Option to suppress resource exceeded alerting (#6173)

The expected use case is to suppress MAU limiting on small instances

synapse/api/auth.py

@@ -25,7 +25,13 @@ from twisted.internet import defer
 import synapse.logging.opentracing as opentracing
 import synapse.types
 from synapse import event_auth
-from synapse.api.constants import EventTypes, JoinRules, Membership, UserTypes
+from synapse.api.constants import (
+    EventTypes,
+    JoinRules,
+    LimitBlockingTypes,
+    Membership,
+    UserTypes,
+)
 from synapse.api.errors import (
     AuthError,
     Codes,
@@ -726,7 +732,7 @@ class Auth(object):
                 self.hs.config.hs_disabled_message,
                 errcode=Codes.RESOURCE_LIMIT_EXCEEDED,
                 admin_contact=self.hs.config.admin_contact,
-                limit_type=self.hs.config.hs_disabled_limit_type,
+                limit_type=LimitBlockingTypes.HS_DISABLED,
             )
         if self.hs.config.limit_usage_by_mau is True:
             assert not (user_id and threepid)
@@ -759,5 +765,5 @@ class Auth(object):
                     "Monthly Active User Limit Exceeded",
                     admin_contact=self.hs.config.admin_contact,
                     errcode=Codes.RESOURCE_LIMIT_EXCEEDED,
-                    limit_type="monthly_active_user",
+                    limit_type=LimitBlockingTypes.MONTHLY_ACTIVE_USER,
                 )

synapse/api/constants.py

@@ -131,3 +131,10 @@ class RelationTypes(object):
     ANNOTATION = "m.annotation"
     REPLACE = "m.replace"
     REFERENCE = "m.reference"
+
+
+class LimitBlockingTypes(object):
+    """Reasons that a server may be blocked"""
+
+    MONTHLY_ACTIVE_USER = "monthly_active_user"
+    HS_DISABLED = "hs_disabled"