Before this work began, we already had a faster alternative to Github Actions cache. Our approach was different: we forked each of the popular first-party actions that depended on Actions cache to point to our faster, colocated cache. So, I set out to reverse engineer GitHub Actions cache itself, with one goal: make it fast. Sniffing out GitHub cache requestsThe first step was fully understanding the inner workings of the GitHub Actions cache. Our prior experience forking the existing cache actions proved helpful, but earlier this year, GitHub threw us a curveball by deprecating its legacy cache actions in favor of a new Twirp-based service using the Azure Blob Storage SDK.