move pubsub traffic over to a pubsub redis connection string

services/real-time/app/coffee/DocumentUpdaterController.coffee

@@ -1,7 +1,7 @@
 logger = require "logger-sharelatex"
 settings = require 'settings-sharelatex'
 redis = require("redis-sharelatex")
-rclient = redis.createClient(settings.redis.documentupdater)
+rclient = redis.createClient(settings.redis.pubsub)
 SafeJsonParse = require "./SafeJsonParse"
 EventLogger = require "./EventLogger"
 HealthCheckManager = require "./HealthCheckManager"

services/real-time/app/coffee/WebsocketLoadBalancer.coffee

@@ -2,8 +2,8 @@ Settings = require 'settings-sharelatex'
 logger = require 'logger-sharelatex'
 redis = require("redis-sharelatex")
 SafeJsonParse = require "./SafeJsonParse"
-rclientPub = redis.createClient(Settings.redis.realtime)
-rclientSub = redis.createClient(Settings.redis.realtime)
+rclientPub = redis.createClient(Settings.redis.pubsub)
+rclientSub = redis.createClient(Settings.redis.pubsub)
 EventLogger = require "./EventLogger"
 HealthCheckManager = require "./HealthCheckManager"
 

services/real-time/config/settings.defaults.coffee

@@ -1,5 +1,11 @@
 settings =
 	redis:
+
+		pubsub:
+			host: process.env['PUBSUB_REDIS_HOST'] or process.env['REDIS_HOST'] or "localhost"
+			port: process.env['PUBSUB_REDIS_PORT'] or process.env['REDIS_PORT'] or "6379"
+			password: process.env["PUBSUB_REDIS_PASSWORD"] or process.env["REDIS_PASSWORD"] or ""
+
 		realtime:
 			host: process.env['REAL_TIME_REDIS_HOST'] or process.env['REDIS_HOST'] or "localhost"
 			port: process.env['REAL_TIME_REDIS_PORT'] or process.env['REDIS_PORT'] or "6379"