handle shutdown signal

cmd/inbound/inbound.go

@@ -108,6 +108,8 @@ func main() {
 	s.MaxRecipients = 10
 	s.AuthDisabled = true
 
+	defer s.Close() // nolint:errcheck
+
 	log.Info("starting health service")
 
 	go runHealthService(cm)
@@ -126,7 +128,17 @@ func main() {
 		}()
 	}
 
-	log.Fatal("server exited", zap.Error(s.ListenAndServe()))
+	go func() {
+		defer cancel()
+
+		if err := s.ListenAndServe(); err != nil {
+			log.Error("listener failed", zap.Error(err))
+		}
+	}()
+
+	<-ctx.Done()
+
+	log.Info("exiting")
 }
 
 func runHealthService(cm *localtls.CertManager) {