Scaling Golang CI by Replacing actions/setup-go

Hey everyone, one of the authors here. This is a "small" improvement that has saved us a LOT of developer time over the last few months. It's actually quite crazy to me that the default actions/setup-go simply does not work well if you want to have more than one golang action running at the same time.

The blogpost has a lot of technical details, but you can also just read the code and try it yourself:

https://github.com/cloudx-io/setup-go

Good question — we'd be happy to submit a PR, but it's not clear to me that they'd be interested. Some background:

- Our approach writes new cache entries all the time. This can get expensive, and is a pretty big change in behavior from how actions/setup-go works today.

- actions/setup-go can basically be considered incredibly critical infrastructure for the public golang ecosystem. Any change in behavior is probably very risky and slow to happen. At this point I'd bet that we see no change, ever, in behavior.

Additionally there are a few relevant issues/prs that have been ignored for years so I'm not optimistic about contributing upstream. Frankly what we've done is write a very small bit of glue code that is likely most effective as a reference for teams writing their own custom caching actions that fit their exact needs:

- https://github.com/actions/setup-go/pull/426

- https://github.com/actions/setup-go/issues/630

- https://github.com/actions/setup-go/issues/395

- https://github.com/actions/setup-go/issues/596

That said we'd be happy if someone used our code and found it valuable! Lukas put a ton of effort into cleaning up my initial version, added the cache trimming, etc. We depend on this for all of our jobs and use it every day and think it's quite good.

Not OP but upstream patches are rarely worth it. Better to share the fork and if the upstream is interested they can integrate. Integration, testing, meeting upstream expectations usually takes 10x the time, and can be handled faster by those with experience.

There are some good off-cuts that didn't make the official post, but which might be of interest to HN!

It only gets a brief mention, but the cache-pruning change was an interesting one. Cache accretion happens in the default actions/setup-go too, but dramatically increasing the number of cache-writes for cloudx-io/setup-go made it an actual issue.

As the cache grows, so does the time it takes to load it from GitHub's actions cache... and that grows until it's a significant time-suck in CI. We prune with basic mark-and-sweep.

Digging deeper, the pluggable `GOCACHEPROG` (introduced in Go 1.24) is a really useful tool. Shimming the normal cache logic for measurement, for example. In theory this should also be attractive for remote caching.

how does this compare to WillAbides/setup-go-faster?

https://github.com/WillAbides/setup-go-faster