We've already migrated all the legacy artifacts to the new realm,
which is ci_job_artifacts table.
It's time to remove the old code base that is no longer used.
Two things at ones, as there was no clean way to seperate the commit and
give me feedback from the tests.
But the model Artifact is now JobArtifact, and the table does not have a
type anymore, but the metadata is now its own model:
Ci::JobArtifactMetadata.
This removes the need for relying on Rails' "dependent" option for data
removal, which is _incredibly_ slow (even when using :delete_all) when
deleting large amounts of data. This also ensures data consistency is
enforced on DB level and not on application level (something Rails is
really bad at).
This commit also includes various migrations to add foreign keys to
tables that eventually point to "projects" to ensure no rows get
orphaned upon removing a project.
It may happen that job meant to remove expired artifacts will be
executed asynchronously when, in the meantime, project associated with
given build gets removed by another asynchronous job. In that case we
should not remove artifacts because such build will be removed anyway,
when project removal is complete.
Shinya Maeda