In the previous post, we discussed the basics of caching in Go and implemented a simple in-memory cache that utilizes a RWMutex to protect concurrent access to the inner map. In this post, we will explore how to further improve the handling of concurrent access to the cache through the use of a concept called “sharding.”

In many cases, a fully featured external cache library is overkill, and for most use cases, writing your own implementation is a better option. You will understand how it works, and will be able to extend it to your needs. This post will cover the basics of implementing a cache in Go, and provide a working template for you to use.