🍵 service: gracefully stop previously started services on error

While here, improve relevant log messages.

Author: database64128

api/api.go

@@ -459,5 +459,9 @@ func (s *Server) Start(ctx context.Context) error {
 //
 // Stop implements [shadowsocks.Service.Stop].
 func (s *Server) Stop() error {
-	return s.server.Close()
+	if err := s.server.Close(); err != nil {
+		return err
+	}
+	s.logger.Info("Stopped API server")
+	return nil
 }

cmd/shadowsocks-go/main.go

@@ -99,13 +99,8 @@ func main() {
 		cancel()
 	}()
 
-	if err = m.Start(ctx); err != nil {
-		logger.Fatal("Failed to start services",
-			zap.String("confPath", confPath),
-			zap.Error(err),
-		)
+	if !m.Run(ctx) {
+		m.Close()
+		os.Exit(1)
 	}
-
-	<-ctx.Done()
-	m.Stop()
 }

service/reload_unix.go

@@ -14,15 +14,11 @@ import (
 )
 
 type reloadNotifier struct {
-	sigCh chan os.Signal
 	fns   []func()
+	sigCh chan os.Signal
 }
 
-func newReloadNotifier(logger *zap.Logger, credmgr *cred.Manager, tlsCertStore *tlscerts.Store) reloadNotifier {
-	rn := reloadNotifier{
-		sigCh: make(chan os.Signal, 1),
-	}
-
+func newReloadNotifier(logger *zap.Logger, credmgr *cred.Manager, tlsCertStore *tlscerts.Store) (rn reloadNotifier) {
 	if cmsCount, cmsSeq := credmgr.Servers(); cmsCount > 0 {
 		cms := slices.AppendSeq(make([]*cred.ManagedServer, 0, cmsCount), cmsSeq)
 		rn.fns = append(rn.fns, func() {
@@ -57,6 +53,7 @@ func (rn *reloadNotifier) start() {
 	if len(rn.fns) == 0 {
 		return
 	}
+	rn.sigCh = make(chan os.Signal, 1)
 	signal.Notify(rn.sigCh, syscall.SIGUSR1)
 	go func() {
 		for range rn.sigCh {

service/service.go

@@ -288,34 +288,46 @@ type Manager struct {
 	logger       *zap.Logger
 }
 
-// Start starts all configured services.
-func (m *Manager) Start(ctx context.Context) error {
+// Run starts all services. If any service fails to start, it stops all running services
+// and returns false. On success, it blocks until the context is canceled, and then stops
+// all services. It returns true if no errors were encountered.
+func (m *Manager) Run(ctx context.Context) bool {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
 	m.notifyReload.start()
+
+	ok := true
+	runningSvcs := make([]shadowsocks.Service, 0, len(m.services))
+
 	for _, s := range m.services {
 		if err := s.Start(ctx); err != nil {
-			kv := s.ZapField()
-			return fmt.Errorf("failed to start %s=%q: %w", kv.Key, kv.String, err)
+			m.logger.Error("Failed to start service", s.ZapField(), zap.Error(err))
+			ok = false
+			break
 		}
+		runningSvcs = append(runningSvcs, s)
 	}
-	return nil
-}
 
-// Stop stops all running services.
-func (m *Manager) Stop() {
-	for _, s := range m.services {
-		kv := s.ZapField()
+	if ok {
+		<-ctx.Done()
+	} else {
+		cancel()
+	}
+
+	for _, s := range runningSvcs {
 		if err := s.Stop(); err != nil {
-			m.logger.Warn("Failed to stop service", kv, zap.Error(err))
-			continue
+			m.logger.Error("Failed to stop service", s.ZapField(), zap.Error(err))
 		}
-		m.logger.Info("Stopped service", kv)
 	}
+
 	m.notifyReload.stop()
+	return ok
 }
 
 // Close closes the manager.
 func (m *Manager) Close() {
 	if err := m.router.Close(); err != nil {
-		m.logger.Warn("Failed to close router", zap.Error(err))
+		m.logger.Error("Failed to close router", zap.Error(err))
 	}
 }

service/tcp.go

@@ -306,5 +306,6 @@ func (s *TCPRelay) Stop() error {
 		}
 	}
 
+	s.logger.Info("Stopped TCP relay service", zap.String("server", s.serverName))
 	return nil
 }

service/udp_nat.go

@@ -652,5 +652,6 @@ func (s *UDPNATRelay) Stop() error {
 		}
 	}
 
+	s.logger.Info("Stopped UDP NAT relay service", zap.String("server", s.serverName))
 	return nil
 }

service/udp_session.go

@@ -741,5 +741,6 @@ func (s *UDPSessionRelay) Stop() error {
 		}
 	}
 
+	s.logger.Info("Stopped UDP session relay service", zap.String("server", s.serverName))
 	return nil
 }

service/udp_transparent_linux.go

@@ -808,5 +808,6 @@ func (s *UDPTransparentRelay) Stop() error {
 		}
 	}
 
+	s.logger.Info("Stopped UDP transparent relay service", zap.String("server", s.serverName))
 	return nil
 }