Backport #5572: Use new loop for web.run_app().

CHANGES/5572.feature

@@ -0,0 +1,2 @@
+Always create a new event loop in ``aiohttp.web.run_app()``.
+This adds better compatibility with ``asyncio.run()`` or if trying to run multiple apps in sequence.

aiohttp/web.py

@@ -477,9 +477,11 @@ def run_app(
     handle_signals: bool = True,
     reuse_address: Optional[bool] = None,
     reuse_port: Optional[bool] = None,
+    loop: Optional[asyncio.AbstractEventLoop] = None,
 ) -> None:
     """Run an app locally"""
-    loop = asyncio.get_event_loop()
+    if loop is None:
+        loop = asyncio.new_event_loop()
 
     # Configure if and only if in debugging mode and using the default logger
     if loop.get_debug() and access_log and access_log.name == "aiohttp.access":
@@ -488,27 +490,29 @@ def run_app(
         if not access_log.hasHandlers():
             access_log.addHandler(logging.StreamHandler())
 
-    try:
-        main_task = loop.create_task(
-            _run_app(
-                app,
-                host=host,
-                port=port,
-                path=path,
-                sock=sock,
-                shutdown_timeout=shutdown_timeout,
-                keepalive_timeout=keepalive_timeout,
-                ssl_context=ssl_context,
-                print=print,
-                backlog=backlog,
-                access_log_class=access_log_class,
-                access_log_format=access_log_format,
-                access_log=access_log,
-                handle_signals=handle_signals,
-                reuse_address=reuse_address,
-                reuse_port=reuse_port,
-            )
+    main_task = loop.create_task(
+        _run_app(
+            app,
+            host=host,
+            port=port,
+            path=path,
+            sock=sock,
+            shutdown_timeout=shutdown_timeout,
+            keepalive_timeout=keepalive_timeout,
+            ssl_context=ssl_context,
+            print=print,
+            backlog=backlog,
+            access_log_class=access_log_class,
+            access_log_format=access_log_format,
+            access_log=access_log,
+            handle_signals=handle_signals,
+            reuse_address=reuse_address,
+            reuse_port=reuse_port,
         )
+    )
+
+    try:
+        asyncio.set_event_loop(loop)
         loop.run_until_complete(main_task)
     except (GracefulExit, KeyboardInterrupt):  # pragma: no cover
         pass

tests/test_run_app.py

@@ -94,7 +94,7 @@ def test_run_app_http(patched_loop) -> None:
     cleanup_handler = make_mocked_coro()
     app.on_cleanup.append(cleanup_handler)
 
-    web.run_app(app, print=stopper(patched_loop))
+    web.run_app(app, print=stopper(patched_loop), loop=patched_loop)
 
     patched_loop.create_server.assert_called_with(
         mock.ANY, None, 8080, ssl=None, backlog=128, reuse_address=None, reuse_port=None
@@ -105,7 +105,7 @@ def test_run_app_http(patched_loop) -> None:
 
 def test_run_app_close_loop(patched_loop) -> None:
     app = web.Application()
-    web.run_app(app, print=stopper(patched_loop))
+    web.run_app(app, print=stopper(patched_loop), loop=patched_loop)
 
     patched_loop.create_server.assert_called_with(
         mock.ANY, None, 8080, ssl=None, backlog=128, reuse_address=None, reuse_port=None
@@ -425,7 +425,7 @@ def test_run_app_mixed_bindings(
     run_app_kwargs, expected_server_calls, expected_unix_server_calls, patched_loop
 ):
     app = web.Application()
-    web.run_app(app, print=stopper(patched_loop), **run_app_kwargs)
+    web.run_app(app, print=stopper(patched_loop), **run_app_kwargs, loop=patched_loop)
 
     assert patched_loop.create_unix_server.mock_calls == expected_unix_server_calls
     assert patched_loop.create_server.mock_calls == expected_server_calls
@@ -435,7 +435,9 @@ def test_run_app_https(patched_loop) -> None:
     app = web.Application()
 
     ssl_context = ssl.create_default_context()
-    web.run_app(app, ssl_context=ssl_context, print=stopper(patched_loop))
+    web.run_app(
+        app, ssl_context=ssl_context, print=stopper(patched_loop), loop=patched_loop
+    )
 
     patched_loop.create_server.assert_called_with(
         mock.ANY,
@@ -453,7 +455,9 @@ def test_run_app_nondefault_host_port(patched_loop, aiohttp_unused_port) -> None
     host = "127.0.0.1"
 
     app = web.Application()
-    web.run_app(app, host=host, port=port, print=stopper(patched_loop))
+    web.run_app(
+        app, host=host, port=port, print=stopper(patched_loop), loop=patched_loop
+    )
 
     patched_loop.create_server.assert_called_with(
         mock.ANY, host, port, ssl=None, backlog=128, reuse_address=None, reuse_port=None
@@ -464,7 +468,7 @@ def test_run_app_multiple_hosts(patched_loop) -> None:
     hosts = ("127.0.0.1", "127.0.0.2")
 
     app = web.Application()
-    web.run_app(app, host=hosts, print=stopper(patched_loop))
+    web.run_app(app, host=hosts, print=stopper(patched_loop), loop=patched_loop)
 
     calls = map(
         lambda h: mock.call(
@@ -483,7 +487,7 @@ def test_run_app_multiple_hosts(patched_loop) -> None:
 
 def test_run_app_custom_backlog(patched_loop) -> None:
     app = web.Application()
-    web.run_app(app, backlog=10, print=stopper(patched_loop))
+    web.run_app(app, backlog=10, print=stopper(patched_loop), loop=patched_loop)
 
     patched_loop.create_server.assert_called_with(
         mock.ANY, None, 8080, ssl=None, backlog=10, reuse_address=None, reuse_port=None
@@ -492,7 +496,13 @@ def test_run_app_custom_backlog(patched_loop) -> None:
 
 def test_run_app_custom_backlog_unix(patched_loop) -> None:
     app = web.Application()
-    web.run_app(app, path="/tmp/tmpsock.sock", backlog=10, print=stopper(patched_loop))
+    web.run_app(
+        app,
+        path="/tmp/tmpsock.sock",
+        backlog=10,
+        print=stopper(patched_loop),
+        loop=patched_loop,
+    )
 
     patched_loop.create_unix_server.assert_called_with(
         mock.ANY, "/tmp/tmpsock.sock", ssl=None, backlog=10
@@ -505,7 +515,7 @@ def test_run_app_http_unix_socket(patched_loop, shorttmpdir) -> None:
 
     sock_path = str(shorttmpdir / "socket.sock")
     printer = mock.Mock(wraps=stopper(patched_loop))
-    web.run_app(app, path=sock_path, print=printer)
+    web.run_app(app, path=sock_path, print=printer, loop=patched_loop)
 
     patched_loop.create_unix_server.assert_called_with(
         mock.ANY, sock_path, ssl=None, backlog=128
@@ -520,7 +530,9 @@ def test_run_app_https_unix_socket(patched_loop, shorttmpdir) -> None:
     sock_path = str(shorttmpdir / "socket.sock")
     ssl_context = ssl.create_default_context()
     printer = mock.Mock(wraps=stopper(patched_loop))
-    web.run_app(app, path=sock_path, ssl_context=ssl_context, print=printer)
+    web.run_app(
+        app, path=sock_path, ssl_context=ssl_context, print=printer, loop=patched_loop
+    )
 
     patched_loop.create_unix_server.assert_called_with(
         mock.ANY, sock_path, ssl=ssl_context, backlog=128
@@ -534,7 +546,10 @@ def test_run_app_abstract_linux_socket(patched_loop) -> None:
     sock_path = b"\x00" + uuid4().hex.encode("ascii")
     app = web.Application()
     web.run_app(
-        app, path=sock_path.decode("ascii", "ignore"), print=stopper(patched_loop)
+        app,
+        path=sock_path.decode("ascii", "ignore"),
+        print=stopper(patched_loop),
+        loop=patched_loop,
     )
 
     patched_loop.create_unix_server.assert_called_with(
@@ -551,7 +566,7 @@ def test_run_app_preexisting_inet_socket(patched_loop, mocker) -> None:
         _, port = sock.getsockname()
 
         printer = mock.Mock(wraps=stopper(patched_loop))
-        web.run_app(app, sock=sock, print=printer)
+        web.run_app(app, sock=sock, print=printer, loop=patched_loop)
 
         patched_loop.create_server.assert_called_with(
             mock.ANY, sock=sock, backlog=128, ssl=None
@@ -569,7 +584,7 @@ def test_run_app_preexisting_inet6_socket(patched_loop) -> None:
         port = sock.getsockname()[1]
 
         printer = mock.Mock(wraps=stopper(patched_loop))
-        web.run_app(app, sock=sock, print=printer)
+        web.run_app(app, sock=sock, print=printer, loop=patched_loop)
 
         patched_loop.create_server.assert_called_with(
             mock.ANY, sock=sock, backlog=128, ssl=None
@@ -588,7 +603,7 @@ def test_run_app_preexisting_unix_socket(patched_loop, mocker) -> None:
         os.unlink(sock_path)
 
         printer = mock.Mock(wraps=stopper(patched_loop))
-        web.run_app(app, sock=sock, print=printer)
+        web.run_app(app, sock=sock, print=printer, loop=patched_loop)
 
         patched_loop.create_server.assert_called_with(
             mock.ANY, sock=sock, backlog=128, ssl=None
@@ -608,7 +623,7 @@ def test_run_app_multiple_preexisting_sockets(patched_loop) -> None:
         _, port2 = sock2.getsockname()
 
         printer = mock.Mock(wraps=stopper(patched_loop))
-        web.run_app(app, sock=(sock1, sock2), print=printer)
+        web.run_app(app, sock=(sock1, sock2), print=printer, loop=patched_loop)
 
         patched_loop.create_server.assert_has_calls(
             [
@@ -664,7 +679,7 @@ def test_startup_cleanup_signals_even_on_failure(patched_loop) -> None:
     app.on_cleanup.append(cleanup_handler)
 
     with pytest.raises(RuntimeError):
-        web.run_app(app, print=stopper(patched_loop))
+        web.run_app(app, print=stopper(patched_loop), loop=patched_loop)
 
     startup_handler.assert_called_once_with(app)
     cleanup_handler.assert_called_once_with(app)
@@ -682,7 +697,7 @@ async def make_app():
         app.on_cleanup.append(cleanup_handler)
         return app
 
-    web.run_app(make_app(), print=stopper(patched_loop))
+    web.run_app(make_app(), print=stopper(patched_loop), loop=patched_loop)
 
     patched_loop.create_server.assert_called_with(
         mock.ANY, None, 8080, ssl=None, backlog=128, reuse_address=None, reuse_port=None
@@ -703,7 +718,12 @@ def test_run_app_default_logger(monkeypatch, patched_loop):
     mock_logger.configure_mock(**attrs)
 
     app = web.Application()
-    web.run_app(app, print=stopper(patched_loop), access_log=mock_logger)
+    web.run_app(
+        app,
+        print=stopper(patched_loop),
+        access_log=mock_logger,
+        loop=patched_loop,
+    )
     mock_logger.setLevel.assert_any_call(logging.DEBUG)
     mock_logger.hasHandlers.assert_called_with()
     assert isinstance(mock_logger.addHandler.call_args[0][0], logging.StreamHandler)
@@ -721,7 +741,12 @@ def test_run_app_default_logger_setup_requires_debug(patched_loop):
     mock_logger.configure_mock(**attrs)
 
     app = web.Application()
-    web.run_app(app, print=stopper(patched_loop), access_log=mock_logger)
+    web.run_app(
+        app,
+        print=stopper(patched_loop),
+        access_log=mock_logger,
+        loop=patched_loop,
+    )
     mock_logger.setLevel.assert_not_called()
     mock_logger.hasHandlers.assert_not_called()
     mock_logger.addHandler.assert_not_called()
@@ -739,7 +764,12 @@ def test_run_app_default_logger_setup_requires_default_logger(patched_loop):
     mock_logger.configure_mock(**attrs)
 
     app = web.Application()
-    web.run_app(app, print=stopper(patched_loop), access_log=mock_logger)
+    web.run_app(
+        app,
+        print=stopper(patched_loop),
+        access_log=mock_logger,
+        loop=patched_loop,
+    )
     mock_logger.setLevel.assert_not_called()
     mock_logger.hasHandlers.assert_not_called()
     mock_logger.addHandler.assert_not_called()
@@ -757,7 +787,12 @@ def test_run_app_default_logger_setup_only_if_unconfigured(patched_loop):
     mock_logger.configure_mock(**attrs)
 
     app = web.Application()
-    web.run_app(app, print=stopper(patched_loop), access_log=mock_logger)
+    web.run_app(
+        app,
+        print=stopper(patched_loop),
+        access_log=mock_logger,
+        loop=patched_loop,
+    )
     mock_logger.setLevel.assert_not_called()
     mock_logger.hasHandlers.assert_called_with()
     mock_logger.addHandler.assert_not_called()
@@ -774,7 +809,7 @@ async def on_startup(app):
 
     app.on_startup.append(on_startup)
 
-    web.run_app(app, print=stopper(patched_loop))
+    web.run_app(app, print=stopper(patched_loop), loop=patched_loop)
     assert task.cancelled()
 
 
@@ -792,7 +827,7 @@ async def on_startup(app):
 
     app.on_startup.append(on_startup)
 
-    web.run_app(app, print=stopper(patched_loop))
+    web.run_app(app, print=stopper(patched_loop), loop=patched_loop)
     assert task.done()
 
 
@@ -818,7 +853,7 @@ async def on_startup(app):
 
     exc_handler = mock.Mock()
     patched_loop.set_exception_handler(exc_handler)
-    web.run_app(app, print=stopper(patched_loop))
+    web.run_app(app, print=stopper(patched_loop), loop=patched_loop)
     assert task.done()
 
     msg = {
@@ -839,7 +874,12 @@ def base_runner_init_spy(self, *args, **kwargs):
 
     app = web.Application()
     monkeypatch.setattr(BaseRunner, "__init__", base_runner_init_spy)
-    web.run_app(app, keepalive_timeout=new_timeout, print=stopper(patched_loop))
+    web.run_app(
+        app,
+        keepalive_timeout=new_timeout,
+        print=stopper(patched_loop),
+        loop=patched_loop,
+    )
 
 
 @pytest.mark.skipif(not PY_37, reason="contextvars support is required")
@@ -871,5 +911,5 @@ async def init():
         count += 1
         return app
 
-    web.run_app(init(), print=stopper(patched_loop))
+    web.run_app(init(), print=stopper(patched_loop), loop=patched_loop)
     assert count == 3

tests/test_web_runner.py

@@ -1,6 +1,7 @@
 import asyncio
 import platform
 import signal
+import sys
 from unittest.mock import patch
 
 import pytest
@@ -162,3 +163,28 @@ async def mock_create_server(*args, **kwargs):
     assert server is runner.server
     assert host is None
     assert port == 8080
+
+
+@pytest.mark.skipif(sys.version_info < (3, 7), reason="Requires asyncio.run()")
+def test_run_after_asyncio_run() -> None:
+    async def nothing():
+        pass
+
+    def spy():
+        spy.called = True
+
+    spy.called = False
+
+    async def shutdown():
+        spy()
+        raise web.GracefulExit()
+
+    # asyncio.run() creates a new loop and closes it.
+    asyncio.run(nothing())
+
+    app = web.Application()
+    # create_task() will delay the function until app is run.
+    app.on_startup.append(lambda a: asyncio.create_task(shutdown()))
+
+    web.run_app(app)
+    assert spy.called, "run_app() should work after asyncio.run()."