I'm learning to develop web applications and I would like to create my own internal site search engine (without using Google or a 3rd party hosting service) that could index my web app. Could I go about using something like Elastic Search for a small web app? I have been reading about it, but I have only seen it used for big sites/apps. Or would I have to implement this myself without any 3rd party APIs? I'm using Golang as my programming language.
Take a look at Bleve - it's pure Go ElasticSearch/Lucene alternative. Looks promising.
Here is nice talk about Bleve at FOSDEM'15 Go DevRoom: https://video.fosdem.org/2015/devroom-go/bleve.mp4 (145M)