feat: release v0.27 unified HTTP limits and safe request shutdown

app/app.go

@@ -33,6 +33,10 @@ type App struct {
 	closeErr         error
 	clientIPResolver *httpx.ClientIPResolver
 	responseEncoder  response.Encoder
+	requests         requestDrain
+	bodyLimits       []routeBodyLimit
+	validateOnce     sync.Once
+	validateErr      error
 }
 
 // Runner is the small lifecycle boundary used by an HTTP server
@@ -100,7 +104,14 @@ func newApp(router httpx.Router, settings config.Config) *App {
 	}
 	middlewares = append(middlewares, middleware.Recovery())
 	application := &App{router: router, config: settings, middlewares: middlewares, clientIPResolver: resolver, responseEncoder: responseEncoder}
-	application.handler = corsPolicy.Wrap(router)
+	application.requests.done = make(chan struct{})
+	application.handler = corsPolicy.Wrap(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.ContentLength > application.hardBodyLimit() {
+			application.adapt(func(*httpx.Context) error { return apierrors.New(413, "BODY_TOO_LARGE", "request body exceeds limit") }).ServeHTTP(w, r)
+			return
+		}
+		router.ServeHTTP(w, r)
+	}))
 	if fallback, ok := router.(httpx.FallbackRouter); ok {
 		adaptError := func(status int, code, message string) http.Handler {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -113,15 +124,31 @@ func newApp(router httpx.Router, settings config.Config) *App {
 }
 
 // Router exposes the underlying routing contract for advanced registration.
-// Serve requests through App or Engine so application CORS policy is applied.
+// Serve through App or Engine for CORS, hard body limits and shutdown tracking.
 func (a *App) Router() httpx.Router { return a.router }
 
 // Engine is kept as a compatibility name for the old API. It returns a
 // standard http.Handler, so callers do not depend on a router type.
-func (a *App) Engine() http.Handler { return a.handler }
+func (a *App) Engine() http.Handler { return a }
 
 // ServeHTTP implements http.Handler for standard servers and HTTP tests.
 func (a *App) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
+	ctx, work := a.requests.begin(request.Context())
+	if work == nil {
+		// Do not invoke encoders, middleware or loggers after their owners close.
+		http.Error(writer, "server shutting down", http.StatusServiceUnavailable)
+		return
+	}
+	defer a.requests.end(work)
+	a.validateOnce.Do(func() { a.validateErr = a.ValidateHTTP() })
+	if a.validateErr != nil {
+		http.Error(writer, "invalid HTTP configuration", http.StatusServiceUnavailable)
+		return
+	}
+	request = request.WithContext(ctx)
+	if request.Body != nil {
+		request.Body = http.MaxBytesReader(writer, request.Body, a.hardBodyLimit())
+	}
 	a.handler.ServeHTTP(writer, request)
 }
 
@@ -143,7 +170,8 @@ func (a *App) Use(middleware ...httpx.Middleware) *App {
 }
 
 // OnShutdown registers a cleanup function owned by the application. Cleanup
-// functions run in reverse registration order when Close or RunContext ends.
+// functions run in reverse registration order after all handlers have returned.
+// Incomplete draining skips these callbacks and returns ErrResourcesRetained.
 // This keeps omni.New as the only public startup entry point while allowing
 // projects to attach databases, loggers and other resources to its lifecycle.
 func (a *App) OnShutdown(cleanup func() error) *App {
@@ -153,9 +181,21 @@ func (a *App) OnShutdown(cleanup func() error) *App {
 	return a
 }
 
-// Close releases application resources. It is safe to call more than once.
+// Close stops admission, cancels active requests and waits for their handlers
+// to return before releasing resources. It is idempotent. If cancellation grace
+// expires, ErrResourcesRetained is permanent and no cleanup callbacks run.
+// Use RunContext/ServeContext for graceful draining before cancellation. Do not
+// call Close from a handler or cleanup callback; it would wait for itself.
 func (a *App) Close() error {
 	a.closeOnce.Do(func() {
+		timeout := a.config.HTTP.ShutdownCancelTimeout
+		if timeout <= 0 {
+			timeout = 5 * time.Second
+		}
+		if err := a.requests.cancelAndWait(timeout); err != nil {
+			a.closeErr = err
+			return
+		}
 		for index := len(a.closers) - 1; index >= 0; index-- {
 			if err := a.closers[index](); err != nil {
 				a.closeErr = errors.Join(a.closeErr, err)
@@ -177,7 +217,7 @@ func (a *App) Run(address ...string) error {
 // Invalid HTTP options panic; RunContext/ServeContext return validation errors.
 // Use RunContext or ServeContext to apply the configured transport and TLS.
 func (a *App) NewServer(address string) *http.Server {
-	if err := a.config.HTTP.Validate(); err != nil {
+	if err := a.ValidateHTTP(); err != nil {
 		panic(err)
 	}
 	if address == "" {
@@ -187,7 +227,7 @@ func (a *App) NewServer(address string) *http.Server {
 		}
 	}
 	cfg := a.config.HTTP
-	return &http.Server{Addr: address, Handler: a.handler,
+	return &http.Server{Addr: address, Handler: a,
 		ReadHeaderTimeout: cfg.ReadHeaderTimeout, ReadTimeout: cfg.ReadTimeout,
 		WriteTimeout: cfg.WriteTimeout, IdleTimeout: cfg.IdleTimeout,
 		MaxHeaderBytes: cfg.MaxHeaderBytes, ErrorLog: cfg.ErrorLog}
@@ -202,6 +242,8 @@ func (a *App) RunContext(ctx context.Context, address ...string) (runErr error)
 	if ctx.Err() != nil {
 		return a.Close()
 	}
+	stopWatching := a.watchShutdown(ctx)
+	defer stopWatching()
 	serve, err := a.prepareTransport()
 	if err != nil {
 		return errors.Join(err, a.Close())
@@ -228,6 +270,11 @@ func (a *App) RunWith(ctx context.Context, runner Runner, address ...string) (ru
 	if ctx.Err() != nil {
 		return a.Close()
 	}
+	if err := a.ValidateHTTP(); err != nil {
+		return errors.Join(err, a.Close())
+	}
+	stopWatching := a.watchShutdown(ctx)
+	defer stopWatching()
 	return errors.Join(runner.Run(ctx, a, a.listenAddress(address...)), a.Close())
 }
 
@@ -261,12 +308,16 @@ func (a *App) serveContext(ctx context.Context, server *http.Server, listener ne
 
 	select {
 	case err := <-serveErr:
+		// Serve returning only proves the accept loop ended. Cancel any remaining
+		// connections before the application completion barrier and cleanup.
+		_ = server.Close()
 		closeErr := a.Close()
 		if err == http.ErrServerClosed {
 			return closeErr
 		}
 		return errors.Join(err, closeErr)
 	case <-ctx.Done():
+		a.requests.stop()
 		shutdownTimeout := a.config.ShutdownTimeout
 		if shutdownTimeout <= 0 {
 			shutdownTimeout = 10 * time.Second
@@ -275,8 +326,8 @@ func (a *App) serveContext(ctx context.Context, server *http.Server, listener ne
 		defer cancel()
 		shutdownErr := server.Shutdown(shutdownCtx)
 		if shutdownErr != nil {
-			// Shutdown leaves active connections open on timeout. Close them so
-			// request contexts are canceled before releasing shared resources.
+			// Closing sockets requests cancellation; App.Close separately waits
+			// for the actual handler return before releasing shared resources.
 			shutdownErr = errors.Join(shutdownErr, server.Close())
 		}
 		if err := <-serveErr; err != nil && err != http.ErrServerClosed {