refactor smtp

smtp/manager.go

@@ -0,0 +1,139 @@
+package smtp
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+	"os"
+	"time"
+
+	"github.com/emersion/go-smtp"
+	"gitlab.com/etke.cc/go/logger"
+	"maunium.net/go/mautrix/id"
+
+	"gitlab.com/etke.cc/postmoogle/utils"
+)
+
+type Config struct {
+	Domains []string
+	Port    string
+
+	TLSCert     string
+	TLSKey      string
+	TLSPort     string
+	TLSRequired bool
+
+	LogLevel string
+	MaxSize  int
+	Bot      matrixbot
+}
+
+type Manager struct {
+	log  *logger.Logger
+	smtp *smtp.Server
+	errs chan error
+
+	port    string
+	tlsPort string
+	tlsCfg  *tls.Config
+}
+
+type matrixbot interface {
+	AllowAuth(string, string) bool
+	GetMapping(string) (id.RoomID, bool)
+	GetIFOptions(id.RoomID) utils.IncomingFilteringOptions
+	IncomingEmail(context.Context, *utils.Email) error
+	SetSendmail(func(string, string, string) error)
+	GetDKIMprivkey() string
+}
+
+// NewManager creates new SMTP server manager
+func NewManager(cfg *Config) *Manager {
+	log := logger.New("smtp.", cfg.LogLevel)
+	mailsrv := &mailServer{
+		log:     log,
+		bot:     cfg.Bot,
+		domains: cfg.Domains,
+	}
+	cfg.Bot.SetSendmail(mailsrv.SendEmail)
+
+	s := smtp.NewServer(mailsrv)
+	s.Domain = cfg.Domains[0]
+	s.ReadTimeout = 10 * time.Second
+	s.WriteTimeout = 10 * time.Second
+	s.MaxMessageBytes = cfg.MaxSize * 1024 * 1024
+	s.AllowInsecureAuth = !cfg.TLSRequired
+	s.EnableREQUIRETLS = cfg.TLSRequired
+	s.EnableSMTPUTF8 = true
+	if log.GetLevel() == "DEBUG" || log.GetLevel() == "TRACE" {
+		s.Debug = os.Stdout
+	}
+
+	m := &Manager{
+		smtp:    s,
+		log:     log,
+		port:    cfg.Port,
+		tlsPort: cfg.TLSPort,
+	}
+	m.loadTLSConfig(cfg.TLSCert, cfg.TLSKey)
+	return m
+}
+
+// Start SMTP server
+func (m *Manager) Start() error {
+	m.errs = make(chan error, 1)
+	go m.listen(m.port, nil)
+	if m.tlsCfg != nil {
+		go m.listen(m.tlsPort, m.tlsCfg)
+	}
+
+	return <-m.errs
+}
+
+// Stop SMTP server
+func (m *Manager) Stop() {
+	err := m.smtp.Close()
+	if err != nil {
+		m.log.Error("cannot stop SMTP server properly: %v", err)
+	}
+	m.log.Info("SMTP server has been stopped")
+}
+
+func (m *Manager) listen(port string, tlsCfg *tls.Config) {
+	var l net.Listener
+	var err error
+	if tlsCfg != nil {
+		l, err = tls.Listen("tcp", ":"+port, tlsCfg)
+	} else {
+		l, err = net.Listen("tcp", ":"+port)
+	}
+	if err != nil {
+		m.log.Error("cannot start listener on %s: %v", port, err)
+		m.errs <- err
+		return
+	}
+
+	m.log.Info("Starting SMTP server on port %s", port)
+
+	err = m.smtp.Serve(l)
+	if err != nil {
+		m.log.Error("cannot start SMTP server on %s: %v", port, err)
+		m.errs <- err
+		close(m.errs)
+	}
+}
+
+func (m *Manager) loadTLSConfig(cert, key string) {
+	if cert == "" || key == "" {
+		m.log.Warn("SSL certificate is not provided")
+		return
+	}
+
+	tlsCert, err := tls.LoadX509KeyPair(cert, key)
+	if err != nil {
+		m.log.Error("cannot load SSL certificate: %v", err)
+		return
+	}
+	m.tlsCfg = &tls.Config{Certificates: []tls.Certificate{tlsCert}}
+	m.smtp.TLSConfig = m.tlsCfg
+}