About ccache and cache storage about ttk

[mwestphal]

@CharlesGueunet

[julien-tierny]

@pierre-guillou

[pierre-guillou]

Hi @mwestphal,

I'm the one that put these workflows into place. I used ccache on Ubuntu & macOS because at that time (3 years ago) I thought it was the simplest solution.

Note that we use sccache on Windows (it was quite a pain to make it work with CMake + clang-cl for OpenMP…). We stuck to an old version of sccache there to avoid a bug but I haven't tried with newer versions yet.

I decided to use GitHub releases to store ccache/sccache data for several reasons:

• I didn't want PRs have a write access to the cache, only a read access
• I wanted a centralized cache accessible to other repositories, in case developpers want to test their code in their fork without creating a PR to the main TTK repository
• GitHub cache action did not seem to work well across different branches/PRs.

So I came up (in several iterations) with the current system that (mis)uses GitHub Releases to store ccache/sccache data at every commit / PR merge in the main repository.

Do you think the current action/cache supports these uses-cases?

We can switch from ccache to sccache in the Ubuntu & macOS jobs but sccache seems a bit more intrusive with its --start-server & --stop-server invocations. Is there any sccache feature that makes it more attractive than ccache?

[mwestphal]

Thanks for your answer.

I didn't want PRs have a write access to the cache, only a read access

Great, github cache behave the same

I wanted a centralized cache accessible to other repositories, in case developpers want to test their code in their fork without creating a PR to the main TTK repository

Great github cache behave the same

GitHub cache action did not seem to work well across different branches/PRs.

It works perfectly actions branches, forks and PRs.
It is designed by github for github users to do exactly that.

Do you think the current action/cache supports these uses-cases?

Yes

Is there any sccache feature that makes it more attractive than ccache?

Windows support

I hope that answers your questions. I cann explain how it works in F3D ci if needed. Maybe I'm missing something regarding TTK needs but so far I do really thing that github cacches + sccache works wonders.

[mwestphal]

BTW I'm thinking of adding a sccache github action that could be used out of the box, I'll let you know If I do that.