From 1a12766e3bfe76681af9ef88cbb6fbf22bb50500 Mon Sep 17 00:00:00 2001
From: Mark Haines <mark.haines@matrix.org>
Date: Thu, 28 Apr 2016 12:31:26 +0100
Subject: [PATCH] Add a comment explaining why automatic metric reporting is
 disabled for JsonResource

---
 synapse/http/server.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/synapse/http/server.py b/synapse/http/server.py
index 2c131a701..29241fa14 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -214,6 +214,10 @@ class JsonResource(HttpServer, resource.Resource):
         self._async_render(request)
         return server.NOT_DONE_YET
 
+    # Disable metric reporting because _async_render does its own metrics.
+    # It does its own metric reporting because _async_render dispatches to
+    # a callback and it's the class name of that callback we want to report
+    # against rather than the JsonResource itself.
     @request_handler(report_metrics=False)
     @defer.inlineCallbacks
     def _async_render(self, request):