docs: ADR for signatures migration

lms/djangoapps/certificates/docs/decisions/007-transfer-certificate-signatures-from-mongo.rst

@@ -0,0 +1,120 @@
+Transfer certificate signatures to Credentials IDA
+==================================================
+
+Status
+------
+Accepted
+
+Context
+-------
+As a part of `Old Mongo Deprecation`_ work, we are planning to remove the support for c4x assets.
+After removing the support for c4x assets from the ``StaticContentServer`` middleware, 
+the certificate signatures for ``Draft (Old) Mongo`` courses with deprecated IDs will become
+unavailable.
+
+.. _`Old Mongo Deprecation`: https://github.com/openedx/public-engineering/issues/62
+
+Decision
+--------
+We will transfer and store certificate signatures in `Credentials`_ IDA and then use them to render HTML
+certificates for ``Draft (Old) Mongo`` courses that have deprecated IDs.
+
+In order to transfer the signatures for ``Draft (Old) Mongo`` and ``Split Mongo`` courses,
+it is necessary to complete the next tasks.
+
+* Extend credentials API to provide an option for adding and retrieving signatures.
+
+  * ``CourseCertificateViewSet`` API should provide a possibility to optionally update
+    or create signatures for the course certificate.
+
+  * ``CourseCertificateViewSet`` API should provide a list of signatures configured for a course certificate.
+
+* Add a new ``OpenEdxPublicSignal`` that is emitted from Studio whenever certificate-related data is changed
+  (e.g., certificate image upload, course import). The signature image can be exposed as a URL.
+
+* Create a signal receiver function, that will copy the certificate configuration including signatures images
+  to ``CourseCertificate`` model in Credentials using ``CourseCertificateViewSet`` API.
+
+* Add a new management command to copy course certificates configurations,
+  including signatures configuration and assets, from MongoDB to Credentials.
+
+* Update render certificate views to get signatures from Credentials
+  ``CourseCertificateViewSet`` for ``Draft (Old) Mongo`` courses only.
+
+Example of the certificate configuration stored in MongoDB:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.. code-block:: json
+
+  {
+    "certificates": {
+      "certificates": [
+        {
+          "id": 853888039,
+          "name": "Name of the certificate",
+          "description": "Description of the certificate",
+          "is_active": true,
+          "version": 1,
+          "signatories": [
+            {
+              "name": "Name",
+              "title": "Title",
+              "organization": "Organization",
+              "signature_image_path": "/c4x/ooniversity/DJ101/asset/png-transparent-circle-white-circle-white-monochrome-black-thumbnail.png",
+              "certificate": 853888039,
+              "id": 1300534915
+            }
+          ],
+          "course_title": "cert"
+        }
+      ]
+    }
+  }
+
+
+Credentials CourseCertificate model:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+* site
+* is_active
+* signatories
+
+  * Signatory fields:
+
+    * name
+    * title
+    * organization_name_override
+    * image
+
+* title
+* course_id
+* course_run
+* certificate_available_date
+* certificate_type
+* user_credentials
+
+.. _Credentials: https://github.com/openedx/credentials
+
+Consequences
+------------
+* After implementing the new ``OpenEdxPublicSignal`` signal receiver,
+  every time the course or course certificate is updated,
+  certificate configuration including signatures configuration for
+  that course will be saved in ``CourseCertificate`` model in Credentials.
+* During the certificate rendering, the certificate configuration fetched from MongoDB
+  will be merged with signatures configuration retrieved from Credentials. 
+* After transferring course certificates configurations from MongoDB to Credentials,
+  it would be easier to migrate certificates management from edx-platform to Credentials IDA. 
+
+
+Alternatives Considered
+-----------------------
+* `BD-11 Credentials Infrastructure + syncing`_ – suggests migrating course certificates
+  configuration to credentials and migrate course certificates frontend to MFEs.
+
+.. _`BD-11 Credentials Infrastructure + syncing`: https://github.com/openedx/credentials/issues/1734
+
+References
+---------------
+- `Migrate signature assets from MongoDB GridFS to the Credentials IDA <https://github.com/openedx/credentials/issues/1765>`_
+- `[DEPR]: DraftModuleStore (Old Mongo Modulestore) <https://github.com/openedx/public-engineering/issues/62>`_
+- `Remove the ability to read and write static assets to Old Mongo <https://github.com/openedx/public-engineering/issues/77>`_
+