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package containerd // import "github.com/docker/docker/plugin/executor/containerd"
import (
"context"
"io"
"sync"
"github.com/containerd/containerd"
"github.com/containerd/containerd/cio"
"github.com/docker/docker/api/types"
"github.com/docker/docker/errdefs"
"github.com/docker/docker/libcontainerd"
libcontainerdtypes "github.com/docker/docker/libcontainerd/types"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// PluginNamespace is the name used for the plugins namespace
const PluginNamespace = "plugins.moby"
// ExitHandler represents an object that is called when the exit event is received from containerd
type ExitHandler interface {
HandleExitEvent(id string) error
}
// New creates a new containerd plugin executor
func New(ctx context.Context, rootDir string, cli *containerd.Client, ns string, exitHandler ExitHandler, runtime types.Runtime) (*Executor, error) {
e := &Executor{
rootDir: rootDir,
exitHandler: exitHandler,
runtime: runtime,
}
client, err := libcontainerd.NewClient(ctx, cli, rootDir, ns, e)
if err != nil {
return nil, errors.Wrap(err, "error creating containerd exec client")
}
e.client = client
return e, nil
}
// Executor is the containerd client implementation of a plugin executor
type Executor struct {
rootDir string
client libcontainerdtypes.Client
exitHandler ExitHandler
runtime types.Runtime
}
// deleteTaskAndContainer deletes plugin task and then plugin container from containerd
func deleteTaskAndContainer(ctx context.Context, cli libcontainerdtypes.Client, id string, p libcontainerdtypes.Process) {
if p != nil {
if _, _, err := p.Delete(ctx); err != nil && !errdefs.IsNotFound(err) {
logrus.WithError(err).WithField("id", id).Error("failed to delete plugin task from containerd")
}
} else {
if _, _, err := cli.DeleteTask(ctx, id); err != nil && !errdefs.IsNotFound(err) {
logrus.WithError(err).WithField("id", id).Error("failed to delete plugin task from containerd")
}
}
if err := cli.Delete(ctx, id); err != nil && !errdefs.IsNotFound(err) {
logrus.WithError(err).WithField("id", id).Error("failed to delete plugin container from containerd")
}
}
// Create creates a new container
func (e *Executor) Create(id string, spec specs.Spec, stdout, stderr io.WriteCloser) error {
ctx := context.Background()
err := e.client.Create(ctx, id, &spec, e.runtime.Shim.Binary, e.runtime.Shim.Opts)
if err != nil {
status, err2 := e.client.Status(ctx, id)
if err2 != nil {
if !errdefs.IsNotFound(err2) {
logrus.WithError(err2).WithField("id", id).Warn("Received an error while attempting to read plugin status")
}
} else {
if status != containerd.Running && status != containerd.Unknown {
if err2 := e.client.Delete(ctx, id); err2 != nil && !errdefs.IsNotFound(err2) {
logrus.WithError(err2).WithField("plugin", id).Error("Error cleaning up containerd container")
}
err = e.client.Create(ctx, id, &spec, e.runtime.Shim.Binary, e.runtime.Shim.Opts)
}
}
if err != nil {
return errors.Wrap(err, "error creating containerd container")
}
}
_, err = e.client.Start(ctx, id, "", false, attachStreamsFunc(stdout, stderr))
if err != nil {
deleteTaskAndContainer(ctx, e.client, id, nil)
}
return err
}
// Restore restores a container
func (e *Executor) Restore(id string, stdout, stderr io.WriteCloser) (bool, error) {
alive, _, p, err := e.client.Restore(context.Background(), id, attachStreamsFunc(stdout, stderr))
if err != nil && !errdefs.IsNotFound(err) {
return false, err
}
if !alive {
deleteTaskAndContainer(context.Background(), e.client, id, p)
}
return alive, nil
}
// IsRunning returns if the container with the given id is running
func (e *Executor) IsRunning(id string) (bool, error) {
status, err := e.client.Status(context.Background(), id)
return status == containerd.Running, err
}
// Signal sends the specified signal to the container
func (e *Executor) Signal(id string, signal int) error {
return e.client.SignalProcess(context.Background(), id, libcontainerdtypes.InitProcessName, signal)
}
// ProcessEvent handles events from containerd
// All events are ignored except the exit event, which is sent of to the stored handler
func (e *Executor) ProcessEvent(id string, et libcontainerdtypes.EventType, ei libcontainerdtypes.EventInfo) error {
switch et {
case libcontainerdtypes.EventExit:
deleteTaskAndContainer(context.Background(), e.client, id, nil)
return e.exitHandler.HandleExitEvent(ei.ContainerID)
}
return nil
}
type rio struct {
cio.IO
wg sync.WaitGroup
}
func (c *rio) Wait() {
c.wg.Wait()
c.IO.Wait()
}
func attachStreamsFunc(stdout, stderr io.WriteCloser) libcontainerdtypes.StdioCallback {
return func(iop *cio.DirectIO) (cio.IO, error) {
if iop.Stdin != nil {
iop.Stdin.Close()
// closing stdin shouldn't be needed here, it should never be open
panic("plugin stdin shouldn't have been created!")
}
rio := &rio{IO: iop}
rio.wg.Add(2)
go func() {
io.Copy(stdout, iop.Stdout)
stdout.Close()
rio.wg.Done()
}()
go func() {
io.Copy(stderr, iop.Stderr)
stderr.Close()
rio.wg.Done()
}()
return rio, nil
}
}
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