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- /*
- Copyright 2014 The Kubernetes Authors.
- Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
- http://www.apache.org/licenses/LICENSE-2.0
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- */
- package attach
- import (
- "fmt"
- "io"
- "net/url"
- "time"
- "github.com/spf13/cobra"
- "k8s.io/klog"
- corev1 "k8s.io/api/core/v1"
- "k8s.io/apimachinery/pkg/runtime"
- "k8s.io/cli-runtime/pkg/genericclioptions"
- "k8s.io/cli-runtime/pkg/resource"
- restclient "k8s.io/client-go/rest"
- "k8s.io/client-go/tools/remotecommand"
- "k8s.io/kubernetes/pkg/kubectl/cmd/exec"
- cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
- "k8s.io/kubernetes/pkg/kubectl/polymorphichelpers"
- "k8s.io/kubernetes/pkg/kubectl/scheme"
- "k8s.io/kubernetes/pkg/kubectl/util/i18n"
- "k8s.io/kubernetes/pkg/kubectl/util/templates"
- )
- var (
- attachExample = templates.Examples(i18n.T(`
- # Get output from running pod 123456-7890, using the first container by default
- kubectl attach 123456-7890
- # Get output from ruby-container from pod 123456-7890
- kubectl attach 123456-7890 -c ruby-container
- # Switch to raw terminal mode, sends stdin to 'bash' in ruby-container from pod 123456-7890
- # and sends stdout/stderr from 'bash' back to the client
- kubectl attach 123456-7890 -c ruby-container -i -t
- # Get output from the first pod of a ReplicaSet named nginx
- kubectl attach rs/nginx
- `))
- )
- const (
- defaultPodAttachTimeout = 60 * time.Second
- defaultPodLogsTimeout = 20 * time.Second
- )
- // AttachOptions declare the arguments accepted by the Attach command
- type AttachOptions struct {
- exec.StreamOptions
- // whether to disable use of standard error when streaming output from tty
- DisableStderr bool
- CommandName string
- ParentCommandName string
- EnableSuggestedCmdUsage bool
- Pod *corev1.Pod
- AttachFunc func(*AttachOptions, *corev1.Container, bool, remotecommand.TerminalSizeQueue) func() error
- Resources []string
- Builder func() *resource.Builder
- AttachablePodFn polymorphichelpers.AttachablePodForObjectFunc
- restClientGetter genericclioptions.RESTClientGetter
- Attach RemoteAttach
- GetPodTimeout time.Duration
- Config *restclient.Config
- }
- // NewAttachOptions creates the options for attach
- func NewAttachOptions(streams genericclioptions.IOStreams) *AttachOptions {
- return &AttachOptions{
- StreamOptions: exec.StreamOptions{
- IOStreams: streams,
- },
- Attach: &DefaultRemoteAttach{},
- AttachFunc: DefaultAttachFunc,
- }
- }
- // NewCmdAttach returns the attach Cobra command
- func NewCmdAttach(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
- o := NewAttachOptions(streams)
- cmd := &cobra.Command{
- Use: "attach (POD | TYPE/NAME) -c CONTAINER",
- DisableFlagsInUseLine: true,
- Short: i18n.T("Attach to a running container"),
- Long: "Attach to a process that is already running inside an existing container.",
- Example: attachExample,
- Run: func(cmd *cobra.Command, args []string) {
- cmdutil.CheckErr(o.Complete(f, cmd, args))
- cmdutil.CheckErr(o.Validate())
- cmdutil.CheckErr(o.Run())
- },
- }
- cmdutil.AddPodRunningTimeoutFlag(cmd, defaultPodAttachTimeout)
- cmd.Flags().StringVarP(&o.ContainerName, "container", "c", o.ContainerName, "Container name. If omitted, the first container in the pod will be chosen")
- cmd.Flags().BoolVarP(&o.Stdin, "stdin", "i", o.Stdin, "Pass stdin to the container")
- cmd.Flags().BoolVarP(&o.TTY, "tty", "t", o.TTY, "Stdin is a TTY")
- return cmd
- }
- // RemoteAttach defines the interface accepted by the Attach command - provided for test stubbing
- type RemoteAttach interface {
- Attach(method string, url *url.URL, config *restclient.Config, stdin io.Reader, stdout, stderr io.Writer, tty bool, terminalSizeQueue remotecommand.TerminalSizeQueue) error
- }
- // DefaultAttachFunc is the default AttachFunc used
- func DefaultAttachFunc(o *AttachOptions, containerToAttach *corev1.Container, raw bool, sizeQueue remotecommand.TerminalSizeQueue) func() error {
- return func() error {
- restClient, err := restclient.RESTClientFor(o.Config)
- if err != nil {
- return err
- }
- req := restClient.Post().
- Resource("pods").
- Name(o.Pod.Name).
- Namespace(o.Pod.Namespace).
- SubResource("attach")
- req.VersionedParams(&corev1.PodAttachOptions{
- Container: containerToAttach.Name,
- Stdin: o.Stdin,
- Stdout: o.Out != nil,
- Stderr: !o.DisableStderr,
- TTY: raw,
- }, scheme.ParameterCodec)
- return o.Attach.Attach("POST", req.URL(), o.Config, o.In, o.Out, o.ErrOut, raw, sizeQueue)
- }
- }
- // DefaultRemoteAttach is the standard implementation of attaching
- type DefaultRemoteAttach struct{}
- // Attach executes attach to a running container
- func (*DefaultRemoteAttach) Attach(method string, url *url.URL, config *restclient.Config, stdin io.Reader, stdout, stderr io.Writer, tty bool, terminalSizeQueue remotecommand.TerminalSizeQueue) error {
- exec, err := remotecommand.NewSPDYExecutor(config, method, url)
- if err != nil {
- return err
- }
- return exec.Stream(remotecommand.StreamOptions{
- Stdin: stdin,
- Stdout: stdout,
- Stderr: stderr,
- Tty: tty,
- TerminalSizeQueue: terminalSizeQueue,
- })
- }
- // Complete verifies command line arguments and loads data from the command environment
- func (o *AttachOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
- var err error
- o.Namespace, _, err = f.ToRawKubeConfigLoader().Namespace()
- if err != nil {
- return err
- }
- o.AttachablePodFn = polymorphichelpers.AttachablePodForObjectFn
- o.GetPodTimeout, err = cmdutil.GetPodRunningTimeoutFlag(cmd)
- if err != nil {
- return cmdutil.UsageErrorf(cmd, err.Error())
- }
- o.Builder = f.NewBuilder
- o.Resources = args
- o.restClientGetter = f
- cmdParent := cmd.Parent()
- if cmdParent != nil {
- o.ParentCommandName = cmdParent.CommandPath()
- }
- if len(o.ParentCommandName) > 0 && cmdutil.IsSiblingCommandExists(cmd, "describe") {
- o.EnableSuggestedCmdUsage = true
- }
- config, err := f.ToRESTConfig()
- if err != nil {
- return err
- }
- o.Config = config
- if o.CommandName == "" {
- o.CommandName = cmd.CommandPath()
- }
- return nil
- }
- // Validate checks that the provided attach options are specified.
- func (o *AttachOptions) Validate() error {
- if len(o.Resources) == 0 {
- return fmt.Errorf("at least 1 argument is required for attach")
- }
- if len(o.Resources) > 2 {
- return fmt.Errorf("expected POD, TYPE/NAME, or TYPE NAME, (at most 2 arguments) saw %d: %v", len(o.Resources), o.Resources)
- }
- if o.GetPodTimeout <= 0 {
- return fmt.Errorf("--pod-running-timeout must be higher than zero")
- }
- return nil
- }
- // Run executes a validated remote execution against a pod.
- func (o *AttachOptions) Run() error {
- if o.Pod == nil {
- b := o.Builder().
- WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
- NamespaceParam(o.Namespace).DefaultNamespace()
- switch len(o.Resources) {
- case 1:
- b.ResourceNames("pods", o.Resources[0])
- case 2:
- b.ResourceNames(o.Resources[0], o.Resources[1])
- }
- obj, err := b.Do().Object()
- if err != nil {
- return err
- }
- o.Pod, err = o.findAttachablePod(obj)
- if err != nil {
- return err
- }
- if o.Pod.Status.Phase == corev1.PodSucceeded || o.Pod.Status.Phase == corev1.PodFailed {
- return fmt.Errorf("cannot attach a container in a completed pod; current phase is %s", o.Pod.Status.Phase)
- }
- // TODO: convert this to a clean "wait" behavior
- }
- // check for TTY
- containerToAttach, err := o.containerToAttachTo(o.Pod)
- if err != nil {
- return fmt.Errorf("cannot attach to the container: %v", err)
- }
- if o.TTY && !containerToAttach.TTY {
- o.TTY = false
- if o.ErrOut != nil {
- fmt.Fprintf(o.ErrOut, "Unable to use a TTY - container %s did not allocate one\n", containerToAttach.Name)
- }
- } else if !o.TTY && containerToAttach.TTY {
- // the container was launched with a TTY, so we have to force a TTY here, otherwise you'll get
- // an error "Unrecognized input header"
- o.TTY = true
- }
- // ensure we can recover the terminal while attached
- t := o.SetupTTY()
- var sizeQueue remotecommand.TerminalSizeQueue
- if t.Raw {
- if size := t.GetSize(); size != nil {
- // fake resizing +1 and then back to normal so that attach-detach-reattach will result in the
- // screen being redrawn
- sizePlusOne := *size
- sizePlusOne.Width++
- sizePlusOne.Height++
- // this call spawns a goroutine to monitor/update the terminal size
- sizeQueue = t.MonitorSize(&sizePlusOne, size)
- }
- o.DisableStderr = true
- }
- if !o.Quiet {
- fmt.Fprintln(o.ErrOut, "If you don't see a command prompt, try pressing enter.")
- }
- if err := t.Safe(o.AttachFunc(o, containerToAttach, t.Raw, sizeQueue)); err != nil {
- return err
- }
- if o.Stdin && t.Raw && o.Pod.Spec.RestartPolicy == corev1.RestartPolicyAlways {
- fmt.Fprintf(o.Out, "Session ended, resume using '%s %s -c %s -i -t' command when the pod is running\n", o.CommandName, o.Pod.Name, containerToAttach.Name)
- }
- return nil
- }
- func (o *AttachOptions) findAttachablePod(obj runtime.Object) (*corev1.Pod, error) {
- attachablePod, err := o.AttachablePodFn(o.restClientGetter, obj, o.GetPodTimeout)
- if err != nil {
- return nil, err
- }
- o.StreamOptions.PodName = attachablePod.Name
- return attachablePod, nil
- }
- // containerToAttach returns a reference to the container to attach to, given
- // by name or the first container if name is empty.
- func (o *AttachOptions) containerToAttachTo(pod *corev1.Pod) (*corev1.Container, error) {
- if len(o.ContainerName) > 0 {
- for i := range pod.Spec.Containers {
- if pod.Spec.Containers[i].Name == o.ContainerName {
- return &pod.Spec.Containers[i], nil
- }
- }
- for i := range pod.Spec.InitContainers {
- if pod.Spec.InitContainers[i].Name == o.ContainerName {
- return &pod.Spec.InitContainers[i], nil
- }
- }
- return nil, fmt.Errorf("container not found (%s)", o.ContainerName)
- }
- if o.EnableSuggestedCmdUsage {
- fmt.Fprintf(o.ErrOut, "Defaulting container name to %s.\n", pod.Spec.Containers[0].Name)
- fmt.Fprintf(o.ErrOut, "Use '%s describe pod/%s -n %s' to see all of the containers in this pod.\n", o.ParentCommandName, o.PodName, o.Namespace)
- }
- klog.V(4).Infof("defaulting container name to %s", pod.Spec.Containers[0].Name)
- return &pod.Spec.Containers[0], nil
- }
- // GetContainerName returns the name of the container to attach to, with a fallback.
- func (o *AttachOptions) GetContainerName(pod *corev1.Pod) (string, error) {
- c, err := o.containerToAttachTo(pod)
- if err != nil {
- return "", err
- }
- return c.Name, nil
- }
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