feat(server): add keep-alive endpoint with timeout handling

- Introduced a keep-alive endpoint to monitor service activity.
- Added timeout-specific shutdown functionality when the endpoint is idle.
- Implemented password-protected access for the keep-alive endpoint.
- Updated server startup to support configurable keep-alive options.

internal/api/server.go

@@ -6,12 +6,14 @@ package api
 
 import (
 	"context"
+	"crypto/subtle"
 	"errors"
 	"fmt"
 	"net/http"
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/api/handlers"
@@ -34,6 +36,9 @@ type serverOptionConfig struct {
 	routerConfigurator   func(*gin.Engine, *handlers.BaseAPIHandler, *config.Config)
 	requestLoggerFactory func(*config.Config, string) logging.RequestLogger
 	localPassword        string
+	keepAliveEnabled     bool
+	keepAliveTimeout     time.Duration
+	keepAliveOnTimeout   func()
 }
 
 // ServerOption customises HTTP server construction.
@@ -71,6 +76,18 @@ func WithLocalManagementPassword(password string) ServerOption {
 	}
 }
 
+// WithKeepAliveEndpoint enables a keep-alive endpoint with the provided timeout and callback.
+func WithKeepAliveEndpoint(timeout time.Duration, onTimeout func()) ServerOption {
+	return func(cfg *serverOptionConfig) {
+		if timeout <= 0 || onTimeout == nil {
+			return
+		}
+		cfg.keepAliveEnabled = true
+		cfg.keepAliveTimeout = timeout
+		cfg.keepAliveOnTimeout = onTimeout
+	}
+}
+
 // WithRequestLoggerFactory customises request logger creation.
 func WithRequestLoggerFactory(factory func(*config.Config, string) logging.RequestLogger) ServerOption {
 	return func(cfg *serverOptionConfig) {
@@ -105,6 +122,14 @@ type Server struct {
 
 	// management handler
 	mgmt *managementHandlers.Handler
+
+	localPassword string
+
+	keepAliveEnabled   bool
+	keepAliveTimeout   time.Duration
+	keepAliveOnTimeout func()
+	keepAliveHeartbeat chan struct{}
+	keepAliveStop      chan struct{}
 }
 
 // NewServer creates and initializes a new API server instance.
@@ -174,6 +199,7 @@ func NewServer(cfg *config.Config, authManager *auth.Manager, accessManager *sdk
 	if optionState.localPassword != "" {
 		s.mgmt.SetLocalPassword(optionState.localPassword)
 	}
+	s.localPassword = optionState.localPassword
 
 	// Setup routes
 	s.setupRoutes()
@@ -181,6 +207,10 @@ func NewServer(cfg *config.Config, authManager *auth.Manager, accessManager *sdk
 		optionState.routerConfigurator(engine, s.handlers, cfg)
 	}
 
+	if optionState.keepAliveEnabled {
+		s.enableKeepAlive(optionState.keepAliveTimeout, optionState.keepAliveOnTimeout)
+	}
+
 	// Create HTTP server
 	s.server = &http.Server{
 		Addr:    fmt.Sprintf(":%d", cfg.Port),
@@ -348,6 +378,84 @@ func (s *Server) setupRoutes() {
 	}
 }
 
+func (s *Server) enableKeepAlive(timeout time.Duration, onTimeout func()) {
+	if timeout <= 0 || onTimeout == nil {
+		return
+	}
+
+	s.keepAliveEnabled = true
+	s.keepAliveTimeout = timeout
+	s.keepAliveOnTimeout = onTimeout
+	s.keepAliveHeartbeat = make(chan struct{}, 1)
+	s.keepAliveStop = make(chan struct{}, 1)
+
+	s.engine.GET("/keep-alive", s.handleKeepAlive)
+
+	go s.watchKeepAlive()
+}
+
+func (s *Server) handleKeepAlive(c *gin.Context) {
+	if s.localPassword != "" {
+		provided := strings.TrimSpace(c.GetHeader("Authorization"))
+		if provided != "" {
+			parts := strings.SplitN(provided, " ", 2)
+			if len(parts) == 2 && strings.EqualFold(parts[0], "bearer") {
+				provided = parts[1]
+			}
+		}
+		if provided == "" {
+			provided = strings.TrimSpace(c.GetHeader("X-Local-Password"))
+		}
+		if subtle.ConstantTimeCompare([]byte(provided), []byte(s.localPassword)) != 1 {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "invalid password"})
+			return
+		}
+	}
+
+	s.signalKeepAlive()
+	c.JSON(http.StatusOK, gin.H{"status": "ok"})
+}
+
+func (s *Server) signalKeepAlive() {
+	if !s.keepAliveEnabled {
+		return
+	}
+	select {
+	case s.keepAliveHeartbeat <- struct{}{}:
+	default:
+	}
+}
+
+func (s *Server) watchKeepAlive() {
+	if !s.keepAliveEnabled {
+		return
+	}
+
+	timer := time.NewTimer(s.keepAliveTimeout)
+	defer timer.Stop()
+
+	for {
+		select {
+		case <-timer.C:
+			log.Warnf("keep-alive endpoint idle for %s, shutting down", s.keepAliveTimeout)
+			if s.keepAliveOnTimeout != nil {
+				s.keepAliveOnTimeout()
+			}
+			return
+		case <-s.keepAliveHeartbeat:
+			if !timer.Stop() {
+				select {
+				case <-timer.C:
+				default:
+				}
+			}
+			timer.Reset(s.keepAliveTimeout)
+		case <-s.keepAliveStop:
+			return
+		}
+	}
+}
+
 // unifiedModelsHandler creates a unified handler for the /v1/models endpoint
 // that routes to different handlers based on the User-Agent header.
 // If User-Agent starts with "claude-cli", it routes to Claude handler,
@@ -394,6 +502,13 @@ func (s *Server) Start() error {
 func (s *Server) Stop(ctx context.Context) error {
 	log.Debug("Stopping API server...")
 
+	if s.keepAliveEnabled {
+		select {
+		case s.keepAliveStop <- struct{}{}:
+		default:
+		}
+	}
+
 	// Shutdown the HTTP server.
 	if err := s.server.Shutdown(ctx); err != nil {
 		return fmt.Errorf("failed to shutdown HTTP server: %v", err)

internal/cmd/run.go

@@ -8,7 +8,9 @@ import (
 	"errors"
 	"os/signal"
 	"syscall"
+	"time"
 
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/api"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy"
 	log "github.com/sirupsen/logrus"
@@ -23,19 +25,30 @@ import (
 //   - configPath: The path to the configuration file
 //   - localPassword: Optional password accepted for local management requests
 func StartService(cfg *config.Config, configPath string, localPassword string) {
-	service, err := cliproxy.NewBuilder().
+	builder := cliproxy.NewBuilder().
 		WithConfig(cfg).
 		WithConfigPath(configPath).
-		WithLocalManagementPassword(localPassword).
+		WithLocalManagementPassword(localPassword)
-		Build()
+
+	ctxSignal, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer cancel()
+
+	runCtx := ctxSignal
+	if localPassword != "" {
+		var keepAliveCancel context.CancelFunc
+		runCtx, keepAliveCancel = context.WithCancel(ctxSignal)
+		builder = builder.WithServerOptions(api.WithKeepAliveEndpoint(10*time.Second, func() {
+			log.Warn("keep-alive endpoint idle for 10s, shutting down")
+			keepAliveCancel()
+		}))
+	}
+
+	service, err := builder.Build()
 	if err != nil {
 		log.Fatalf("failed to build proxy service: %v", err)
 	}
 
-	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	err = service.Run(runCtx)
-	defer cancel()
-
-	err = service.Run(ctx)
 	if err != nil && !errors.Is(err, context.Canceled) {
 		log.Fatalf("proxy service exited with error: %v", err)
 	}