Improve process addition and removal

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

implement pause and resume

Add godeps

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Add readme

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

supervisor.go

@@ -26,6 +26,7 @@ func NewSupervisor(stateDir string, concurrency int) (*Supervisor, error) {
 	s := &Supervisor{
 		stateDir:   stateDir,
 		containers: make(map[string]Container),
+		processes:  make(map[int]Container),
 		runtime:    runtime,
 		tasks:      make(chan *startTask, concurrency*100),
 		journal:    j,
@@ -43,6 +44,8 @@ type Supervisor struct {
 
 	containers map[string]Container
 
+	processes map[int]Container
+
 	runtime Runtime
 
 	journal *journal
@@ -76,6 +79,16 @@ func (s *Supervisor) Start(events chan *Event) error {
 			case ExitEventType:
 				logrus.WithFields(logrus.Fields{"pid": e.Pid, "status": e.Status}).
 					Debug("containerd: process exited")
+				// is it the child process of a container
+				if container, ok := s.processes[e.Pid]; ok {
+					if err := container.RemoveProcess(e.Pid); err != nil {
+						logrus.WithField("error", err).Error("containerd: find container for pid")
+					}
+					delete(s.processes, e.Pid)
+					close(e.Err)
+					continue
+				}
+				// is it the main container's process
 				container, err := s.getContainerForPid(e.Pid)
 				if err != nil {
 					if err != errNoContainerForPid {
@@ -143,6 +156,30 @@ func (s *Supervisor) Start(events chan *Event) error {
 					e.Err <- err
 					continue
 				}
+				s.processes[e.Pid] = container
+			case UpdateContainerEventType:
+				container, ok := s.containers[e.ID]
+				if !ok {
+					e.Err <- ErrContainerNotFound
+					continue
+				}
+				if e.State.Status != "" {
+					switch e.State.Status {
+					case Running:
+						if err := container.Resume(); err != nil {
+							e.Err <- ErrUnknownContainerStatus
+							continue
+						}
+					case Paused:
+						if err := container.Pause(); err != nil {
+							e.Err <- ErrUnknownContainerStatus
+							continue
+						}
+					default:
+						e.Err <- ErrUnknownContainerStatus
+						continue
+					}
+				}
 			}
 			close(e.Err)
 		}