新增一种缓存的实现方式 (#110)

Author: caoyingjunz

practise/k8s-practise/gin-informer2.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"path/filepath"
+
+	"github.com/gin-gonic/gin"
+	"k8s.io/apimachinery/pkg/labels"
+	"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() {
+	config, err := clientcmd.BuildConfigFromFlags("", filepath.Join(homedir.HomeDir(), ".kube", "config"))
+	if err != nil {
+		panic(err)
+	}
+	clientSet, err := kubernetes.NewForConfig(config)
+	if err != nil {
+		panic(err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	sharedInformers := informers.NewSharedInformerFactory(clientSet, 0)
+	// refer to https://github.com/kubernetes/kubernetes/blob/ea0764452222146c47ec826977f49d7001b0ea8c/staging/src/k8s.io/client-go/dynamic/dynamicinformer/informer_test.go#L107
+
+	// TODO: 可以追加更多的 gvr
+	//gvrs := []schema.GroupVersionResource{
+	//	{Group: "apps", Version: "v1", Resource: "deployments"},
+	//	{Group: "", Version: "v1", Resource: "pods"},
+	//}
+	//for _, gvr := range gvrs {
+	//	if _, err = sharedInformers.ForResource(gvr); err != nil {
+	//		panic(err)
+	//	}
+	//}
+
+	lsListerSynced := sharedInformers.Core().V1().Pods().Informer().HasSynced
+
+	// Start all informers.
+	sharedInformers.Start(ctx.Done())
+	// Wait for all caches to sync.
+	sharedInformers.WaitForCacheSync(ctx.Done())
+
+	if !cache.WaitForNamedCacheSync("pods", ctx.Done(), lsListerSynced) {
+		return
+	}
+
+	log.Printf("all informers has been started")
+
+	// 构造 pod podLister，用于 gin 的查询
+	podLister := sharedInformers.Core().V1().Pods().Lister()
+	// 启动 gin router
+	// 仅做演示，无封装，无异常处理
+	// 启动之后， curl 127.0.0.1:8088/pods 测试效果
+	r := gin.Default()
+	r.GET("/pods", func(c *gin.Context) {
+		pods, err := podLister.Pods("default").List(labels.Everything())
+		if err != nil {
+			panic(err)
+			c.JSON(http.StatusBadRequest, gin.H{"message": err, "code": 400})
+			return
+		}
+		c.JSON(http.StatusOK, gin.H{"message": "pong", "code": 200, "result": pods})
+	})
+
+	_ = r.Run(":8088")
+}