Added custom configuration to slave connections

lib/lhm/invoker.rb

@@ -68,7 +68,8 @@ def normalize_options(options)
       end
 
       if options[:throttler]
-        options[:throttler] = Throttler::Factory.create_throttler(options[:throttler])
+        throttler_options = options[:throttler_options] || {}
+        options[:throttler] = Throttler::Factory.create_throttler(options[:throttler], throttler_options)
       else
         options[:throttler] = Lhm.throttler
       end

lib/lhm/throttler/slave_lag.rb

@@ -15,7 +15,7 @@ def initialize(options = {})
         @timeout_seconds = INITIAL_TIMEOUT
         @stride = options[:stride] || DEFAULT_STRIDE
         @allowed_lag = options[:allowed_lag] || DEFAULT_MAX_ALLOWED_LAG
-        @slave_connections = {}
+        @slave_connection = options[:slave_connection]
       end
 
       def execute
@@ -74,10 +74,14 @@ def slave_lag(slave)
       end
 
       def slave_connection(slave)
-        adapter_method = defined?(Mysql2) ? 'mysql2_connection' : 'mysql_connection'
-        config = ActiveRecord::Base.connection_pool.spec.config.dup
-        config[:host] = slave
-        ActiveRecord::Base.send(adapter_method, config)
+        unless @slave_connection
+          adapter_method = defined?(Mysql2) ? 'mysql2_connection' : 'mysql_connection'
+          config = ActiveRecord::Base.connection_pool.spec.config.dup
+          config[:host] = slave
+          ActiveRecord::Base.send(adapter_method, config)
+        else
+          @slave_connection.call(slave)
+        end
       end
 
       # This method fetch the Seconds_Behind_Master, when exec_query is no available, on AR 2.3.

spec/unit/throttler/slave_lag_spec.rb

@@ -62,6 +62,19 @@ def @throttler.max_current_slave_lag
     end
   end
 
+  describe '#custom_slave_connection' do
+    describe 'with a custom slave connection' do
+      before do
+        @connection = Object.new # just an object to see if the method returns what we return
+        @throttler = Lhm::Throttler::SlaveLag.new(slave_connection: lambda {|host| @connection})
+      end
+
+      it 'should use the custom slave connection' do
+        assert_equal(@connection, @throttler.send(:slave_connection, "slave.db.local"))
+      end
+    end
+  end
+
   describe '#slave_hosts' do
     describe 'with no slaves' do
       before do