Use cases#

The general idea is that a deposit can be created either in a single request or by multiple requests to allow the user to add elements to the deposit piece by piece (be it the deposited data or the metadata describing it).

An update request that does not have the In-Progress: true HTTP header will de facto declare the deposit as completed (aka in the deposited status; see below) and thus ready for ingestion.

Once the deposit is declared complete by the user, the server performs a few validation checks. Then, if valid, schedule the ingestion of the deposited data in the Software Heritage Archive (SWH).

There is a status property attached to a deposit allowing to follow the processing workflow of the deposit. For example, when this ingestion task completes successfully, the deposit is marked as done.

Possible deposit statuses are:

partial: The deposit is partially received, since it can be done in multiple requests.
expired: Deposit was there too long and is new deemed ready to be garbage-collected.
deposited: Deposit is complete, ready to be checked.
rejected: Deposit failed the checks.
verified: Deposit passed the checks and is ready for loading.
loading: Injection is ongoing on SWH’s side.
done: Loading is successful.
failed: Loading failed.

This document describes the possible scenarios for creating or updating a deposit.

Deposit creation#

From client’s deposit repository server to SWH’s repository server:

The client requests for the server’s abilities and its associated collections using the SD/service document uri (GET /1/servicedocument/).
The server answers the client with the service document which lists the collections linked to the user account (most of the time, there will one and only one collection linked to the user’s account). Each of these collection can be used to push a deposit via its COL/collection IRI.
The client sends a deposit (a zip archive, some metadata or both) through the COL/collection uri.

This can be done in:
- one POST request (metadata + archive) without the In-Progress: true header:
  - POST /1/(str:collection-name)/
- one POST request (metadata or archive) with In-Progress: true header:
  - POST /1/(str:collection-name)/
  plus one or more PUT or POST requests to the update uris (edit-media iri or edit iri):
Then:
1. Server validates the client’s input or returns detailed error if any.
2. Server stores information received (metadata or software archive source code or both).
The server creates a loading task and submits it to the Job Scheduler
The server notifies the client it acknowledged the client’s request. An http 201 Created response with a deposit receipt in the body response is sent back. That deposit receipt will hold the necessary information to eventually complete the deposit later on if it was incomplete (also known as status partial).

Schema representation#

Scenario: pushing a deposit via the SWORDv2 protocol (nominal scenario):

Deposit update#

Client updates existing deposit through the update uris (one or more POST or PUT requests to either the edit-media iri or edit iri).

Server validates the client’s input or returns detailed error if any

Server stores information received (metadata or software archive source code or both)

This would be the case for example if the client initially posted a partial deposit (e.g. only metadata with no archive, or an archive without metadata, or a split archive because the initial one exceeded the limit size imposed by swh repository deposit).

The content of a deposit can only be updated while it is in the partial state; this causes the content to be replaced (the old version is discarded).

Its metadata, however, can also be updated while in the done state; see below.

Schema representation#

Scenario: updating a deposit via SWORDv2 protocol:

Deposit deletion (or associated archive, or associated metadata)#

Deposit deletion is possible as long as the deposit is still in partial state.

Server validates the client’s input or returns detailed error if any

Server actually delete information according to request

Schema representation#

Scenario: deleting a deposit via SWORDv2 protocol:

Client asks for operation status#

At any time during the next step, operation status can be read through a GET query to the state iri.

Deposit loading#

In one of the previous steps, when a deposit was created or loaded without In-Progress: true, the deposit server created a load task and submitted it to swh-scheduler.

This triggers the following steps:

Server: Triggering deposit checks#

Once the status deposited is reached for a deposit, checks for the associated archive(s) and metadata will be triggered. If those checks fail, the status is changed to rejected and nothing more happens there. Otherwise, the status is changed to verified.

Server: Triggering deposit load#

Once the status verified is reached for a deposit, loading the deposit with its associated metadata will be triggered.

The loading will result on status update, either done or failed (depending on the loading’s status).

This is described in the loading specifications document.

Completing the deposit#

When this is all done, the loaders notify the deposit server, which sets the deposit status to done.

This can then be polled by deposit clients, using the state iri.

Deposit metadata updates#

We saw earlier that a deposit can only be updated when in partial state.

This is one exception to this rule: its metadata can be updated while in the done state; which adds a new version of the metadata in the SWH archive, in addition to the old one(s). In this state, In-Progress is not allowed, so the deposit cannot go back in the partial state, but only to deposited. As a failsafe, to avoid accidentally updating the wrong deposit, this requires the X-Check-SWHID HTTP header to be set to the value of the SWHID of the deposit’s content (returned after the deposit finished loading).

Metadata-only deposit#

Finally, as an extension to the SWORD protocol, swh-deposit allows a special type of deposit: metadata-only deposits. Unlike regular deposit (described above), they do not have a code archive. Instead, they describe an existing software artifact present in the archive.

This use case is triggered by a <reference> tag in the Atom document, see the protocol reference for details.

In the current implementation, these deposits are loaded (or rejected) immediately after a request without In-Progress: true is made, ie. they skip the loading state. This may change in a future version.