Django Channels / Daphne中的Websocket超时

Question

简短的问题版本：我的Daphne配置，消费者代码或客户代码在做什么？

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

详情如下：

---

我正在尝试使用Django Channels和Daphne接口服务器保持持久的Websocket连接打开。我发动达芙妮与大多默认参数：daphne -b 0.0.0.0 -p 8000 my_app.asgi:channel_layer。

我看到连接在浏览器中闲置一段时间后（超过20秒）关闭。在CloseEvent与断开送了一个code价值1006（异常关闭），不reason设置，并wasClean设置为false。这应该是服务器在不发送显式关闭帧的情况下关闭连接。

Daphne CLI具有--ping-interval和--ping-timeout标志，其默认值分别为20和30秒。对于前者，这记录为“ WebSocket在发送保持活动ping之前必须处于空闲状态的秒数”，对于“后者，如果没有响应，则关闭WebSocket之前的秒数”。我读到这是因为Daphne将等到WebSocket闲置20秒后发送ping，如果30秒后未收到响应，它将关闭Websocket。相反，我看到的是空闲20秒后连接关闭。（在尝试使用默认值的三个尝试中，分别在20081ms，20026ms和20032ms之后关闭）

如果我将服务器更改为以启动daphne -b 0.0.0.0 -p 8000 --ping-interval 10 --ping-timeout 60 my_app.asgi:channel_layer，则连接仍会关闭，大约有20秒的空闲时间。（经过三次尝试并更新ping之后，在19892ms，20011ms，19956ms之后关闭）

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

根本的问题原来是接口服务器前面的nginx代理。代理设置为proxy_read_timeout 20s;。如果从服务器生成了keepalive ping，则这些计数不会计入上游读取超时。将此超时值增大到一个较大的值可使Websocket保持打开状态的时间更长。我一直proxy_connect_timeout和proxy_send_timeout在20s。