Use a field name selected cache

The controller-runtime is missing filtering it's cache by labels or
fields [1], this means that all the kubernetes-nmstate-handlers will
read all the nodes and nodenetworkstates every period, clearly dies does
not scale since kubernetes-nmstate-handler runs at as daemonset meaning
that there is one handler running at every node so the bigger the
cluster the bigger the problem.

This change replace the default controller-runtime cache with an
implementation that can be configured to use some field selectors
depending on the resource, this way we can filter by "metadata.name"
using the node name for "node" and "nodenetworkstate" so only one
instance of them is feteched.

[1] kubernetes-sigs/controller-runtime#244

Signed-off-by: Quique Llorente <ellorent@redhat.com>

controllers/node_controller.go

@@ -110,7 +110,7 @@ func (r *NodeReconciler) SetupWithManager(mgr ctrl.Manager) error {
 	// but we only want to watch create/delete for current node.
 	onCreationForThisNode := predicate.Funcs{
 		CreateFunc: func(createEvent event.CreateEvent) bool {
-			return nmstate.EventIsForThisNode(createEvent.Meta)
+			return true
 		},
 		DeleteFunc: func(event.DeleteEvent) bool {
 			return false

controllers/nodenetworkconfigurationpolicy_controller.go

@@ -78,8 +78,7 @@ var (
 			return false
 		},
 		UpdateFunc: func(updateEvent event.UpdateEvent) bool {
-			labelsChanged := !reflect.DeepEqual(updateEvent.MetaOld.GetLabels(), updateEvent.MetaNew.GetLabels())
-			return labelsChanged && nmstate.EventIsForThisNode(updateEvent.MetaNew)
+			return !reflect.DeepEqual(updateEvent.MetaOld.GetLabels(), updateEvent.MetaNew.GetLabels())
 		},
 		GenericFunc: func(event.GenericEvent) bool {
 			return false
@@ -101,8 +100,9 @@ func init() {
 // NodeNetworkConfigurationPolicyReconciler reconciles a NodeNetworkConfigurationPolicy object
 type NodeNetworkConfigurationPolicyReconciler struct {
 	client.Client
-	Log    logr.Logger
-	Scheme *runtime.Scheme
+	APIReader client.Reader
+	Log       logr.Logger
+	Scheme    *runtime.Scheme
 }
 
 func (r *NodeNetworkConfigurationPolicyReconciler) waitEnactmentCreated(enactmentKey types.NamespacedName) error {
@@ -230,7 +230,7 @@ func (r *NodeNetworkConfigurationPolicyReconciler) Reconcile(request ctrl.Reques
 	// Policy conditions will be updated at the end so updating it
 	// does not impact at applying state, it will increase just
 	// reconcile time.
-	defer policyconditions.Update(r.Client, request.NamespacedName)
+	defer policyconditions.Update(r.Client, r.APIReader, request.NamespacedName)
 
 	policySelectors := selectors.NewFromPolicy(r.Client, *instance)
 	unmatchingNodeLabels, err := policySelectors.UnmatchedNodeLabels(nodeName)

controllers/nodenetworkstate_controller.go

@@ -94,11 +94,11 @@ func (r *NodeNetworkStateReconciler) SetupWithManager(mgr ctrl.Manager) error {
 			return false
 		},
 		DeleteFunc: func(deleteEvent event.DeleteEvent) bool {
-			return nmstate.EventIsForThisNode(deleteEvent.Meta)
+			return true
 		},
 		UpdateFunc: func(updateEvent event.UpdateEvent) bool {
-			return nmstate.EventIsForThisNode(updateEvent.MetaNew) &&
-				shouldForceRefresh(updateEvent)
+			return shouldForceRefresh(updateEvent)
+
 		},
 		GenericFunc: func(event.GenericEvent) bool {
 			return false

main.go

@@ -41,6 +41,7 @@ import (
 	nmstatev1alpha1 "github.com/nmstate/kubernetes-nmstate/api/v1alpha1"
 	nmstatev1beta1 "github.com/nmstate/kubernetes-nmstate/api/v1beta1"
 	"github.com/nmstate/kubernetes-nmstate/controllers"
+	"github.com/nmstate/kubernetes-nmstate/pkg/cache"
 	"github.com/nmstate/kubernetes-nmstate/pkg/environment"
 	"github.com/nmstate/kubernetes-nmstate/pkg/webhook"
 )
@@ -93,6 +94,11 @@ func main() {
 	if environment.IsWebhook() {
 		ctrlOptions.LeaderElection = true
 		ctrlOptions.LeaderElectionID = "5d2e944a.nmstate.io"
+	} else if environment.IsHandler() {
+		ctrlOptions.NewCache = cache.Builder(cache.Options{FieldSelectorByResource: map[string]string{
+			"nodes":             fmt.Sprintf("metadata.name=%s", environment.NodeName()),
+			"nodenetworkstates": fmt.Sprintf("metadata.name=%s", environment.NodeName()),
+		}})
 	}
 
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrlOptions)
@@ -151,9 +157,10 @@ func main() {
 			os.Exit(1)
 		}
 		if err = (&controllers.NodeNetworkConfigurationPolicyReconciler{
-			Client: mgr.GetClient(),
-			Log:    ctrl.Log.WithName("controllers").WithName("NodeNetworkConfigurationPolicy"),
-			Scheme: mgr.GetScheme(),
+			Client:    mgr.GetClient(),
+			APIReader: mgr.GetAPIReader(),
+			Log:       ctrl.Log.WithName("controllers").WithName("NodeNetworkConfigurationPolicy"),
+			Scheme:    mgr.GetScheme(),
 		}).SetupWithManager(mgr); err != nil {
 			setupLog.Error(err, "unable to create NodeNetworkConfigurationPolicy controller", "controller", "NMState")
 			os.Exit(1)

pkg/cache/cache.go

@@ -0,0 +1,79 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cache
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/nmstate/kubernetes-nmstate/pkg/cache/internal"
+	"k8s.io/client-go/kubernetes/scheme"
+	"k8s.io/client-go/rest"
+	ctrl "sigs.k8s.io/controller-runtime"
+	crcache "sigs.k8s.io/controller-runtime/pkg/cache"
+	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
+)
+
+var log = ctrl.Log.WithName("object-cache")
+
+var defaultResyncTime = 10 * time.Hour
+
+// Options are the optional arguments for creating a new InformersMap object
+type Options struct {
+	crcache.Options
+	FieldSelectorByResource map[string]string
+}
+
+// New initializes and returns a new Cache.
+func New(config *rest.Config, opts Options) (crcache.Cache, error) {
+	opts, err := defaultOpts(config, opts)
+	if err != nil {
+		return nil, err
+	}
+	im := internal.NewInformersMap(config, opts.Scheme, opts.Mapper, *opts.Resync, opts.Namespace, opts.FieldSelectorByResource)
+	return &informerCache{InformersMap: im}, nil
+}
+
+func Builder(opts Options) crcache.NewCacheFunc {
+	return func(config *rest.Config, cropts crcache.Options) (crcache.Cache, error) {
+		opts.Options = cropts
+		return New(config, opts)
+	}
+}
+
+func defaultOpts(config *rest.Config, opts Options) (Options, error) {
+	// Use the default Kubernetes Scheme if unset
+	if opts.Scheme == nil {
+		opts.Scheme = scheme.Scheme
+	}
+
+	// Construct a new Mapper if unset
+	if opts.Mapper == nil {
+		var err error
+		opts.Mapper, err = apiutil.NewDiscoveryRESTMapper(config)
+		if err != nil {
+			log.WithName("setup").Error(err, "Failed to get API Group-Resources")
+			return opts, fmt.Errorf("could not create RESTMapper from config")
+		}
+	}
+
+	// Default the resync period to 10 hours if unset
+	if opts.Resync == nil {
+		opts.Resync = &defaultResyncTime
+	}
+	return opts, nil
+}

pkg/cache/doc.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package cache provides object caches that act as caching client.Reader
+// instances and help drive Kubernetes-object-based event handlers.
+package cache