FIX: Don't configure Redis connector if Redis slave config is not set.

app/models/global_setting.rb

@@ -37,29 +37,39 @@ class GlobalSetting
     {"production" => hash}
   end
 
+  # For testing purposes
+  def self.reset_redis_config!
+    @config = nil
+  end
+
   def self.redis_config
     @config ||=
       begin
         c = {}
         c[:host] = redis_host if redis_host
         c[:port] = redis_port if redis_port
-        c[:slave_host] = redis_slave_host if redis_slave_host
-        c[:slave_port] = redis_slave_port if redis_slave_port
+
+        if redis_slave_host && redis_slave_port
+          c[:slave_host] = redis_slave_host
+          c[:slave_port] = redis_slave_port
+          c[:connector] = DiscourseRedis::Connector
+        end
+
         c[:password] = redis_password if redis_password.present?
         c[:db] = redis_db if redis_db != 0
         c[:db] = 1 if Rails.env == "test"
+
         if redis_sentinels.present?
           c[:sentinels] = redis_sentinels.split(",").map do |address|
             host,port = address.split(":")
             {host: host, port: port}
           end.to_a
         end
-        c[:connector] = DiscourseRedis::Connector
+
         c.freeze
       end
   end
 
-
   class BaseProvider
     def self.coerce(setting)
       return setting == "true" if setting == "true" || setting == "false"

spec/models/global_setting_spec.rb

@@ -1,6 +1,26 @@
 require 'rails_helper'
 require 'tempfile'
 
+describe GlobalSetting do
+  describe '.redis_config' do
+    describe 'when slave config is not present' do
+      it "should not set any connector" do
+        expect(GlobalSetting.redis_config[:connector]).to eq(nil)
+      end
+    end
+
+    describe 'when slave config is present' do
+      it "should set the right connector" do
+        GlobalSetting.reset_redis_config!
+        GlobalSetting.expects(:redis_slave_port).returns(6379).at_least_once
+        GlobalSetting.expects(:redis_slave_host).returns('0.0.0.0').at_least_once
+
+        expect(GlobalSetting.redis_config[:connector]).to eq(DiscourseRedis::Connector)
+      end
+    end
+  end
+end
+
 describe GlobalSetting::EnvProvider do
   it "can detect keys from env" do
     ENV['DISCOURSE_BLA'] = '1'
@@ -9,6 +29,7 @@ describe GlobalSetting::EnvProvider do
     expect(GlobalSetting::EnvProvider.new.keys).to include(:bla_2)
   end
 end
+
 describe GlobalSetting::FileProvider do
   it "can parse a simple file" do
     f = Tempfile.new('foo')
@@ -48,5 +69,4 @@ describe GlobalSetting::FileProvider do
 
     f.unlink
   end
-
 end