Add NewTask support to client

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

client.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/containerd/containerd/api/services/containers"
 	contentapi "github.com/containerd/containerd/api/services/content"
+	"github.com/containerd/containerd/api/services/execution"
 	snapshotapi "github.com/containerd/containerd/api/services/snapshot"
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/images"
@@ -161,3 +162,7 @@ func (c *Client) content() content.Store {
 func (c *Client) snapshotter() snapshot.Snapshotter {
 	return snapshotservice.NewSnapshotterFromClient(snapshotapi.NewSnapshotClient(c.conn))
 }
+
+func (c *Client) tasks() execution.TasksClient {
+	return execution.NewTasksClient(c.conn)
+}

container.go

@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 
 	"github.com/containerd/containerd/api/services/containers"
+	"github.com/containerd/containerd/api/services/execution"
+	"github.com/containerd/containerd/api/types/mount"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 )
 
@@ -18,7 +20,8 @@ func containerFromProto(client *Client, c containers.Container) *Container {
 type Container struct {
 	client *Client
 
-	c containers.Container
+	c    containers.Container
+	task *Task
 }
 
 // ID returns the container's unique id
@@ -45,3 +48,43 @@ func (c *Container) Delete(ctx context.Context) error {
 	})
 	return err
 }
+
+func (c *Container) Task() *Task {
+	return c.task
+}
+
+func (c *Container) NewTask(ctx context.Context, ioCreate IOCreation) (*Task, error) {
+	i, err := ioCreate()
+	if err != nil {
+		return nil, err
+	}
+	request := &execution.CreateRequest{
+		ContainerID: c.c.ID,
+		Terminal:    i.Terminal,
+		Stdin:       i.Stdin,
+		Stdout:      i.Stdout,
+		Stderr:      i.Stderr,
+	}
+	// get the rootfs from the snapshotter and add it to the request
+	mounts, err := c.client.snapshotter().Mounts(ctx, c.c.RootFS)
+	if err != nil {
+		return nil, err
+	}
+	for _, m := range mounts {
+		request.Rootfs = append(request.Rootfs, &mount.Mount{
+			Type:    m.Type,
+			Source:  m.Source,
+			Options: m.Options,
+		})
+	}
+	response, err := c.client.tasks().Create(ctx, request)
+	if err != nil {
+		return nil, err
+	}
+	return &Task{
+		client:      c.client,
+		io:          i,
+		containerID: response.ContainerID,
+		pid:         response.Pid,
+	}, nil
+}

task.go

@@ -0,0 +1,186 @@
+package containerd
+
+import (
+	"context"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+	"syscall"
+
+	"github.com/containerd/containerd/api/services/execution"
+	"github.com/containerd/fifo"
+)
+
+type IO struct {
+	Terminal bool
+	Stdin    string
+	Stdout   string
+	Stderr   string
+
+	closer io.Closer
+}
+
+func (i *IO) Close() error {
+	if i.closer == nil {
+		return nil
+	}
+	return i.closer.Close()
+}
+
+type IOCreation func() (*IO, error)
+
+// STDIO returns an IO implementation to be used for a task
+// that outputs the container's IO as the current processes STDIO
+func STDIO() (*IO, error) {
+	paths, err := fifoPaths()
+	if err != nil {
+		return nil, err
+	}
+	set := &ioSet{
+		in:  os.Stdin,
+		out: os.Stdout,
+		err: os.Stderr,
+	}
+	closer, err := copyIO(paths, set, false)
+	if err != nil {
+		return nil, err
+	}
+	return &IO{
+		Terminal: false,
+		Stdin:    paths.in,
+		Stdout:   paths.out,
+		Stderr:   paths.err,
+		closer:   closer,
+	}, nil
+}
+
+func fifoPaths() (*fifoSet, error) {
+	dir, err := ioutil.TempDir(filepath.Join(os.TempDir(), "containerd"), "")
+	if err != nil {
+		return nil, err
+	}
+	return &fifoSet{
+		dir: dir,
+		in:  filepath.Join(dir, "stdin"),
+		out: filepath.Join(dir, "stdout"),
+		err: filepath.Join(dir, "stderr"),
+	}, nil
+}
+
+type fifoSet struct {
+	// dir is the directory holding the task fifos
+	dir          string
+	in, out, err string
+}
+
+type ioSet struct {
+	in       io.Reader
+	out, err io.Writer
+}
+
+func copyIO(fifos *fifoSet, ioset *ioSet, tty bool) (closer io.Closer, err error) {
+	var (
+		ctx = context.Background()
+		wg  = &sync.WaitGroup{}
+	)
+
+	f, err := fifo.OpenFifo(ctx, fifos.in, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700)
+	if err != nil {
+		return nil, err
+	}
+	defer func(c io.Closer) {
+		if err != nil {
+			c.Close()
+		}
+	}(f)
+	go func(w io.WriteCloser) {
+		io.Copy(w, ioset.in)
+		w.Close()
+	}(f)
+
+	f, err = fifo.OpenFifo(ctx, fifos.out, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700)
+	if err != nil {
+		return nil, err
+	}
+	defer func(c io.Closer) {
+		if err != nil {
+			c.Close()
+		}
+	}(f)
+	wg.Add(1)
+	go func(r io.ReadCloser) {
+		io.Copy(ioset.out, r)
+		r.Close()
+		wg.Done()
+	}(f)
+
+	f, err = fifo.OpenFifo(ctx, fifos.err, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700)
+	if err != nil {
+		return nil, err
+	}
+	defer func(c io.Closer) {
+		if err != nil {
+			c.Close()
+		}
+	}(f)
+
+	if !tty {
+		wg.Add(1)
+		go func(r io.ReadCloser) {
+			io.Copy(ioset.err, r)
+			r.Close()
+			wg.Done()
+		}(f)
+	}
+	return &wgCloser{
+		wg: wg,
+	}, nil
+}
+
+type wgCloser struct {
+	wg *sync.WaitGroup
+}
+
+func (g *wgCloser) Close() error {
+	g.wg.Wait()
+	return nil
+}
+
+type Task struct {
+	client *Client
+
+	io          *IO
+	containerID string
+	pid         uint32
+}
+
+// Pid returns the pid or process id for the task
+func (t *Task) Pid() uint32 {
+	return t.pid
+}
+
+func (t *Task) Kill(ctx context.Context, s os.Signal) error {
+	_, err := t.client.tasks().Kill(ctx, &execution.KillRequest{
+		ContainerID: t.containerID,
+		PidOrAll: &execution.KillRequest_All{
+			All: true,
+		},
+	})
+	return err
+}
+
+// Delete deletes the task and its runtime state
+// it returns the exit status of the task and any errors that were encountered
+// during cleanup
+func (t *Task) Delete(ctx context.Context) (uint32, error) {
+	cerr := t.io.Close()
+	r, err := t.client.tasks().Delete(ctx, &execution.DeleteRequest{
+		t.containerID,
+	})
+	if err != nil {
+		return 255, err
+	}
+	return r.ExitStatus, cerr
+}