1648260 - mozregression should provide a way to intelligently prune my downloaded-builds-cache

Status: NEW

(Testing :: mozregression, enhancement)

Description

[Daniel Holbert [:dholbert]]

Feature request:

It would be great if mozregression offered a command to prune its cache of downloaded builds (to save disk space) in a way that maximizes the usefulness of the builds that are left behind.

Something like the following (I'm just spitballing): a command like mozregression --clean-cache which would do the following:
(1) Delete all cached taskcluster builds (i.e. anything that's not a nightly build), based on the assumption that it's unlikely that any two regressions will arrive at the precise 1-day regression range and will benefit from having cached taskcluster builds.
(2) For cached nightlies older than 1 year: Preserve one per month, and delete the rest.
(3) For cached nightlies between 1-12months old: Preserve one per week, and delete the rest.
(4) For cached nightlies between 0-1 months old: Don't delete any of these.

The hope here would be that the remaining older builds would be sparser, but they'd still be likely to be chosen as approximate "close enough" builds as we bisect through time, to let future mozregression sessions avoid downloading new builds until it really narrows in on a short time range.