+ # If the given pdh is an old-format docker image, old-format images
+ # aren't supported by the compute nodes according to site config,
+ # and a migrated new-format image is available, return the migrated
+ # image's pdh. Otherwise, just return pdh.
+ def self.docker_migration_pdh(read_users, pdh)
+ if Rails.configuration.docker_image_formats.include?('v1')
+ return pdh
+ end
+ Collection.readable_by(*read_users).
+ joins('INNER JOIN links ON head_uuid=portable_data_hash').
+ where('tail_uuid=? AND link_class=? AND links.owner_uuid=?',
+ pdh, 'docker_image_migration', system_user_uuid).
+ order('links.created_at desc').
+ select('portable_data_hash').
+ first.andand.portable_data_hash || pdh
+ end
+