fix(loop): create separate loop for sync playwright execution (microsoft#354)

Author: pavelfeldman

playwright/accessibility.py

@@ -57,6 +57,7 @@ class Accessibility:
     def __init__(self, channel: Channel) -> None:
         self._channel = channel
         self._loop = channel._connection._loop
+        self._dispatcher_fiber = channel._connection._dispatcher_fiber
 
     async def snapshot(
         self, interestingOnly: bool = None, root: ElementHandle = None

playwright/connection.py

@@ -15,13 +15,13 @@
 import asyncio
 import sys
 import traceback
+from pathlib import Path
 from typing import Any, Callable, Dict, Optional, Union
 
 from greenlet import greenlet
 from pyee import AsyncIOEventEmitter
 
 from playwright.helper import ParsedMessagePayload, parse_error
-from playwright.sync_base import dispatcher_fiber
 from playwright.transport import Transport
 
 
@@ -74,6 +74,7 @@ def __init__(
     ) -> None:
         super().__init__(loop=parent._loop)
         self._loop: asyncio.AbstractEventLoop = parent._loop
+        self._dispatcher_fiber: Any = parent._dispatcher_fiber
         self._type = type
         self._guid = guid
         self._connection: Connection = (
@@ -116,33 +117,30 @@ def __init__(self, connection: "Connection") -> None:
 
 class Connection:
     def __init__(
-        self,
-        input: asyncio.StreamReader,
-        output: asyncio.StreamWriter,
-        object_factory: Any,
-        loop: asyncio.AbstractEventLoop,
+        self, dispatcher_fiber: Any, object_factory: Any, driver_executable: Path
     ) -> None:
-        self._transport = Transport(input, output, loop)
+        self._dispatcher_fiber: Any = dispatcher_fiber
+        self._transport = Transport(driver_executable)
         self._transport.on_message = lambda msg: self._dispatch(msg)
         self._waiting_for_object: Dict[str, Any] = {}
         self._last_id = 0
-        self._loop = loop
         self._objects: Dict[str, ChannelOwner] = {}
         self._callbacks: Dict[int, ProtocolCallback] = {}
-        self._root_object = RootChannelOwner(self)
         self._object_factory = object_factory
         self._is_sync = False
 
-    def run_sync(self) -> None:
+    async def run_as_sync(self) -> None:
         self._is_sync = True
-        self._transport.run_sync()
+        await self.run()
 
-    def run_async(self) -> None:
-        self._transport.run_async()
+    async def run(self) -> None:
+        self._loop = asyncio.get_running_loop()
+        self._root_object = RootChannelOwner(self)
+        await self._transport.run()
 
     def stop_sync(self) -> None:
         self._transport.stop()
-        dispatcher_fiber().switch()
+        self._dispatcher_fiber.switch()
 
     def stop_async(self) -> None:
         self._transport.stop()

playwright/file_chooser.py

@@ -27,6 +27,7 @@ def __init__(
     ) -> None:
         self._page = page
         self._loop = page._loop
+        self._dispatcher_fiber = page._dispatcher_fiber
         self._element_handle = element_handle
         self._is_multiple = is_multiple
 

playwright/input.py

@@ -20,6 +20,7 @@ class Keyboard:
     def __init__(self, channel: Channel) -> None:
         self._channel = channel
         self._loop = channel._connection._loop
+        self._dispatcher_fiber = channel._connection._dispatcher_fiber
 
     async def down(self, key: str) -> None:
         await self._channel.send("keyboardDown", locals_to_params(locals()))
@@ -41,6 +42,7 @@ class Mouse:
     def __init__(self, channel: Channel) -> None:
         self._channel = channel
         self._loop = channel._connection._loop
+        self._dispatcher_fiber = channel._connection._dispatcher_fiber
 
     async def move(self, x: float, y: float, steps: int = None) -> None:
         await self._channel.send("mouseMove", locals_to_params(locals()))
@@ -83,6 +85,7 @@ class Touchscreen:
     def __init__(self, channel: Channel) -> None:
         self._channel = channel
         self._loop = channel._connection._loop
+        self._dispatcher_fiber = channel._connection._dispatcher_fiber
 
     async def tap(self, x: float, y: float) -> None:
         await self._channel.send("touchscreenTap", locals_to_params(locals()))

playwright/main.py

@@ -28,7 +28,6 @@
 from playwright.path_utils import get_file_dirname
 from playwright.playwright import Playwright
 from playwright.sync_api import Playwright as SyncPlaywright
-from playwright.sync_base import dispatcher_fiber, set_dispatcher_fiber
 
 
 def compute_driver_executable() -> Path:
@@ -39,47 +38,43 @@ def compute_driver_executable() -> Path:
     return package_path / "driver" / "playwright-cli"
 
 
-async def run_driver_async() -> Connection:
-    driver_executable = compute_driver_executable()
-
-    proc = await asyncio.create_subprocess_exec(
-        str(driver_executable),
-        "run-driver",
-        stdin=asyncio.subprocess.PIPE,
-        stdout=asyncio.subprocess.PIPE,
-        stderr=sys.stderr,
-        limit=32768,
-    )
-    assert proc.stdout
-    assert proc.stdin
-    connection = Connection(
-        proc.stdout, proc.stdin, create_remote_object, asyncio.get_event_loop()
-    )
-    return connection
-
-
-def run_driver() -> Connection:
-    loop = asyncio.get_event_loop()
-    if loop.is_running():
-        raise Error("Can only run one Playwright at a time.")
-    return loop.run_until_complete(run_driver_async())
-
-
 class SyncPlaywrightContextManager:
     def __init__(self) -> None:
-        self._connection = run_driver()
         self._playwright: SyncPlaywright
 
     def __enter__(self) -> SyncPlaywright:
+        def greenlet_main() -> None:
+            loop = None
+            own_loop = None
+            try:
+                loop = asyncio.get_running_loop()
+            except RuntimeError:
+                loop = asyncio.new_event_loop()
+                own_loop = loop
+
+            if loop.is_running():
+                raise Error("Can only run one Playwright at a time.")
+
+            loop.run_until_complete(self._connection.run_as_sync())
+
+            if own_loop:
+                loop.run_until_complete(loop.shutdown_asyncgens())
+                loop.close()
+
+        dispatcher_fiber = greenlet(greenlet_main)
+        self._connection = Connection(
+            dispatcher_fiber, create_remote_object, compute_driver_executable()
+        )
+
         g_self = greenlet.getcurrent()
 
         def callback_wrapper(playwright_impl: Playwright) -> None:
             self._playwright = SyncPlaywright(playwright_impl)
             g_self.switch()
 
         self._connection.call_on_object_with_known_name("Playwright", callback_wrapper)
-        set_dispatcher_fiber(greenlet(lambda: self._connection.run_sync()))
-        dispatcher_fiber().switch()
+
+        dispatcher_fiber.switch()
         playwright = self._playwright
         playwright.stop = self.__exit__  # type: ignore
         return playwright
@@ -96,8 +91,12 @@ def __init__(self) -> None:
         self._connection: Connection
 
     async def __aenter__(self) -> AsyncPlaywright:
-        self._connection = await run_driver_async()
-        self._connection.run_async()
+        self._connection = Connection(
+            None, create_remote_object, compute_driver_executable()
+        )
+        loop = asyncio.get_running_loop()
+        self._connection._loop = loop
+        loop.create_task(self._connection.run())
         playwright = AsyncPlaywright(
             await self._connection.wait_for_object_with_known_name("Playwright")
         )
@@ -113,8 +112,7 @@ async def __aexit__(self, *args: Any) -> None:
 
 if sys.platform == "win32":
     # Use ProactorEventLoop in 3.7, which is default in 3.8
-    loop = asyncio.ProactorEventLoop()
-    asyncio.set_event_loop(loop)
+    asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
 
 
 def main() -> None:

playwright/sync_api.py

@@ -577,7 +577,7 @@ def expect_event(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def isClosed(self) -> bool:
@@ -3198,7 +3198,7 @@ def expect_load_state(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForLoadState(state, timeout)
+            self, self._impl_obj.waitForLoadState(state, timeout)
         )
 
     def expect_navigation(
@@ -3227,7 +3227,7 @@ def expect_navigation(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForNavigation(url, waitUntil, timeout)
+            self, self._impl_obj.waitForNavigation(url, waitUntil, timeout)
         )
 
 
@@ -5561,7 +5561,7 @@ def expect_event(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def expect_console_message(
@@ -5590,7 +5590,7 @@ def expect_console_message(
         """
         event = "console"
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def expect_download(
@@ -5619,7 +5619,7 @@ def expect_download(
         """
         event = "download"
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def expect_file_chooser(
@@ -5648,7 +5648,7 @@ def expect_file_chooser(
         """
         event = "filechooser"
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def expect_load_state(
@@ -5676,7 +5676,7 @@ def expect_load_state(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForLoadState(state, timeout)
+            self, self._impl_obj.waitForLoadState(state, timeout)
         )
 
     def expect_navigation(
@@ -5705,7 +5705,7 @@ def expect_navigation(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForNavigation(url, waitUntil, timeout)
+            self, self._impl_obj.waitForNavigation(url, waitUntil, timeout)
         )
 
     def expect_popup(
@@ -5734,7 +5734,7 @@ def expect_popup(
         """
         event = "popup"
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def expect_request(
@@ -5763,7 +5763,7 @@ def expect_request(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForRequest(url, predicate, timeout)
+            self, self._impl_obj.waitForRequest(url, predicate, timeout)
         )
 
     def expect_response(
@@ -5792,7 +5792,7 @@ def expect_response(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForResponse(url, predicate, timeout)
+            self, self._impl_obj.waitForResponse(url, predicate, timeout)
         )
 
     def expect_worker(
@@ -5821,7 +5821,7 @@ def expect_worker(
         """
         event = "worker"
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
 
@@ -6241,7 +6241,7 @@ def expect_event(
             page.setDefaultTimeout(timeout) methods.
         """
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )
 
     def expect_page(
@@ -6270,7 +6270,7 @@ def expect_page(
         """
         event = "page"
         return EventContextManager(
-            self._loop, self._impl_obj.waitForEvent(event, predicate, timeout)
+            self, self._impl_obj.waitForEvent(event, predicate, timeout)
         )