From: Ben Kochie <bjk@gitlab.com>
Date: Mon, 30 Oct 2017 15:51:58 +0000 (+0100)
Subject: Wrap DNS lookup metric time defer
X-Git-Url: https://vcs.fsf.org/?a=commitdiff_plain;h=3612bba5d5200f80da0516e039703e357ba837b0;p=blackbox_exporter.git

Wrap DNS lookup metric time defer

Wrap the DNS lookup time `defer` in an anonymous function to avoid
arguments being evaluated early.

Closes: https://github.com/prometheus/blackbox_exporter/issues/253
---

diff --git a/prober/utils.go b/prober/utils.go
index 42a93ba..524341d 100644
--- a/prober/utils.go
+++ b/prober/utils.go
@@ -43,7 +43,9 @@ func chooseProtocol(preferredIPProtocol string, target string, registry *prometh
 	level.Info(logger).Log("msg", "Resolving target address", "preferred_ip_protocol", preferredIPProtocol)
 	resolveStart := time.Now()
 
-	defer probeDNSLookupTimeSeconds.Add(time.Since(resolveStart).Seconds())
+	defer func() {
+		probeDNSLookupTimeSeconds.Add(time.Since(resolveStart).Seconds())
+	}()
 
 	ip, err := net.ResolveIPAddr(preferredIPProtocol, target)
 	if err != nil {