[change] Added variable to configure daphne websocket timeout

This timeout value is also used for configuring the "group_expiry"
of CHANNEL_LAYERS.

README.md

@@ -910,6 +910,8 @@ Below are listed all the variables you can customize (you may also want to take
     openwisp2_uwsgi_threads: 2
     # number of daphne process to spawn. Default value is 1
     openwisp2_daphne_processes: 2
+    # maximum time to allow a websocket to be connected (in seconds)
+    openwisp2_daphne_websocket_timeout: 1800
     # the following setting controls which ip address range
     # is allowed to access the openwisp2 admin web interface
     # (by default any IP is allowed)

defaults/main.yml

@@ -137,6 +137,7 @@ postfix_smtpd_relay_restrictions_override: "permit_sasl_authenticated, permit_my
 openwisp2_uwsgi_processes: 1
 openwisp2_uwsgi_threads: 1
 openwisp2_daphne_processes: 1
+openwisp2_daphne_websocket_timeout: 3600 # in seconds
 # internationalization
 openwisp2_internationalization: false
 openwisp2_users_auth_api: true

templates/openwisp2/settings.py

@@ -147,7 +147,10 @@
 CHANNEL_LAYERS = {
     'default': {
         'BACKEND': 'channels_redis.core.RedisChannelLayer',
-        'CONFIG': {'hosts': [('{{ openwisp2_redis_host }}', {{ openwisp2_redis_port }})]},
+        'CONFIG': {
+            'hosts': [('{{ openwisp2_redis_host }}', {{ openwisp2_redis_port }})],
+            'group_expiry': {{ openwisp2_daphne_websocket_timeout }},
+        },
     },
 }
 ASGI_APPLICATION = 'openwisp2.routing.application'

templates/supervisor/daphne.j2

@@ -2,7 +2,7 @@
 user={{ www_user }}
 socket=unix://{{ openwisp2_path }}/daphne0.sock
 directory={{ openwisp2_path }}
-command={{ openwisp2_path }}/env/bin/daphne --fd 0 -u {{ openwisp2_path }}/daphne%(process_num)d.sock --access-log - --proxy-headers openwisp2.asgi:application
+command={{ openwisp2_path }}/env/bin/daphne --fd 0 -u {{ openwisp2_path }}/daphne%(process_num)d.sock --access-log - --websocket_timeout {{ openwisp2_daphne_websocket_timeout }} --proxy-headers openwisp2.asgi:application
 process_name=asgi%(process_num)d
 numprocs={{ openwisp2_daphne_processes }}
 autostart=true