Experiment: CAS

[yhakbar]

Share your feedback on the cas experiment.

If you believe that we're ready to end the experiment, and support the feature by default, share that opinion!

[FlorinAndrei]

How does CAS interact with parallel runs? I assume the cache is shared somehow, but what if two parallel runs want to create the same entry?

How are repo tag versions handled? E.g. I might use this block for some resource:

terraform {
  source = "${include.compcommon.locals.base_source_url}?ref=v5.21.0"
}

But I might use this block for some other resource:

terraform {
  source = "${include.compcommon.locals.base_source_url}?ref=v5.20.0"
}

[yhakbar]

How does CAS interact with parallel runs? I assume the cache is shared somehow, but what if two parallel runs want to create the same entry?

It's designed to be safe to run concurrently. The CAS store gets populated with every unique file cloned from Git for all runs being performed, and each unit gets an independent directory created with files that are hard links to the shared CAS store.

How are repo tag versions handled?

If you only change one file between version v5.20.0 and v5.21.0, then you'll have a copy of every file in v5.20.0 and an extra copy of the file that changed between them in your store.