fix(namespace): executor/router/buildermgr RemoveNamespace + per-NS informer lifecycle

- Add RemoveNamespace(ctx, ns) to executortype.ExecutorType interface
- Implement RemoveNamespace in poolmgr, newdeploy, container executor types
- Add per-namespace context cancellation (nsCancels map) in all three types so
  informer factories are stopped when namespace is removed (fixes goroutine leak)
- Add PoolPodController.RemoveNamespace to clear envLister/podLister maps
- Add deregisterNamespace() in executor multitenant subscriber
- Switch executor/router/buildermgr watcher strategy from TrackOnly to DispatchRemove
  so RemoveFunc is called when fission.io/managed label is removed
- Add RemoveFunc to executor/router/buildermgr namespace subscribers
- Add RemoveNamespace to environmentWatcher and packageWatcher with per-NS cancel
- Add RemoveNamespace to HTTPTriggerSet: cancels informers, removes from maps, calls syncTriggers
- Fix ns_watcher_test.go fakeExecutorType to implement new RemoveNamespace method

Fixes:
- Executor dedup gap: re-added namespace was silently skipped (envLister/deplLister still present)
- Goroutine/FD leak: old informer factories ran forever after namespace removal
- Router stale routes: HTTPTriggers for removed namespace stayed in routing table

pkg/executor/executortype/container/containermgr.go

@@ -90,6 +90,10 @@ type (
 		objectReaperIntervalSecond time.Duration
 
 		enableOwnerReferences bool
+
+		// nsCancels holds per-namespace context cancel functions so informer
+		// factories started in AddNamespace can be stopped on RemoveNamespace.
+		nsCancels map[string]context.CancelFunc
 	}
 )
 
@@ -132,8 +136,7 @@ func MakeContainer(
 		deplLister:                 make(map[string]appslisters.DeploymentLister),
 		deplListerSynced:           make(map[string]k8sCache.InformerSynced),
 		svcLister:                  make(map[string]corelisters.ServiceLister),
-		svcListerSynced:            make(map[string]k8sCache.InformerSynced),
-
+		svcListerSynced:            make(map[string]k8sCache.InformerSynced), nsCancels: make(map[string]context.CancelFunc),
 		enableOwnerReferences: utils.IsOwnerReferencesEnabled(),
 	}
 
@@ -833,9 +836,36 @@ func (caaf *Container) AddNamespace(ctx context.Context, ns string, mgr manager.
 		return fmt.Errorf("AddNamespace %s (container): add function handler: %w", ns, err)
 	}
 
-	finformer.Start(ctx.Done())
-	cnmInformer.Start(ctx.Done())
+	// Create a per-namespace cancellable context so RemoveNamespace can stop
+	// these specific informer factories without affecting the whole process.
+	nsCtx, nsCancel := context.WithCancel(ctx)
+	caaf.nsCancels[ns] = nsCancel
+
+	finformer.Start(nsCtx.Done())
+	cnmInformer.Start(nsCtx.Done())
 
 	caaf.logger.Info("AddNamespace: done (container)", zap.String("namespace", ns))
 	return nil
 }
+
+// RemoveNamespace deregisters a namespace from the container executor.
+// Cancels the per-namespace informer context and clears all lister maps so that
+// a subsequent AddNamespace call will re-register the namespace correctly.
+func (caaf *Container) RemoveNamespace(ctx context.Context, ns string) error {
+	if ns == "" {
+		return nil
+	}
+	caaf.logger.Info("RemoveNamespace: cleaning up namespace (container)", zap.String("namespace", ns))
+
+	if cancel, ok := caaf.nsCancels[ns]; ok {
+		cancel()
+		delete(caaf.nsCancels, ns)
+	}
+
+	delete(caaf.deplLister, ns)
+	delete(caaf.deplListerSynced, ns)
+	delete(caaf.svcLister, ns)
+	delete(caaf.svcListerSynced, ns)
+
+	return nil
+}

pkg/executor/executortype/executortype.go

@@ -74,4 +74,9 @@ type ExecutorType interface {
 	// starts watching Fission CRDs and K8s resources in it without a pod restart.
 	// Called when a Namespace with label fission.io/managed=true appears.
 	AddNamespace(ctx context.Context, ns string, mgr manager.Interface) error
+
+	// RemoveNamespace deregisters a namespace from the executor, cancelling its
+	// informer goroutines and clearing dedup state so that a re-add works correctly.
+	// Called when a Namespace with label fission.io/managed=true is removed.
+	RemoveNamespace(ctx context.Context, ns string) error
 }

pkg/executor/executortype/newdeploy/newdeploymgr.go

@@ -94,6 +94,10 @@ type (
 		objectReaperIntervalSecond time.Duration
 
 		enableOwnerReferences bool
+
+		// nsCancels holds per-namespace context cancel functions so informer
+		// factories started in AddNamespace can be stopped on RemoveNamespace.
+		nsCancels map[string]context.CancelFunc
 	}
 )
 
@@ -140,8 +144,7 @@ func MakeNewDeploy(
 		deplLister:       make(map[string]appslisters.DeploymentLister),
 		deplListerSynced: make(map[string]k8sCache.InformerSynced),
 		svcLister:        make(map[string]corelisters.ServiceLister),
-		svcListerSynced:  make(map[string]k8sCache.InformerSynced),
-
+		svcListerSynced:  make(map[string]k8sCache.InformerSynced), nsCancels: make(map[string]context.CancelFunc),
 		enableOwnerReferences: utils.IsOwnerReferencesEnabled(),
 	}
 
@@ -949,9 +952,36 @@ func (deploy *NewDeploy) AddNamespace(ctx context.Context, ns string, mgr manage
 		return fmt.Errorf("AddNamespace %s (newdeploy): add environment handler: %w", ns, err)
 	}
 
-	finformer.Start(ctx.Done())
-	ndmInformer.Start(ctx.Done())
+	// Create a per-namespace cancellable context so RemoveNamespace can stop
+	// these specific informer factories without affecting the whole process.
+	nsCtx, nsCancel := context.WithCancel(ctx)
+	deploy.nsCancels[ns] = nsCancel
+
+	finformer.Start(nsCtx.Done())
+	ndmInformer.Start(nsCtx.Done())
 
 	deploy.logger.Info("AddNamespace: done (newdeploy)", zap.String("namespace", ns))
 	return nil
 }
+
+// RemoveNamespace deregisters a namespace from the newdeploy executor.
+// Cancels the per-namespace informer context and clears all lister maps so that
+// a subsequent AddNamespace call will re-register the namespace correctly.
+func (deploy *NewDeploy) RemoveNamespace(ctx context.Context, ns string) error {
+	if ns == "" {
+		return nil
+	}
+	deploy.logger.Info("RemoveNamespace: cleaning up namespace (newdeploy)", zap.String("namespace", ns))
+
+	if cancel, ok := deploy.nsCancels[ns]; ok {
+		cancel()
+		delete(deploy.nsCancels, ns)
+	}
+
+	delete(deploy.deplLister, ns)
+	delete(deploy.deplListerSynced, ns)
+	delete(deploy.svcLister, ns)
+	delete(deploy.svcListerSynced, ns)
+
+	return nil
+}

pkg/executor/executortype/poolmgr/gpm.go

@@ -98,6 +98,10 @@ type (
 
 		podSpecPatch               *apiv1.PodSpec
 		objectReaperIntervalSecond time.Duration
+
+		// nsCancels holds per-namespace context cancel functions so informer
+		// factories started in AddNamespace can be stopped on RemoveNamespace.
+		nsCancels map[string]context.CancelFunc
 	}
 	request struct {
 		requestType
@@ -159,6 +163,7 @@ func MakeGenericPoolManager(ctx context.Context,
 		objectReaperIntervalSecond: time.Duration(executorUtils.GetObjectReaperInterval(logger, fv1.ExecutorTypePoolmgr, 5)) * time.Second,
 		podLister:                  make(map[string]corelisters.PodLister),
 		podListerSynced:            make(map[string]k8sCache.InformerSynced),
+		nsCancels:                  make(map[string]context.CancelFunc),
 	}
 	for ns, informerFactory := range gpmInformerFactory {
 		gpm.podLister[ns] = informerFactory.Core().V1().Pods().Lister()
@@ -833,10 +838,40 @@ func (gpm *GenericPoolManager) AddNamespace(ctx context.Context, ns string, mgr
 		return fmt.Errorf("AddNamespace %s: register informers: %w", ns, err)
 	}
 
+	// Create a per-namespace cancellable context so RemoveNamespace can stop
+	// these specific informer factories without affecting the whole process.
+	nsCtx, nsCancel := context.WithCancel(ctx)
+	gpm.nsCancels[ns] = nsCancel
+
 	// Start the factories — they will begin syncing immediately.
-	finformer.Start(ctx.Done())
-	gpmInformer.Start(ctx.Done())
+	finformer.Start(nsCtx.Done())
+	gpmInformer.Start(nsCtx.Done())
 
 	gpm.logger.Info("AddNamespace: informers started for namespace", zap.String("namespace", ns))
 	return nil
 }
+
+// RemoveNamespace deregisters a namespace from the poolmgr executor.
+// Cancels the per-namespace informer context and clears all lister maps so that
+// a subsequent AddNamespace call will re-register the namespace correctly.
+func (gpm *GenericPoolManager) RemoveNamespace(ctx context.Context, ns string) error {
+	if ns == "" {
+		return nil
+	}
+	gpm.logger.Info("RemoveNamespace: cleaning up namespace (poolmgr)", zap.String("namespace", ns))
+
+	// Stop informer factories for this namespace.
+	if cancel, ok := gpm.nsCancels[ns]; ok {
+		cancel()
+		delete(gpm.nsCancels, ns)
+	}
+
+	// Clear gpm-level lister maps so dedup passes on next AddNamespace.
+	delete(gpm.podLister, ns)
+	delete(gpm.podListerSynced, ns)
+
+	// Clear PoolPodController lister maps.
+	gpm.poolPodC.RemoveNamespace(ns)
+
+	return nil
+}

pkg/executor/executortype/poolmgr/poolpodcontroller.go

@@ -528,3 +528,14 @@ func (p *PoolPodController) AddNamespaceInformers(
 	p.logger.Info("AddNamespaceInformers: registered informers for namespace", zap.String("namespace", ns))
 	return nil
 }
+
+// RemoveNamespace clears all per-namespace lister state in the PoolPodController.
+// Called from GenericPoolManager.RemoveNamespace so the dedup check in AddNamespace
+// will pass if the namespace is re-added later.
+func (p *PoolPodController) RemoveNamespace(ns string) {
+	delete(p.envLister, ns)
+	delete(p.envListerSynced, ns)
+	delete(p.podLister, ns)
+	delete(p.podListerSynced, ns)
+	p.logger.Info("PoolPodController.RemoveNamespace: cleared lister state", zap.String("namespace", ns))
+}

pkg/executor/multitenant/namespace_subscriber.go

@@ -24,6 +24,9 @@ func NewNamespaceSubscriber(
 			registerNamespace(ctx, logger, kubernetesClient, record.Name, executorTypes, mgr)
 			return nil
 		},
+		RemoveFunc: func(ctx context.Context, record utils.NamespaceRecord) error {
+			return deregisterNamespace(ctx, logger, record.Name, executorTypes)
+		},
 		ResyncFunc: func(ctx context.Context, record utils.NamespaceRecord) error {
 			registerNamespace(ctx, logger, kubernetesClient, record.Name, executorTypes, mgr)
 			return nil

pkg/executor/multitenant/ns_watcher.go

@@ -87,7 +87,9 @@ func StartNSWatcher(
 	executorTypes map[fv1.ExecutorType]executortype.ExecutorType,
 	mgr manager.Interface,
 ) {
-	_, err := utils.RunManagedNamespaceWatcher(ctx, logger, kubernetesClient, mgr, utils.NewDefaultManagedNamespaceWatcherConfig("multitenant.NSWatcher", NewNamespaceSubscriber(logger, kubernetesClient, executorTypes, mgr)))
+	config := utils.NewDefaultManagedNamespaceWatcherConfig("multitenant.NSWatcher", NewNamespaceSubscriber(logger, kubernetesClient, executorTypes, mgr))
+	config.RemovalStrategy = utils.NamespaceRemovalStrategyDispatchRemove
+	_, err := utils.RunManagedNamespaceWatcher(ctx, logger, kubernetesClient, mgr, config)
 	if err != nil {
 		logger.Error("multitenant.NSWatcher: BootstrapAndDispatch failed", zap.Error(err))
 	}
@@ -135,3 +137,26 @@ func registerExecutorTypes(
 	}
 	return joinErr
 }
+
+// deregisterNamespace calls RemoveNamespace on every executor type for the given namespace.
+// Called when a Namespace with label fission.io/managed=true is removed.
+func deregisterNamespace(
+	ctx context.Context,
+	logger *zap.Logger,
+	ns string,
+	executorTypes map[fv1.ExecutorType]executortype.ExecutorType,
+) error {
+	var joinErr error
+
+	for _, et := range executorTypes {
+		if err := et.RemoveNamespace(ctx, ns); err != nil {
+			logger.Error("multitenant.NSWatcher: RemoveNamespace failed",
+				zap.String("namespace", ns),
+				zap.Error(err),
+			)
+			joinErr = errors.Join(joinErr, err)
+		}
+	}
+	logger.Info("multitenant.NSWatcher: deregistered namespace", zap.String("namespace", ns))
+	return joinErr
+}

pkg/executor/multitenant/ns_watcher_test.go

@@ -46,6 +46,7 @@ func (f *fakeExecutorType) AddNamespace(ctx context.Context, ns string, mgr mana
 	f.lastNamespace = ns
 	return f.addErr
 }
+func (f *fakeExecutorType) RemoveNamespace(ctx context.Context, ns string) error { return nil }
 
 var _ executortype.ExecutorType = (*fakeExecutorType)(nil)