Decouple plugin manager from libcontainerd package

libcontainerd has a bunch of platform dependent code and huge interfaces
that are a pain implement.
To make the plugin manager a bit easier to work with, extract the plugin
executor into an interface and move the containerd implementation to a
separate package.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/plugin/executor/containerd/containerd.go b/plugin/executor/containerd/containerd.go
new file mode 100644
index 0000000000..74cf530cf1
--- /dev/null
+++ b/plugin/executor/containerd/containerd.go
@@ -0,0 +1,77 @@
+package containerd
+
+import (
+	"io"
+
+	"github.com/docker/docker/libcontainerd"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
+)
+
+// 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(remote libcontainerd.Remote, exitHandler ExitHandler) (*Executor, error) {
+	e := &Executor{exitHandler: exitHandler}
+	client, err := remote.Client(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 {
+	client      libcontainerd.Client
+	exitHandler ExitHandler
+}
+
+// Create creates a new container
+func (e *Executor) Create(id string, spec specs.Spec, stdout, stderr io.WriteCloser) error {
+	return e.client.Create(id, "", "", spec, attachStreamsFunc(stdout, stderr))
+}
+
+// Restore restores a container
+func (e *Executor) Restore(id string, stdout, stderr io.WriteCloser) error {
+	return e.client.Restore(id, attachStreamsFunc(stdout, stderr))
+}
+
+// IsRunning returns if the container with the given id is running
+func (e *Executor) IsRunning(id string) (bool, error) {
+	pids, err := e.client.GetPidsForContainer(id)
+	return len(pids) > 0, err
+}
+
+// Signal sends the specified signal to the container
+func (e *Executor) Signal(id string, signal int) error {
+	return e.client.Signal(id, signal)
+}
+
+// StateChanged handles state changes from containerd
+// All events are ignored except the exit event, which is sent of to the stored handler
+func (e *Executor) StateChanged(id string, event libcontainerd.StateInfo) error {
+	switch event.State {
+	case libcontainerd.StateExit:
+		return e.exitHandler.HandleExitEvent(id)
+	}
+	return nil
+}
+
+func attachStreamsFunc(stdout, stderr io.WriteCloser) func(libcontainerd.IOPipe) error {
+	return func(iop libcontainerd.IOPipe) error {
+		iop.Stdin.Close()
+		go func() {
+			io.Copy(stdout, iop.Stdout)
+			stdout.Close()
+		}()
+		go func() {
+			io.Copy(stderr, iop.Stderr)
+			stderr.Close()
+		}()
+		return nil
+	}
+}