* URIExtractionNamespace: Treat null values in lookup maps as missing entries.
This is useful when many logical lookups are derived from the same base JSON file,
and some lookups' values may be unknown sometimes.
* Add test, logging message, and address other comments.
* Update docs.
* Return better lastVersion from JDBCExtractionNamespaceCacheFactory's cache populator callable
* Return the lastVersion if URI lookup last modified date is not later than the last cached, from URIExtractionNamespaceCacheFactory's cache populator callable
* Fix a race condition in NamespaceExtractionCacheManager.cancelFuture()
* Don't delete cache from NamespaceExtractionCacheManager if the ExtractionNamespaceCacheFactory returned the same version as the last; Better exception treatment in the scheduled cache updater runnable in NamespaceExtractionCacheManager (in particular, don't consume Errors); throw AssertionError in StaticMapExtractionNamespaceCacheFactory if the lastVersion != null)
* In NamespaceExtractionCacheManager, put NamespaceImplData.latestVersion update in the same synchronized() block with swapAndClearCache(id, cacheId); Turn getPostRunnable which returns a callback into a simple updateNamespace() method
* In StaticMapExtractionNamespaceCacheFactory.getCachePopulator(), check the input directly, not inside a callback
* In URIExtractionNamespaceCacheFactory, allow URI last modified time to go backwards
* Better logging in NamespaceExtractionCacheManager
* Add comment on lastVersion nullability in URIExtractionNamespaceCacheFactory
* Async lookups-cached-global by default
* Also better lookup docs
* Fix test timeouts
* Fix timing of deserialized test
* Fix problem with 0 wait failing immediately
* support LookupReferencesManager registration of namespaced lookup and eliminate static configurations for lookup from namespecd lookup extensions
- druid-namespace-lookup and druid-kafka-extraction-namespace are modified
- However, druid-namespace-lookup still has configuration about ON/OFF
HEAP cache manager selection, which is not namespace wide
configuration but node wide configuration as multiple namespace shares
the same cache manager
* update KafkaExtractionNamespaceTest to reflect argument signature changes
* Add more synchronization functionality to NamespaceLookupExtractorFactory
* Remove old way of using extraction namespaces
* resolve compile error by supporting LookupIntrospectHandler
* Remove kafka lookups
* Remove unused stuff
* Fix start and stop behavior to be consistent with new javadocs
* Remove unused strings
* Add timeout option
* Address comments on configurations and improve docs
* Add more options and update hash key and replaces
* Move monitoring to the overriding classes
* Add better start/stop logging
* Remove old docs about namespace names
* Fix bad comma
* Add `@JsonIgnore` to lookup factory
* Address code review comments
* Remove ExtractionNamespace from module json registration
* Fix problems with naming and initialization. Add tests
* Optimize imports / reformat
* Fix future not being properly cancelled on failed initial scheduling
* Fix delete returns
* Add more docs about whole introspection
* Add `/version` introspection point for lookups
* Add more tests and address comments
* Add StaticMap extraction namespace for testing. Also add a bunch of tests
* Move cache system property to `druid.lookup.namespace.cache.type`
* Make VERSION lower case
* Change poll period to 0ms for StaticMap
* Move cache key to bytebuffer
* Change hashCode and equals on static map extraction fn
* Add more comments on StaticMap
* Address comments
* Make scheduleAndWait use a latch
* Sanity renames and fix imports
* Remove extra info in docs
* Fix review comments
* Strengthen failure on start from warn to error
* Address comments
* Rename namespace-lookup to lookups-cached-global
* Fix injective mis-naming
* Also add serde test
Gian Merlino
Roman Leventov
Charles Allen
Akash Dwivedi
Slim