initial, rought, not-user-friendly support for multi-domain setup

smtp/msa.go

@@ -13,10 +13,10 @@ import (
 
 // msa is mail submission agent, implements smtp.Backend
 type msa struct {
-	log    *logger.Logger
-	domain string
-	bot    Bot
-	mta    utils.MTA
+	log     *logger.Logger
+	domains []string
+	bot     Bot
+	mta     utils.MTA
 }
 
 func (m *msa) newSession(from string, incoming bool) *msasession {
@@ -27,7 +27,7 @@ func (m *msa) newSession(from string, incoming bool) *msasession {
 		incoming: incoming,
 		log:      m.log,
 		bot:      m.bot,
-		domain:   m.domain,
+		domains:  m.domains,
 	}
 }
 

smtp/msasession.go

@@ -19,10 +19,10 @@ import (
 // - receiving emails from remote servers, in which case: `incoming = true`
 // - sending emails from local users, in which case: `incoming = false`
 type msasession struct {
-	log    *logger.Logger
-	bot    Bot
-	mta    utils.MTA
-	domain string
+	log     *logger.Logger
+	bot     Bot
+	mta     utils.MTA
+	domains []string
 
 	ctx      context.Context
 	incoming bool
@@ -46,8 +46,16 @@ func (s *msasession) Rcpt(to string) error {
 	sentry.GetHubFromContext(s.ctx).Scope().SetTag("to", to)
 	s.to = to
 
+	//nolint:nestif // TODO
 	if s.incoming {
-		if utils.Hostname(to) != s.domain {
+		var domainok bool
+		for _, domain := range s.domains {
+			if utils.Hostname(to) == domain {
+				domainok = true
+				break
+			}
+		}
+		if !domainok {
 			s.log.Debug("wrong domain of %s", to)
 			return smtp.ErrAuthRequired
 		}

smtp/server.go

@@ -11,8 +11,8 @@ import (
 )
 
 type Config struct {
-	Domain string
-	Port   string
+	Domains []string
+	Port    string
 
 	TLSCert     string
 	TLSKey      string
@@ -39,15 +39,15 @@ func NewServer(cfg *Config) *Server {
 	log := logger.New("smtp/msa.", cfg.LogLevel)
 	sender := NewMTA(cfg.LogLevel)
 	receiver := &msa{
-		log:    log,
-		mta:    sender,
-		bot:    cfg.Bot,
-		domain: cfg.Domain,
+		log:     log,
+		mta:     sender,
+		bot:     cfg.Bot,
+		domains: cfg.Domains,
 	}
 	receiver.bot.SetMTA(sender)
 
 	s := smtp.NewServer(receiver)
-	s.Domain = cfg.Domain
+	s.Domain = cfg.Domains[0]
 	s.ReadTimeout = 10 * time.Second
 	s.WriteTimeout = 10 * time.Second
 	s.MaxMessageBytes = cfg.MaxSize * 1024 * 1024