Move zulip.com-related statsd configuration out of main settings.py.

This also removes the convenient way to run statsd in the Dev VM,
because we don't anticipate anyone doing that.  It's just 2 lines of
config to configure it anyway:

STATSD_HOST = 'localhost'
STATSD_PREFIX = 'user'

(imported from commit 5b09422ee0e956bc7f336dd1e575634380b8bfa2)

zerver/lib/utils.py

@@ -40,7 +40,7 @@ class StatsDWrapper(object):
         # Hand off to statsd if we have it enabled
         # otherwise do nothing
         if name in ['timer', 'timing', 'incr', 'decr', 'gauge']:
-            if settings.USING_STATSD:
+            if settings.STATSD_HOST != '':
                 from django_statsd.clients import statsd
                 if name == 'gauge':
                     return self._our_gauge

zerver/management/commands/send_stats.py

@@ -18,7 +18,7 @@ class Command(BaseCommand):
         name = options['name']
         val = options['val']
 
-        if settings.USING_STATSD:
+        if settings.STATSD_HOST != '':
             from statsd import statsd
 
             func = getattr(statsd, operation)

zproject/local_settings.py

@@ -41,12 +41,15 @@ NOREPLY_EMAIL_ADDRESS = "noreply@zulip.com"
 
 SESSION_SERIALIZER = "django.contrib.sessions.serializers.PickleSerializer"
 
+STATSD_HOST = 'stats.zulip.net'
+
 if ZULIP_COM_STAGING:
     EXTERNAL_HOST = 'staging.zulip.com'
+    STATSD_PREFIX = 'staging'
 else:
     EXTERNAL_HOST = 'zulip.com'
     EXTERNAL_API_PATH = 'api.zulip.com'
-
+    STATSD_PREFIX = 'app'
 
 S3_BUCKET="humbug-user-uploads"
 S3_AUTH_UPLOADS_BUCKET = "zulip-user-uploads"

zproject/settings.py

@@ -154,6 +154,7 @@ DEFAULT_SETTINGS = {'TWITTER_CONSUMER_KEY': '',
                     'EXTERNAL_URI_SCHEME': "https://",
                     'ZULIP_COM': False,
                     'ZULIP_COM_STAGING': False,
+                    'STATSD_HOST': '',
                     'GOOGLE_CLIENT_ID': '',
                     'DBX_APNS_CERT_FILE': None,
                     }
@@ -481,24 +482,9 @@ else:
 # STATSD CONFIGURATION
 ########################################################################
 
-LOCAL_STATSD = (False)
-USING_STATSD = ZULIP_COM or LOCAL_STATSD
-
-# These must be named STATSD_PREFIX for the statsd module
-# to pick them up
-if ZULIP_COM_STAGING:
-    STATSD_PREFIX = 'staging'
-elif PRODUCTION:
-    STATSD_PREFIX = 'app'
-else:
-    STATSD_PREFIX = 'user'
-
-if USING_STATSD:
-    if LOCAL_STATSD:
-        STATSD_HOST = 'localhost'
-    else:
-        STATSD_HOST = 'stats.zulip.net'
-
+# Statsd is not super well supported; if you want to use it you'll need
+# to set STATSD_HOST and STATSD_PREFIX.
+if STATSD_HOST != '':
     INSTALLED_APPS += ['django_statsd']
     STATSD_PORT = 8125
     STATSD_CLIENT = 'django_statsd.clients.normal'