Django频道不会使用CHANNEL_LAYERS启动redis服务器

Question

我试图复制Mikhail Andreev与Django频道聊天：https://gearheart.io/blog/creating-a-chat-with-django-channels/

当我运行服务器：$ python3 ./manage.py runserver时，redis服务器无法启动。这是完整的信息：

 Performing system checks...

 System check identified no issues (0 silenced).
 April 27, 2017 - 20:59:01
 Django version 1.10.3, using settings 'multichat.settings'
 Starting Channels development server at http://127.0.0.1:8000/
 Channel layer default (asgi_redis.core.RedisChannelLayer)
 Quit the server with CONTROL-C.
 2017-04-27 20:59:01,278 - INFO - worker - Listening on channels http.request, websocket.connect, websocket.receive
 2017-04-27 20:59:01,279 - INFO - worker - Listening on channels http.request, websocket.connect, websocket.receive
 2017-04-27 20:59:01,282 - INFO - worker - Listening on channels http.request, websocket.connect, websocket.receive
 2017-04-27 20:59:01,282 - INFO - worker - Listening on channels http.request, websocket.connect, websocket.receive
 2017-04-27 20:59:01,283 - INFO - server - HTTP/2 support not enabled (install the http2 and tls Twisted extras)
 2017-04-27 20:59:01,283 - INFO - server - Using busy-loop synchronous mode on channel layer
 2017-04-27 20:59:01,284 - INFO - server - Listening on endpoint tcp:port=8000:interface=127.0.0.1
 2017-04-27 20:59:01,294 - ERROR - server - Error trying to receive messages: Error 61 connecting to localhost:6379. Connection refused.
 Exception in thread Thread-1:
 Traceback (most recent call last):
   File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 439, in connect
     sock = self._connect()
   File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 494, in _connect
     raise err
   File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 482, in _connect
     sock.connect(socket_address)
 ConnectionRefusedError: [Errno 61] Connection refused 

我可以通过从不同的终端运行redis服务器来解决它，但这就是Django Channels在设置中应该做的事情：

redis_host = os.environ.get('REDIS_HOST', 'localhost')
# Channel layer definitions
# http://channels.readthedocs.org/en/latest/deploying.html#setting-up-
a-channel-backend
CHANNEL_LAYERS = {
    "default": {
        # This example app uses the Redis channel layer implementation asgi_redis
    "BACKEND": "asgi_redis.RedisChannelLayer",
    "CONFIG": {
        "hosts": [(redis_host, 6379)],
    },
   "ROUTING": "multichat.routing.channel_routing", # We will create it in a moment
    },
}

感谢任何帮助和建议。

非常感谢！

Answer 1

见https://github.com/django/daphne#http2-support

你应该安装Twisted pip install -U Twisted[tls,http2]

Answer 2

Django频道不会自动启动Redis。 Redis是一项单独的服务，应该已经在您的机器或其他地方运行。频道依赖Redis作为消息代理的后端。

来自Redis：

Redis是一个开源（BSD许可），内存数据结构存储，用作数据库，缓存和消息代理。

您需要遵循Redis的Installation说明并使用以下命令启动它：

$ /path/to/redis-server

您的Django应用程序也应该是正确的configured to use Redis。如果你使用的话，你还需要在Python virtual environment中安装asgi_redis包。

从您粘贴的错误消息中可以看出，Django Channels无法连接到localhost：6379，因为Redis可能没有运行。

2017-04-27 20:59:01,294 - ERROR - server - Error trying to receive messages: Error 61 connecting to localhost:6379. Connection refused. 
  Exception in thread Thread-1: 
  Traceback (most recent call last):
    File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 439, in connect 
      sock = self._connect() 
    File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 494, in _connect 
      raise err 
    File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 482, in _connect 
      sock.connect(socket_address) 
  ConnectionRefusedError: [Errno 61] Connection refused

更新（2019-02-26）：

asgi_redis包用于Channels 1.x，而对于Channels 2.x，则需要channels_redis。

Answer 3

我认为你已经在virtualenv中安装了redis频道。我遇到了同样的问题然后我也在我的本地安装了redis然后它工作正常。您将看到服务（本地）在那里找到Redis Server。

对于redis安装，您可以点击此链接获取ubuntu：https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-redis-on-ubuntu-18-04