Add support for external container

External containers are containers created outside of Podman.
For example Buildah and CRI-O Containers.

$ buildah from alpine
alpine-working-container
$ buildah run alpine-working-container touch /test
$ podman container exists --external alpine-working-container

$ podman container diff alpine-working-container
C /etc
A /test

Added --external flag to refer to external containers, rather then --storage.

Added --external for podman container exists and modified podman ps to use
--external rather then --storage.  It was felt that --storage would confuse
the user into thinking about changing the storage driver or options.

--storage is still supported through the use of aliases.

Finally podman contianer diff, does not require the --external flag, since it
there is little change of users making the mistake, and would just be a pain
for the user to remember the flag.

podman container exists --external is required because it could fool scripts
that rely on the existance of a Podman container, and there is a potential
for a partial deletion of a container, which could mess up existing users.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/cmd/podman/diff.go b/cmd/podman/diff.go
index 51a04bf46..9d2236abe 100644
--- a/cmd/podman/diff.go
+++ b/cmd/podman/diff.go
@@ -48,7 +48,10 @@ func diff(cmd *cobra.Command, args []string) error {
 		return containers.Diff(cmd, args, diffOpts)
 	}
 
-	if found, err := registry.ContainerEngine().ContainerExists(registry.GetContext(), args[0]); err != nil {
+	options := entities.ContainerExistsOptions{
+		External: true,
+	}
+	if found, err := registry.ContainerEngine().ContainerExists(registry.GetContext(), args[0], options); err != nil {
 		return err
 	} else if found.Value {
 		return containers.Diff(cmd, args, diffOpts)