Django通道/ Daphne中的Websocket超时

Question

简短的问题版本:我在我的Daphne配置，我的消费者代码，或者我的客户端代码中做错了什么？

channels==1.1.8
daphne==1.3.0
Django==1.11.7

详情如下：

我试图使用Django通道和Daphne接口服务器保持持久的Websocket连接打开。我正在使用大多数默认参数：daphne -b 0.0.0.0 -p 8000 my_app.asgi:channel_layer启动Daphne。

在浏览器中空闲一段时间后，我看到连接正在关闭，大约超过20秒。与断开一起发送的CloseEvent的code值为1006 (异常闭包)，没有reason集，wasClean设置为false。这应该是服务器关闭连接，而不发送显式关闭帧。

Daphne具有--ping-interval和--ping-timeout标志，默认值分别为20秒和30秒。对于前者，这被记录为“WebSocket必须处于空闲状态的秒数”，对于前者，对于前者来说，这是“WebSocket关闭之前的秒数”，对于后者来说，如果没有对保持活动ping的响应，则为“秒数”。我阅读这篇文章时，Daphne将等待WebSocket空闲20秒才发送ping，如果30秒后没有收到响应，则关闭Websocket。相反，我看到的是在空闲20秒后连接被关闭。(经过三次默认尝试，分别在20081ms、20026ms和20032ms之后关闭)

如果我将服务器更改为使用daphne -b 0.0.0.0 -p 8000 --ping-interval 10 --ping-timeout 60 my_app.asgi:channel_layer启动，则连接仍将关闭，空闲时间约为20秒。(经过三次尝试，更新后的pings，19892ms，20011ms，19956ms后关闭)

代码如下：

consumer.py

import logging

from channels import Group
from channels.generic.websockets import JsonWebsocketConsumer

from my_app import utilities

logger = logging.getLogger(__name__)

class DemoConsumer(JsonWebsocketConsumer):
    """
    Consumer echos the incoming message to all connected Websockets,
    and attaches the username to the outgoing message.
    """
    channel_session = True
    http_user_and_session = True

    @classmethod
    def decode_json(cls, text):
        return utilities.JSONDecoder.loads(text)

    @classmethod
    def encode_json(cls, content):
        return utilities.JSONEncoder.dumps(content)

    def connection_groups(self, **kwargs):
        return ['demo']

    def connect(self, message, **kwargs):
        super(DemoConsumer, self).connect(message, **kwargs)
        logger.info('Connected to DemoConsumer')

    def disconnect(self, message, **kwargs):
        super(DemoConsumer, self).disconnect(message, **kwargs)
        logger.info('Disconnected from DemoConsumer')

    def receive(self, content, **kwargs):
        super(DemoConsumer, self).receive(content, **kwargs)
        content['user'] = self.message.user.username
        # echo back content to all groups
        for group in self.connection_groups():
            self.group_send(group, content)

routing.py

from channels.routing import route

from . import consumers

channel_routing = [
    consumers.DemoConsumer.as_route(path=r'^/demo/'),
]

demo.js

// Tracks the cursor and sends position via a Websocket
// Listens for updated cursor positions and moves an icon to that location
$(function () {
  var socket = new WebSocket('ws://' + window.location.host + '/demo/');
  var icon;
  var moveTimer = null;
  var position = {x: null, y: null};
  var openTime = null;
  var lastTime = null;
  function sendPosition() {
    if (socket.readyState === socket.OPEN) {
      console.log('Sending ' + position.x + ', ' + position.y);
      socket.send(JSON.stringify(position));
      lastTime = Date.now();
    } else {
      console.log('Socket is closed');
    }
    // sending at-most 20Hz
    setTimeout(function () { moveTimer = null; }, 50);
  };
  socket.onopen = function (e) {
    var box = $('#websocket_box');
    icon = $('<div class="pointer_icon"></div>').insertAfter(box);
    box.on('mousemove', function (me) {
      // some browsers will generate these events much closer together
      // rather than overwhelm the server, batch them up and send at a reasonable rate
      if (moveTimer === null) {
        moveTimer = setTimeout(sendPosition, 0);
      }
      position.x = me.offsetX;
      position.y = me.offsetY;
    });
    openTime = lastTime = Date.now();
  };
  socket.onclose = function (e) {
    console.log("!!! CLOSING !!! " + e.code + " " + e.reason + " --" + e.wasClean);
    console.log('Time since open: ' + (Date.now() - openTime) + 'ms');
    console.log('Time since last: ' + (Date.now() - lastTime) + 'ms');
    icon.remove();
  };
  socket.onmessage = function (e) {
    var msg, box_offset;
    console.log(e);
    msg = JSON.parse(e.data);
    box_offset = $('#websocket_box').offset();
    if (msg && Number.isFinite(msg.x) && Number.isFinite(msg.y)) {
      console.log((msg.x + box_offset.left) + ', ' + (msg.y + box_offset.top));
      icon.offset({
        left: msg.x + box_offset.left,
        top: msg.y + box_offset.top
      }).text(msg.user || '');
    }
  };
});

asgi.py

import os
from channels.asgi import get_channel_layer

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "my_project.settings")

channel_layer = get_channel_layer()

settings.py

CHANNEL_LAYERS = {
    'default': {
        'BACKEND': 'asgi_redis.RedisChannelLayer',
        'ROUTING': 'main.routing.channel_routing',
        'CONFIG': {
            'hosts': [
                'redis://redis:6379/2',
            ],
            'symmetric_encryption_keys': [
                SECRET_KEY,
            ],
        }
    }
}

Answer 1

根本的问题是接口服务器前面的nginx代理。代理被设置为proxy_read_timeout 20s;。如果有从服务器生成的保持活动的pings，则不会将其计算为上游读取超时。将此超时时间增加到更大的值，可以使Websocket保持更长的打开时间。我把proxy_connect_timeout和proxy_send_timeout留在了20s。