displayTmplError(w, http.StatusInternalServerError, "lost.html", map[string]interface{}{"error": "Unable to connect to email server: " + err.Error()})
+			return
 		}
+	} else {
+		// Using local sendmail: delegate to the local admin sys the responsability to transport the mail
+		s = gomail.SendFunc(func(from string, to []string, msg io.WriterTo) error {
+			cmd := exec.Command("sendmail", "-t")
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
 
-		err = cmd.Start()
-		if err != nil {
-			return err
-		}
-
-		var errs [3]error
-		_, errs[0] = m.WriteTo(pw)
-		errs[1] = pw.Close()
-		errs[2] = cmd.Wait()
-		for _, err = range errs {
+			pw, err := cmd.StdinPipe()
 			if err != nil {
 				return err
 			}
-		}
-		return nil
-	})
+
+			err = cmd.Start()
+			if err != nil {
+				return err
+			}
+
+			var errs [3]error
+			_, errs[0] = m.WriteTo(pw)
+			errs[1] = pw.Close()
+			errs[2] = cmd.Wait()
+			for _, err = range errs {
+				if err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+	}
 
 	if err := gomail.Send(s, m); err != nil {
 		log.Println("Unable to send email: " + err.Error())

main.go

@@ -18,9 +18,10 @@ import (
 )
 
 var myLDAP = LDAP{
-	Host:   "localhost",
-	Port:   389,
-	BaseDN: "dc=example,dc=com",
+	Host:     "localhost",
+	Port:     389,
+	BaseDN:   "dc=example,dc=com",
+	MailPort: 587,
 }
 
 type ResponseWriterPrefix struct {
@@ -125,6 +126,23 @@ func main() {
 		myLDAP.ServicePassword = val
 	}
 
+	if val, ok := os.LookupEnv("SMTP_HOST"); ok {
+		myLDAP.MailHost = val
+	}
+	if val, ok := os.LookupEnv("SMTP_PORT"); ok {
+		if port, err := strconv.Atoi(val); err == nil {
+			myLDAP.MailPort = port
+		} else {
+			log.Println("Invalid value for SMTP_PORT:", val)
+		}
+	}
+	if val, ok := os.LookupEnv("SMTP_USER"); ok {
+		myLDAP.MailUser = val
+	}
+	if val, ok := os.LookupEnv("SMTP_PASSWORD"); ok {
+		myLDAP.MailPassword = val
+	}
+
 	// Prepare graceful shutdown
 	interrupt := make(chan os.Signal, 1)
 	signal.Notify(interrupt, os.Interrupt, syscall.SIGTERM)