Add Ready Notification

Hub, Exporter and Agent now write a single line to stdout, which can be
used as a ready notification for the service supervisor.

For systemd, you can use a wrapper like
https://github.com/holesch/sdnotify-wrapper-py

not_my_board/_hub.py

@@ -46,18 +46,7 @@ async def _handle_lifespan(scope, receive, send):
         message = await receive()
         if message["type"] == "lifespan.startup":
             try:
-                config_file = os.environ.get("NOT_MY_BOARD_HUB_CONFIG")
-                if not config_file:
-                    config_file = "/etc/not-my-board/hub.toml"
-                config_file = pathlib.Path(config_file)
-
-                if config_file.exists():
-                    config = util.toml_loads(config_file.read_text())
-                else:
-                    config = {}
-
-                hub = Hub(config, http.Client())
-                await hub.startup()
+                hub = await _on_startup()
                 scope["state"]["hub"] = hub
             except Exception as err:
                 await send({"type": "lifespan.startup.failed", "message": str(err)})
@@ -75,6 +64,25 @@ async def _handle_lifespan(scope, receive, send):
             logger.warning("Unknown lifespan message %s", message["type"])
 
 
+async def _on_startup():
+    config_file = os.environ.get("NOT_MY_BOARD_HUB_CONFIG")
+    if not config_file:
+        config_file = "/etc/not-my-board/hub.toml"
+    config_file = pathlib.Path(config_file)
+
+    if config_file.exists():
+        config = util.toml_loads(config_file.read_text())
+    else:
+        logger.warning('Config file "%s" not found', config_file)
+        config = {}
+
+    hub = Hub(config, http.Client())
+    await hub.startup()
+    print("ready", flush=True)  # noqa: T201
+
+    return hub
+
+
 @asgineer.to_asgi
 async def _handle_request(request):
     hub = request.scope["state"]["hub"]

not_my_board/_usbip.py

@@ -536,6 +536,7 @@ async def _main():
             server = util.Server(usbip_server.handle_client, port=args.port)
             async with server:
                 logger.info("listening")
+                print("ready", flush=True)  # noqa: T201
                 await server.serve_forever()
 
 

not_my_board/cli/__init__.py

@@ -168,6 +168,7 @@ async def _export_command(args):
         args.hub_url, args.export_description, http_client, token_src
     ) as exporter:
         await exporter.register_place()
+        print("ready", flush=True)
         await exporter.serve_forever()
 
 
@@ -177,6 +178,7 @@ async def _agent_command(args):
     token_src = _token_src(args, http_client)
 
     async with agent.Agent(args.hub_url, io, token_src) as agent_:
+        print("ready", flush=True)
         await agent_.serve_forever()