/* Copyright 2014 The Kubernetes Authors All rights reserved. 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 cmd import ( "fmt" "io" "os" "os/signal" "syscall" "github.com/docker/docker/pkg/term" "github.com/golang/glog" "github.com/spf13/cobra" "k8s.io/kubernetes/pkg/api" client "k8s.io/kubernetes/pkg/client/unversioned" "k8s.io/kubernetes/pkg/client/unversioned/remotecommand" cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util" ) const ( attach_example = `# 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 date # 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` ) func NewCmdAttach(f *cmdutil.Factory, cmdIn io.Reader, cmdOut, cmdErr io.Writer) *cobra.Command { options := &AttachOptions{ In: cmdIn, Out: cmdOut, Err: cmdErr, Attach: &DefaultRemoteAttach{}, } cmd := &cobra.Command{ Use: "attach POD -c CONTAINER", Short: "Attach to a running container.", Long: "Attach to a a process that is already running inside an existing container.", Example: attach_example, Run: func(cmd *cobra.Command, args []string) { cmdutil.CheckErr(options.Complete(f, cmd, args)) cmdutil.CheckErr(options.Validate()) cmdutil.CheckErr(options.Run()) }, } // TODO support UID cmd.Flags().StringVarP(&options.ContainerName, "container", "c", "", "Container name. If omitted, the first container in the pod will be chosen") cmd.Flags().BoolVarP(&options.Stdin, "stdin", "i", false, "Pass stdin to the container") cmd.Flags().BoolVarP(&options.TTY, "tty", "t", false, "Stdin is a TTY") return cmd } // RemoteAttach defines the interface accepted by the Attach command - provided for test stubbing type RemoteAttach interface { Attach(req *client.Request, config *client.Config, stdin io.Reader, stdout, stderr io.Writer, tty bool) error } // DefaultRemoteAttach is the standard implementation of attaching type DefaultRemoteAttach struct{} func (*DefaultRemoteAttach) Attach(req *client.Request, config *client.Config, stdin io.Reader, stdout, stderr io.Writer, tty bool) error { attach := remotecommand.NewAttach(req, config, stdin, stdout, stderr, tty) return attach.Execute() } // AttachOptions declare the arguments accepted by the Exec command type AttachOptions struct { Namespace string PodName string ContainerName string Stdin bool TTY bool In io.Reader Out io.Writer Err io.Writer Attach RemoteAttach Client *client.Client Config *client.Config } // Complete verifies command line arguments and loads data from the command environment func (p *AttachOptions) Complete(f *cmdutil.Factory, cmd *cobra.Command, argsIn []string) error { if len(argsIn) == 0 { return cmdutil.UsageError(cmd, "POD is required for attach") } if len(argsIn) > 1 { return cmdutil.UsageError(cmd, fmt.Sprintf("expected a single argument: POD, saw %d: %s", len(argsIn), argsIn)) } p.PodName = argsIn[0] namespace, _, err := f.DefaultNamespace() if err != nil { return err } p.Namespace = namespace config, err := f.ClientConfig() if err != nil { return err } p.Config = config client, err := f.Client() if err != nil { return err } p.Client = client return nil } // Validate checks that the provided attach options are specified. func (p *AttachOptions) Validate() error { if len(p.PodName) == 0 { return fmt.Errorf("pod name must be specified") } if p.Out == nil || p.Err == nil { return fmt.Errorf("both output and error output must be provided") } if p.Attach == nil || p.Client == nil || p.Config == nil { return fmt.Errorf("client, client config, and attach must be provided") } return nil } // Run executes a validated remote execution against a pod. func (p *AttachOptions) Run() error { pod, err := p.Client.Pods(p.Namespace).Get(p.PodName) if err != nil { return err } if pod.Status.Phase != api.PodRunning { return fmt.Errorf("pod %s is not running and cannot be attached to; current phase is %s", p.PodName, pod.Status.Phase) } // TODO: refactor with terminal helpers from the edit utility once that is merged var stdin io.Reader tty := p.TTY if p.Stdin { stdin = p.In if tty { if file, ok := stdin.(*os.File); ok { inFd := file.Fd() if term.IsTerminal(inFd) { oldState, err := term.SetRawTerminal(inFd) if err != nil { glog.Fatal(err) } // this handles a clean exit, where the command finished defer term.RestoreTerminal(inFd, oldState) // SIGINT is handled by term.SetRawTerminal (it runs a goroutine that listens // for SIGINT and restores the terminal before exiting) // this handles SIGTERM sigChan := make(chan os.Signal, 1) signal.Notify(sigChan, syscall.SIGTERM) go func() { <-sigChan term.RestoreTerminal(inFd, oldState) os.Exit(0) }() } else { fmt.Fprintln(p.Err, "STDIN is not a terminal") } } else { tty = false fmt.Fprintln(p.Err, "Unable to use a TTY - input is not the right kind of file") } } } // TODO: consider abstracting into a client invocation or client helper req := p.Client.RESTClient.Post(). Resource("pods"). Name(pod.Name). Namespace(pod.Namespace). SubResource("attach"). Param("container", p.GetContainerName(pod)) return p.Attach.Attach(req, p.Config, stdin, p.Out, p.Err, tty) } // GetContainerName returns the name of the container to attach to, with a fallback. func (p *AttachOptions) GetContainerName(pod *api.Pod) string { if len(p.ContainerName) > 0 { return p.ContainerName } glog.V(4).Infof("defaulting container name to %s", pod.Spec.Containers[0].Name) return pod.Spec.Containers[0].Name }