chore: add informer util (#3796)

Makefile

@@ -59,7 +59,7 @@ PWD := $(CURDIR)
 INITC_PATH := cmd/initContainer
 INITC_IMAGE := kyvernopre
 initContainer: fmt vet
-	GOOS=$(GOOS) go build -o $(PWD)/$(INITC_PATH)/kyvernopre -ldflags=$(LD_FLAGS) $(PWD)/$(INITC_PATH)/main.go
+	GOOS=$(GOOS) go build -o $(PWD)/$(INITC_PATH)/kyvernopre -ldflags=$(LD_FLAGS) $(PWD)/$(INITC_PATH)
 
 .PHONY: docker-build-initContainer docker-push-initContainer
 
@@ -84,7 +84,7 @@ docker-get-initContainer-digest:
 	@docker buildx imagetools inspect --raw $(REPO)/$(INITC_IMAGE):$(IMAGE_TAG) | perl -pe 'chomp if eof' | openssl dgst -sha256 | sed 's/^.* //'
 
 docker-build-initContainer-local:
-	CGO_ENABLED=0 GOOS=linux go build -o $(PWD)/$(INITC_PATH)/kyvernopre -ldflags=$(LD_FLAGS) $(PWD)/$(INITC_PATH)/main.go
+	CGO_ENABLED=0 GOOS=linux go build -o $(PWD)/$(INITC_PATH)/kyvernopre -ldflags=$(LD_FLAGS) $(PWD)/$(INITC_PATH)
 	@docker build -f $(PWD)/$(INITC_PATH)/localDockerfile -t $(REPO)/$(INITC_IMAGE):$(IMAGE_TAG_DEV) $(PWD)/$(INITC_PATH)
 	@docker tag $(REPO)/$(INITC_IMAGE):$(IMAGE_TAG_DEV) $(REPO)/$(INITC_IMAGE):latest
 
@@ -111,7 +111,7 @@ local:
 	go build -ldflags=$(LD_FLAGS) $(PWD)/$(CLI_PATH)
 
 kyverno: fmt vet
-	GOOS=$(GOOS) go build -o $(PWD)/$(KYVERNO_PATH)/kyverno -ldflags=$(LD_FLAGS) $(PWD)/$(KYVERNO_PATH)/main.go
+	GOOS=$(GOOS) go build -o $(PWD)/$(KYVERNO_PATH)/kyverno -ldflags=$(LD_FLAGS) $(PWD)/$(KYVERNO_PATH)
 
 docker-publish-kyverno: docker-buildx-builder docker-build-kyverno docker-push-kyverno
 
@@ -119,7 +119,7 @@ docker-build-kyverno: docker-buildx-builder
 	@docker buildx build --file $(PWD)/$(KYVERNO_PATH)/Dockerfile --progress plane --platform linux/arm64,linux/amd64,linux/s390x --tag $(REPO)/$(KYVERNO_IMAGE):$(IMAGE_TAG) . --build-arg LD_FLAGS=$(LD_FLAGS)
 
 docker-build-kyverno-local:
-	CGO_ENABLED=0 GOOS=linux go build -o $(PWD)/$(KYVERNO_PATH)/kyverno -ldflags=$(LD_FLAGS_DEV) $(PWD)/$(KYVERNO_PATH)/main.go
+	CGO_ENABLED=0 GOOS=linux go build -o $(PWD)/$(KYVERNO_PATH)/kyverno -ldflags=$(LD_FLAGS_DEV) $(PWD)/$(KYVERNO_PATH)
 	@docker build -f $(PWD)/$(KYVERNO_PATH)/localDockerfile -t $(REPO)/$(KYVERNO_IMAGE):$(IMAGE_TAG_DEV) -t $(REPO)/$(KYVERNO_IMAGE):latest $(PWD)/$(KYVERNO_PATH)
 	@docker tag $(REPO)/$(KYVERNO_IMAGE):$(IMAGE_TAG_DEV) $(REPO)/$(KYVERNO_IMAGE):$(IMAGE_TAG_LATEST_DEV)-latest
 
@@ -174,7 +174,7 @@ CLI_PATH := cmd/cli/kubectl-kyverno
 KYVERNO_CLI_IMAGE := kyverno-cli
 
 cli:
-	GOOS=$(GOOS) go build -o $(PWD)/$(CLI_PATH)/kyverno -ldflags=$(LD_FLAGS) $(PWD)/$(CLI_PATH)/main.go
+	GOOS=$(GOOS) go build -o $(PWD)/$(CLI_PATH)/kyverno -ldflags=$(LD_FLAGS) $(PWD)/$(CLI_PATH)
 
 docker-publish-cli: docker-buildx-builder docker-build-cli docker-push-cli
 

cmd/kyverno/informer.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"reflect"
+)
+
+// TODO: eventually move this in an util package
+type informer interface {
+	Start(stopCh <-chan struct{})
+	WaitForCacheSync(stopCh <-chan struct{}) map[reflect.Type]bool
+}
+
+func startInformers(stopCh <-chan struct{}, informers ...informer) {
+	for i := range informers {
+		informers[i].Start(stopCh)
+	}
+}
+
+func waitForCacheSync(stopCh <-chan struct{}, informers ...informer) {
+	for i := range informers {
+		informers[i].WaitForCacheSync(stopCh)
+	}
+}
+
+func startInformersAndWaitForCacheSync(stopCh <-chan struct{}, informers ...informer) {
+	startInformers(stopCh, informers...)
+	waitForCacheSync(stopCh, informers...)
+}

cmd/kyverno/main.go

@@ -343,9 +343,7 @@ func main() {
 	registerWrapperRetry := common.RetryFunc(time.Second, webhookRegistrationTimeout, webhookCfg.Register, "failed to register webhook", setupLog)
 	registerWebhookConfigurations := func() {
 		certManager.InitTLSPemPair()
-		kyvernoInformer.WaitForCacheSync(stopCh)
+		waitForCacheSync(stopCh, kyvernoInformer, kubeInformer, kubeKyvernoInformer)
-		kubeInformer.WaitForCacheSync(stopCh)
-		kubeKyvernoInformer.WaitForCacheSync(stopCh)
 
 		// validate the ConfigMap format
 		if err := webhookCfg.ValidateWebhookConfigurations(config.KyvernoNamespace, configData.GetInitConfigMapName()); err != nil {
@@ -459,12 +457,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	kyvernoInformer.Start(stopCh)
+	startInformersAndWaitForCacheSync(stopCh, kyvernoInformer, kubeInformer, kubeKyvernoInformer)
-	kubeInformer.Start(stopCh)
-	kubeKyvernoInformer.Start(stopCh)
-	kyvernoInformer.WaitForCacheSync(stopCh)
-	kubeInformer.WaitForCacheSync(stopCh)
-	kubeKyvernoInformer.WaitForCacheSync(stopCh)
 
 	pCacheController.CheckPolicySync(stopCh)