Changed GetContainerStats to return ErrCtrStateInvalid

This results in some functionality changes:

If a ErrCtrStateInvalid is returned to GetPodStats, the container is ommitted from the stats.
As such, if an empty slice of Container stats are returned to GetPodStats in varlink, an error will occur.
GetContainerStats will return the ErrCtrStateInvalid as well.
Finally, if ErrCtrStateInvalid is returned to the podman stats call, the container will be ommitted from the stats.

Signed-off-by: haircommander <pehunt@redhat.com>

Closes: #1319
Approved by: baude

cmd/podman/stats.go

@@ -138,7 +138,7 @@ func statsCmd(c *cli.Context) error {
 			id := ctr.ID()
 			if _, ok := containerStats[ctr.ID()]; !ok {
 				initialStats, err := ctr.GetContainerStats(&libpod.ContainerStats{})
-				if errors.Cause(err) == libpod.ErrCtrRemoved || errors.Cause(err) == libpod.ErrNoSuchCtr {
+				if errors.Cause(err) == libpod.ErrCtrRemoved || errors.Cause(err) == libpod.ErrNoSuchCtr || errors.Cause(err) == libpod.ErrCtrStateInvalid {
 					// skip dealing with a container that is gone
 					continue
 				}

cmd/podman/varlink/io.podman.varlink

@@ -441,7 +441,8 @@ method ExportContainer(name: string, path: string) -> (tarfile: string)
 
 # GetContainerStats takes the name or ID of a container and returns a single ContainerStats structure which
 # contains attributes like memory and cpu usage.  If the container cannot be found, a
-# [ContainerNotFound](#ContainerNotFound)  error will be returned.
+# [ContainerNotFound](#ContainerNotFound) error will be returned. If the container is not running, a [NoContainerRunning](#NoContainerRunning)
+# error will be returned
 # #### Example
 # ~~~
 # $ varlink call -m unix:/run/podman/io.podman/io.podman.GetContainerStats '{"name": "c33e4164f384"}'
@@ -759,6 +760,7 @@ method TopPod() -> (notimplemented: NotImplemented)
 
 # GetPodStats takes the name or ID of a pod and returns a pod name and slice of ContainerStats structure which
 # contains attributes like memory and cpu usage.  If the pod cannot be found, a [PodNotFound](#PodNotFound)
+# error will be returned.  If the pod has no running containers associated with it, a [NoContainerRunning](#NoContainerRunning)
 # error will be returned.
 # #### Example
 # ~~~
@@ -792,6 +794,9 @@ error ImageNotFound (name: string)
 # ContainerNotFound means the container could not be found by the provided name or ID in local storage.
 error ContainerNotFound (name: string)
 
+# NoContainerRunning means none of the containers requested are running in a command that requires a running container.
+error NoContainerRunning ()
+
 # PodNotFound means the pod could not be found by the provided name or ID in local storage.
 error PodNotFound (name: string)
 

libpod/pod.go

@@ -4,6 +4,7 @@ import (
 	"time"
 
 	"github.com/containers/storage"
+	"github.com/pkg/errors"
 )
 
 // Pod represents a group of containers that are managed together.
@@ -192,10 +193,14 @@ func (p *Pod) GetPodStats(previousContainerStats map[string]*ContainerStats) (ma
 			prevStat = &ContainerStats{}
 		}
 		newStats, err := c.GetContainerStats(prevStat)
-		if err != nil {
+		// If the container wasn't running, don't include it
+		// but also suppress the error
+		if err != nil && errors.Cause(err) != ErrCtrStateInvalid {
 			return nil, err
 		}
-		newContainerStats[c.ID()] = newStats
+		if err == nil {
+			newContainerStats[c.ID()] = newStats
+		}
 	}
 	return newContainerStats, nil
 }

libpod/pod_ffjson.go

@@ -1,5 +1,5 @@
 // Code generated by ffjson <https://github.com/pquerna/ffjson>. DO NOT EDIT.
-// source: libpod/pod.go
+// source: /home/pehunt/go/src/github.com/containers/libpod/libpod/pod.go
 
 package libpod
 

libpod/stats.go

@@ -26,7 +26,7 @@ func (c *Container) GetContainerStats(previousStats *ContainerStats) (*Container
 	}
 
 	if c.state.State != ContainerStateRunning {
-		return stats, nil
+		return stats, ErrCtrStateInvalid
 	}
 
 	cgroupPath, err := c.CGroupPath()

pkg/varlinkapi/containers.go

@@ -207,6 +207,9 @@ func (i *LibpodAPI) GetContainerStats(call iopodman.VarlinkCall, name string) er
 	}
 	containerStats, err := ctr.GetContainerStats(&libpod.ContainerStats{})
 	if err != nil {
+		if errors.Cause(err) == libpod.ErrCtrStateInvalid {
+			return call.ReplyNoContainerRunning()
+		}
 		return call.ReplyErrorOccurred(err.Error())
 	}
 	cs := iopodman.ContainerStats{

pkg/varlinkapi/pods.go

@@ -199,6 +199,9 @@ func (i *LibpodAPI) GetPodStats(call iopodman.VarlinkCall, name string) error {
 	if err != nil {
 		return call.ReplyErrorOccurred(err.Error())
 	}
+	if len(podStats) == 0 {
+		return call.ReplyNoContainerRunning()
+	}
 	containersStats := make([]iopodman.ContainerStats, 0)
 	for ctrID, containerStats := range podStats {
 		cs := iopodman.ContainerStats{