Grok is a tool to parse crappy unstructured log data into something structured and queryable. Grok is heavily used in Logstash to provide log data as input for ElasticSearch.
Snaps are applications packaged with all their dependencies to run on all popular Linux distributions from a single build. They update automatically and roll back gracefully.
Snaps are discoverable and installable from the Snap Store, an app store with an audience of millions.