zilencer: Implement do_reactivate_remote_server utility function.

The inverse of do_deactivate_remote_server. It's just flipping the
.deactivated flag, but we also should have an AuditLog for these events.

corporate/lib/stripe.py

@@ -4699,6 +4699,28 @@ def do_change_remote_server_plan_type(remote_server: RemoteZulipServer, plan_typ
     )
 
 
+@transaction.atomic
+def do_reactivate_remote_server(remote_server: RemoteZulipServer) -> None:
+    """
+    Utility function for reactivating deactivated registrations.
+    """
+
+    if not remote_server.deactivated:
+        billing_logger.warning(
+            "Cannot reactivate remote server with ID %d, server is already active.",
+            remote_server.id,
+        )
+        return
+
+    remote_server.deactivated = False
+    remote_server.save(update_fields=["deactivated"])
+    RemoteZulipServerAuditLog.objects.create(
+        event_type=RealmAuditLog.REMOTE_SERVER_REACTIVATED,
+        server=remote_server,
+        event_time=timezone_now(),
+    )
+
+
 @transaction.atomic
 def do_deactivate_remote_server(
     remote_server: RemoteZulipServer, billing_session: RemoteServerBillingSession

corporate/tests/test_stripe.py

@@ -66,6 +66,7 @@ from corporate.lib.stripe import (
     customer_has_last_n_invoices_open,
     do_change_remote_server_plan_type,
     do_deactivate_remote_server,
+    do_reactivate_remote_server,
     downgrade_small_realms_behind_on_payments_as_needed,
     get_latest_seat_count,
     get_plan_renewal_or_end_date,
@@ -4761,7 +4762,7 @@ class BillingHelpersTest(ZulipTestCase):
         self.assertEqual(remote_realm_audit_log.extra_data, expected_extra_data)
         self.assertEqual(remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_BUSINESS)
 
-    def test_deactivate_remote_server(self) -> None:
+    def test_deactivate_reactivate_remote_server(self) -> None:
         server_uuid = str(uuid.uuid4())
         remote_server = RemoteZulipServer.objects.create(
             uuid=server_uuid,
@@ -4792,6 +4793,23 @@ class BillingHelpersTest(ZulipTestCase):
                 ],
             )
 
+        do_reactivate_remote_server(remote_server)
+        remote_server.refresh_from_db()
+        self.assertFalse(remote_server.deactivated)
+        remote_realm_audit_log = RemoteZulipServerAuditLog.objects.latest("id")
+        self.assertEqual(remote_realm_audit_log.event_type, RealmAuditLog.REMOTE_SERVER_REACTIVATED)
+        self.assertEqual(remote_realm_audit_log.server, remote_server)
+
+        with self.assertLogs("corporate.stripe", "WARN") as warning_log:
+            do_reactivate_remote_server(remote_server)
+            self.assertEqual(
+                warning_log.output,
+                [
+                    "WARNING:corporate.stripe:Cannot reactivate remote server with ID "
+                    f"{remote_server.id}, server is already active."
+                ],
+            )
+
 
 class AnalyticsHelpersTest(ZulipTestCase):
     def test_get_realms_to_default_discount_dict(self) -> None:

zerver/models/realm_audit_logs.py

@@ -130,6 +130,7 @@ class AbstractRealmAuditLog(models.Model):
     # value used for the same purpose in RealmAuditLog (e.g.
     # REALM_DEACTIVATED = 201, and REMOTE_SERVER_DEACTIVATED = 10201).
     REMOTE_SERVER_DEACTIVATED = 10201
+    REMOTE_SERVER_REACTIVATED = 10202
     REMOTE_SERVER_PLAN_TYPE_CHANGED = 10204
     REMOTE_SERVER_DISCOUNT_CHANGED = 10209
     REMOTE_SERVER_SPONSORSHIP_APPROVED = 10210