feat: support cache resources configurable #7 (#13)

Signed-off-by: Yusan Kurban <[email protected]>

cmd/app/options/options.go

@@ -1,7 +1,10 @@
 package options
 
 import (
+	"strings"
+
 	"github.com/spf13/pflag"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/component-base/cli/globalflag"
 	"k8s.io/klog/v2"
 	"sigs.k8s.io/controller-runtime/pkg/metrics"
@@ -38,6 +41,8 @@ type Options struct {
 	KubeAPIQPS float32
 	// KubeAPIBurst is the burst to allow while talking with kube-apiserver.
 	KubeAPIBurst int
+	// PreCacheResources is a list of resources name to pre-cache when start up.
+	PreCacheResources string
 }
 
 // NewOptions builds an empty options.
@@ -58,6 +63,8 @@ func (o *Options) AddFlags(flags *pflag.FlagSet) {
 	flags.StringVar(&o.TLSMinVersion, "tls-min-version", defaultTLSMinVersion, "Minimum TLS version supported. Possible values: 1.0, 1.1, 1.2, 1.3.")
 	flags.Float32Var(&o.KubeAPIQPS, "kube-api-qps", 40.0, "QPS to use while talking with kube-apiserver. Doesn't cover events and node heartbeat apis which rate limiting is controlled by a different set of flags.")
 	flags.IntVar(&o.KubeAPIBurst, "kube-api-burst", 60, "Burst to use while talking with kube-apiserver. Doesn't cover events and node heartbeat apis which rate limiting is controlled by a different set of flags.")
+	flags.StringVar(&o.PreCacheResources, "pre-cache-resources", "Deployment/apps/v1,Replicas/apps/v1", "Resources list separate by comma, for example: Pod/v1,Deployment/apps/v1"+
+		". Will pre cache those resources to get it quicker when policies refer resources from cluster.")
 
 	globalflag.AddGlobalFlags(flags, "global")
 }
@@ -68,3 +75,32 @@ func PrintFlags(flags *pflag.FlagSet) {
 		klog.Infof("FLAG: --%s=%q", flag.Name, flag.Value)
 	})
 }
+
+func (o *Options) PreCacheResourcesToGVKList() []schema.GroupVersionKind {
+	var (
+		resourceList = strings.Split(o.PreCacheResources, ",")
+		gvkList      = make([]schema.GroupVersionKind, 0, len(resourceList))
+	)
+
+	for _, resource := range resourceList {
+		items := strings.Split(resource, "/")
+		if len(items) <= 1 {
+			// ignore it
+			continue
+		}
+
+		gvk := schema.GroupVersionKind{
+			Kind:    items[0],
+			Version: items[1],
+		}
+
+		if len(items) == 3 {
+			gvk.Group = items[1]
+			gvk.Version = items[2]
+		}
+
+		gvkList = append(gvkList, gvk)
+	}
+
+	return gvkList
+}

cmd/app/options/options_test.go

@@ -0,0 +1,60 @@
+package options
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+func TestOptions_PreCacheResourcesToGVKList(t *testing.T) {
+	type fields struct {
+		PreCacheResources string
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   []schema.GroupVersionKind
+	}{
+		{
+			name:   "empty",
+			fields: fields{},
+			want:   make([]schema.GroupVersionKind, 0),
+		},
+		{
+			name: "pod",
+			fields: fields{
+				PreCacheResources: "Pod/v1",
+			},
+			want: []schema.GroupVersionKind{
+				{
+					Version: "v1",
+					Kind:    "Pod",
+				},
+			},
+		},
+		{
+			name: "Deployment",
+			fields: fields{
+				PreCacheResources: "Pod/apps/v1",
+			},
+			want: []schema.GroupVersionKind{
+				{
+					Group:   "apps",
+					Version: "v1",
+					Kind:    "Pod",
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			o := &Options{
+				PreCacheResources: tt.fields.PreCacheResources,
+			}
+			if got := o.PreCacheResourcesToGVKList(); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("PreCacheResourcesToGVKList() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

cmd/app/webhook.go

@@ -107,7 +107,9 @@ func Run(ctx context.Context, opts *options.Options) error {
 		return err
 	}
 
-	sm := &setupManager{}
+	sm := &setupManager{
+		opts: opts,
+	}
 	if err := sm.init(hookManager, ctx.Done()); err != nil {
 		klog.ErrorS(err, "init setup manager failed")
 		return err
@@ -167,6 +169,7 @@ func Run(ctx context.Context, opts *options.Options) error {
 }
 
 type setupManager struct {
+	opts                     *options.Options
 	hookManager              manager.Manager
 	done                     <-chan struct{}
 	client                   client.Client
@@ -201,20 +204,8 @@ func (s *setupManager) init(hm manager.Manager, done <-chan struct{}) (err error
 func (s *setupManager) waitForCacheSync(ctx context.Context) error {
 	eg, _ := errgroup.WithContext(ctx)
 	eg.Go(func() error {
-		err := s.drLister.RegisterNewResource(true,
-			// pre cached resources
-			schema.GroupVersionKind{
-				Group:   "apps",
-				Version: "v1",
-				Kind:    "Deployment",
-			}, schema.GroupVersionKind{
-				Version: "v1",
-				Kind:    "Pod",
-			}, schema.GroupVersionKind{
-				Group:   "apps",
-				Version: "v1",
-				Kind:    "ReplicaSet",
-			})
+		// pre cached resources
+		err := s.drLister.RegisterNewResource(true, s.opts.PreCacheResourcesToGVKList()...)
 		if err != nil {
 			klog.ErrorS(err, "failed to register resource to lister")
 		}