Add comments to the Prometheus recording rules to make it clear which set of...

Add comments to the Prometheus recording rules to make it clear which set of rules you need for Grafana or Prometheus Console. (#13876)

changelog.d/13876.misc

+Add comments to the Prometheus recording rules to make it clear which set of rules you need for Grafana or Prometheus Console.
\ No newline at end of file

contrib/prometheus/synapse-v2.rules

 groups:
 - name: synapse
   rules:
-  # These 3 rules are used in the included Prometheus console
+
+  ###
+  ### Prometheus Console Only
+  ### The following rules are only needed if you use the Prometheus Console
+  ### in contrib/prometheus/consoles/synapse.html
+  ###
   - record: 'synapse_federation_client_sent'
     labels:
       type: "EDU"
@@ -15,7 +20,6 @@ groups:
       type: "Query"
     expr: 'sum(synapse_federation_client_sent_queries) by (job)'
 
-  # These 3 rules are used in the included Prometheus console
   - record: 'synapse_federation_server_received'
     labels:
       type: "EDU"
@@ -29,7 +33,6 @@ groups:
       type: "Query"
     expr: 'sum(synapse_federation_server_received_queries) by (job)'
 
-  # These 2 rules are used in the included Prometheus console
   - record: 'synapse_federation_transaction_queue_pending'
     labels:
       type: "EDU"
@@ -38,8 +41,16 @@ groups:
     labels:
       type: "PDU"
     expr: 'synapse_federation_transaction_queue_pending_pdus + 0'
+  ###
+  ### End of 'Prometheus Console Only' rules block
+  ###
+
 
-  # These 3 rules are used in the included Grafana dashboard
+  ###
+  ### Grafana Only
+  ### The following rules are only needed if you use the Grafana dashboard
+  ### in contrib/grafana/synapse.json
+  ###
   - record: synapse_storage_events_persisted_by_source_type
     expr: sum without(type, origin_type, origin_entity) (synapse_storage_events_persisted_events_sep_total{origin_type="remote"})
     labels:
@@ -53,11 +64,11 @@ groups:
     labels:
       type: bridges
 
-  # This rule is used in the included Grafana dashboard
   - record: synapse_storage_events_persisted_by_event_type
     expr: sum without(origin_entity, origin_type) (synapse_storage_events_persisted_events_sep_total)
 
-  # This rule is used in the included Grafana dashboard
   - record: synapse_storage_events_persisted_by_origin
     expr: sum without(type) (synapse_storage_events_persisted_events_sep_total)
-
+  ###
+  ### End of 'Grafana Only' rules block
+  ###