Improve reliability of reload (#631)

Author: Dreamsorcerer

aiohttp_devtools/runserver/serve.py

@@ -3,10 +3,11 @@
 import json
 import mimetypes
 import sys
+import time
 import warnings
 from errno import EADDRINUSE
 from pathlib import Path
-from typing import Any, Iterator, NoReturn, Optional, Set, Tuple
+from typing import Any, Iterator, List, NoReturn, Optional, Set, Tuple
 
 from aiohttp import WSMsgType, web
 from aiohttp.hdrs import LAST_MODIFIED, CONTENT_LENGTH
@@ -33,6 +34,7 @@
 LIVE_RELOAD_LOCAL_SNIPPET = b'\n<script src="/livereload.js"></script>\n'
 HOST = '0.0.0.0'
 
+LAST_RELOAD = web.AppKey("LAST_RELOAD", List[float])
 LIVERELOAD_SCRIPT = web.AppKey("LIVERELOAD_SCRIPT", bytes)
 STATIC_PATH = web.AppKey("STATIC_PATH", str)
 STATIC_URL = web.AppKey("STATIC_URL", str)
@@ -240,6 +242,8 @@ async def src_reload(app: web.Application, path: Optional[str] = None) -> int:
         else:
             reloads += 1
 
+    app[LAST_RELOAD][0] = len(app[WS])
+    app[LAST_RELOAD][1] = time.time()
     if reloads:
         s = '' if reloads == 1 else 's'
         aux_logger.info('prompted reload of %s on %d client%s', path or 'page', reloads, s)
@@ -256,6 +260,7 @@ def create_auxiliary_app(
         browser_cache: bool = False) -> web.Application:
     app = web.Application()
     ws: Set[Tuple[web.WebSocketResponse, str]] = set()
+    app[LAST_RELOAD] = [0, 0.]
     app[STATIC_PATH] = static_path or ""
     app[STATIC_URL] = static_url
     app[WS] = ws

aiohttp_devtools/runserver/watch.py

@@ -2,6 +2,7 @@
 import os
 import signal
 import sys
+import time
 from contextlib import suppress
 from multiprocessing import Process
 from pathlib import Path
@@ -14,7 +15,7 @@
 from ..exceptions import AiohttpDevException
 from ..logs import rs_dft_logger as logger
 from .config import Config
-from .serve import STATIC_PATH, WS, serve_main_app, src_reload
+from .serve import LAST_RELOAD, STATIC_PATH, WS, serve_main_app, src_reload
 
 
 class WatchTask:
@@ -27,7 +28,7 @@ def __init__(self, path: Union[Path, str]):
     async def start(self, app: web.Application) -> None:
         self._app = app
         self.stopper = asyncio.Event()
-        self._awatch = awatch(self._path, stop_event=self.stopper)
+        self._awatch = awatch(self._path, stop_event=self.stopper, step=250)
         self._task = asyncio.create_task(self._run())
 
     async def _run(self) -> None:
@@ -71,8 +72,20 @@ def is_static(changes: Iterable[Tuple[object, str]]) -> bool:
 
             async for changes in self._awatch:
                 self._reloads += 1
+                logger.debug("file changes: %s", changes)
                 if any(f.endswith('.py') for _, f in changes):
                     logger.debug('%d changes, restarting server', len(changes))
+
+                    count, t = self._app[LAST_RELOAD]
+                    if len(self._app[WS]) < count:
+                        wait_delay = max(t + 5 - time.time(), 0)
+                        logger.debug("waiting upto %s seconds before restarting", wait_delay)
+
+                        for i in range(int(wait_delay / 0.1)):
+                            await asyncio.sleep(0.1)
+                            if len(self._app[WS]) >= count:
+                                break
+
                     await self._stop_dev_server()
                     self._start_dev_server()
                     await self._src_reload_when_live(live_checks)

tests/test_runserver_serve.py

@@ -13,7 +13,7 @@
 from aiohttp_devtools.runserver.config import Config
 from aiohttp_devtools.runserver.log_handlers import fmt_size
 from aiohttp_devtools.runserver.serve import (
-    STATIC_PATH, STATIC_URL, WS, check_port_open, cleanup_aux_app,
+    LAST_RELOAD, STATIC_PATH, STATIC_URL, WS, check_port_open, cleanup_aux_app,
     modify_main_app, src_reload)
 
 from .conftest import SIMPLE_APP, create_future
@@ -36,6 +36,7 @@ async def test_aux_reload(smart_caplog):
     aux_app = Application()
     ws = MagicMock()
     ws.send_str = MagicMock(return_value=create_future())
+    aux_app[LAST_RELOAD] = [0, 0.]
     aux_app[STATIC_PATH] = "/path/to/static_files/"
     aux_app[STATIC_URL] = "/static/"
     aux_app[WS] = set(((ws, "/foo/bar"),))  # type: ignore[misc]
@@ -56,6 +57,7 @@ async def test_aux_reload_no_path():
     aux_app = Application()
     ws = MagicMock()
     ws.send_str = MagicMock(return_value=create_future())
+    aux_app[LAST_RELOAD] = [0, 0.]
     aux_app[STATIC_PATH] = "/path/to/static_files/"
     aux_app[STATIC_URL] = "/static/"
     aux_app[WS] = set(((ws, "/foo/bar"),))  # type: ignore[misc]
@@ -74,6 +76,7 @@ async def test_aux_reload_html_different():
     aux_app = Application()
     ws = MagicMock()
     ws.send_str = MagicMock(return_value=create_future())
+    aux_app[LAST_RELOAD] = [0, 0.]
     aux_app[STATIC_PATH] = "/path/to/static_files/"
     aux_app[STATIC_URL] = "/static/"
     aux_app[WS] = set(((ws, "/foo/bar"),))  # type: ignore[misc]
@@ -86,6 +89,7 @@ async def test_aux_reload_runtime_error(smart_caplog):
     ws = MagicMock()
     ws.send_str = MagicMock(return_value=create_future())
     ws.send_str = MagicMock(side_effect=RuntimeError('foobar'))
+    aux_app[LAST_RELOAD] = [0, 0.]
     aux_app[STATIC_PATH] = "/path/to/static_files/"
     aux_app[STATIC_URL] = "/static/"
     aux_app[WS] = set(((ws, "/foo/bar"),))  # type: ignore[misc]

tests/test_runserver_watch.py

@@ -1,12 +1,13 @@
 import asyncio
+import time
 from functools import partial
-from typing import Set, Tuple
-from unittest.mock import MagicMock, call
+from typing import Any, Set, Tuple
+from unittest.mock import AsyncMock, MagicMock, call
 
 from aiohttp import ClientSession
 from aiohttp.web import Application, WebSocketResponse
 
-from aiohttp_devtools.runserver.serve import STATIC_PATH, WS
+from aiohttp_devtools.runserver.serve import LAST_RELOAD, STATIC_PATH, WS
 from aiohttp_devtools.runserver.watch import AppTask, LiveReloadTask
 
 from .conftest import create_future
@@ -81,6 +82,7 @@ async def test_python_no_server(event_loop, mocker):
     stop_mock = mocker.patch.object(app_task, "_stop_dev_server", autospec=True)
     mocker.patch.object(app_task, "_run", partial(app_task._run, live_checks=2))
     app = Application()
+    app[LAST_RELOAD] = [0, 0.]
     app[STATIC_PATH] = "/path/to/"
     app.src_reload = MagicMock()
     mock_ws = MagicMock()
@@ -192,3 +194,35 @@ async def test_stop_process_dirty(mocker):
     await app_task._stop_dev_server()
     assert mock_kill.call_args_list == [call(321, 2)]
     assert process_mock.kill.called_once()
+
+
+async def test_restart_after_connection_loss(mocker):
+    mocked_awatch = mocker.patch("aiohttp_devtools.runserver.watch.awatch", autospec=True, spec_set=True)
+    mocked_awatch.side_effect = create_awatch_mock({("x", "/path/to/file.py")})
+    app_task = AppTask(MagicMock())
+    start_mock = mocker.patch.object(app_task, "_start_dev_server", autospec=True, spec_set=True)
+    mock_reload = mocker.patch.object(app_task, "_src_reload_when_live", autospec=True, spec_set=True)
+    mocker.patch.object(app_task, "_stop_dev_server", autospec=True, spec_set=True)
+
+    app = mocker.create_autospec(Application, spec_set=True, instance=True)
+    # Simulate connection lost from recent restart.
+    ws: Set[Any] = set()
+    d = {WS: ws, LAST_RELOAD: [1, time.time()]}
+    app.__getitem__.side_effect = lambda k: d.get(k, MagicMock())
+
+    def update_ws(i):
+        ws.add(MagicMock(spec_set=()))
+        return AsyncMock()
+
+    sleep_mock = mocker.patch("asyncio.sleep", autospec=True, spec_set=True)
+    sleep_mock.side_effect = update_ws
+
+    await app_task.start(app)
+    assert app_task._task is not None
+    await app_task._task
+    assert sleep_mock.call_count < 5
+    assert call(0.1) in sleep_mock.call_args_list
+    mock_reload.assert_called_once()
+    assert start_mock.call_count == 2
+    assert app_task._session is not None
+    await app_task._session.close()