fix(transport): handle connection error correctly (#672)

Author: mxschmitt

playwright/_impl/_browser_type.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import asyncio
 from pathlib import Path
 from typing import Dict, List, Optional, Union, cast
 
@@ -21,6 +22,7 @@
     ProxySettings,
     ViewportSize,
 )
+from playwright._impl._api_types import Error
 from playwright._impl._browser import Browser, normalize_context_params
 from playwright._impl._browser_context import BrowserContext
 from playwright._impl._connection import (
@@ -37,6 +39,7 @@
     not_installed_error,
 )
 from playwright._impl._transport import WebSocketTransport
+from playwright._impl._wait_helper import throw_on_timeout
 
 
 class BrowserType(ChannelOwner):
@@ -172,8 +175,10 @@ async def connect(
         slow_mo: float = None,
         headers: Dict[str, str] = None,
     ) -> Browser:
-        transport = WebSocketTransport(ws_endpoint, timeout, headers)
+        if timeout is None:
+            timeout = 30000
 
+        transport = WebSocketTransport(self._connection._loop, ws_endpoint, headers)
         connection = Connection(
             self._connection._dispatcher_fiber,
             self._connection._object_factory,
@@ -182,8 +187,20 @@ async def connect(
         connection._is_sync = self._connection._is_sync
         connection._loop = self._connection._loop
         connection._loop.create_task(connection.run())
+        future = connection._loop.create_task(
+            connection.wait_for_object_with_known_name("Playwright")
+        )
+        timeout_future = throw_on_timeout(timeout, Error("Connection timed out"))
+        done, pending = await asyncio.wait(
+            {transport.on_error_future, future, timeout_future},
+            return_when=asyncio.FIRST_COMPLETED,
+        )
+        if not future.done():
+            future.cancel()
+        if not timeout_future.done():
+            timeout_future.cancel()
+        playwright = next(iter(done)).result()
         self._connection._child_ws_connections.append(connection)
-        playwright = await connection.wait_for_object_with_known_name("Playwright")
         pre_launched_browser = playwright._initializer.get("preLaunchedBrowser")
         assert pre_launched_browser
         browser = cast(Browser, from_channel(pre_launched_browser))

playwright/_impl/_transport.py

@@ -41,8 +41,10 @@ def _get_stderr_fileno() -> Optional[int]:
 
 
 class Transport(ABC):
-    def __init__(self) -> None:
+    def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
+        self._loop = loop
         self.on_message = lambda _: None
+        self.on_error_future: asyncio.Future = loop.create_future()
 
     @abstractmethod
     def request_stop(self) -> None:
@@ -55,9 +57,9 @@ def dispose(self) -> None:
     async def wait_until_stopped(self) -> None:
         pass
 
+    @abstractmethod
     async def run(self) -> None:
-        self._loop = asyncio.get_running_loop()
-        self.on_error_future: asyncio.Future = asyncio.Future()
+        pass
 
     @abstractmethod
     def send(self, message: Dict) -> None:
@@ -78,11 +80,12 @@ def deserialize_message(self, data: bytes) -> Any:
 
 
 class PipeTransport(Transport):
-    def __init__(self, driver_executable: Path) -> None:
-        super().__init__()
+    def __init__(
+        self, loop: asyncio.AbstractEventLoop, driver_executable: Path
+    ) -> None:
+        super().__init__(loop)
         self._stopped = False
         self._driver_executable = driver_executable
-        self._loop: asyncio.AbstractEventLoop
 
     def request_stop(self) -> None:
         self._stopped = True
@@ -93,17 +96,21 @@ async def wait_until_stopped(self) -> None:
         await self._proc.wait()
 
     async def run(self) -> None:
-        await super().run()
         self._stopped_future: asyncio.Future = asyncio.Future()
 
-        self._proc = proc = await asyncio.create_subprocess_exec(
-            str(self._driver_executable),
-            "run-driver",
-            stdin=asyncio.subprocess.PIPE,
-            stdout=asyncio.subprocess.PIPE,
-            stderr=_get_stderr_fileno(),
-            limit=32768,
-        )
+        try:
+            self._proc = proc = await asyncio.create_subprocess_exec(
+                str(self._driver_executable),
+                "run-driver",
+                stdin=asyncio.subprocess.PIPE,
+                stdout=asyncio.subprocess.PIPE,
+                stderr=_get_stderr_fileno(),
+                limit=32768,
+            )
+        except Exception as exc:
+            self.on_error_future.set_exception(exc)
+            return
+
         assert proc.stdout
         assert proc.stdin
         self._output = proc.stdin
@@ -138,16 +145,17 @@ def send(self, message: Dict) -> None:
 
 class WebSocketTransport(AsyncIOEventEmitter, Transport):
     def __init__(
-        self, ws_endpoint: str, timeout: float = None, headers: Dict[str, str] = None
+        self,
+        loop: asyncio.AbstractEventLoop,
+        ws_endpoint: str,
+        headers: Dict[str, str] = None,
     ) -> None:
-        super().__init__()
-        Transport.__init__(self)
+        super().__init__(loop)
+        Transport.__init__(self, loop)
 
         self._stopped = False
         self.ws_endpoint = ws_endpoint
-        self.timeout = timeout
         self.headers = headers
-        self._loop: asyncio.AbstractEventLoop
 
     def request_stop(self) -> None:
         self._stopped = True
@@ -160,15 +168,13 @@ async def wait_until_stopped(self) -> None:
         await self._connection.wait_closed()
 
     async def run(self) -> None:
-        await super().run()
-
-        options: Dict[str, Any] = {}
-        if self.timeout is not None:
-            options["close_timeout"] = self.timeout / 1000
-            options["ping_timeout"] = self.timeout / 1000
-        if self.headers is not None:
-            options["extra_headers"] = self.headers
-        self._connection = await websockets.connect(self.ws_endpoint, **options)
+        try:
+            self._connection = await websockets.connect(
+                self.ws_endpoint, extra_headers=self.headers
+            )
+        except Exception as exc:
+            self.on_error_future.set_exception(Error(f"websocket.connect: {str(exc)}"))
+            return
 
         while not self._stopped:
             try:
@@ -188,8 +194,8 @@ async def run(self) -> None:
                 )
                 break
             except Exception as exc:
-                print(f"Received unhandled exception: {exc}")
                 self.on_error_future.set_exception(exc)
+                break
 
     def send(self, message: Dict) -> None:
         if self._stopped or self._connection.closed:

playwright/_impl/_wait_helper.py

@@ -91,3 +91,11 @@ def listener(event_data: Any = None) -> None:
 
     def result(self) -> asyncio.Future:
         return self._result
+
+
+def throw_on_timeout(timeout: float, exception: Exception) -> asyncio.Task:
+    async def throw() -> None:
+        await asyncio.sleep(timeout / 1000)
+        raise exception
+
+    return asyncio.create_task(throw())

playwright/async_api/_context_manager.py

@@ -28,14 +28,23 @@ def __init__(self) -> None:
 
     async def __aenter__(self) -> AsyncPlaywright:
         self._connection = Connection(
-            None, create_remote_object, PipeTransport(compute_driver_executable())
+            None,
+            create_remote_object,
+            PipeTransport(asyncio.get_event_loop(), 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")
+        playwright_future = asyncio.create_task(
+            self._connection.wait_for_object_with_known_name("Playwright")
         )
+        done, pending = await asyncio.wait(
+            {self._connection._transport.on_error_future, playwright_future},
+            return_when=asyncio.FIRST_COMPLETED,
+        )
+        if not playwright_future.done():
+            playwright_future.cancel()
+        playwright = AsyncPlaywright(next(iter(done)).result())
         playwright.stop = self.__aexit__  # type: ignore
         return playwright
 

playwright/sync_api/_context_manager.py

@@ -31,21 +31,20 @@ def __init__(self) -> None:
         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(
-                    """It looks like you are using Playwright Sync API inside the asyncio loop.
+        loop: asyncio.AbstractEventLoop
+        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(
+                """It looks like you are using Playwright Sync API inside the asyncio loop.
 Please use the Async API instead."""
-                )
+            )
 
+        def greenlet_main() -> None:
             loop.run_until_complete(self._connection.run_as_sync())
 
             if own_loop:
@@ -56,7 +55,7 @@ def greenlet_main() -> None:
         self._connection = Connection(
             dispatcher_fiber,
             create_remote_object,
-            PipeTransport(compute_driver_executable()),
+            PipeTransport(loop, compute_driver_executable()),
         )
 
         g_self = greenlet.getcurrent()

tests/async/test_browsertype_connect.py

@@ -182,3 +182,13 @@ async def test_prevent_getting_video_path(
         == "Path is not available when using browserType.connect(). Use save_as() to save a local copy."
     )
     remote_server.kill()
+
+
+async def test_connect_to_closed_server_without_hangs(
+    browser_type: BrowserType, launch_server
+):
+    remote_server = launch_server()
+    remote_server.kill()
+    with pytest.raises(Error) as exc:
+        await browser_type.connect(remote_server.ws_endpoint)
+    assert "websocket.connect: " in exc.value.message

tests/sync/test_browsertype_connect.py

@@ -145,3 +145,13 @@ def test_browser_type_connect_should_forward_close_events_to_pages(
     assert events == ["page::close", "context::close", "browser::disconnected"]
     remote.kill()
     assert events == ["page::close", "context::close", "browser::disconnected"]
+
+
+def test_connect_to_closed_server_without_hangs(
+    browser_type: BrowserType, launch_server
+):
+    remote_server = launch_server()
+    remote_server.kill()
+    with pytest.raises(Error) as exc:
+        browser_type.connect(remote_server.ws_endpoint)
+    assert "websocket.connect: " in exc.value.message