Delete an artifact version

After this guide you can remove one version of an artifact, or the whole artifact, and you know what that removes and what it does not. Lakana cannot undo a deletion: the files are removed from storage. If your bucket keeps old object versions, a deleted file stays in the bucket until the bucket's own rule removes it.

You need DROP_TABLE on the artifact. The roles DATA_ENGINEER and ADMIN have it. A task token never has it: a running task cannot delete anything, whatever its principal may do.

If you only want to keep fewer versions over time, set keep_versions instead: Limit how many versions are kept.

Delete one version

1. Find the number. The artifact versions list subcommand of lakana, with the artifact's name, shows the versions, newest first. Note the number of the one to delete. Numbers can have gaps.

2. Delete it. Give the name and the version number. The example removes version 3 of models.scratch_model, a test artifact made only for this page: it has three versions, which artifact upload stored one after the other (see upload). Put the name of your artifact there. --yes skips the question, so check the name before you press Enter:

lakana artifact versions delete models.scratch_model 3 --env dev --yes

Without --yes the command first asks, naming what it will remove: Delete version 3 of dev/models.scratch_model (33 B, 1 file)? Its bytes are removed from Lakana's storage. Lakana cannot bring them back. [y/N]: Answer y to go on; any other answer, or just Enter, stops. Without a terminal, for example in a script, it refuses and says Refusing without a terminal; pass --yes to confirm. Add --yes only when you are sure.

The command prints what it did. Version 3 had one file that no other version shares, so the file is freed:

Deleted version 3 of dev/models.scratch_model. Freed 1 file (33 B).

What the answer says

The command tells you how many files and bytes it freed from Lakana's storage, and, when a file stayed, how many and why. In this example version 1 and version 2 of models.scratch_twin hold the same file, so deleting version 1 frees nothing: version 2 still needs the file.

lakana artifact versions delete models.scratch_twin 1 --env dev --yes

Deleted version 1 of dev/models.scratch_twin. Freed no files.
Kept 1 file (33 B) that version 2 also uses.

A file stays for one of three reasons:

A file that two paths of one version share counts once. With --output json the answer has the same numbers: freed_files, freed_bytes, kept_files, kept_bytes and kept, a list of reason, files, bytes and version. In the SDK delete_version returns them on the version it gives back, see the reference.

What deleting a version means

• The files are removed from storage, except a file that another live version of the same artifact still has, or an open upload names, or that the clean-up decides about ("What the answer says"). Lakana cannot bring them back. If your bucket keeps old object versions, a deleted file stays there until the bucket's own rule removes it.
• The record stays. artifact versions list still shows the version, marked deleted, with who deleted it and when. Its number is never used again. The lineage that names it stays.
• If you delete the newest version, the one before it becomes current. Assets that read the current version then read the older one. This is how you roll back a bad model.
• Copies are not recalled. A copy that someone downloaded stays on their machine, and a backup of your storage still holds the file.
• The names and hashes of its files stay in the catalog, with the record. The contents do not.

In a protected environment

A protected environment accepts changes only from runs of the deployed code. To delete a version there you need MANAGE_ENVIRONMENT as well as DROP_TABLE, and a reason of 10 to 500 characters on one line. Put your own artifact's name, version and environment in the example: it removes version 3 of models.scratch_model in prod, and the --reason text goes into the audit log:

lakana artifact versions delete models.scratch_model 3 --env prod --break-glass --reason "Model 3 was trained on the wrong customers"

The command warns that the write is audited. Without the two options the server refuses: Environment 'prod' is protected: only runs of the deployed project version may write. See `lakana run`. --break-glass without --reason is a usage error, and so is --reason alone.

Drop the whole artifact

Dropping removes every version with its files, and the artifact's grants. The example drops models.scratch_model, the test artifact from above, whose version 3 is already deleted. Put the name of your artifact there. --yes skips the question, so check the name before you press Enter:

lakana artifact drop models.scratch_model --env dev --yes

Without --yes the command asks first, and without a terminal it refuses, as for a version. In the example, version 3 was deleted before, so the question is Drop artifact dev/models.scratch_model and delete its 2 versions (66 B, 1 more already deleted)? This cannot be undone. [y/N]: The command prints:

Dropped artifact dev/models.scratch_model; its files are removed from storage, and Lakana's periodic clean-up removes any it could not.

• The name becomes free. If you create an artifact of that name again, it starts at version 1 as a new artifact. Grants given on the old artifact itself are gone; grants on its namespace still apply.
• The drop includes versions that were stored after you were asked to confirm.
• If the asset that produces it is still deployed, its next run creates the artifact again, owned by the run's principal, at version 1. To stop that, remove or change the asset and deploy.
• A table is not dropped with this command. For a table, use the table delete subcommand.
• The server removes the files inside the request, so a very large artifact can take minutes. A reverse proxy in front of the server must allow a request that long, or you see a 504 for a drop that still finishes. Check with the artifact list subcommand before you run it again.

When it fails

Every option is in the reference.