Non-running containers now report statistics via the `podman stats`

command

Previously, if a container was not running, and the user ran the `podman
stats` command, an error would be reported: `Error: container state
improper`.

Podman now reports stats as the fields' default values for their
respective type if the container is not running:

```
$ podman stats --no-stream demo

ID            NAME        CPU %       MEM USAGE / LIMIT  MEM %       NET IO      BLOCK IO    PIDS        CPU TIME    AVG CPU %
4b4bf8ce84ed  demo        0.00%       0B / 0B            0.00%       0B / 0B     0B / 0B     0           0s          0.00%
```

Closes: #14498

Signed-off-by: Jake Correnti <jcorrenti13@gmail.com>

5 files changed, 15 insertions, 25 deletions

diff --git a/cmd/podman/containers/stats.go b/cmd/podman/containers/stats.go
index 500671d31..02f8c6970 100644
--- a/cmd/podman/containers/stats.go
+++ b/cmd/podman/containers/stats.go
@@ -214,10 +214,6 @@ func (s *containerStats) BlockIO() string {
 }
 
 func (s *containerStats) PIDS() string {
-	if s.PIDs == 0 {
-		// If things go bazinga, return a safe value
-		return "--"
-	}
 	return fmt.Sprintf("%d", s.PIDs)
 }
 
@@ -231,7 +227,7 @@ func (s *containerStats) MemUsageBytes() string {
 
 func floatToPercentString(f float64) string {
 	strippedFloat, err := utils.RemoveScientificNotationFromFloat(f)
-	if err != nil || strippedFloat == 0 {
+	if err != nil {
 		// If things go bazinga, return a safe value
 		return "--"
 	}
@@ -239,16 +235,10 @@ func floatToPercentString(f float64) string {
 }
 
 func combineHumanValues(a, b uint64) string {
-	if a == 0 && b == 0 {
-		return "-- / --"
-	}
 	return fmt.Sprintf("%s / %s", units.HumanSize(float64(a)), units.HumanSize(float64(b)))
 }
 
 func combineBytesValues(a, b uint64) string {
-	if a == 0 && b == 0 {
-		return "-- / --"
-	}
 	return fmt.Sprintf("%s / %s", units.BytesSize(float64(a)), units.BytesSize(float64(b)))
 }
 
diff --git a/libpod/stats.go b/libpod/stats.go
index 25baa378d..d2ffc3b32 100644
--- a/libpod/stats.go
+++ b/libpod/stats.go
@@ -34,8 +34,9 @@ func (c *Container) GetContainerStats(previousStats *define.ContainerStats) (*de
 		}
 	}
 
+	// returns stats with the fields' default values respective of their type
 	if c.state.State != define.ContainerStateRunning && c.state.State != define.ContainerStatePaused {
-		return stats, define.ErrCtrStateInvalid
+		return stats, nil
 	}
 
 	if previousStats == nil {
diff --git a/pkg/api/handlers/compat/containers_stats.go b/pkg/api/handlers/compat/containers_stats.go
index 77b16b03e..6855e369b 100644
--- a/pkg/api/handlers/compat/containers_stats.go
+++ b/pkg/api/handlers/compat/containers_stats.go
@@ -44,18 +44,6 @@ func StatsContainer(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// If the container isn't running, then let's not bother and return
-	// immediately.
-	state, err := ctnr.State()
-	if err != nil {
-		utils.InternalServerError(w, err)
-		return
-	}
-	if state != define.ContainerStateRunning {
-		utils.Error(w, http.StatusConflict, define.ErrCtrStateInvalid)
-		return
-	}
-
 	stats, err := ctnr.GetContainerStats(nil)
 	if err != nil {
 		utils.InternalServerError(w, errors.Wrapf(err, "failed to obtain Container %s stats", name))
diff --git a/test/e2e/pause_test.go b/test/e2e/pause_test.go
index 402719de2..566aca07e 100644
--- a/test/e2e/pause_test.go
+++ b/test/e2e/pause_test.go
@@ -82,7 +82,7 @@ var _ = Describe("Podman pause", func() {
 		// check we can read stats for a paused container
 		result = podmanTest.Podman([]string{"stats", "--no-stream", cid})
 		result.WaitWithDefaultTimeout()
-		Expect(result).To(ExitWithError())
+		Expect(result).Should(Exit(0))
 	})
 
 	It("podman pause a running container by id", func() {
diff --git a/test/e2e/stats_test.go b/test/e2e/stats_test.go
index b43a81cd3..3000a819f 100644
--- a/test/e2e/stats_test.go
+++ b/test/e2e/stats_test.go
@@ -236,4 +236,15 @@ var _ = Describe("Podman stats", func() {
 
 		Expect(customLimit).To(BeNumerically("<", defaultLimit))
 	})
+
+	It("podman stats with a container that is not running", func() {
+		ctr := "created_container"
+		session := podmanTest.Podman([]string{"create", "--name", ctr, ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"stats", "--no-stream", ctr})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+	})
 })