I'm new to ElasticSearch but come from a fair amount of experience
with another HTTP wrapper for Lucene which shall remain nameless. I
gather from earlier mailing list posts that ES has a plugin
architecture, but I can't for the life of me find a shred of
documentation on it. In particular, I'm looking for basics like what
endpoints in the HTTP API are available to plugin authors, basic
plugin configuration, etc. Is there anything out there someone can
point me to?
I think that you're thinking of plugins in the wrong way. They are not
the equivalent of solr's request handlers. They are used to extend the
core functionality of ElasticSearch itself, eg adding thrift transport,
Unlike solr, you send your search requests directly to ElasticSearch,
either over HTTP (using one of the many APIs that are available for eg
Perl, Ruby, Python, PHP etc) or via the Java API, which speaks
ElasticSearch's own protocol.