I have a custom ValueSourceParser that sets up a Zookeeper Watcher on some frequently changing metadata that a custom ValueSource depends on.
Basic flow of events is - VSP watches for metadata changes, which triggers a refresh of some expensive data that my custom ValueSource uses at query time. Think of the data in Zookeeper as a pointer to some larger dataset that is computed offline and then loaded into memory for use by my custom ValueSource. In my ValueSourceParser, I connect to Zookeeper using an instance of the SolrZkClient class and am receiving WatchedEvents when my metadata changes (as expected). All this works great until core reload happens. From what I can tell, there's no shutdown hook for ValueSourceParsers, so what's happening is that my code ends up adding multiple Watchers and thus receives multiple update events when the metadata changes. What I need is either 1) a shutdown hook in my VSP that allows me to clean-up the SolrZkClient instance my code is managing, or 2) access to the ZkController instance owned by the CoreContainer from my VSP. For me #2 is better as I'd prefer to just re-use Solr's instance of SolrZkClient. I can go and hack either of these in pretty easily but wanted to see if someone knows a better way to get 1 or 2? In general, it might be handy to allow plug-ins to get access to the Zookeeper client SolrCloud is using. Thanks. Tim
