This go module provides a very simple in-memory key/value cache. It uses 1 mutex lock only during start and stop; utilizes only 1 go routine, 2 channels, and 1 or 2 tickers depending on if you enable the pruner. The module also exports git/miss statistics that you can plug into expvar, or other metrics modules.
This module has a concept of pruning. Items can be marked prunable,
or not prunable. Those marked prunable are deleted after they have not
had a get request within a specified duration. Those marked not-prunable
have a different configurable maximum unused age.
I wrote this to cache data from mysql queries for an nginx auth proxy. I've since began using it in plenty of other places as a global data store. See a simple example in cache_test.go.