Python进程不能pickle

Question

代码：

from aiohttp import web
from aiortc.mediastreams import MediaStreamTrack
from aiortc import RTCPeerConnection, RTCSessionDescription
from aiortc.contrib.media import MediaPlayer
import asyncio
import json
import os
from multiprocessing import Process, freeze_support
from queue import Queue
import sys
import threading
from time import sleep
import fractions
import time

class RadioServer(Process):
    def __init__(self,q):
        super().__init__()
        self.q = q
        self.ROOT = os.path.dirname(__file__)
        self.pcs = []
        self.channels = []
        self.stream_offers = []
        self.requests = []
    
    def run(self):
        self.app = web.Application()
        self.app.on_shutdown.append(self.on_shutdown)
        self.app.router.add_get("/", self.index)
        self.app.router.add_get("/radio.js", self.javascript)
        self.app.router.add_get("/jquery-3.5.1.min.js", self.jquery)
        self.app.router.add_post("/offer", self.offer)
        
        threading.Thread(target=self.fill_the_queues).start()
        web.run_app(self.app, access_log=None, host="192.168.1.20", port="8080", ssl_context=None)

    def fill_the_queues(self):
        while(True):
            frame = self.q.get()
            for stream_offer in self.stream_offers:
                stream_offer.q.put(frame)

    async def index(self,request):
        content = open(os.path.join(self.ROOT, "index.html"), encoding="utf8").read()
        return web.Response(content_type="text/html", text=content)


    async def javascript(self,request):
        content = open(os.path.join(self.ROOT, "radio.js"), encoding="utf8").read()
        return web.Response(content_type="application/javascript", text=content)

    async def jquery(self,request):
        content = open(os.path.join(self.ROOT, "jquery-3.5.1.min.js"), encoding="utf8").read()
        return web.Response(content_type="application/javascript", text=content)

    async def offer(self,request):  
        params = await request.json()
        offer = RTCSessionDescription(sdp=params["sdp"], type=params["type"])

        pc = RTCPeerConnection()
        self.pcs.append(pc)
        self.requests.append(request)
        
        # prepare epalxeis media
        self.stream_offers.append(CustomRadioStream())
        pc.addTrack(self.stream_offers[-1])


        @pc.on("iceconnectionstatechange")
        async def on_iceconnectionstatechange():
            if pc.iceConnectionState == "failed":
                self.pcs.remove(pc)
                self.requests.remove(request)
                print(str(request.remote)+" disconnected from radio server")
                print("Current peer connections:"+str(len(self.pcs)))

        # handle offer
        await pc.setRemoteDescription(offer)

        # send answer
        answer = await pc.createAnswer()
        await pc.setLocalDescription(answer)
        
            

        return web.Response(content_type="application/json",text=json.dumps({"sdp": pc.localDescription.sdp, "type": pc.localDescription.type}))

    async def on_shutdown(self,app):
        # close peer connections
        if self.pcs:
            coros = [pc.close() for pc in self.pcs]
            await asyncio.gather(*coros)
            self.pcs = []
            self.channels = []
            self.stream_offers = []
            
"""
some other classes here such as CustomRadioStream and RadioOutputStream
"""


if __name__ == "__main__":
    freeze_support()
    q = Queue()
    custom_server_child_process = RadioServer(q)
    custom_server_child_process.start()

错误

Traceback (most recent call last):
  File "123.py", line 106, in <module>
    custom_server_child_process.start()
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/process.py", line 121, i
n start
    self._popen = self._Popen(self)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/context.py", line 224, i
n _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/context.py", line 327, i
n _Popen
    return Popen(process_obj)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/popen_spawn_win32.py", l
ine 93, in __init__
    reduction.dump(process_obj, to_child)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/reduction.py", line 60,
in dump
    ForkingPickler(file, protocol).dump(obj)
TypeError: cannot pickle '_thread.lock' object

我做错了什么？ 如果我直接调用run函数（而不是start），那么就没有问题了，但是我想对这个类使用processing

编辑：使用多处理确定。队列工作正常，但现在使用类似代码时出现以下错误：

$ python "Papinhio_player.py"
Traceback (most recent call last):
  File "Papinhio_player.py", line 3078, in <module>
    program = PapinhioPlayerCode()
  File "Papinhio_player.py", line 250, in __init__
    self.manage_decks_instance = Manage_Decks(self)
  File "C:\python\scripts\Papinhio player\src\main\python_files/manage_decks.py"
, line 356, in __init__
    self.custom_server_child_process.start()
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/process.py", line 121, i
n start
    self._popen = self._Popen(self)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/context.py", line 224, i
n _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/context.py", line 327, i
n _Popen
    return Popen(process_obj)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/popen_spawn_win32.py", l
ine 93, in __init__
    reduction.dump(process_obj, to_child)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/reduction.py", line 60,
in dump
    ForkingPickler(file, protocol).dump(obj)
  File "stringsource", line 2, in av.audio.codeccontext.AudioCodecContext.__redu
ce_cython__
TypeError: self.parser,self.ptr cannot be converted to a Python object for pickl
ing
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/spawn.py", line 116, in
spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "C:/msys64/mingw64/lib/python3.8/multiprocessing/spawn.py", line 126, in
_main
    self = reduction.pickle.load(from_parent)
EOFError: Ran out of input

Answer 1

某些对象无法序列化，然后无法取消序列化

您发布的堆栈跟踪提到：

TypeError: cannot pickle '_thread.lock' object

锁在内存中保持状态，并保证没有其他进程可以在同一时刻拥有相同的锁，对于此操作来说，它通常是一个非常糟糕的候选对象。反序列化它时应该创建什么

---

要解决此问题，请选择一种方法来选择要序列化的对象的相关字段，并对该部分进行pickle/unpickle