Django channels with redis-server and nginx

Question

I've been following this http://channels.readthedocs.io/en/latest/getting-started.html

My current setup (before adding channels) was nginx, uwsgi, django.

On my local, I'm running all this on a vagrant box which forwards port 5000
Django server currently runs on 0.0.0.0:5000
My nginx config listens on 8000 and serves static files
It also has:

location / {
    include uwsgi_params;
    uwsgi_pass unix:{{backend_uwsgi_socket}};
}

While following the tutorial, everything works until I get to the point of changing my settings.py from

CHANNEL_LAYERS = {
  "default": {        
    "BACKEND": "asgiref.inmemory.ChannelLayer",        
    "ROUTING": "myapp.routing.channel_routing",
  },
}

to

CHANNEL_LAYERS = {
 "default": {
    "BACKEND": "asgi_redis.RedisChannelLayer",        
    "CONFIG": {
        #"hosts": [os.environ.get('REDIS_URL', 'redis://localhost:6379')],
        #"hosts": [("redis-server-name", 6379)],           
        "hosts": [("localhost", 6379)],
    },
    "ROUTING": "myapp.routing.channel_routing",
 },
}

So the tutorial says to install redis-server, then just run the command again:
manage.py runserver 0.0.0.0:80000

If I turn off nginx, and run this it complains:

ConnectionError: Error 111 connecting to localhost:6379. Connection refused.

I tried adding a listener for this port in my nginx server block, then I get the below error:

^Cvagrant@vagrant-ubuntu-trusty-64:/srv/myproj/backend$ sudo python manage.py runserver 0.0.0.0:8000
Performing system checks...

System check identified no issues (0 silenced).
December 28, 2017 - 17:10:25
Django version 1.10, using settings 'backend.settings'
Starting Channels development server at http://0.0.0.0:8000/
Channel layer default (asgi_redis.core.RedisChannelLayer)
Quit the server with CONTROL-C.
2017-12-28 17:10:25,883 - INFO - worker - Listening on channels http.request, websocket.connect, websocket.disconnect, websocket.receive
Exception in thread Thread-1:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
self.run()
File "/usr/local/lib/python2.7/dist-packages/channels/management/commands/runserver.py", line 176, in run
worker.run()
File "/usr/local/lib/python2.7/dist-packages/channels/worker.py", line 87, in run
channel, content = self.channel_layer.receive_many(channels, block=True)
File "/usr/local/lib/python2.7/dist-packages/asgiref/base_layer.py", line 43, in receive_many
return self.receive(channels, block)
File "/usr/local/lib/python2.7/dist-packages/asgi_redis/core.py", line 168, in receive
result = connection.blpop(list_names, timeout=self.blpop_timeout)
File "/usr/local/lib/python2.7/dist-packages/redis/client.py", line 1269, in blpop
return self.execute_command('BLPOP', *keys)
File "/usr/local/lib/python2.7/dist-packages/redis/client.py", line 668, in execute_command
return self.parse_response(connection, command_name, **options)
File "/usr/local/lib/python2.7/dist-packages/redis/client.py", line 680, in parse_response
response = connection.read_response()
File "/usr/local/lib/python2.7/dist-packages/redis/connection.py", line 624, in read_response
response = self._parser.read_response()
File "/usr/local/lib/python2.7/dist-packages/redis/connection.py", line 292, in read_response
(str(byte), str(response)))
InvalidResponse: Protocol Error: <, html>

After this print out, it just constantly prints the following msg:

ERROR - server - Error trying to receive messages: Protocol Error: <, html>

I'm struggling to find answers for this and have gotten myself confused following a few different tutorials/examples.
I know it will be me having missed something obvious, or have misunderstood something.

Any pointers or help would be greatly appreciated.

As soon as I posted this, I thought to myself "is the redis-server running?".. I ran it... this all works again. Feels like a major bit to have missed from the tutorial. — user2616166

Eugene Prikazchikov Eugene Prikazchikov · Accepted Answer · 2017-12-28T20:28:21

ConnectionError: Error 111 connecting to localhost:6379. Connection refused.

6379 is port where redis server should be running. You should not configure nginx to listen it.

The stacktrace you posted means that django server is trying to connect to redis (port 6379) and it does not like the response (because nginx listens there, not redis).

Django channels with redis-server and nginx

1 Answers