Add a "cache" command to bst

bst has no cache management command like:

bst cache clean

to remove all cache.

bst cache refs

to list all references active in the cache, with time stamp and commit referenced in source code.

bst cache set-ref

In order to set reference to be used in next build or shell command.

This feature request may have some relation to issue #135 (closed)

assigned to @Qinusty

I am working on a solution to this and the intended command set so far is:

• : bst cache clean : Clear the local artifact cache.
• : bst cache status : Show the quota and the current size of the cache folder.
• : bst cache refs : List all references active in the cache, with time stamp and commit referenced in source code.
• : bst cache set-ref: Set reference to be used in next build or shell command.

Does this overlap with the planned bst artifacts subcommand @tristanvb?

This will be further implemented and a merge request created once !563 (merged) lands in master.

I do think there is clearly overlap yes, we should probably put these functionalities into the same subcommand group.

That said, this might be tied into some low level CAS manipulation stuff, we have to consider:

• If we want any of these CAS only (not "artifact") related functionality should be exposed in the CLI
• If we do end up exposing these internals, the things which pertain only to CAS but not to BuildStream usage, should probably be split out.

I also think we need a proposal on the ML for the refs related stuff; from a glance of this report; I think this means we allow the user to tag specific things with symbolic names for convenience. Sounds interesting but raises the question of whether we should allow these symbolic names to be pushed to an artifact share, I think this needs discussion.

I would be inclined to avoid exposing CAS specific functionality to the CLI, however the base ArtifactCache class has enough functionality to allow us to clean and provide a status on the cache in use.

As for the refs commands, that'd up to @esodan to elaborate on.

unassigned @Qinusty

I believe we mostly have this functionality now in the bst artifact command:

• cache clean -> artifact delete
• cache refs -> artifact show/artifact list-contents

We're still missing a full-clean operation, and I'm not particularly fond of set-ref personally (and this sort of option generally hasn't seen much contemplation).

Any other use cases are covered by #773 (closed), I believe, so let's close this issue.

closed