Ensure SizeRw is shown when a user does 'inspect --size -t container'.

Currently, if a user requests the size on a container (inspect --size -t container),
the SizeRw does not show up if the value is 0. It's because InspectContainerData is
defined as int64 and there is an omit when empty.

We do want to display it even if the value is empty. I have changed the type of SizeRw to be a pointer to an int64 instead of an int64. It will allow us todistinguish the empty value to the missing value.

I updated the test "podman inspect container with size" to ensure we check thatSizeRw is displayed correctly.

Closes #4744

Signed-off-by: NevilleC <neville.cain@qonto.eu>

3 files changed, 13 insertions, 9 deletions

diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index 22afc61cc..639dd6e91 100644
--- a/libpod/container_inspect.go
+++ b/libpod/container_inspect.go
@@ -118,7 +118,7 @@ type InspectContainerData struct {
 	BoundingCaps    []string                    `json:"BoundingCaps"`
 	ExecIDs         []string                    `json:"ExecIDs"`
 	GraphDriver     *driver.Data                `json:"GraphDriver"`
-	SizeRw          int64                       `json:"SizeRw,omitempty"`
+	SizeRw          *int64                      `json:"SizeRw,omitempty"`
 	SizeRootFs      int64                       `json:"SizeRootFs,omitempty"`
 	Mounts          []InspectMount              `json:"Mounts"`
 	Dependencies    []string                    `json:"Dependencies"`
@@ -809,12 +809,13 @@ func (c *Container) getContainerInspectData(size bool, driverData *driver.Data)
 		if err != nil {
 			logrus.Errorf("error getting rootfs size %q: %v", config.ID, err)
 		}
+		data.SizeRootFs = rootFsSize
+
 		rwSize, err := c.rwSize()
 		if err != nil {
 			logrus.Errorf("error getting rw size %q: %v", config.ID, err)
 		}
-		data.SizeRootFs = rootFsSize
-		data.SizeRw = rwSize
+		data.SizeRw = &rwSize
 	}
 	return data, nil
 }
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index 9d97ac5d6..562f783a7 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -84,7 +84,7 @@ func (c *Container) rootFsSize() (int64, error) {
 	return size + layerSize, err
 }
 
-// rwSize Gets the size of the mutable top layer of the container.
+// rwSize gets the size of the mutable top layer of the container.
 func (c *Container) rwSize() (int64, error) {
 	if c.config.Rootfs != "" {
 		var size int64
@@ -103,14 +103,16 @@ func (c *Container) rwSize() (int64, error) {
 		return 0, err
 	}
 
-	// Get the size of the top layer by calculating the size of the diff
-	// between the layer and its parent.  The top layer of a container is
-	// the only RW layer, all others are immutable
-	layer, err := c.runtime.store.Layer(container.LayerID)
+	// The top layer of a container is
+	// the only readable/writeable layer, all others are immutable.
+	rwLayer, err := c.runtime.store.Layer(container.LayerID)
 	if err != nil {
 		return 0, err
 	}
-	return c.runtime.store.DiffSize(layer.Parent, layer.ID)
+
+	// Get the size of the top layer by calculating the size of the diff
+	// between the layer and its parent.
+	return c.runtime.store.DiffSize(rwLayer.Parent, rwLayer.ID)
 }
 
 // bundlePath returns the path to the container's root filesystem - where the OCI spec will be
diff --git a/test/e2e/inspect_test.go b/test/e2e/inspect_test.go
index 2d81ef0d8..9d23384ea 100644
--- a/test/e2e/inspect_test.go
+++ b/test/e2e/inspect_test.go
@@ -86,6 +86,7 @@ var _ = Describe("Podman inspect", func() {
 		Expect(result.ExitCode()).To(Equal(0))
 		conData := result.InspectContainerToJSON()
 		Expect(conData[0].SizeRootFs).To(BeNumerically(">", 0))
+		Expect(*conData[0].SizeRw).To(BeNumerically(">=", 0))
 	})
 
 	It("podman inspect container and image", func() {