Filter containers by status.

A continuation of #7616.
Adds `docker ps --filter=status=(restarting|running|paused|stopped)` option.

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Upstream-commit: ea09f036824aee74112a75ac99579ae4f10251b5
Component: engine

components/engine/daemon/list.go

@@ -28,6 +28,7 @@ func (daemon *Daemon) Containers(job *engine.Job) engine.Status {
 		size        = job.GetenvBool("size")
 		psFilters   filters.Args
 		filt_exited []int
+		filt_status []string
 	)
 	outs := engine.NewTable("Created", 0)
 
@@ -45,6 +46,8 @@ func (daemon *Daemon) Containers(job *engine.Job) engine.Status {
 		}
 	}
 
+	filt_status, _ = psFilters["status"]
+
 	names := map[string][]string{}
 	daemon.ContainerGraph().Walk("/", func(p string, e *graphdb.Entity) error {
 		names[e.ID()] = append(names[e.ID()], p)
@@ -99,6 +102,11 @@ func (daemon *Daemon) Containers(job *engine.Job) engine.Status {
 				return nil
 			}
 		}
+		for _, status := range filt_status {
+			if container.State.StateString() != strings.ToLower(status) {
+				return nil
+			}
+		}
 		displayed++
 		out := &engine.Env{}
 		out.Set("Id", container.ID)

components/engine/daemon/state.go

@@ -46,6 +46,20 @@ func (s *State) String() string {
 	return fmt.Sprintf("Exited (%d) %s ago", s.ExitCode, units.HumanDuration(time.Now().UTC().Sub(s.FinishedAt)))
 }
 
+// StateString returns a single string to describe state
+func (s *State) StateString() string {
+	if s.Running {
+		if s.Paused {
+			return "paused"
+		}
+		if s.Restarting {
+			return "restarting"
+		}
+		return "running"
+	}
+	return "exited"
+}
+
 func wait(waitChan <-chan struct{}, timeout time.Duration) error {
 	if timeout < 0 {
 		<-waitChan