feature: add cli attach command

Signed-off-by: zhangyue <zy675793960@yeah.net>

cli/attach.go

@@ -0,0 +1,186 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/alibaba/pouch/apis/types"
+	"github.com/alibaba/pouch/client"
+
+	"github.com/docker/docker/pkg/ioutils"
+	"github.com/docker/docker/pkg/term"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+// AttachDescription is used to describe attach command in detail and auto generate command doc.
+var AttachDescription = "Attach local standard input, output, and error streams to a running container"
+
+var defaultEscapeKeys = []byte{16, 17}
+
+// AttachCommand is used to implement 'attach' command.
+type AttachCommand struct {
+	baseCommand
+
+	// flags for attach command
+	noStdin    bool
+	detachKeys string
+}
+
+// Init initialize "attach" command.
+func (ac *AttachCommand) Init(c *Cli) {
+	ac.cli = c
+	ac.cmd = &cobra.Command{
+		Use:   "attach [OPTIONS] CONTAINER",
+		Short: "Attach local standard input, output, and error streams to a running container",
+		Long:  AttachDescription,
+		Args:  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return ac.runAttach(args)
+		},
+		Example: ac.example(),
+	}
+	ac.addFlags()
+}
+
+// addFlags adds flags for specific command.
+func (ac *AttachCommand) addFlags() {
+	flagSet := ac.cmd.Flags()
+	flagSet.BoolVar(&ac.noStdin, "no-stdin", false, "Do not attach STDIN")
+	flagSet.StringVar(&ac.detachKeys, "detach-keys", "", "Override the key sequence for detaching a container")
+	// TODO: sig-proxy will be supported in the future.
+	//flagSet.BoolVar(&ac.sigProxy, "sig-proxy", true, "Proxy all received signals to the process")
+}
+
+func inspectAndCheckState(ctx context.Context, cli client.CommonAPIClient, name string) (*types.ContainerJSON, error) {
+	c, err := cli.ContainerGet(ctx, name)
+	if err != nil {
+		return nil, err
+	}
+	if !c.State.Running {
+		return nil, errors.New("You cannot attach to a stopped container, start it first")
+	}
+	if c.State.Paused {
+		return nil, errors.New("You cannot attach to a paused container, unpause it first")
+	}
+	if c.State.Restarting {
+		return nil, errors.New("You cannot attach to a restarting container, wait until it is running")
+	}
+
+	return c, nil
+}
+
+// runAttach is used to attach a container.
+func (ac *AttachCommand) runAttach(args []string) error {
+	name := args[0]
+
+	ctx := context.Background()
+	apiClient := ac.cli.Client()
+
+	c, err := inspectAndCheckState(ctx, apiClient, name)
+	if err != nil {
+		return err
+	}
+
+	var inReader io.Reader = os.Stdin
+	if !ac.noStdin && c.Config.Tty {
+		if term.IsTerminal(os.Stdin.Fd()) {
+			in, out, err := setRawMode(!ac.noStdin, false)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "failed to set raw mode %s", err)
+				return fmt.Errorf("failed to set raw mode")
+			}
+			defer func() {
+				if err := restoreMode(in, out); err != nil {
+					fmt.Fprintf(os.Stderr, "failed to restore term mode %s", err)
+				}
+			}()
+		}
+
+		escapeKeys := defaultEscapeKeys
+		// Wrap the input to detect detach escape sequence.
+		// Use default escape keys if an invalid sequence is given.
+		if ac.detachKeys != "" {
+			customEscapeKeys, err := term.ToBytes(ac.detachKeys)
+			if err != nil {
+				return fmt.Errorf("Invalid detach keys (%s) provided", ac.detachKeys)
+			}
+			escapeKeys = customEscapeKeys
+		}
+		inReader = ioutils.NewReadCloserWrapper(term.NewEscapeProxy(os.Stdin, escapeKeys), os.Stdin.Close)
+	}
+
+	conn, br, err := apiClient.ContainerAttach(ctx, name, !ac.noStdin)
+	if err != nil {
+		return fmt.Errorf("failed to attach container: %v", err)
+	}
+	defer conn.Close()
+
+	// double check in case container in wrong state
+	_, err = inspectAndCheckState(ctx, apiClient, name)
+	if err != nil {
+		return err
+	}
+
+	outputDone := make(chan error, 1)
+	go func() {
+		var err error
+		_, err = io.Copy(os.Stdout, br)
+		if err != nil {
+			logrus.Debugf("Error receive stdout: %s", err)
+		}
+		outputDone <- err
+	}()
+
+	inputDone := make(chan struct{})
+	detached := make(chan error, 1)
+	go func() {
+		if !ac.noStdin {
+			_, err := io.Copy(conn, inReader)
+			if _, ok := err.(term.EscapeError); ok {
+				detached <- err
+			}
+			if err != nil {
+				logrus.Debugf("Error send stdin: %s", err)
+			}
+		}
+		close(inputDone)
+
+	}()
+
+	select {
+	case err := <-outputDone:
+		if err != nil {
+			logrus.Debugf("receive stdout error: %s", err)
+			return err
+		}
+	case <-inputDone:
+		select {
+		// Wait for output to complete streaming.
+		case err := <-outputDone:
+			logrus.Debugf("receive stdout error: %s", err)
+			return err
+		case <-ctx.Done():
+		}
+	case err := <-detached:
+		// Got a detach key sequence.
+		return err
+	case <-ctx.Done():
+	}
+
+	return nil
+}
+
+// example shows examples in attach command, and is used in auto-generated cli docs.
+func (ac *AttachCommand) example() string {
+	return `$ pouch run -d --name foo busybox sh -c 'while true; do sleep 1; echo hello; done'
+Name     ID       Status    Image                              Runtime
+foo      71b9c1   Running   docker.io/library/busybox:latest   runc
+$ pouch attach foo
+hello
+hello
+hello`
+}

cli/main.go

@@ -18,6 +18,7 @@ func main() {
 	cli.AddCommand(base, &PullCommand{})
 	cli.AddCommand(base, &CreateCommand{})
 	cli.AddCommand(base, &StartCommand{})
+	cli.AddCommand(base, &AttachCommand{})
 	cli.AddCommand(base, &StopCommand{})
 	cli.AddCommand(base, &PsCommand{})
 	cli.AddCommand(base, &RmCommand{})

pkg/ioutils/readers.go

@@ -0,0 +1,25 @@
+package ioutils
+
+import "io"
+
+// ReadCloserWrapper wraps an io.Reader, and implements an io.ReadCloser
+// It calls the given callback function when closed. It should be constructed
+// with NewReadCloserWrapper
+type ReadCloserWrapper struct {
+	io.Reader
+	closer func() error
+}
+
+// NewReadCloserWrapper returns a new io.ReadCloser.
+func NewReadCloserWrapper(r io.Reader, closer func() error) io.ReadCloser {
+	return &ReadCloserWrapper{
+		Reader: r,
+		closer: closer,
+	}
+
+}
+
+// Close calls back the passed closer function
+func (r *ReadCloserWrapper) Close() error {
+	return r.closer()
+}

test/cli_attach_test.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"io"
+	"os/exec"
+	"strings"
+
+	"github.com/alibaba/pouch/test/command"
+	"github.com/alibaba/pouch/test/environment"
+
+	"github.com/go-check/check"
+	"github.com/gotestyourself/gotestyourself/icmd"
+)
+
+// PouchCreateSuite is the test suite for attach CLI.
+type PouchAttachSuite struct{}
+
+func init() {
+	check.Suite(&PouchAttachSuite{})
+}
+
+// SetUpSuite does common setup in the beginning of each test suite.
+func (suite *PouchAttachSuite) SetUpSuite(c *check.C) {
+	SkipIfFalse(c, environment.IsLinux)
+
+	environment.PruneAllContainers(apiClient)
+
+	PullImage(c, busyboxImage)
+}
+
+// TearDownTest does cleanup work in the end of each test.
+func (suite *PouchAttachSuite) TearDownTest(c *check.C) {
+}
+
+// TestPouchAttachRunningContainer is to verify the correctness of attach a running container.
+func (suite *PouchAttachSuite) TestPouchAttachRunningContainer(c *check.C) {
+	name := "TestPouchAttachRunningContainer"
+
+	res := command.PouchRun("run", "-d", "--name", name, busyboxImage, "/bin/sh", "-c", "while true; do echo hello; done")
+
+	defer DelContainerForceMultyTime(c, name)
+	res.Assert(c, icmd.Success)
+
+	cmd := exec.Command(environment.PouchBinary, "attach", name)
+
+	out, err := cmd.StdoutPipe()
+	if err != nil {
+		c.Fatal(err)
+	}
+	defer out.Close()
+
+	if err := cmd.Start(); err != nil {
+		c.Fatal(err)
+	}
+
+	buf := make([]byte, 1024)
+
+	if _, err := out.Read(buf); err != nil && err != io.EOF {
+		c.Fatal(err)
+	}
+
+	if !strings.Contains(string(buf), "hello") {
+		c.Fatalf("unexpected output %s expected hello\n", string(buf))
+	}
+}