Deletion

Depositors request deletions through the Registry UI. Once a deletion has been requested and approved by an institutional admin, the Registry creates a deletion WorkItem and pushes the WorkItem ID into NSQ's delete_item topic.

The apt_delete worker reads from this topic and deletes files or entire intellectual objects, as requested.

For single file deletions, the worker deletes all copies of the file from preservation storage, creates a deletion Premis event for the file in Registry, and marks changes the state of the Generic File object in Registry from "A" (active) to "D" (deleted).

For intellectual object deletions, the worker does the above for all of the object's files, then created a deletion Premis event for the object and changes its state from "A" to "D."

Finally, it marks the WorkItem complete.

For items using the Standard storage option, apt_delete expunges both the S3 copy and the Glacier copy of every file. All other storage options keep files in a single bucket or vault, so apt_delete has to expunge from only a single location.

Note

Also see the section on Bulk Deletions on the overview page. APTrust has internal documentation on how to create bulk deletion requests and the safeguards surrounding the process. See the internal docs for more information.

Resources

apt_delete uses little CPU, memory, and network bandwidth.

External Services

Service	Function
S3 Preservation Buckets	Long-term storage area from which files are deleted.
Glacier Preservation Buckets	Long-term storage area from which files are deleted.
Glacier Deep Archive Buckets	Long-term storage area from which files are deleted.
Wasabi Buckets	Long-term storage area from which files are deleted.
Registry	Source of WorkItem record describing work to be done. Deletion workers update files and objects, and create deletion Premis events here.
NSQ	Distributes WorkItem IDs to workers and tracks their status.

Source Files

Worker	Service	Files	Definition
Deletion Manager	Deletion	Task Worker App	Deletes files and objects from preservation storage.
APT Queue	Deletion and Restoration	No Task File Worker App	This cron job periodically scans Registry for restoration and deletion requests that have not been queued in NSQ.