Add container attach support.
Signed-off-by: Lantao Liu <lantaol@google.com>
This commit is contained in:
Lantao Liu
317
pkg/server/io/io.go
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317
pkg/server/io/io.go
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@@ -0,0 +1,317 @@
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/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package agents
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import (
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"errors"
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"io"
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"os"
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"strings"
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"sync"
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"syscall"
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"github.com/containerd/containerd"
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"github.com/containerd/fifo"
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"github.com/golang/glog"
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"golang.org/x/net/context"
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"github.com/kubernetes-incubator/cri-containerd/pkg/ioutil"
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"github.com/kubernetes-incubator/cri-containerd/pkg/util"
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)
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// StreamType is the type of the stream, stdout/stderr.
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type StreamType string
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const (
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// Stdin stream type.
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Stdin StreamType = "stdin"
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// Stdout stream type.
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Stdout StreamType = "stdout"
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// Stderr stream type.
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Stderr StreamType = "stderr"
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)
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type wgCloser struct {
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ctx context.Context
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wg *sync.WaitGroup
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set []io.Closer
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cancel context.CancelFunc
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}
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func (g *wgCloser) Wait() {
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g.wg.Wait()
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}
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func (g *wgCloser) Close() {
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for _, f := range g.set {
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f.Close()
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}
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}
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func (g *wgCloser) Cancel() {
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g.cancel()
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}
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// streamKey generates a key for the stream.
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func streamKey(id, name string, stream StreamType) string {
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return strings.Join([]string{id, name, string(stream)}, "-")
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}
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// ContainerIO holds the container io.
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type ContainerIO struct {
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dir string
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stdinPath string
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stdoutPath string
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stderrPath string
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id string
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tty bool
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stdin bool
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stdout *ioutil.WriterGroup
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stderr *ioutil.WriterGroup
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closer *wgCloser
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}
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var _ containerd.IO = &ContainerIO{}
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// Opts sets specific information to newly created ContainerIO.
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type Opts func(*ContainerIO) error
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// WithStdin enables stdin of the container io.
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func WithStdin(stdin bool) Opts {
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return func(c *ContainerIO) error {
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c.stdin = stdin
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return nil
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}
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}
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// WithOutput adds output stream to the container io.
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func WithOutput(name string, stdout, stderr io.WriteCloser) Opts {
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return func(c *ContainerIO) error {
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if stdout != nil {
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if err := c.stdout.Add(streamKey(c.id, name, Stdout), stdout); err != nil {
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return err
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}
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}
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if stderr != nil {
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if err := c.stderr.Add(streamKey(c.id, name, Stderr), stderr); err != nil {
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return err
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}
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}
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return nil
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}
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}
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// WithTerminal enables tty of the container io.
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func WithTerminal(tty bool) Opts {
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return func(c *ContainerIO) error {
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c.tty = tty
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return nil
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}
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}
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// NewContainerIO creates container io.
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func NewContainerIO(id string, opts ...Opts) (*ContainerIO, error) {
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fifos, err := containerd.NewFifos(id)
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if err != nil {
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return nil, err
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}
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c := &ContainerIO{
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id: id,
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dir: fifos.Dir,
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stdoutPath: fifos.Out,
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stderrPath: fifos.Err,
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stdout: ioutil.NewWriterGroup(),
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stderr: ioutil.NewWriterGroup(),
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}
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for _, opt := range opts {
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if err := opt(c); err != nil {
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return nil, err
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}
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}
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if c.stdin {
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c.stdinPath = fifos.In
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}
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return c, nil
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}
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// Config returns io config.
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func (c *ContainerIO) Config() containerd.IOConfig {
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return containerd.IOConfig{
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Terminal: c.tty,
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Stdin: c.stdinPath,
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Stdout: c.stdoutPath,
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Stderr: c.stderrPath,
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}
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}
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// Pipe creates container fifos and pipe container output
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// to output stream.
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func (c *ContainerIO) Pipe() (err error) {
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var (
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f io.ReadWriteCloser
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set []io.Closer
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ctx, cancel = context.WithCancel(context.Background())
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wg = &sync.WaitGroup{}
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)
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defer func() {
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if err != nil {
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for _, f := range set {
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f.Close()
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}
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cancel()
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}
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}()
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if c.stdinPath != "" {
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// Just create the stdin, only open it when used.
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if f, err = fifo.OpenFifo(ctx, c.stdinPath, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
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return err
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}
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f.Close()
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}
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if f, err = fifo.OpenFifo(ctx, c.stdoutPath, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
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return err
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}
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set = append(set, f)
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wg.Add(1)
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go func(r io.ReadCloser) {
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if _, err := io.Copy(c.stdout, r); err != nil {
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glog.Errorf("Failed to redirect stdout of container %q: %v", c.id, err)
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}
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r.Close()
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c.stdout.Close()
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wg.Done()
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glog.V(2).Infof("Finish piping stdout of container %q", c.id)
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}(f)
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if f, err = fifo.OpenFifo(ctx, c.stderrPath, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
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return err
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}
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set = append(set, f)
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if !c.tty {
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wg.Add(1)
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go func(r io.ReadCloser) {
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if _, err := io.Copy(c.stderr, r); err != nil {
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glog.Errorf("Failed to redirect stderr of container %q: %v", c.id, err)
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}
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r.Close()
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c.stderr.Close()
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wg.Done()
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glog.V(2).Infof("Finish piping stderr of container %q", c.id)
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}(f)
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}
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c.closer = &wgCloser{
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wg: wg,
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set: set,
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ctx: ctx,
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cancel: cancel,
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}
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return nil
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}
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// Attach attaches container stdio.
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func (c *ContainerIO) Attach(stdin io.Reader, stdout, stderr io.WriteCloser) error {
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if c.closer == nil {
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return errors.New("container io is not initialized")
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}
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var wg sync.WaitGroup
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key := util.GenerateID()
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stdinKey := streamKey(c.id, "attach-"+key, Stdin)
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stdoutKey := streamKey(c.id, "attach-"+key, Stdout)
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stderrKey := streamKey(c.id, "attach-"+key, Stderr)
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var stdinCloser io.Closer
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if c.stdinPath != "" && stdin != nil {
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f, err := fifo.OpenFifo(c.closer.ctx, c.stdinPath, syscall.O_WRONLY|syscall.O_NONBLOCK, 0700)
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if err != nil {
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return err
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}
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// Also increase wait group here, so that `closer.Wait` will
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// also wait for this fifo to be closed.
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c.closer.wg.Add(1)
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wg.Add(1)
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go func(w io.WriteCloser) {
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if _, err := io.Copy(w, stdin); err != nil {
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glog.Errorf("Failed to redirect stdin for container attach %q: %v", c.id, err)
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}
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w.Close()
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glog.V(2).Infof("Attach stream %q closed", stdinKey)
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// No matter what, when stdin is closed (io.Copy unblock), close stdout and stderr
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if stdout != nil {
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c.stdout.Remove(stdoutKey)
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}
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if stderr != nil {
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c.stderr.Remove(stderrKey)
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}
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wg.Done()
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c.closer.wg.Done()
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}(f)
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stdinCloser = f
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}
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attachStream := func(key string, close <-chan struct{}) {
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<-close
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glog.V(2).Infof("Attach stream %q closed", key)
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// Make sure stdin gets closed.
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if stdinCloser != nil {
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stdinCloser.Close()
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}
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wg.Done()
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}
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if stdout != nil {
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wg.Add(1)
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wc, close := ioutil.NewWriteCloseInformer(stdout)
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if err := c.stdout.Add(stdoutKey, wc); err != nil {
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return err
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}
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go attachStream(stdoutKey, close)
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}
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if !c.tty && stderr != nil {
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wg.Add(1)
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wc, close := ioutil.NewWriteCloseInformer(stderr)
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if err := c.stderr.Add(stderrKey, wc); err != nil {
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return err
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}
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go attachStream(stderrKey, close)
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}
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wg.Wait()
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return nil
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}
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// Cancel cancels container io.
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func (c *ContainerIO) Cancel() {
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c.closer.Cancel()
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}
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// Wait waits container io to finish.
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func (c *ContainerIO) Wait() {
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c.closer.Wait()
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}
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// Close closes all FIFOs.
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func (c *ContainerIO) Close() error {
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if c.closer != nil {
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c.closer.Close()
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}
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if c.dir != "" {
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return os.RemoveAll(c.dir)
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}
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return nil
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}
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