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>

2 files changed, 10 insertions, 8 deletions

diff --git a/pkg/bindings/containers/containers.go b/pkg/bindings/containers/containers.go
index 708ad06cb..b5cd2128b 100644
--- a/pkg/bindings/containers/containers.go
+++ b/pkg/bindings/containers/containers.go
@@ -322,12 +322,14 @@ func Wait(ctx context.Context, nameOrID string, condition *define.ContainerStatu
 // Exists is a quick, light-weight way to determine if a given container
 // exists in local storage.  The nameOrID can be a container name
 // or a partial/full ID.
-func Exists(ctx context.Context, nameOrID string) (bool, error) {
+func Exists(ctx context.Context, nameOrID string, external bool) (bool, error) {
 	conn, err := bindings.GetClient(ctx)
 	if err != nil {
 		return false, err
 	}
-	response, err := conn.DoRequest(nil, http.MethodGet, "/containers/%s/exists", nil, nil, nameOrID)
+	params := url.Values{}
+	params.Set("external", strconv.FormatBool(external))
+	response, err := conn.DoRequest(nil, http.MethodGet, "/containers/%s/exists", params, nil, nameOrID)
 	if err != nil {
 		return false, err
 	}
diff --git a/pkg/bindings/test/containers_test.go b/pkg/bindings/test/containers_test.go
index 408b4769d..0fb677768 100644
--- a/pkg/bindings/test/containers_test.go
+++ b/pkg/bindings/test/containers_test.go
@@ -405,7 +405,7 @@ var _ = Describe("Podman containers ", func() {
 
 	It("podman bogus container does not exist in local storage", func() {
 		// Bogus container existence check should fail
-		containerExists, err := containers.Exists(bt.conn, "foobar")
+		containerExists, err := containers.Exists(bt.conn, "foobar", false)
 		Expect(err).To(BeNil())
 		Expect(containerExists).To(BeFalse())
 	})
@@ -415,7 +415,7 @@ var _ = Describe("Podman containers ", func() {
 		var name = "top"
 		_, err := bt.RunTopContainer(&name, bindings.PFalse, nil)
 		Expect(err).To(BeNil())
-		containerExists, err := containers.Exists(bt.conn, name)
+		containerExists, err := containers.Exists(bt.conn, name, false)
 		Expect(err).To(BeNil())
 		Expect(containerExists).To(BeTrue())
 	})
@@ -425,7 +425,7 @@ var _ = Describe("Podman containers ", func() {
 		var name = "top"
 		cid, err := bt.RunTopContainer(&name, bindings.PFalse, nil)
 		Expect(err).To(BeNil())
-		containerExists, err := containers.Exists(bt.conn, cid)
+		containerExists, err := containers.Exists(bt.conn, cid, false)
 		Expect(err).To(BeNil())
 		Expect(containerExists).To(BeTrue())
 	})
@@ -435,7 +435,7 @@ var _ = Describe("Podman containers ", func() {
 		var name = "top"
 		cid, err := bt.RunTopContainer(&name, bindings.PFalse, nil)
 		Expect(err).To(BeNil())
-		containerExists, err := containers.Exists(bt.conn, cid[0:12])
+		containerExists, err := containers.Exists(bt.conn, cid[0:12], false)
 		Expect(err).To(BeNil())
 		Expect(containerExists).To(BeTrue())
 	})
@@ -455,7 +455,7 @@ var _ = Describe("Podman containers ", func() {
 		Expect(err).To(BeNil())
 		err = containers.Kill(bt.conn, name, "SIGINT")
 		Expect(err).To(BeNil())
-		_, err = containers.Exists(bt.conn, name)
+		_, err = containers.Exists(bt.conn, name, false)
 		Expect(err).To(BeNil())
 	})
 
@@ -466,7 +466,7 @@ var _ = Describe("Podman containers ", func() {
 		Expect(err).To(BeNil())
 		err = containers.Kill(bt.conn, cid, "SIGTERM")
 		Expect(err).To(BeNil())
-		_, err = containers.Exists(bt.conn, cid)
+		_, err = containers.Exists(bt.conn, cid, false)
 		Expect(err).To(BeNil())
 	})