Add option to restore cache only

[ForsakenHarmony]

Description:
It would be nice to have the option to restore only and not save.

Justification:
In bigger repos, it's easy to hit the 10gb cache limit. Not caching in PRs can help with this.
Right now, I have to manually delete caches to help keep the caches on main alive.

Are you willing to submit a PR?

References

actions/toolkit#1308
Swatinem/rust-cache#95 (has a save-if option https://github.com/Swatinem/rust-cache#example-usage)

[e-korolevskii]

Hello @ForsakenHarmony! Thank you for the suggested idea!
We will consider adding this feature and will let you know as soon as we have any decision.

[gwatts]

@ForsakenHarmony likely seen this already, but if not you might find this helpful too to automatically delete PR caches when the PR is closed: https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#force-deleting-cache-entries

[ForsakenHarmony]

@gwatts yes, I'm doing that, doing it after each commit's CI is done actually, but it's an ugly workaround

[dsame]

Hello @ForsakenHarmony, if i understood your request correctly you need the "restore cache only" action https://github.com/actions/cache/blob/main/restore/README.md

Does it solve the problem?

[lzap]

We would love this feature too. Our CI pipeline consist of:

• build job (runs go build)
• test job (runs go test)

When cache is enabled (default in v4) and there is a change in go.sum both jobs run in parallel but because our build job is slower, test job wins and uploads the cache. Problem is, the test job does not build all code path - only those which are executed by unit tests. The next time cache is downloaded, build job will use the cache created by test job which is not 100% so this is leading to wasted CPU cycles.

We would like to configure test job to "download only", basically ability to disable the setup-go post hook uploading the cache.

[lzap]

How do I use lookup-only with setup-go?

[dsame]

Hello @lzap,
you need to disable go caching and use https://github.com/actions/cache/blob/main/restore/README.md

[lzap]

Unfortunately, I am having hard time figuring out how setup-go creates the cache key. The SHA sums for my case do not match for some reason: setup-go-Linux-go-1.19.6-2ecd730a3adf2d5167ee1676ce4793359350a5aef4bc40807996837393159830

It does not match:

$ sha256sum go.sum go.mod
8aeed24d8b1117586e0d269bbe1861de7bfcde3cbdf78e8dea77c6e0bea565cf  go.sum
f1da5013a602ea3becd1c57d497592f7cdce5390d7ddc0ebab0d7b0b8475e33f  go.mod

Are you saying that I need to completely disable go caching and write caching myself (both store and retrieve)? That is exactly what I don’t want to do and the primary reason why I 👍🏻 on this issue.

Frankly either a key prefix/suffix or some sort of "lookup-only" flag that would be passed into the cache action would be really cool. I don’t know TS/JS so crossing my fingers this gets picked up sometime. Not a big deal for our project right now, we disabled caching for some actions for now.