Couchbase 5.0 is releasing full text search capabilities built on the open source Bleve engine. You enable indexing for full text and start using against existing JSON documents in the database.
Some slides and presentation video covering the topic, mentioning Elasticsearch and Lucene as well... https://www.slideshare.net/Couchbase/fulltext-search-how-it-works-and-what-it-can-do
