问当发布到龙卷风HTTP服务器时间歇性的requests.exceptions.ConnectionError？

EN

#! /usr/bin/env python3

import time
import multiprocessing
import random

import requests
import tornado.ioloop
import tornado.web

class Client(multiprocessing.Process):
    def __init__(self, client_id):
        multiprocessing.Process.__init__(self)
        self.client_id = client_id
        self.host = 'http://localhost:8888/log'
        self.sample_record = 'x'*300
        self.start()

    def run(self):
        # Wait until top of current 5 sec interval so all clients start together.
        time.sleep(5 - time.time()%5)

        #time.sleep(random.random()) # This seems to eliminate the problem.

        # requests.Session will do keep-alive by default.
        session = requests.Session()
        payload = { 'record': 'x'*300 }
        attempt_count = 0
        while True:
            try:
                response = session.post(self.host, data=payload, timeout=10)
                break
            except requests.exceptions.ConnectionError:
                print('Retry: id=', self.client_id)
                attempt_count += 1
                assert attempt_count < 10
                continue
        assert response.status_code == 200 and response.text == 'Success'

post_received_count = 0

class LogHandler(tornado.web.RequestHandler):
    def post(self):
        global post_received_count
        post_received_count += 1
        if post_received_count%100 == 0:
            print('post count=', post_received_count)
        self.write('Success')

def make_app():
    return tornado.web.Application(
        [
            (r"/log", LogHandler),      # http://localhost:8888/log
        ],
        cookie_secret = "__TODO:_GENERATE_YOUR_OWN_RANDOM_VALUE_HERE__",
    )

if __name__ == "__main__":
    time.sleep(6 - time.time()%5)  # Wait until one sec into next 5 sec interval.
    print('Start clients...')
    client_list = [Client(i) for i in range(500)]
    print('Done.')

    app = make_app()
    app.listen(8888)
    try:
        tornado.ioloop.IOLoop.current().start()
    except KeyboardInterrupt:
        pass

$ ulimit -n 10000
$ test_log_server.py
Start clients...
Done.
post count= 100
post count= 200
post count= 300
post count= 400
post count= 500
^\Quit (core dumped)
$ test_log_server.py
Start clients...
Done.
post count= 100
Retry: id= 223
Retry: id= 340
Retry: id= 116
Retry: id= 164
Retry: id= 258
Retry: id= 150
Retry: id= 290
Retry: id= 16
Retry: id= 40
Retry: id= 5
post count= 200
post count= 300
post count= 400
post count= 500
^\Quit (core dumped)
$

Process Client-102:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 387, in _make_request
    six.raise_from(e, None)
  File "<string>", line 3, in raise_from
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 383, in _make_request
    httplib_response = conn.getresponse()
  File "/usr/lib/python3.6/http/client.py", line 1373, in getresponse
    response.begin()
  File "/usr/lib/python3.6/http/client.py", line 311, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python3.6/http/client.py", line 272, in _read_status
    line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
  File "/usr/lib/python3.6/socket.py", line 586, in readinto
    return self._sock.recv_into(b)
ConnectionResetError: [Errno 104] Connection reset by peer

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/requests/adapters.py", line 440, in send
    timeout=timeout
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 639, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "/usr/lib/python3/dist-packages/urllib3/util/retry.py", line 367, in increment
    raise six.reraise(type(error), error, _stacktrace)
  File "/usr/lib/python3/dist-packages/six.py", line 692, in reraise
    raise value.with_traceback(tb)
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 387, in _make_request
    six.raise_from(e, None)
  File "<string>", line 3, in raise_from
  File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 383, in _make_request
    httplib_response = conn.getresponse()
  File "/usr/lib/python3.6/http/client.py", line 1373, in getresponse
    response.begin()
  File "/usr/lib/python3.6/http/client.py", line 311, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python3.6/http/client.py", line 272, in _read_status
    line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
  File "/usr/lib/python3.6/socket.py", line 586, in readinto
    return self._sock.recv_into(b)
urllib3.exceptions.ProtocolError: ('Connection aborted.', ConnectionResetError(104, 'Connection reset by peer'))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "./test_log_server.py", line 31, in run
    response = session.post(self.host, data=payload, timeout=10)
  File "/usr/lib/python3/dist-packages/requests/sessions.py", line 567, in post
    return self.request('POST', url, data=data, json=json, **kwargs)
  File "/usr/lib/python3/dist-packages/requests/sessions.py", line 520, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/lib/python3/dist-packages/requests/sessions.py", line 630, in send
    r = adapter.send(request, **kwargs)
  File "/usr/lib/python3/dist-packages/requests/adapters.py", line 490, in send
    raise ConnectionError(err, request=request)
requests.exceptions.ConnectionError: ('Connection aborted.', ConnectionResetError(104, 'Connection reset by peer'))