fix: stabilize federated agent runtime updates (#550)

go-gost/x/socket/service_test.go

@@ -7,6 +7,8 @@ import (
 	corelogger "github.com/go-gost/core/logger"
 	"github.com/go-gost/core/service"
 	"github.com/go-gost/x/config"
+	_ "github.com/go-gost/x/handler/auto"
+	_ "github.com/go-gost/x/listener/tcp"
 	xlogger "github.com/go-gost/x/logger"
 	"github.com/go-gost/x/registry"
 )
@@ -15,6 +17,43 @@ type recordingService struct {
 	closed int
 }
 
+func TestUpdateServicesParseFailureRestoresPreviousRuntime(t *testing.T) {
+	corelogger.SetDefault(xlogger.Nop())
+
+	name := "restore_after_failed_update_tdd"
+	existing := &recordingService{}
+	registry.ServiceRegistry().Unregister(name)
+	t.Cleanup(func() { registry.ServiceRegistry().Unregister(name) })
+	if err := registry.ServiceRegistry().Register(name, service.Service(existing)); err != nil {
+		t.Fatalf("register existing service: %v", err)
+	}
+
+	originalConfig := config.Global()
+	t.Cleanup(func() { config.Set(originalConfig) })
+	serviceConfig := config.ServiceConfig{Name: name, Addr: "127.0.0.1:0"}
+	config.Set(&config.Config{Services: []*config.ServiceConfig{&serviceConfig}})
+
+	invalid := serviceConfig
+	invalid.Listener = &config.ListenerConfig{Type: "listener-does-not-exist"}
+	if err := updateServices(updateServicesRequest{Data: []config.ServiceConfig{invalid}}); err == nil {
+		t.Fatalf("expected invalid service update to fail")
+	}
+	if existing.closed != 1 {
+		t.Fatalf("expected old runtime to be closed once, got %d", existing.closed)
+	}
+	if registry.ServiceRegistry().Get(name) == nil {
+		t.Fatalf("expected previous runtime to be restored")
+	}
+
+	cfg := config.Global()
+	if len(cfg.Services) != 1 || cfg.Services[0] == nil || cfg.Services[0].Name != name {
+		t.Fatalf("expected previous config to remain, got %#v", cfg.Services)
+	}
+	if cfg.Services[0].Listener != nil {
+		t.Fatalf("expected previous listener config to remain unchanged")
+	}
+}
+
 func (s *recordingService) Serve() error   { return nil }
 func (s *recordingService) Addr() net.Addr { return nil }
 func (s *recordingService) Close() error {