chore: add crd client-go example

Author: colin404

.todo.md

@@ -27,7 +27,6 @@
 
 [?] https://github.com/samber/lo
 [?] loki: https://github.com/piupuer/gin-web
-[?] 使用 clientBuilder，参考clusternet-agent源码
 [?] 使用 gin + mysql 实现类似kube-apiserver
 [?] loft 调研
 [?] onex-apiserver 后端对接 ES
@@ -131,3 +130,4 @@
 [✔] 缓存服务添加
 [✔] 项目文档补全
 [✔] 课程目录补全（精细版）
+[✔] 使用 clientBuilder，参考clusternet-agent源码

examples/client-go/crd/main.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/dynamic"
+	"k8s.io/client-go/tools/clientcmd"
+)
+
+func main() {
+	configLoader := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
+		clientcmd.NewDefaultClientConfigLoadingRules(),
+		&clientcmd.ConfigOverrides{},
+	)
+
+	namespace, _, err := configLoader.Namespace()
+	if err != nil {
+		panic(err)
+	}
+
+	cfg, err := configLoader.ClientConfig()
+	if err != nil {
+		panic(err)
+	}
+
+	dc, err := dynamic.NewForConfig(cfg)
+	if err != nil {
+		panic(err)
+	}
+
+	// identify out custom resource
+	gvr := schema.GroupVersionResource{
+		Group:    "webapp.my.domain",
+		Version:  "v1",
+		Resource: "guestbooks",
+	}
+	// retrieve the resource of kind Pizza named 'margherita'
+	res, err := dc.Resource(gvr).
+		Namespace(namespace).
+		Get(context.TODO(), "guestbook-sample", metav1.GetOptions{})
+	if err != nil {
+		if errors.IsNotFound(err) {
+			return
+		}
+		panic(err)
+	}
+	data, _ := json.Marshal(res)
+	fmt.Println(string(data))
+
+	// grab the status if exists
+	status, ok := res.Object["status"]
+	if !ok {
+		// otherwise create it
+		status = make(map[string]interface{})
+	}
+
+	// change the 'margherita' price
+	status.(map[string]interface{})["cost"] = 6.50
+	res.Object["status"] = status
+
+	// update the 'margherita' custom resource with the new price
+	_, err = dc.Resource(gvr).Namespace(namespace).Update(context.TODO(), res, metav1.UpdateOptions{})
+	if err != nil {
+		panic(err)
+	}
+}