From 9b8f8a6c8371c53b795eedefa22bb1ab9034d0f0 Mon Sep 17 00:00:00 2001
From: Tom Wilkie <tom@weave.works>
Date: Thu, 5 May 2016 12:07:57 +0100
Subject: [PATCH] Have probe query kube dns to find the app.

---
 probe/appclient/resolver.go | 1 +
 prog/main.go                | 2 ++
 prog/probe.go               | 6 +++++-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/probe/appclient/resolver.go b/probe/appclient/resolver.go
index 265428384..97037d783 100644
--- a/probe/appclient/resolver.go
+++ b/probe/appclient/resolver.go
@@ -137,6 +137,7 @@ func (r staticResolver) resolveOne(t target) []string {
 		var err error
 		addrs, err = r.lookup(t.host)
 		if err != nil {
+			log.Debugf("Error resolving %s: %v", t.host, err)
 			return []string{}
 		}
 	}
diff --git a/prog/main.go b/prog/main.go
index d3c9d154a..0f701109b 100644
--- a/prog/main.go
+++ b/prog/main.go
@@ -67,6 +67,7 @@ type probeFlags struct {
 	insecure        bool
 	logPrefix       string
 	logLevel        string
+	resolver        string
 
 	dockerEnabled  bool
 	dockerInterval time.Duration
@@ -132,6 +133,7 @@ func main() {
 	flag.StringVar(&flags.probe.pluginsRoot, "probe.plugins.root", "/var/run/scope/plugins", "Root directory to search for plugins")
 	flag.BoolVar(&flags.probe.useConntrack, "probe.conntrack", true, "also use conntrack to track connections")
 	flag.BoolVar(&flags.probe.insecure, "probe.insecure", false, "(SSL) explicitly allow \"insecure\" SSL connections and transfers")
+	flag.StringVar(&flags.probe.resolver, "probe.resolver", "", "IP address & port of resolver to use.  Default is to use system resolver.")
 	flag.StringVar(&flags.probe.logPrefix, "probe.log.prefix", "<probe>", "prefix for each log line")
 	flag.StringVar(&flags.probe.logLevel, "probe.log.level", "info", "logging threshold level: debug|info|warn|error|fatal|panic")
 	flag.BoolVar(&flags.probe.dockerEnabled, "probe.docker", false, "collect Docker-related attributes for processes")
diff --git a/prog/probe.go b/prog/probe.go
index 075255f97..2295175c9 100644
--- a/prog/probe.go
+++ b/prog/probe.go
@@ -113,7 +113,11 @@ func probeMain(flags probeFlags) {
 	})
 	defer clients.Stop()
 
-	resolver := appclient.NewResolver(targets, net.LookupIP, clients.Set)
+	dnsLookupFn := net.LookupIP
+	if flags.resolver != "" {
+		dnsLookupFn = appclient.LookupUsing(flags.resolver)
+	}
+	resolver := appclient.NewResolver(targets, dnsLookupFn, clients.Set)
 	defer resolver.Stop()
 
 	processCache := process.NewCachingWalker(process.NewWalker(flags.procRoot))