feat: Add pod_network setting for pod network inheritance

newsfragments/pod_network_inheritance.feature

@@ -0,0 +1 @@
+Add x-podman.pod_network setting to enable pod network inheritance for external/macvlan networks.

podman_compose.py

@@ -1016,6 +1016,13 @@ def get_net_args_from_network_mode(compose: PodmanCompose, cnt: dict[str, Any])
 
 
 def get_net_args(compose: PodmanCompose, cnt: dict[str, Any]) -> list[str]:
+    # If container should inherit network from pod, skip network args
+    # This allows podman to automatically set NetNS=FromPod when --pod is
+    # passed without --network, enabling pod network inheritance for
+    # macvlan, external networks, or other pod-level network configurations.
+    if compose.should_inherit_net_from_pod(cnt):
+        return []
+
     net = cnt.get("network_mode")
     if net:
         return get_net_args_from_network_mode(compose, cnt)
@@ -2053,6 +2060,7 @@ class XPodmanSettingKey(Enum):
         NAME_SEPARATOR_COMPAT = "name_separator_compat"
         IN_POD = "in_pod"
         POD_ARGS = "pod_args"
+        POD_NETWORK = "pod_network"
 
     def __init__(self) -> None:
         self.podman: Podman
@@ -2193,6 +2201,33 @@ def resolve_pod_args(self) -> list[str]:
             PodmanCompose.XPodmanSettingKey.POD_ARGS, ["--infra=false", "--share="]
         )
 
+    def resolve_pod_network(self) -> str | None:
+        """
+        Returns the network name for the pod if pod_network is configured.
+        This enables pod network inheritance where containers join the pod's
+        network namespace instead of having their own network configuration.
+        """
+        return self.x_podman.get(PodmanCompose.XPodmanSettingKey.POD_NETWORK)
+
+    def should_inherit_net_from_pod(self, cnt: dict[str, Any]) -> bool:
+        """
+        Determines if a container should inherit its network from the pod.
+        This is true when:
+        1. The container is assigned to a pod
+        2. pod_network is configured (indicating the pod has network settings)
+        3. The container doesn't have explicit network_mode or networks set
+        """
+        pod_network = self.resolve_pod_network()
+        if not pod_network:
+            return False
+        pod = cnt.get("pod", "")
+        if not pod:
+            return False
+        # If container has explicit network configuration, don't inherit from pod
+        if cnt.get("network_mode") or cnt.get("networks"):
+            return False
+        return True
+
     def join_name_parts(self, *parts: str) -> str:
         setting = self.x_podman.get(PodmanCompose.XPodmanSettingKey.NAME_SEPARATOR_COMPAT, False)
         if try_parse_bool(setting):
@@ -3101,6 +3136,14 @@ async def create_pods(compose: PodmanCompose) -> None:
             "--name=" + pod["name"],
         ] + compose.resolve_pod_args()
 
+        # Add network to pod if pod_network is configured
+        # This enables pod network inheritance where containers join the pod's
+        # network namespace (via --pod without --network) instead of having
+        # their own network configuration.
+        pod_network = compose.resolve_pod_network()
+        if pod_network:
+            podman_args.append(f"--network={pod_network}")
+
         ports = pod.get("ports", [])
         if isinstance(ports, str):
             ports = [ports]

tests/unit/test_container_to_args.py

@@ -23,6 +23,8 @@ def create_compose_mock(project_name: str = "test_project_name") -> PodmanCompos
     compose.x_podman = {}
     compose.join_name_parts = mock.Mock(side_effect=lambda *args: '_'.join(args))
     compose.format_name = mock.Mock(side_effect=lambda *args: '_'.join([project_name, *args]))
+    # Default behavior: don't inherit network from pod (backwards compatible)
+    compose.should_inherit_net_from_pod = mock.Mock(return_value=False)
 
     async def podman_output(*args: Any, **kwargs: Any) -> None:
         pass

tests/unit/test_get_net_args.py

@@ -331,3 +331,103 @@ def test_network__mode_service(self) -> None:
         expected_args = ["--network=container:container_2"]
         args = get_net_args(compose, container)
         self.assertListEqual(expected_args, args)
+
+    def test_pod_network_inheritance_enabled(self) -> None:
+        """
+        Test that when pod_network is configured and container is in a pod,
+        get_net_args returns empty list to allow pod network inheritance.
+        """
+        from podman_compose import PodmanCompose
+
+        compose = get_networked_compose()
+        # Set up pod_network via x_podman
+        compose.x_podman = {PodmanCompose.XPodmanSettingKey.POD_NETWORK: "external_macvlan"}
+        # Mock the methods that use x_podman
+        compose.resolve_pod_network = lambda: "external_macvlan"
+        compose.should_inherit_net_from_pod = lambda cnt: (
+            compose.resolve_pod_network() is not None
+            and cnt.get("pod")
+            and not cnt.get("network_mode")
+            and not cnt.get("networks")
+        )
+
+        container = get_minimal_container()
+        container["pod"] = "pod_test_project_name"
+
+        expected_args: list = []
+        args = get_net_args(compose, container)
+        self.assertListEqual(expected_args, args)
+
+    def test_pod_network_inheritance_disabled_no_pod(self) -> None:
+        """
+        Test that when pod_network is configured but container is not in a pod,
+        get_net_args returns normal network args.
+        """
+        from podman_compose import PodmanCompose
+
+        compose = get_networked_compose()
+        compose.x_podman = {PodmanCompose.XPodmanSettingKey.POD_NETWORK: "external_macvlan"}
+        compose.resolve_pod_network = lambda: "external_macvlan"
+        compose.should_inherit_net_from_pod = lambda cnt: (
+            compose.resolve_pod_network() is not None
+            and cnt.get("pod")
+            and not cnt.get("network_mode")
+            and not cnt.get("networks")
+        )
+
+        container = get_minimal_container()
+        # No pod assigned
+
+        expected_args = [f"--network={PROJECT_NAME}_net0:alias={SERVICE_NAME}"]
+        args = get_net_args(compose, container)
+        self.assertListEqual(expected_args, args)
+
+    def test_pod_network_inheritance_disabled_explicit_networks(self) -> None:
+        """
+        Test that when container has explicit networks config,
+        pod network inheritance is skipped even if pod_network is set.
+        """
+        from podman_compose import PodmanCompose
+
+        compose = get_networked_compose()
+        compose.x_podman = {PodmanCompose.XPodmanSettingKey.POD_NETWORK: "external_macvlan"}
+        compose.resolve_pod_network = lambda: "external_macvlan"
+        compose.should_inherit_net_from_pod = lambda cnt: (
+            compose.resolve_pod_network() is not None
+            and cnt.get("pod")
+            and not cnt.get("network_mode")
+            and not cnt.get("networks")
+        )
+
+        container = get_minimal_container()
+        container["pod"] = "pod_test_project_name"
+        container["networks"] = {"net0": {}}  # Explicit networks config
+
+        expected_args = [f"--network={PROJECT_NAME}_net0:alias={SERVICE_NAME}"]
+        args = get_net_args(compose, container)
+        self.assertListEqual(expected_args, args)
+
+    def test_pod_network_inheritance_disabled_network_mode(self) -> None:
+        """
+        Test that when container has explicit network_mode,
+        pod network inheritance is skipped even if pod_network is set.
+        """
+        from podman_compose import PodmanCompose
+
+        compose = get_networked_compose()
+        compose.x_podman = {PodmanCompose.XPodmanSettingKey.POD_NETWORK: "external_macvlan"}
+        compose.resolve_pod_network = lambda: "external_macvlan"
+        compose.should_inherit_net_from_pod = lambda cnt: (
+            compose.resolve_pod_network() is not None
+            and cnt.get("pod")
+            and not cnt.get("network_mode")
+            and not cnt.get("networks")
+        )
+
+        container = get_minimal_container()
+        container["pod"] = "pod_test_project_name"
+        container["network_mode"] = "host"  # Explicit network_mode
+
+        expected_args = ["--network=host"]
+        args = get_net_args(compose, container)
+        self.assertListEqual(expected_args, args)