mirror of
https://github.com/kubernetes/client-go.git
synced 2025-06-09 07:05:11 +00:00
166 lines
4.6 KiB
Go
166 lines
4.6 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Note: the example only works with the code within the same release/branch.
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package main
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import (
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"bufio"
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"flag"
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"fmt"
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"os"
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"k8s.io/apimachinery/pkg/api/errors"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/client-go/kubernetes"
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apiv1 "k8s.io/api/core/v1"
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appsv1beta1 "k8s.io/api/apps/v1beta1"
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"k8s.io/client-go/tools/clientcmd"
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// Uncomment the following line to load the gcp plugin (only required to authenticate against GKE clusters).
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// _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
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)
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func main() {
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kubeconfig := flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
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flag.Parse()
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if *kubeconfig == "" {
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panic("-kubeconfig not specified")
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}
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config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
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if err != nil {
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panic(err)
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}
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clientset, err := kubernetes.NewForConfig(config)
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if err != nil {
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panic(err)
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}
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deploymentsClient := clientset.AppsV1beta1().Deployments(apiv1.NamespaceDefault)
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deployment := &appsv1beta1.Deployment{
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ObjectMeta: metav1.ObjectMeta{
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Name: "demo-deployment",
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},
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Spec: appsv1beta1.DeploymentSpec{
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Replicas: int32Ptr(2),
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Template: apiv1.PodTemplateSpec{
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ObjectMeta: metav1.ObjectMeta{
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Labels: map[string]string{
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"app": "demo",
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},
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},
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Spec: apiv1.PodSpec{
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Containers: []apiv1.Container{
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{
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Name: "web",
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Image: "nginx:1.13",
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Ports: []apiv1.ContainerPort{
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{
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Name: "http",
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Protocol: apiv1.ProtocolTCP,
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ContainerPort: 80,
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},
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},
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},
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},
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},
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},
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},
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}
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// Create Deployment
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fmt.Println("Creating deployment...")
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result, err := deploymentsClient.Create(deployment)
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if err != nil {
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panic(err)
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}
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fmt.Printf("Created deployment %q.\n", result.GetObjectMeta().GetName())
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// Update Deployment
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prompt()
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fmt.Println("Updating deployment...")
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// You have two options to Update() this Deployment:
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//
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// 1. Modify the "deployment" variable and call: Update(deployment).
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// This works like the "kubectl replace" command and it overwrites/loses changes
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// made by other clients between you Create() and Update() the object.
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// 2. Modify the "result" returned by Create()/Get() and retry Update(result) until
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// you no longer get a conflict error. This way, you can preserve changes made
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// by other clients between Create() and Update(). This is implemented below:
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for {
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result.Spec.Replicas = int32Ptr(1) // reduce replica count
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result.Spec.Template.Annotations = map[string]string{ // add annotations
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"foo": "bar",
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}
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if _, err := deploymentsClient.Update(result); errors.IsConflict(err) {
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// Deployment is modified in the meanwhile, query the latest version
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// and modify the retrieved object.
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fmt.Println("encountered conflict, retrying")
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result, err = deploymentsClient.Get("demo-deployment", metav1.GetOptions{})
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if err != nil {
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panic(fmt.Errorf("Get failed: %+v", err))
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}
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} else if err != nil {
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panic(err)
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} else {
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break
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}
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// TODO: You should sleep here with an exponential backoff to avoid
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// exhausting the apiserver, and add a limit/timeout on the retries to
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// avoid getting stuck in this loop indefintiely.
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}
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fmt.Println("Updated deployment...")
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// List Deployments
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prompt()
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fmt.Printf("Listing deployments in namespace %q:\n", apiv1.NamespaceDefault)
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list, err := deploymentsClient.List(metav1.ListOptions{})
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if err != nil {
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panic(err)
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}
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for _, d := range list.Items {
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fmt.Printf(" * %s (%d replicas)\n", d.Name, *d.Spec.Replicas)
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}
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// Delete Deployment
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prompt()
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fmt.Println("Deleting deployment...")
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deletePolicy := metav1.DeletePropagationForeground
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if err := deploymentsClient.Delete("demo-deployment", &metav1.DeleteOptions{
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PropagationPolicy: &deletePolicy,
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}); err != nil {
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panic(err)
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}
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fmt.Println("Deleted deployment.")
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}
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func prompt() {
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fmt.Printf("-> Press Return key to continue.")
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scanner := bufio.NewScanner(os.Stdin)
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for scanner.Scan() {
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break
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}
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if err := scanner.Err(); err != nil {
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panic(err)
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}
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fmt.Println()
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}
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func int32Ptr(i int32) *int32 { return &i }
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