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>

4 files changed, 19 insertions, 5 deletions

diff --git a/cmd/podman/containers/exists.go b/cmd/podman/containers/exists.go
index 283f6df18..1d79b684d 100644
--- a/cmd/podman/containers/exists.go
+++ b/cmd/podman/containers/exists.go
@@ -12,10 +12,10 @@ var (
 	containerExistsDescription = `If the named container exists in local storage, podman container exists exits with 0, otherwise the exit code will be 1.`
 
 	existsCommand = &cobra.Command{
-		Use:   "exists CONTAINER",
+		Use:   "exists [flags] CONTAINER",
 		Short: "Check if a container exists in local storage",
 		Long:  containerExistsDescription,
-		Example: `podman container exists containerID
+		Example: `podman container exists --external containerID
   podman container exists myctr || podman run --name myctr [etc...]`,
 		RunE:                  exists,
 		Args:                  cobra.ExactArgs(1),
@@ -29,10 +29,19 @@ func init() {
 		Command: existsCommand,
 		Parent:  containerCmd,
 	})
+	flags := existsCommand.Flags()
+	flags.Bool("external", false, "Check external storage containers as well as Podman containers")
 }
 
 func exists(cmd *cobra.Command, args []string) error {
-	response, err := registry.ContainerEngine().ContainerExists(context.Background(), args[0])
+	external, err := cmd.Flags().GetBool("external")
+	if err != nil {
+		return err
+	}
+	options := entities.ContainerExistsOptions{
+		External: external,
+	}
+	response, err := registry.ContainerEngine().ContainerExists(context.Background(), args[0], options)
 	if err != nil {
 		return err
 	}
diff --git a/cmd/podman/containers/ps.go b/cmd/podman/containers/ps.go
index 65bfc97da..41d309f51 100644
--- a/cmd/podman/containers/ps.go
+++ b/cmd/podman/containers/ps.go
@@ -58,7 +58,7 @@ func init() {
 func listFlagSet(flags *pflag.FlagSet) {
 	flags.BoolVarP(&listOpts.All, "all", "a", false, "Show all the containers, default is only running containers")
 	flags.StringSliceVarP(&filters, "filter", "f", []string{}, "Filter output based on conditions given")
-	flags.BoolVar(&listOpts.Storage, "storage", false, "Show containers in storage not controlled by Podman")
+	flags.BoolVar(&listOpts.Storage, "external", false, "Show containers in storage not controlled by Podman")
 	flags.StringVar(&listOpts.Format, "format", "", "Pretty-print containers to JSON or using a Go template")
 	flags.IntVarP(&listOpts.Last, "last", "n", -1, "Print the n last created containers (all states)")
 	flags.BoolVar(&listOpts.Namespace, "ns", false, "Display namespace information")
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)
diff --git a/cmd/podman/utils/alias.go b/cmd/podman/utils/alias.go
index ff31e82ea..10b96fa98 100644
--- a/cmd/podman/utils/alias.go
+++ b/cmd/podman/utils/alias.go
@@ -21,6 +21,8 @@ func AliasFlags(f *pflag.FlagSet, name string) pflag.NormalizedName {
 		name = "time"
 	case "namespace":
 		name = "ns"
+	case "storage":
+		name = "external"
 	}
 	return pflag.NormalizedName(name)
 }