finish builder close allocated resources and store state (e.g., sqlite3 databases).

delete ?log t id removes id from the store, along with all of its dependencies. This is for testing. Note that is not safe to perform builds while deleting: the delete might fail because an item got a new child during the delete, or we might delete something that the build is using.

• parameter log

  Called just before deleting each item, so it can be displayed.

prune t ~before n attempts to remove up to n items from the store, all of which were last used before before. Returns the number of items removed.

• parameter log

  Called just before deleting each item, so it can be displayed.

healthcheck t performs a check that t is working correctly.

• parameter timeout

  Cancel and report failure after this many seconds. This excludes the time to fetch the base image.