_transport.py

# Copyright (c) Microsoft Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import asyncio
import io
import json
import os
import subprocess
import sys
from abc import ABC, abstractmethod
from pathlib import Path
from typing import Callable, Dict, Optional, Union

from playwright._impl._driver import get_driver_env
from playwright._impl._helper import ParsedMessagePayload


# Sourced from: https://github.com/pytest-dev/pytest/blob/da01ee0a4bb0af780167ecd228ab3ad249511302/src/_pytest/faulthandler.py#L69-L77
def _get_stderr_fileno() -> Optional[int]:
    try:
        # when using pythonw, sys.stderr is None.
        # when Pyinstaller is used, there is no closed attribute because Pyinstaller monkey-patches it with a NullWriter class
        if sys.stderr is None or not hasattr(sys.stderr, "closed"):
            return None
        if sys.stderr.closed:
            return None

        return sys.stderr.fileno()
    except (AttributeError, io.UnsupportedOperation):
        # pytest-xdist monkeypatches sys.stderr with an object that is not an actual file.
        # https://docs.python.org/3/library/faulthandler.html#issue-with-file-descriptors
        # This is potentially dangerous, but the best we can do.
        if not hasattr(sys, "__stderr__") or not sys.__stderr__:
            return None
        return sys.__stderr__.fileno()


class Transport(ABC):
    def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
        self._loop = loop
        self.on_message: Callable[[ParsedMessagePayload], None] = lambda _: None
        self.on_error_future: asyncio.Future = loop.create_future()

    @abstractmethod
    def request_stop(self) -> None:
        pass

    def dispose(self) -> None:
        pass

    @abstractmethod
    async def wait_until_stopped(self) -> None:
        pass

    @abstractmethod
    async def connect(self) -> None:
        pass

    @abstractmethod
    async def run(self) -> None:
        pass

    @abstractmethod
    def send(self, message: Dict) -> None:
        pass

    def serialize_message(self, message: Dict) -> bytes:
        msg = json.dumps(message)
        if "DEBUGP" in os.environ:  # pragma: no cover
            print("\x1b[32mSEND>\x1b[0m", json.dumps(message, indent=2))
        return msg.encode()

    def deserialize_message(self, data: Union[str, bytes]) -> ParsedMessagePayload:
        obj = json.loads(data)

        if "DEBUGP" in os.environ:  # pragma: no cover
            print("\x1b[33mRECV>\x1b[0m", json.dumps(obj, indent=2))
        return obj


class PipeTransport(Transport):
    def __init__(
        self, loop: asyncio.AbstractEventLoop, driver_executable: Path
    ) -> None:
        super().__init__(loop)
        self._stopped = False
        self._driver_executable = driver_executable

    def request_stop(self) -> None:
        assert self._output
        self._stopped = True
        self._output.close()

    async def wait_until_stopped(self) -> None:
        await self._stopped_future

    async def connect(self) -> None:
        self._stopped_future: asyncio.Future = asyncio.Future()
        creationflags = 0
        if sys.platform == "win32":
            creationflags = subprocess.CREATE_NO_WINDOW

        try:
            # For pyinstaller
            env = get_driver_env()
            if getattr(sys, "frozen", False):
                env.setdefault("PLAYWRIGHT_BROWSERS_PATH", "0")

            self._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,
                creationflags=creationflags,
                env=env,
            )
        except Exception as exc:
            self.on_error_future.set_exception(exc)
            raise exc

        self._output = self._proc.stdin

    async def run(self) -> None:
        assert self._proc.stdout
        assert self._proc.stdin
        while not self._stopped:
            try:
                buffer = await self._proc.stdout.readexactly(4)
                if self._stopped:
                    break
                length = int.from_bytes(buffer, byteorder="little", signed=False)
                buffer = bytes(0)
                while length:
                    to_read = min(length, 32768)
                    data = await self._proc.stdout.readexactly(to_read)
                    if self._stopped:
                        break
                    length -= to_read
                    if len(buffer):
                        buffer = buffer + data
                    else:
                        buffer = data
                if self._stopped:
                    break

                obj = self.deserialize_message(buffer)
                self.on_message(obj)
            except asyncio.IncompleteReadError:
                break
            await asyncio.sleep(0)

        await self._proc.wait()
        self._stopped_future.set_result(None)

    def send(self, message: Dict) -> None:
        assert self._output
        data = self.serialize_message(message)
        self._output.write(
            len(data).to_bytes(4, byteorder="little", signed=False) + data
        )