package containerd // import "github.com/docker/docker/plugin/executor/containerd" import ( "context" "io" "path/filepath" "sync" "github.com/containerd/containerd/cio" "github.com/containerd/containerd/linux/runctypes" "github.com/docker/docker/errdefs" "github.com/docker/docker/libcontainerd" "github.com/opencontainers/runtime-spec/specs-go" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) // PluginNamespace is the name used for the plugins namespace var 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(rootDir string, remote libcontainerd.Remote, exitHandler ExitHandler) (*Executor, error) { e := &Executor{ rootDir: rootDir, exitHandler: exitHandler, } client, err := remote.NewClient(PluginNamespace, 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 libcontainerd.Client exitHandler ExitHandler } // Create creates a new container func (e *Executor) Create(id string, spec specs.Spec, stdout, stderr io.WriteCloser) error { opts := runctypes.RuncOptions{ RuntimeRoot: filepath.Join(e.rootDir, "runtime-root"), } ctx := context.Background() err := e.client.Create(ctx, id, &spec, &opts) if err != nil { return err } _, err = e.client.Start(ctx, id, "", false, attachStreamsFunc(stdout, stderr)) return err } // Restore restores a container func (e *Executor) Restore(id string, stdout, stderr io.WriteCloser) error { alive, _, err := e.client.Restore(context.Background(), id, attachStreamsFunc(stdout, stderr)) if err != nil && !errdefs.IsNotFound(err) { return err } if !alive { _, _, err = e.client.DeleteTask(context.Background(), id) if err != nil && !errdefs.IsNotFound(err) { logrus.WithError(err).Errorf("failed to delete container plugin %s task from containerd", id) return err } err = e.client.Delete(context.Background(), id) if err != nil && !errdefs.IsNotFound(err) { logrus.WithError(err).Errorf("failed to delete container plugin %s from containerd", id) return err } } return 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 == libcontainerd.StatusRunning, 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, libcontainerd.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 libcontainerd.EventType, ei libcontainerd.EventInfo) error { switch et { case libcontainerd.EventExit: // delete task and container if _, _, err := e.client.DeleteTask(context.Background(), id); err != nil { logrus.WithError(err).Errorf("failed to delete container plugin %s task from containerd", id) } if err := e.client.Delete(context.Background(), id); err != nil { logrus.WithError(err).Errorf("failed to delete container plugin %s from containerd", id) } 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) libcontainerd.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 } }