From eb4b3e8772d1aed68a574160a2f8f88ac7526e6f Mon Sep 17 00:00:00 2001
From: Michael Crosby <crosbymichael@gmail.com>
Date: Fri, 26 Jul 2019 17:48:00 +0000
Subject: [PATCH] Fast path getting pid from task

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
---
 runtime/task.go          |  3 +++
 runtime/v1/linux/task.go |  5 +++++
 runtime/v2/shim.go       |  5 +++++
 services/tasks/local.go  | 13 ++++++-------
 4 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/runtime/task.go b/runtime/task.go
index 981e290c6..ab9017ba5 100644
--- a/runtime/task.go
+++ b/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
diff --git a/runtime/v1/linux/task.go b/runtime/v1/linux/task.go
index 043f25b17..0970c3ea3 100644
--- a/runtime/v1/linux/task.go
+++ b/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)
diff --git a/runtime/v2/shim.go b/runtime/v2/shim.go
index 41f908c3e..38cf79899 100644
--- a/runtime/v2/shim.go
+++ b/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
 }
diff --git a/services/tasks/local.go b/services/tasks/local.go
index 163ed0186..2f17b158c 100644
--- a/services/tasks/local.go
+++ b/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
 }