fastlane: Separate votes on some links and their comments.

If a specific link has ridiculous traffic, we can inform the
apps (via ZK live config) that votes on it should be sent to a
separate, dedicated, queue to avoid overwhelming the rest of the
system.

r2/example.ini

@@ -496,6 +496,8 @@ beaker.session_secret = somesecret
 [live_config]
 # make frontpage 100% dart
 frontpage_dart = false
+# links that get their own infrastructure (comma-delimited list of id36s)
+fastlane_links =
 # spotlight links for subreddit discovery
 sr_discovery_links = 
 # probability of the subreddit suggester showing up in the spotlight box

r2/r2/lib/app_globals.py

@@ -186,6 +186,7 @@ class Globals(object):
         ],
         ConfigValue.tuple: [
             'sr_discovery_links',
+            'fastlane_links',
         ],
     }
 

r2/r2/lib/db/queries.py

@@ -1284,6 +1284,7 @@ def _run_commentstree(msgs, chan):
 
 vote_link_q = 'vote_link_q'
 vote_comment_q = 'vote_comment_q'
+vote_fastlane_q = 'vote_fastlane_q'
 
 def queue_vote(user, thing, dir, ip, organic = False,
                cheater = False, store = True):
@@ -1294,9 +1295,16 @@ def queue_vote(user, thing, dir, ip, organic = False,
     if store:
         if g.amqp_host:
             if isinstance(thing, Link):
-                qname = vote_link_q
+                if thing._id36 in g.live_config["fastlane_links"]:
+                    qname = vote_fastlane_q
+                else:
+                    qname = vote_link_q
+
             elif isinstance(thing, Comment):
-                qname = vote_comment_q
+                if utils.to36(thing.link_id) in g.live_config["fastlane_links"]:
+                    qname = vote_fastlane_q
+                else:
+                    qname = vote_comment_q
             else:
                 log.warning("%s tried to vote on %r. that's not a link or comment!",
                             user, thing)

r2/r2/lib/queues.py

@@ -73,6 +73,7 @@ def queues(self):
         self._q('register_vote_q', self_refer=True)
         self._q('vote_link_q', self_refer=True)
         self._q('vote_comment_q', self_refer=True)
+        self._q('vote_fastlane_q', self_refer=True)
         self._q('log_q', self_refer=True)
         self._q('usage_q', self_refer=True, durable=False)