From: Anbang Wen <anbang@cloudflare.com>
Date: Tue, 10 Jul 2018 08:02:59 +0000 (-0700)
Subject: modules/http: run prometheus collector on leader only
X-Git-Tag: v3.2.0~35^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=72e0a76b69dc99196cd98a4cf40c954c5c5a4c01;p=thirdparty%2Fknot-resolver.git

modules/http: run prometheus collector on leader only

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

diff --git a/NEWS b/NEWS
index 0a2e8de5f..5a8dc6b2c 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,11 @@ Module API changes
 - kr_request::qsource.tcp renamed to ::qsource.flags.tcp
 - kr_request::has_tls renamed to ::qsource.flags.tls
 
+Bugfixes
+--------
+- http module: only run prometheus in parent process if using --forks=N,
+  as the submodule collects metrics from all sub-processes as well.
+
 
 Knot Resolver 3.1.0 (2018-11-02)
 ================================
diff --git a/modules/http/http.lua b/modules/http/http.lua
index dabdeba1c..00d4a00e1 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