logging and cert handling

cmd/inbound/inbound.go

@@ -24,12 +24,15 @@ import (
 var (
 	listenPort int
 	healthPort int
+
+	enableTLS bool
 )
 
 var allowedDomains []string
 
 func init() {
 	flag.IntVar(&listenPort, "smtp", 2525, "port on which to listen for incoming emails")
+	flag.IntVar(&listenPort, "smtps", 2526, "port on which to listen for incoming secure emails")
 	flag.IntVar(&healthPort, "health", 8080, "port on which to listen for health checks")
 }
 
@@ -37,6 +40,8 @@ func main() {
 	var err error
 	var log *zap.Logger
 
+	flag.Parse()
+
 	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer cancel()
 
@@ -60,7 +65,12 @@ func main() {
 		log.Fatal("no allowed domains")
 	}
 
-	cm, err := localtls.NewCertManager(os.Getenv("CERTIFICATE_NAME"), os.Getenv("CERTIFICATE_NAMESPACE"))
+	var cm *localtls.CertManager
+
+	if tlsCertFile, ok := os.LookupEnv("TLS_CERT_FILE"); ok {
+		enableTLS = true
+
+		cm, err = localtls.NewCertManager(tlsCertFile, os.Getenv("TLS_KEY_FILE"))
 		if err != nil {
 			log.Fatal("failed to create certificate manager", zap.Error(err))
 		}
@@ -74,12 +84,12 @@ func main() {
 				cancel()
 			}
 		}()
+	}
 
 	be := &server.Backend{
 		AllowedDomains: allowedDomains,
 		Log:            log,
 		LMTPAddress:    os.Getenv("LMTP_ADDRESS"),
-		RootContext:    ctx,
 		RSpam:          milter.NewDefaultClient("tcp", "rspamd:11334"),
 		OverallLimiter: rate.NewLimiter(rate.Limit(10), 20),
 	}
@@ -91,24 +101,37 @@ func main() {
 
 	s.Addr = ":2525"
 	s.Domain = "cycore.io"
+	s.Debug = os.Stderr
 	s.WriteTimeout = 10 * time.Second
 	s.WriteTimeout = 10 * time.Second
 	s.MaxMessageBytes = 300 * 1024 * 1024 // 300 MiB
 	s.MaxRecipients = 10
-	s.TLSConfig = &tls.Config{
-		GetCertificate: cm.Get,
-	}
+	s.AuthDisabled = true
 
 	log.Info("starting health service")
 
 	go runHealthService(cm)
 
-	log.Fatal("server exited", zap.Error(s.ListenAndServeTLS()))
+	if enableTLS {
+		s.TLSConfig = &tls.Config{
+			GetCertificate: cm.Get,
+		}
+
+		go func() {
+			defer cancel()
+
+			if err := s.ListenAndServeTLS(); err != nil {
+				log.Error("TLS listener failed", zap.Error(err))
+			}
+		}()
+	}
+
+	log.Fatal("server exited", zap.Error(s.ListenAndServe()))
 }
 
 func runHealthService(cm *localtls.CertManager) {
 	http.HandleFunc("/health", func(w http.ResponseWriter, req *http.Request) {
-		if !cm.Ready() {
+		if cm != nil && !cm.Ready() {
 			http.Error(w, "no TLS cert", http.StatusInternalServerError)
 
 			return

pkg/tls/tls.go

@@ -41,10 +41,16 @@ func NewCertManager(certFile, keyFile string) (*CertManager, error) {
 }
 
 func (cm *CertManager) Get(_ *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	cm.Log.Info("received request for certificate")
+
 	if cm.cert == nil {
+		cm.Log.Error("no certificate available")
+
 		return nil, errors.New("no certificate")
 	}
 
+	cm.Log.Info("returning certificate to requester")
+
 	return cm.cert, nil
 }
 
@@ -66,12 +72,16 @@ func (cm *CertManager) Ready() bool {
 func (cm *CertManager) Watch(ctx context.Context, log *zap.Logger) error {
 	cm.Log = log
 
+	log.Info("loading certificate")
+
 	if err := cm.Load(); err != nil {
 		log.Error("failed to load initial certificate", zap.Error(err))
 
 		return err
 	}
 
+	log.Info("certificate loaded")
+
 	for {
 		select {
 		case <-time.After(time.Hour):
@@ -79,10 +89,14 @@ func (cm *CertManager) Watch(ctx context.Context, log *zap.Logger) error {
 			return ctx.Err()
 		}
 
+		log.Info("reloading certificate")
+
 		if err := cm.Load(); err != nil {
 			log.Error("failed to reload new certificate", zap.Error(err))
 
 			continue
 		}
+
+		log.Info("certificate reloaded")
 	}
 }

server/server.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"bytes"
-	"context"
 	"crypto/rand"
 	"errors"
 	"fmt"
@@ -47,8 +46,6 @@ type Backend struct {
 
 	Log *zap.Logger
 
-	RootContext context.Context
-
 	RSpam *milter.Client
 
 	OverallLimiter *rate.Limiter
@@ -56,8 +53,7 @@ type Backend struct {
 
 // NewSession implements smtp.Backend
 func (b *Backend) NewSession(conn *smtp.Conn) (smtp.Session, error) {
-	ctx, cancel := context.WithTimeout(b.RootContext, ConnectionTimeout)
-	defer cancel()
+	b.Log.Info("new connection")
 
 	traceID, err := ulid.New(ulid.Now(), rand.Reader)
 	if err != nil {
@@ -68,14 +64,18 @@ func (b *Backend) NewSession(conn *smtp.Conn) (smtp.Session, error) {
 
 	log := b.Log.With(zap.String("traceid", traceID.String()), zap.String("remote", conn.Conn().RemoteAddr().String()))
 
-	log.Debug("received new connection", zap.String("remote", conn.Conn().RemoteAddr().String()))
+	log.Info("received new connection", zap.String("remote", conn.Conn().RemoteAddr().String()))
+
+	if !b.OverallLimiter.Allow() {
+		log.Info("rate limited connection")
 
-	if err := b.OverallLimiter.Wait(ctx); err != nil {
 		return nil, ErrRateLimit
 	}
 
 	rs, err := b.RSpam.Session()
 	if err != nil {
+		log.Error("failed to create new rspam session", zap.Error(err))
+
 		return nil, ErrBadGateway
 	}