[系统运维]kubectl通过插件获取pod列表

一 获取pod基础信息并且格式化展示

package main

import (
	"context"
	"github.com/olekukonko/tablewriter"
	"github.com/spf13/cobra"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/client-go/kubernetes"
	"log"
	"os"
)

var client = InitClient() //这是 clientset

//核心的执行函数
func run(c *cobra.Command, args []string) error {
	//获取ns
	ns, err := c.Flags().GetString("namespace")
	if err != nil {
		return err
	}
	if ns == "" {
		ns = "default"
	}
	//拿到具体的数据
	list, err := client.CoreV1().Pods(ns).List(context.Background(), v1.ListOptions{})
	if err != nil {
		return err
	}
	//表格处理
	table := tablewriter.NewWriter(os.Stdout)
	table.SetHeader([]string{"名称", "命名空间", "IP", "状态"})

	for _, pod := range list.Items {
		table.Append([]string{pod.Name, pod.Namespace, pod.Status.PodIP,
			string(pod.Status.Phase)})
	}
	table.Render()
	return nil

}

var cfgFlags *genericclioptions.ConfigFlags

//通过config 获取clientset client
func InitClient() *kubernetes.Clientset {
	//拿到config
	cfgFlags = genericclioptions.NewConfigFlags(true)
	config, err := cfgFlags.ToRawKubeConfigLoader().ClientConfig()
	if err != nil {
		log.Fatalln(err)
	}
	//获取clientset
	c, err := kubernetes.NewForConfig(config)
	if err != nil {
		log.Fatalln(err)
	}
	return c
}

//执行cmd 核心是rune
func RunCmd(f func(c *cobra.Command, args []string) error) {
	cmd := &cobra.Command{
		Use:          "kubectl pods [flags]",
		Short:        "list pods ",
		Example:      "kubectl pods [flags]",
		SilenceUsage: true,
		RunE:         f,
	}
	//AddFlags 将客户端配置标志绑定到给定的标志集
	cfgFlags.AddFlags(cmd.Flags())

	err := cmd.Execute()
	if err != nil {
		log.Fatalln(err)
	}
}

func main() {
	RunCmd(run)
}

go build main.go
mv main /Users/qushuaibo/temp/kubectl-plugins/kubectl-pods
kubectl pods 

二 给pod添加标签选项

package main

import (
	"context"
	"fmt"
	"github.com/olekukonko/tablewriter"
	"github.com/spf13/cobra"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/client-go/kubernetes"
	"log"
	"os"
)

var (
	ShowLabels bool
	client = InitClient() //这是 clientset
)

func InitClient() *kubernetes.Clientset{
	cfgFlags =genericclioptions.NewConfigFlags(true)
	config,err:= cfgFlags.ToRawKubeConfigLoader().ClientConfig()
	if err!=nil{log.Fatalln(err)}
	c,err:=kubernetes.NewForConfig(config)
	if err!=nil{log.Fatalln(err)}
	return c
}

func InitHeader(table *tablewriter.Table) []string  {
	commonHeaders:=[]string{"名称", "命名空间", "IP","状态"}
	if  ShowLabels{
		commonHeaders=append(commonHeaders,"标签")
	}
	return commonHeaders
}


func Map2String(m map[string]string) (ret string )  {
	for k,v:=range m{
		ret+=fmt.Sprintf("%s=%s\n",k,v)
	}
	return
}

func run(c *cobra.Command, args []string) error {
	ns, err := c.Flags().GetString("namespace")
	if err != nil {
		return err
	}
	if ns == "" {
		ns = "default"
	}
	list, err := client.CoreV1().Pods(ns).List(context.Background(), v1.ListOptions{})
	if err != nil {
		return err
	}
	table := tablewriter.NewWriter(os.Stdout)
	//设置头
	table.SetHeader(InitHeader(table))
	for _, pod := range list.Items {
		podRow := []string{pod.Name, pod.Namespace, pod.Status.PodIP,
			string(pod.Status.Phase)}
		if ShowLabels {
			podRow = append(podRow, Map2String(pod.Labels))
		}
		table.Append(podRow)
	}
	table.SetAutoWrapText(false)
	table.SetAutoFormatHeaders(true)
	table.SetHeaderAlignment(tablewriter.ALIGN_LEFT)
	table.SetAlignment(tablewriter.ALIGN_LEFT)
	table.SetCenterSeparator("")
	table.SetColumnSeparator("")
	table.SetRowSeparator("")
	table.SetHeaderLine(false)
	table.SetBorder(false)
	table.SetTablePadding("\t") // pad with tabs
	table.SetNoWhiteSpace(true)
	table.Render()
	return nil

}

func RunCmd(f func(c *cobra.Command, args []string) error ) {
	cmd := &cobra.Command{
		Use:          "kubectl pods [flags]",
		Short:        "list pods ",
		Example:      "kubectl pods [flags]",
		SilenceUsage: true,
		RunE:         f,
	}

	cfgFlags.AddFlags(cmd.Flags())

	cmd.Flags().BoolVar(&ShowLabels,"show-labels",false,"kubectl pods --show-lables")

	err:=cmd.Execute()
	if err!=nil{
		log.Fatalln(err)
	}

}




func main() {
	RunCmd(run)
}