Parametrizing Django diskcache path and size (#474)

* Parametrizing Django diskcache path and size

* Cache directory permissions fix

web/README.md

@@ -78,6 +78,9 @@ change them unless you know what you want.
   you must specify any social login provider in `INSTALLED_APPS` instead.
   See [settings.py][1] for implementation details.
 
+- `DISKCACHE_PATH` and `DISKCACHE_SIZE`: Django Diskcache location path and
+  size respectively. Defaults are `/opt/mailman-web-data/diskcache` and 1G.
+
 [1]: https://github.com/maxking/docker-mailman/blob/master/web/mailman-web/settings.py
 
 Running

web/docker-entrypoint.sh

@@ -158,4 +158,6 @@ fi
 # directory for it. Also chown the logs directory to write the files.
 chown mailman:mailman /opt/mailman-web-data -R
 
+[[ -v DISKCACHE_PATH ]] && chown mailman:mailman "${DISKCACHE_PATH}" -R
+
 exec $@

web/mailman-web/settings.py

@@ -391,12 +391,15 @@ Q_CLUSTER = {
 
 POSTORIUS_TEMPLATE_BASE_URL =  os.environ.get('POSTORIUS_TEMPLATE_BASE_URL', 'http://mailman-web:8000')
 
+DISKCACHE_PATH = os.environ.get('DISKCACHE_PATH', '/opt/mailman-web-data/diskcache')
+DISKCACHE_SIZE = os.environ.get('DISKCACHE_SIZE', 2 ** 30) # 1 gigabyte
+
 CACHES = {
     'default': {
         'BACKEND': 'diskcache.DjangoCache',
-        'LOCATION': '/opt/mailman-web-data/diskcache',
+        'LOCATION': DISKCACHE_PATH,
         'OPTIONS': {
-            'size_limit': 2 ** 30   # 1 gigabyte
+            'size_limit': DISKCACHE_SIZE,
         },
     },
 }