Re-purpose RemoteArtifact.pulp_last_updated to read a failed_at

A fix was introduced in pulpcore==3.69 which relied on a new DateTimeField
called 'failed_at'.
Do enable backporting that, this commits removes the migration and, as
a workaround, re-purpose a compatible field (pulp_last_updated) to serve
the same purpose.

Co-authored-by: Matthias Dellweg <[email protected]>

pulpcore/app/models/content.py

@@ -703,7 +703,9 @@ class RemoteArtifact(BaseModel, QueryMixin):
         sha256 (models.CharField): The expected SHA-256 checksum of the file.
         sha384 (models.CharField): The expected SHA-384 checksum of the file.
         sha512 (models.CharField): The expected SHA-512 checksum of the file.
-        failed_at (models.DateTimeField): The datetime of last download attempt failure.
+        pulp_last_updated (models.DateTimeField):
+            Re-purposed this field to enable a backport that contained a migration.
+            See https://github.com/pulp/pulpcore/pull/6196
 
     Relations:
 
@@ -722,7 +724,6 @@ class RemoteArtifact(BaseModel, QueryMixin):
     sha256 = models.CharField(max_length=64, null=True, db_index=True)
     sha384 = models.CharField(max_length=96, null=True, db_index=True)
     sha512 = models.CharField(max_length=128, null=True, db_index=True)
-    failed_at = models.DateTimeField(null=True)
 
     content_artifact = models.ForeignKey(ContentArtifact, on_delete=models.CASCADE)
     remote = models.ForeignKey("Remote", on_delete=models.CASCADE)

pulpcore/content/handler.py

@@ -852,11 +852,10 @@ async def _stream_content_artifact(self, request, response, content_artifact):
             ClientConnectionError,
         )
 
-        protection_time = settings.REMOTE_CONTENT_FETCH_FAILURE_COOLDOWN
         remote_artifacts = (
             content_artifact.remoteartifact_set.select_related("remote")
             .order_by_acs()
-            .exclude(failed_at__gte=timezone.now() - timedelta(seconds=protection_time))
+            .exclude(pulp_last_updated__gte=timezone.now())
         )
         async for remote_artifact in remote_artifacts:
             try:
@@ -1166,8 +1165,12 @@ async def finalize():
         try:
             download_result = await downloader.run()
         except DigestValidationError:
-            remote_artifact.failed_at = timezone.now()
-            await remote_artifact.asave()
+            # Using this otherwise unused dbfield is a workaround to allow this fix to be
+            # backported. Read "failed_at" instead.
+            await RemoteArtifact.objects.filter(pulp_id=remote_artifact.pulp_id).aupdate(
+                pulp_last_updated=timezone.now()
+                + timedelta(settings.REMOTE_CONTENT_FETCH_FAILURE_COOLDOWN)
+            )
             await downloader.session.close()
             close_tcp_connection(request.transport._sock)
             REMOTE_CONTENT_FETCH_FAILURE_COOLDOWN = settings.REMOTE_CONTENT_FETCH_FAILURE_COOLDOWN