From 11f0f1b9b22a40e9001c0416f814eb047fc2b448 Mon Sep 17 00:00:00 2001
From: Guillaume Desforges <guillaume.desforges.pro@gmail.com>
Date: Wed, 24 Jul 2024 19:37:41 +0200
Subject: [PATCH] fix: handle docker network host

Fixes #4236.

PR #669 allowed usage of the host network for Docker containers,
but that feature was removed in PR #5279.

This change reintroduces setting `network_mode` to `host` when `docker_network`
is `host`, and adds some additional debug logging to ease debugging.
---
 samcli/local/docker/container.py          | 31 ++++++++++++++++-------
 tests/unit/local/docker/test_container.py |  2 +-
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/samcli/local/docker/container.py b/samcli/local/docker/container.py
index a34e96c7c1b..5ee7273d8ab 100644
--- a/samcli/local/docker/container.py
+++ b/samcli/local/docker/container.py
@@ -154,6 +154,7 @@ def __init__(
             self.rapid_port_host = find_free_port(
                 network_interface=self._container_host_interface, start=self._start_port_range, end=self._end_port_range
             )
+
         except NoFreePortsError as ex:
             raise ContainerNotStartableException(str(ex)) from ex
 
@@ -216,15 +217,25 @@ def create(self):
         if self._env_vars:
             kwargs["environment"] = self._env_vars
 
-        kwargs["ports"] = {self.RAPID_PORT_CONTAINER: (self._container_host_interface, self.rapid_port_host)}
-
-        if self._exposed_ports:
-            kwargs["ports"].update(
-                {
-                    container_port: (self._container_host_interface, host_port)
-                    for container_port, host_port in self._exposed_ports.items()
-                }
-            )
+        if self.network_id == "host":
+            kwargs["network_mode"] = self.network_id
+            # When using host network, aws-lambda-rie will bind to 8080
+            self.rapid_port_host = int(self.RAPID_PORT_CONTAINER)
+            LOG.warning("Using host network mode will bind to port %s", self.RAPID_PORT_CONTAINER)
+
+        # It is not possible to both use host network and expose ports
+        if "network_mode" in kwargs and kwargs["network_mode"] == "host":
+            LOG.warning("Using host network mode, ignoring any port mappings")
+        else:
+            kwargs["ports"] = {self.RAPID_PORT_CONTAINER: (self._container_host_interface, self.rapid_port_host)}
+
+            if self._exposed_ports:
+                kwargs["ports"].update(
+                    {
+                        container_port: (self._container_host_interface, host_port)
+                        for container_port, host_port in self._exposed_ports.items()
+                    }
+                )
 
         if self._entrypoint:
             kwargs["entrypoint"] = self._entrypoint
@@ -236,6 +247,8 @@ def create(self):
         if self._extra_hosts:
             kwargs["extra_hosts"] = self._extra_hosts
 
+        LOG.debug("Docker will start with the following arguments: %s", kwargs)
+
         try:
             real_container = self.docker_client.containers.create(self._image, **kwargs)
         except DockerAPIError as ex:
diff --git a/tests/unit/local/docker/test_container.py b/tests/unit/local/docker/test_container.py
index b181ce33fa0..3345bed9cea 100644
--- a/tests/unit/local/docker/test_container.py
+++ b/tests/unit/local/docker/test_container.py
@@ -307,7 +307,7 @@ def test_must_connect_to_host_network_on_create(self, mock_resolve_symlinks):
             self.image,
             command=self.cmd,
             working_dir=self.working_dir,
-            ports=self.always_exposed_ports,
+            network_mode="host",
             tty=False,
             use_config_proxy=True,
             volumes=expected_volumes,