Neilj/mau tracking config explainer (#5284)

Improve documentation of monthly active user blocking and mau_trial_days

changelog.d/5284.misc

+Improve sample config for monthly active user blocking. 

docs/sample_config.yaml

@@ -261,6 +261,22 @@ listeners:
 
 # Monthly Active User Blocking
 #
+# Used in cases where the admin or server owner wants to limit to the
+# number of monthly active users.
+#
+# 'limit_usage_by_mau' disables/enables monthly active user blocking. When
+# anabled and a limit is reached the server returns a 'ResourceLimitError'
+# with error type Codes.RESOURCE_LIMIT_EXCEEDED
+#
+# 'max_mau_value' is the hard limit of monthly active users above which
+# the server will start blocking user actions.
+#
+# 'mau_trial_days' is a means to add a grace period for active users. It
+# means that users must be active for this number of days before they
+# can be considered active and guards against the case where lots of users
+# sign up in a short space of time never to return after their initial
+# session.
+#
 #limit_usage_by_mau: False
 #max_mau_value: 50
 #mau_trial_days: 2

synapse/config/server.py

@@ -585,6 +585,22 @@ class ServerConfig(Config):
 
         # Monthly Active User Blocking
         #
+        # Used in cases where the admin or server owner wants to limit to the
+        # number of monthly active users.
+        #
+        # 'limit_usage_by_mau' disables/enables monthly active user blocking. When
+        # anabled and a limit is reached the server returns a 'ResourceLimitError'
+        # with error type Codes.RESOURCE_LIMIT_EXCEEDED
+        #
+        # 'max_mau_value' is the hard limit of monthly active users above which
+        # the server will start blocking user actions.
+        #
+        # 'mau_trial_days' is a means to add a grace period for active users. It
+        # means that users must be active for this number of days before they
+        # can be considered active and guards against the case where lots of users
+        # sign up in a short space of time never to return after their initial
+        # session.
+        #
         #limit_usage_by_mau: False
         #max_mau_value: 50
         #mau_trial_days: 2