realm: Create RealmAuditLog entry for removing a realm domain.

Fixes a part of #21268.

zerver/lib/actions.py

@@ -8157,6 +8157,23 @@ def do_remove_realm_domain(
     realm = realm_domain.realm
     domain = realm_domain.domain
     realm_domain.delete()
+
+    RealmAuditLog.objects.create(
+        realm=realm,
+        acting_user=acting_user,
+        event_type=RealmAuditLog.REALM_DOMAIN_REMOVED,
+        event_time=timezone_now(),
+        extra_data=orjson.dumps(
+            {
+                "realm_domains": get_realm_domains(realm),
+                "removed_domain": {
+                    "domain": realm_domain.domain,
+                    "allow_subdomains": realm_domain.allow_subdomains,
+                },
+            }
+        ).decode(),
+    )
+
     if RealmDomain.objects.filter(realm=realm).count() == 0 and realm.emails_restricted_to_domains:
         # If this was the last realm domain, we mark the realm as no
         # longer restricted to domain, because the feature doesn't do

zerver/models.py

@@ -4064,6 +4064,7 @@ class AbstractRealmAuditLog(models.Model):
     REALM_ORG_TYPE_CHANGED = 217
     REALM_DOMAIN_ADDED = 218
     REALM_DOMAIN_CHANGED = 219
+    REALM_DOMAIN_REMOVED = 220
 
     SUBSCRIPTION_CREATED = 301
     SUBSCRIPTION_ACTIVATED = 302

zerver/tests/test_audit_log.py

@@ -31,6 +31,7 @@ from zerver.lib.actions import (
     do_reactivate_realm,
     do_reactivate_user,
     do_regenerate_api_key,
+    do_remove_realm_domain,
     do_rename_stream,
     do_set_realm_authentication_methods,
     do_set_realm_message_editing,
@@ -707,3 +708,24 @@ class TestRealmAuditLog(ZulipTestCase):
             ).count(),
             1,
         )
+
+        now = timezone_now()
+        do_remove_realm_domain(realm_domain, acting_user=user)
+        removed_domain = {
+            "domain": "zulip.org",
+            "allow_subdomains": True,
+        }
+        expected_extra_data = {
+            "realm_domains": initial_domains,
+            "removed_domain": removed_domain,
+        }
+        self.assertEqual(
+            RealmAuditLog.objects.filter(
+                realm=user.realm,
+                event_type=RealmAuditLog.REALM_DOMAIN_REMOVED,
+                event_time__gte=now,
+                acting_user=user,
+                extra_data=orjson.dumps(expected_extra_data).decode(),
+            ).count(),
+            1,
+        )