k8s_spawn.go

package main

import (
	"fmt"
	"os"
	"path/filepath"
	"time"

	apiv1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
)

const ns = "demo"

func main() {
	clientset := mustNewClientFromOutside()

	listPods(clientset)
	deletePod := deployPod(clientset)
	listPods(clientset)
	time.Sleep(5 * time.Second)
	deletePod()
	listPods(clientset)
}

func listPods(clientset *kubernetes.Clientset) {
	pods, err := clientset.CoreV1().Pods(ns).List(metav1.ListOptions{})
	noerror(err)

	for _, pod := range pods.Items {
		fmt.Printf("%s\n", pod.Name)
	}
}

func deployPod(clientset *kubernetes.Clientset) func() {
	podClient := clientset.CoreV1().Pods(ns)
	pod, err := podClient.Create(&apiv1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name: "test-pod",
		},
		Spec: apiv1.PodSpec{
			Containers: []apiv1.Container{
				{
					Name:  "test-pod-container",
					Image: "b4fun/counter:2018062103",
				},
			},
		},
	})
	noerror(err)

	fmt.Printf("created pod: %s\n", pod.Name)

	return func() {
		noerror(podClient.Delete(pod.Name, nil))
	}
}

func mustNewClientFromOutside() *kubernetes.Clientset {
	homedir := os.Getenv("HOME")
	kubeconfig := filepath.Join(homedir, ".kube", "config")

	config, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
	noerror(err)

	clientset, err := kubernetes.NewForConfig(config)
	noerror(err)

	return clientset
}

func noerror(err error) {
	if err != nil {
		panic(err)
	}
}

func int32Ptr(i int32) *int32 { return &i }