Informer Sample Code

informer-example-coce.go

package main

import (
	"flag"
	"log"
	"path/filepath"
    _ "k8s.io/client-go/plugin/pkg/client/auth"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/informers"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
)

func main() {
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" {
		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file")
	} else {
		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
	}
	flag.Parse()

	// Use the current context in kubeconfig
	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
	if err != nil {
		panic(err)
	}

	// 创建 clientSet 对象，用于与Kubernetes API Server进行交互
	clientSet, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err)
	}

	//创建stopCh对象，该对象用于在程序进程退出之前通知Informer提前退出，因为Informer是一个持久运行的 goroutine
	stopCh := make(chan struct{})
	defer close(stopCh)

	// Create InformerFactory
	informerFactory := informers.NewSharedInformerFactory(clientSet, 0)
	// Create pod informer by informerFactory
	podInformer := informerFactory.Core().V1().Pods()

	/*
	   为 Pod 资源添加资源事件回调方法，支持 AddFunc、UpdateFunc 及 DeleteFunc
	   - AddFunc：   当创建Pod资源对象时触发的事件回调方法。
	   - UpdateFunc：当更新Pod资源对象时触发的事件回调方法。
	   - DeleteFunc：当删除Pod资源对象时触发的事件回调方法。
	*/
	podInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc: func(obj interface{}) {
			mObj := obj.(v1.Object)
			log.Printf("New Pod Added to Store: %s", mObj.GetName())
		},
		UpdateFunc: func(oldObj, newObj interface{}) {
			oObj := oldObj.(v1.Object)
			nObj := newObj.(v1.Object)
			log.Printf("%s Pod Updated to %s", oObj.GetName(), nObj.GetName())

		},
		DeleteFunc: func(obj interface{}) {
			mObj := obj.(v1.Object)
			log.Printf("Pod Deleted from Store: %s", mObj.GetName())
		},
	})

	podInformer.Informer().Run(stopCh)
}