youtube/vitess — pull request #233 by guokeno0 (2014-12-12 00:47:40+00:00)
Title: file-based and zookeeper based custom rule implementation

To enable dynamic custom rule configuration for vttablet, this patch implements two sets of dynamic rule updating mechanisms:

ZkCustomRule: zookeeper based custom rule manager
FileCustomRule: file based custom rule manager

This patch also sets up an interface, the CustomRuleManager. Future custom rule implementations which conforms with CustomRuleManager interface can be easily plugged in.