Enables TCPSite for WSL

It listens on 127.0.0.1 only.

system_setup/cmd/server.py

@@ -42,6 +42,13 @@ def make_server_args_parser():
     parser.add_argument('--output-base', action='store', dest='output_base',
                         default='.subiquity',
                         help='in dryrun, control basedir of files')
+    parser.add_argument('--tcp-port',
+                        dest='tcp_port',
+                        type=int,
+                        choices=range(49152, 60999),
+                        help='The TCP port Subiquity must listen to. It means '
+                        'TCP will be used instead of Unix domain sockets. '
+                        'Only localhost connections are accepted.')
     return parser
 
 

system_setup/server/server.py

@@ -13,6 +13,8 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+from aiohttp import web
+
 from system_setup.common.wsl_utils import is_reconfigure
 from subiquity.server.server import SubiquityServer
 from system_setup.models.system_setup import SystemSetupModel
@@ -37,6 +39,7 @@ INSTALL_MODEL_NAMES = ModelNames({
 
 POSTINSTALL_MODEL_NAMES = ModelNames(set())
 
+LOCALHOST_ADDR="127.0.0.1"
 
 class SystemSetupServer(SubiquityServer):
     prefillInfo = None
@@ -88,3 +91,13 @@ class SystemSetupServer(SubiquityServer):
     async def wait_for_cloudinit(self):
         self.cloud_init_ok = True
         return
+
+    async def start_site(self, runner: web.AppRunner):
+        port = self.opts.tcp_port
+        if port is None:
+            return await super().start_site(runner)
+
+        # Subiquity runs with root privileges. We don't wont outsiders to
+        # connect to it.
+        site = web.TCPSite(runner, host=LOCALHOST_ADDR, port=port)
+        await site.start()