Ensure non-zero exit code when startup fails (#1278)

* Ensure non-zero exit code when startup fails

* Make sure it only works on standalone uvicorn run

* Fix test

* Rename constant name

tests/test_cli.py

@@ -57,7 +57,7 @@ def test_cli_call_server_run() -> None:
     with mock.patch.object(Server, "run") as mock_run:
         result = runner.invoke(cli, ["tests.test_cli:App"])
 
-    assert result.exit_code == 0
+    assert result.exit_code == 3
     mock_run.assert_called_once()
 
 

tests/test_main.py

@@ -74,3 +74,15 @@ def test_run_invalid_app_config_combination(caplog: pytest.LogCaptureFixture) ->
         "You must pass the application as an import string to enable "
         "'reload' or 'workers'."
     )
+
+
+def test_run_startup_failure(caplog: pytest.LogCaptureFixture) -> None:
+    async def app(scope, receive, send):
+        assert scope["type"] == "lifespan"
+        message = await receive()
+        if message["type"] == "lifespan.startup":
+            raise RuntimeError("Startup failed")
+
+    with pytest.raises(SystemExit) as exit_exception:
+        run(app, lifespan="on")
+    assert exit_exception.value.code == 3

uvicorn/main.py

@@ -30,6 +30,8 @@
 LOOP_CHOICES = click.Choice([key for key in LOOP_SETUPS.keys() if key != "none"])
 INTERFACE_CHOICES = click.Choice(INTERFACES)
 
+STARTUP_FAILURE = 3
+
 logger = logging.getLogger("uvicorn.error")
 
 
@@ -449,6 +451,9 @@ def run(app: typing.Union[ASGIApplication, str], **kwargs: typing.Any) -> None:
     if config.uds:
         os.remove(config.uds)  # pragma: py-win32
 
+    if not server.started and not config.should_reload and config.workers == 1:
+        sys.exit(STARTUP_FAILURE)
+
 
 if __name__ == "__main__":
     main()  # pragma: no cover