kubernetes/client-go--使用 Clientset 获取 Kubernetes 资源对象

 

git clone  https://github.com/kubernetes/client-go.git

 

root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# go env  GOPROXY=https://goproxy.cn

root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# go build -o app .
go: downloading github.com/imdario/mergo v0.3.5

 

List

root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# go build -o app .
go: downloading k8s.io/api v0.0.0-20210702094336-49e8721f8489

 

o: downloading k8s.io/api v0.0.0-20210702094336-49e8721f8489
root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# ./app
There are 32 pods in the cluster
Pod example-xxxxx in namespace default not found
^C
root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# 

 

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.Error())
        }

        // create the clientset
        clientset, err := kubernetes.NewForConfig(config)
        if err != nil {
                panic(err.Error())
        }
        for {
                pods, err := clientset.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{})
                if err != nil {
                        panic(err.Error())
                }
                fmt.Printf("There are %d pods in the cluster\n", len(pods.Items))

                // Examples for error handling:
                // - Use helper functions like e.g. errors.IsNotFound()
                // - And/or cast to StatusError and use its properties like e.g. ErrStatus.Message
                namespace := "volcano-system"
                pod := "volcano-scheduler-7f48dddb8f-8g6b5"
                _, err = clientset.CoreV1().Pods(namespace).Get(context.TODO(), pod, metav1.GetOptions{})
                if errors.IsNotFound(err) {
                        fmt.Printf("Pod %s in namespace %s not found\n", pod, namespace)
                } else if statusError, isStatus := err.(*errors.StatusError); isStatus {
                        fmt.Printf("Error getting pod %s in namespace %s: %v\n",
                                pod, namespace, statusError.ErrStatus.Message)
                } else if err != nil {
                        panic(err.Error())
                } else {
                        fmt.Printf("Found pod %s in namespace %s\n", pod, namespace)
                }

                time.Sleep(10 * time.Second)
        }
}

 

root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# ./app
There are 32 pods in the cluster
Found pod volcano-scheduler-7f48dddb8f-8g6b5 in namespace volcano-system
There are 32 pods in the cluster
Found pod volcano-scheduler-7f48dddb8f-8g6b5 in namespace volcano-system
^C

 

volcano-system   volcano-admission-6cc49fdc5-5zgzs          1/1     Running            0          23h     10.244.29.8      bogon     <none>           <none>
volcano-system   volcano-admission-init-qgh9b               0/1     Completed          0          23h     10.244.29.6      bogon     <none>           <none>
volcano-system   volcano-controllers-5f5c4f4785-8dbgl       1/1     Running            0          23h     10.244.29.7      bogon     <none>           <none>
volcano-system   volcano-scheduler-7f48dddb8f-8g6b5         1/1     Running            0          23h     10.244.29.5      bogon     <none>           <none>

 

 

kubernetes.NewForConfig

package main

import (
        "context"
        "flag"
        "fmt"
        "path/filepath"
        //"time"

        //"k8s.io/apimachinery/pkg/api/errors"
        metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
        "k8s.io/client-go/kubernetes"
        "k8s.io/client-go/tools/clientcmd"
        "k8s.io/client-go/util/homedir"
        //
        // Uncomment to load all auth plugins
        // _ "k8s.io/client-go/plugin/pkg/client/auth"
        //
        // Or uncomment to load specific auth plugins
        // _ "k8s.io/client-go/plugin/pkg/client/auth/azure"
        // _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
        // _ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
        // _ "k8s.io/client-go/plugin/pkg/client/auth/openstack"
)

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.Error())
        }

        // create the clientset
        clientset, err := kubernetes.NewForConfig(config)
        if err != nil {
                panic(err.Error())
        }
          // 使用 clientsent 获取 Deployments
        deployments, err := clientset.AppsV1().Deployments("default").List(context.TODO(),metav1.ListOptions{})
        if err != nil {
                          panic(err)
       }
      for idx, deploy := range deployments.Items {
          fmt.Printf("%d -> %s\n", idx+1, deploy.Name)
    }
}

 

root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# go build -o app .
root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# ./app 
1 -> example-foo

 

root@ubuntu:~/sample-controller# kubectl get deployment
NAME          READY   UP-TO-DATE   AVAILABLE   AGE
example-foo   1/1     1            1           3h16m
root@ubuntu:~/sample-controller# 

 

 

 

root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# kubectl get deployments
NAME            READY   UP-TO-DATE   AVAILABLE   AGE
apache-app      2/2     2            2           32d
coffee          2/2     2            2           12d
example-foo     1/1     1            1           59d
igh-agent       1/1     1            1           3d19h
nginx-app       2/2     2            2           32d
nginx-karmada   2/2     2            2           13d
tea             3/3     3            3           12d
wdtest          1/1     1            1           24h
web2            1/1     1            1           34d
web3            1/1     1            1           34d
root@ubuntu:~/client-go/examples/out-of-cluster-client-configuration# ./app
1 -> apache-app
2 -> coffee
3 -> example-foo
4 -> igh-agent
5 -> nginx-app
6 -> nginx-karmada
7 -> tea
8 -> wdtest
9 -> web2
10 -> web3

 

 

使用 Clientset 获取 Kubernetes 资源对象