From: Anbang Wen <anbang@cloudflare.com>
Date: Tue, 10 Jul 2018 08:02:59 +0000 (-0700)
Subject: http: run prometheus metrics collector on leader only
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a058a4159596eaee3ef6529103f72fd4995490c7;p=thirdparty%2Fknot-resolver.git

http: run prometheus metrics collector on leader only

Metrics are collected and merged in http.prometheus, no need to be run
on every worker.
---

diff --git a/modules/http/http.lua b/modules/http/http.lua
index e4baf8fdd..a81935997 100644
--- a/modules/http/http.lua
+++ b/modules/http/http.lua
@@ -366,7 +366,10 @@ end
 
 -- @function Init module
 function M.init()
-	worker.coroutine(prometheus.init)
+	-- collect and merge metrics only on leader
+	if worker.id == 0 then
+		worker.coroutine(prometheus.init)
+	end
 end
 
 -- @function Cleanup module