client-go使用总结一，获取pod状态

client-go使用总结一，获取pod状态

本文主要介绍如何使用client-go对k8s集群中的Pod进行相关操作，也是自己在工作和学习中使用client-go的相关经验总结

一、初始化Pod连接客户端

本质上是对创建与k8s交互客户端的二次封装，可以基于返回的结构体对象扩展不同的方法，每个方法对应着pod不同的操作，既提高了代码的可读性又避免了在对pod进行不同操作时需要反复初始化客户端的问题

type PodBox struct { Clientset kubernetes.Interface Config *restclient.Config}func NewPodBox() (*PodBox, error) { kubeconfig := "k8s集群config配置文件" //kubecofig转换为clientConfig clientConfig,err := clientcmd.NewClientConfigFromBytes([]byte(kubeconfig)) if err != nil { return nil,tracerr.Wrap(err) } //clientConfig转换为rest.config config,err := clientConfig.ClientConfig() if err != nil { return nil,tracerr.Wrap(err) } //创建k8s客户端 cs,err := kubernetes.NewForConfig(config) if err != nil { return nil,tracerr.Wrap(err) } podBox := &PodBox{ Clientset: cs, Config: config, } return podBox,nil}

二、获取Pod实例

func (box *PodBox) Get(podName, namespace string) (*coreV1.Pod,error) { return box.Clientset.CoreV1().Pods(namespace).Get(context.TODO(),podName,metav1.GetOptions{})}

2.1 获取Pod状态

const ( ContainersReady string = "ContainersReady" PodInitialized string = "Initialized" PodReady string = "Ready" PodScheduled string = "PodScheduled")const ( ConditionTrue string = "True" ConditionFalse string = "False" ConditionUnknown string = "Unknown")// GetPodStatus// 获取Pod状态// Pending// Running// Successed// Unavailable// Initializing// Scheduling// NotReady// Failedfunc GetPodStatus(pod *coreV1.Pod) string { for _,cond := range pod.Status.Conditions { if string(cond.Type) == ContainersReady { if string(cond.Status) != ConditionTrue { return "Unavailable" } } else if string(cond.Type) == PodInitialized && string(cond.Status) != ConditionTrue { return "Initializing" } else if string(cond.Type) == PodReady { if string(cond.Status) != ConditionTrue { return "Unavailable" } for _,containerState := range pod.Status.ContainerStatuses { if !containerState.Ready { return "Unavailable" } } } else if string(cond.Type) == PodScheduled && string(cond.Status) != ConditionTrue { return "Scheduling" } } return string(pod.Status.Phase)}

2.2 获取Pod内容器最大重启次数

func MaxContainerRestarts(pod *coreV1.Pod) int { maxRestarts := 0 for _, c := range pod.Status.ContainerStatuses { maxRestarts = integer.IntMax(maxRestarts, int(c.RestartCount)) } return maxRestarts}

2.3 获取pod内容器日志

// WatchContainerLogWithPodNameAndContainerName// 根据命名空间和pod名称以及容器名称，从k8s-apiserver读取容器日志流//入参：//Container:容器名称//Follow:跟踪Pod的日志流，默认为false（关闭）对应kubectl logs命令中的 -f 参数//TailLines:如果设置，则显示从日志末尾开始的行数。如果未指定，则从容器的创建开始或从秒开始或从时间开始显示日志//Previous:返回以前终止的容器日志。默认为false（关闭）func WatchContainerLogWithPodNameAndContainerName(clientset *kubernetes.Clientset, namespace, podName, containerName string,tailLine int64, previous bool) (io.ReadCloser, error) { logOpt := &coreV1.PodLogOptions{ Container: containerName, Follow: true, TailLines: &tailLine, Previous: previous, } req := clientset.CoreV1().Pods(namespace).GetLogs(podName,logOpt) return req.Stream(context.TODO())}

三、根据deployment名称获取pod列表

// PodsGetWithDeploymentNameAndNS// 根据命名空间和deployment名称，从k8s处获取deployment拥有的pod列表func PodsGetWithDeploymentNameAndNS(clientset *kubernetes.Clientset, namespace, deploymentName string) ([]coreV1.Pod, error) { label := "app="+deploymentName podList,err := clientset.CoreV1().Pods(namespace).List(context.TODO(),metav1.ListOptions{LabelSelector: label}) if err != nil { return nil,tracerr.Wrap(err) } return podList.Items,nil}

四、删除Pod

func (box *PodBox) Delete(podName, namespace string) error { return box.Clientset.CoreV1().Pods(namespace).Delete(context.TODO(),podName,metav1.DeleteOptions{})}

五、在Pod的容器中执行命令

func (box *PodBox) Exec(cmd []string, ptyHandler PtyHandler, namespace, podName, containerName string) error { defer func() { ptyHandler.Done() }() req := box.Clientset.CoreV1().RESTClient().Post(). Resource("pods").Name(podName). Namespace(namespace).SubResource("exec"). VersionedParams(&coreV1.PodExecOptions{ Container: containerName, Command: cmd, Stdin: !(ptyHandler.Stdin() == nil), Stdout: !(ptyHandler.Stdout() == nil), Stderr: !(ptyHandler.Stderr() == nil), TTY: ptyHandler.Tty(), },scheme.ParameterCodec) exec,err := remotecommand.NewSPDYExecutor(box.Config,"POST",req.URL()) if err != nil { return tracerr.Wrap(err) } err = exec.Stream(remotecommand.StreamOptions{ Stdin: ptyHandler.Stdin(), Stdout: ptyHandler.Stdout(), Stderr: ptyHandler.Stderr(), TerminalSizeQueue: ptyHandler, Tty: ptyHandler.Tty(), }) if err != nil { return tracerr.Wrap(err) } return nil}

六、Pod内文件下载

func (box *PodBox) CopyFromPod(namespace, podName, containerName, filePath string) (io.Reader,error) { filedir,filename := filepath.Split(filePath) cmd := []string {"sh", "-c", fmt.Sprintf("cd %s && if [ ! -f ./%s ]; then exit 100; fi && tar cf - %s", filedir,filename,filename)} reader,outstream := io.Pipe() ts := NewTerminalSession(nil,outstream,outstream) go func() { defer outstream.Close() err := box.Exec(cmd,ts,namespace,podName,containerName) if err != nil { tracerr.Print(err) } }() return reader,nil}type sizeQueue struct { resizeChan chan remotecommand.TerminalSize doneChan chan struct{}}type TerminalSession struct { stdin io.Reader stdout io.Writer stderr io.Writer sizeQueue tty bool}func NewTerminalSession(stdin io.Reader,stdout io.Writer,stderr io.Writer) *TerminalSession { return &TerminalSession{ stdin: stdin, stdout: stdout, stderr: stderr, tty: false, sizeQueue: sizeQueue{ resizeChan: make(chan remotecommand.TerminalSize), doneChan: make(chan struct{}), }, }}

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