dragonpilot/system/webrtc/webrtcd.py

#!/usr/bin/env python3

import argparse
import asyncio
import json
import uuid
import logging
from dataclasses import dataclass, field
from typing import Any, List, Optional, Union

# aiortc and its dependencies have lots of internal warnings :(
import warnings
warnings.filterwarnings("ignore", category=DeprecationWarning)

import aiortc
from aiortc.mediastreams import VideoStreamTrack, AudioStreamTrack
from aiortc.contrib.media import MediaBlackhole
from aiortc.exceptions import InvalidStateError
from aiohttp import web
import capnp
from teleoprtc import WebRTCAnswerBuilder
from teleoprtc.info import parse_info_from_offer

from openpilot.system.webrtc.device.video import LiveStreamVideoStreamTrack
from openpilot.system.webrtc.device.audio import AudioInputStreamTrack, AudioOutputSpeaker

from cereal import messaging


class CerealOutgoingMessageProxy:
  def __init__(self, sm: messaging.SubMaster):
    self.sm = sm
    self.channels: List[aiortc.RTCDataChannel] = []

  def add_channel(self, channel: aiortc.RTCDataChannel):
    self.channels.append(channel)

  def to_json(self, msg_content: Any):
    if isinstance(msg_content, capnp._DynamicStructReader):
      msg_dict = msg_content.to_dict()
    elif isinstance(msg_content, capnp._DynamicListReader):
      msg_dict = [self.to_json(msg) for msg in msg_content]
    elif isinstance(msg_content, bytes):
      msg_dict = msg_content.decode()
    else:
      msg_dict = msg_content

    return msg_dict

  def update(self):
    # this is blocking in async context...
    self.sm.update(0)
    for service, updated in self.sm.updated.items():
      if not updated:
        continue
      msg_dict = self.to_json(self.sm[service])
      mono_time, valid = self.sm.logMonoTime[service], self.sm.valid[service]
      outgoing_msg = {"type": service, "logMonoTime": mono_time, "valid": valid, "data": msg_dict}
      encoded_msg = json.dumps(outgoing_msg).encode()
      for channel in self.channels:
        channel.send(encoded_msg)


class CerealIncomingMessageProxy:
  def __init__(self, pm: messaging.PubMaster):
    self.pm = pm

  def send(self, message: bytes):
    msg_json = json.loads(message)
    msg_type, msg_data = msg_json["type"], msg_json["data"]
    size = None
    if not isinstance(msg_data, dict):
      size = len(msg_data)

    msg = messaging.new_message(msg_type, size=size)
    setattr(msg, msg_type, msg_data)
    self.pm.send(msg_type, msg)


class CerealProxyRunner:
  def __init__(self, proxy: CerealOutgoingMessageProxy):
    self.proxy = proxy
    self.is_running = False
    self.task = None
    self.logger = logging.getLogger("webrtcd")

  def start(self):
    assert self.task is None
    self.task = asyncio.create_task(self.run())

  def stop(self):
    if self.task is None or self.task.done():
      return
    self.task.cancel()
    self.task = None

  async def run(self):
    while True:
      try:
        self.proxy.update()
      except InvalidStateError:
        self.logger.warning("Cereal outgoing proxy invalid state (connection closed)")
        break
      except Exception as ex:
        self.logger.error("Cereal outgoing proxy failure: %s", ex)
      await asyncio.sleep(0.01)


class StreamSession:
  def __init__(self, sdp: str, cameras: List[str], incoming_services: List[str], outgoing_services: List[str], debug_mode: bool = False):
    config = parse_info_from_offer(sdp)
    builder = WebRTCAnswerBuilder(sdp)

    assert len(cameras) == config.n_expected_camera_tracks, "Incoming stream has misconfigured number of video tracks"
    for cam in cameras:
      track = LiveStreamVideoStreamTrack(cam) if not debug_mode else VideoStreamTrack()
      builder.add_video_stream(cam, track)
    if config.expected_audio_track:
      track = AudioInputStreamTrack() if not debug_mode else AudioStreamTrack()
      builder.add_audio_stream(track)
    if config.incoming_audio_track:
      self.audio_output_cls = AudioOutputSpeaker if not debug_mode else MediaBlackhole
      builder.offer_to_receive_audio_stream()

    self.stream = builder.stream()
    self.identifier = str(uuid.uuid4())

    self.outgoing_bridge = CerealOutgoingMessageProxy(messaging.SubMaster(outgoing_services))
    self.incoming_bridge = CerealIncomingMessageProxy(messaging.PubMaster(incoming_services))
    self.outgoing_bridge_runner = CerealProxyRunner(self.outgoing_bridge)

    self.audio_output: Optional[Union[AudioOutputSpeaker, MediaBlackhole]] = None
    self.run_task: Optional[asyncio.Task] = None
    self.logger = logging.getLogger("webrtcd")
    self.logger.info("New stream session (%s), cameras %s, audio in %s out %s, incoming services %s, outgoing services %s",
                      self.identifier, cameras, config.incoming_audio_track, config.expected_audio_track, incoming_services, outgoing_services)

  def start(self):
    self.run_task = asyncio.create_task(self.run())

  def stop(self):
    if self.run_task.done():
      return
    self.run_task.cancel()
    self.run_task = None
    asyncio.run(self.post_run_cleanup())

  async def get_answer(self):
    return await self.stream.start()

  async def message_handler(self, message: bytes):
    try:
      self.incoming_bridge.send(message)
    except Exception as ex:
      self.logger.error("Cereal incoming proxy failure: %s", ex)

  async def run(self):
    try:
      await self.stream.wait_for_connection()
      if self.stream.has_messaging_channel():
        self.stream.set_message_handler(self.message_handler)
        channel = self.stream.get_messaging_channel()
        self.outgoing_bridge_runner.proxy.add_channel(channel)
        self.outgoing_bridge_runner.start()
      if self.stream.has_incoming_audio_track():
        track = self.stream.get_incoming_audio_track(buffered=False)
        self.audio_output = self.audio_output_cls()
        self.audio_output.addTrack(track)
        self.audio_output.start()
      self.logger.info("Stream session (%s) connected", self.identifier)

      await self.stream.wait_for_disconnection()
      await self.post_run_cleanup()

      self.logger.info("Stream session (%s) ended", self.identifier)
    except Exception as ex:
      self.logger.error("Stream session failure: %s", ex)

  async def post_run_cleanup(self):
    await self.stream.stop()
    self.outgoing_bridge_runner.stop()
    if self.audio_output:
      self.audio_output.stop()


@dataclass
class StreamRequestBody:
  sdp: str
  cameras: List[str]
  bridge_services_in: List[str] = field(default_factory=list)
  bridge_services_out: List[str] = field(default_factory=list)


async def get_stream(request: web.Request):
  stream_dict, debug_mode = request.app['streams'], request.app['debug']
  raw_body = await request.json()
  body = StreamRequestBody(**raw_body)

  session = StreamSession(body.sdp, body.cameras, body.bridge_services_in, body.bridge_services_out, debug_mode)
  answer = await session.get_answer()
  session.start()

  stream_dict[session.identifier] = session

  return web.json_response({"sdp": answer.sdp, "type": answer.type})


async def on_shutdown(app: web.Application):
  for session in app['streams'].values():
    session.stop()
  del app['streams']


def webrtcd_thread(host: str, port: int, debug: bool):
  logging.basicConfig(level=logging.CRITICAL, handlers=[logging.StreamHandler()])
  logging_level = logging.DEBUG if debug else logging.INFO
  logging.getLogger("WebRTCStream").setLevel(logging_level)
  logging.getLogger("webrtcd").setLevel(logging_level)

  app = web.Application()

  app['streams'] = dict()
  app['debug'] = debug
  app.on_shutdown.append(on_shutdown)
  app.router.add_post("/stream", get_stream)

  web.run_app(app, host=host, port=port)


def main():
  parser = argparse.ArgumentParser(description="WebRTC daemon")
  parser.add_argument("--host", type=str, default="0.0.0.0", help="Host to listen on")
  parser.add_argument("--port", type=int, default=5001, help="Port to listen on")
  parser.add_argument("--debug", action="store_true", help="Enable debug mode")
  args = parser.parse_args()

  webrtcd_thread(args.host, args.port, args.debug)


if __name__=="__main__":
  main()