Merge pull request #3461 from crosbymichael/pid-fastpath

Fast path getting pid from task

runtime/task.go

@@ -33,6 +33,7 @@ type TaskInfo struct {
 
 // Process is a runtime object for an executing process inside a container
 type Process interface {
+	// ID of the process
 	ID() string
 	// State returns the process state
 	State(context.Context) (State, error)
@@ -54,6 +55,8 @@ type Process interface {
 type Task interface {
 	Process
 
+	// PID of the process
+	PID() uint32
 	// Namespace that the task exists in
 	Namespace() string
 	// Pause pauses the container process

runtime/v1/linux/task.go

@@ -84,6 +84,11 @@ func (t *Task) Namespace() string {
 	return t.namespace
 }
 
+// PID of the task
+func (t *Task) PID() uint32 {
+	return uint32(t.pid)
+}
+
 // Delete the task and return the exit status
 func (t *Task) Delete(ctx context.Context) (*runtime.Exit, error) {
 	rsp, err := t.shim.Delete(ctx, empty)

runtime/v2/shim.go

@@ -195,6 +195,11 @@ func (s *shim) ID() string {
 	return s.bundle.ID
 }
 
+// PID of the task
+func (s *shim) PID() uint32 {
+	return uint32(s.taskPid)
+}
+
 func (s *shim) Namespace() string {
 	return s.bundle.Namespace
 }

services/tasks/local.go

@@ -182,24 +182,23 @@ func (l *local) Create(ctx context.Context, r *api.CreateTaskRequest, _ ...grpc.
 	if err != nil {
 		return nil, err
 	}
-	if _, err := rtime.Get(ctx, r.ContainerID); err != runtime.ErrTaskNotExists {
+	_, err = rtime.Get(ctx, r.ContainerID)
+	if err != nil && err != runtime.ErrTaskNotExists {
+		return nil, errdefs.ToGRPC(err)
+	}
+	if err == nil {
 		return nil, errdefs.ToGRPC(fmt.Errorf("task %s already exists", r.ContainerID))
 	}
 	c, err := rtime.Create(ctx, r.ContainerID, opts)
 	if err != nil {
 		return nil, errdefs.ToGRPC(err)
 	}
-	// TODO: fast path for getting pid on create
 	if err := l.monitor.Monitor(c); err != nil {
 		return nil, errors.Wrap(err, "monitor task")
 	}
-	state, err := c.State(ctx)
-	if err != nil {
-		log.G(ctx).Error(err)
-	}
 	return &api.CreateTaskResponse{
 		ContainerID: r.ContainerID,
-		Pid:         state.Pid,
+		Pid:         c.PID(),
 	}, nil
 }