Migrate x-podman dictionary to x-podman.* fields in container root

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>

docs/Extensions.md

@@ -1,6 +1,30 @@
 # Podman specific extensions to the docker-compose format
 
-Podman-compose supports the following extension to the docker-compose format.
+Podman-compose supports the following extension to the docker-compose format. These extensions
+are generally specified under fields with "x-podman" prefix in the compose file.
+
+## Container management
+
+The following extension keys are available under container configuration:
+
+* `x-podman.uidmap` - Run the container in a new user namespace using the supplied UID mapping.
+
+* `x-podman.gidmap` - Run the container in a new user namespace using the supplied GID mapping.
+
+* `x-podman.rootfs` - Run the container without requiring any image management; the rootfs of the
+container is assumed to be managed externally.
+
+For example, the following docker-compose.yml allows running a podman container with externally managed rootfs.
+```yml
+version: "3"
+services:
+    my_service:
+        command: ["/bin/busybox"]
+        x-podman.rootfs: "/path/to/rootfs"
+```
+
+For explanations of these extensions, please refer to the [Podman Documentation](https://docs.podman.io/).
+
 
 ## Per-network MAC-addresses
 
@@ -65,27 +89,3 @@ In addition, podman-compose supports the following podman-specific values for `n
 
 The options to the network modes are passed to the `--network` option of the `podman create` command
 as-is.
-
-# Service management
-
-Podman-compose extends the compose specification to support some unique features of Podman. These extensions can be specified in the compose file under the "x-podman" field.
-
-Currently, podman-compose supports the following extensions:
-
-* `uidmap` - Run the container in a new user namespace using the supplied UID mapping.
-
-* `gidmap` - Run the container in a new user namespace using the supplied GID mapping.
-
-* `rootfs` - Run the container without requiring any image management; the rootfs of the container is assumed to be managed externally.
-
-For example, the following docker-compose.yml allows running a podman container with externally managed rootfs.
-```yml
-version: "3"
-services:
-    my_service:
-      command: ["/bin/busybox"]
-      x-podman:
-        rootfs: "/path/to/rootfs"
-```
-
-For explanations of these extensions, please refer to the [Podman Documentation](https://docs.podman.io/).

podman_compose.py

@@ -1144,21 +1144,22 @@ async def container_to_args(compose, cnt, detached=True):
         podman_args.extend(["--healthcheck-retries", str(healthcheck["retries"])])
 
     # handle podman extension
-    x_podman = cnt.get("x-podman", None)
+    if 'x-podman' in cnt:
+        raise ValueError(
+            'Configuration under x-podman has been migrated to x-podman.uidmap and '
+            'x-podman.gidman fields'
+        )
+
     rootfs_mode = False
-    if x_podman is not None:
-        for uidmap in x_podman.get("uidmaps", []):
+    for uidmap in cnt.get('x-podman.uidmaps', []):
         podman_args.extend(["--uidmap", uidmap])
-        for gidmap in x_podman.get("gidmaps", []):
+    for gidmap in cnt.get('x-podman.gidmaps', []):
         podman_args.extend(["--gidmap", gidmap])
-        rootfs = x_podman.get("rootfs", None)
+    rootfs = cnt.get('x-podman.rootfs', None)
     if rootfs is not None:
         rootfs_mode = True
         podman_args.extend(["--rootfs", rootfs])
-            log.warning(
-                "WARNING: x-podman.rootfs and image both specified, \
-            image field ignored"
-            )
+        log.warning("WARNING: x-podman.rootfs and image both specified, image field ignored")
 
     if not rootfs_mode:
         podman_args.append(cnt["image"])  # command, ..etc.

pytests/test_container_to_args.py

@@ -162,14 +162,21 @@ class TestContainerToArgs(unittest.IsolatedAsyncioTestCase):
             ],
         )
 
+    async def test_uidmaps_extension_old_path(self):
+        c = create_compose_mock()
+
+        cnt = get_minimal_container()
+        cnt['x-podman'] = {'uidmaps': ['1000:1000:1']}
+
+        with self.assertRaises(ValueError):
+            await container_to_args(c, cnt)
+
     async def test_rootfs_extension(self):
         c = create_compose_mock()
 
         cnt = get_minimal_container()
         del cnt["image"]
-        cnt["x-podman"] = {
-            "rootfs": "/path/to/rootfs",
-        }
+        cnt["x-podman.rootfs"] = "/path/to/rootfs"
 
         args = await container_to_args(c, cnt)
         self.assertEqual(