From 427bf29db129056a2000f765f1adabb39695229d Mon Sep 17 00:00:00 2001
From: Brian Brazil <brian.brazil@robustperception.io>
Date: Sun, 8 Nov 2015 11:42:18 +0000
Subject: [PATCH] Add in default port after relabelling.

For the SNMP and blackbox exporters where
the ports tends to not be 80/443 and indeed
there may not be a port this makes the relabelling
a bit simpler as you don't have to figure out this
logic exists and strip off the :80.

This is a breaking change for the example configs of
those exporters.
---
 retrieval/targetmanager.go      | 26 +++++++++++++-------------
 retrieval/targetmanager_test.go |  9 ++++++++-
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/retrieval/targetmanager.go b/retrieval/targetmanager.go
index fb9858913..d021a40c8 100644
--- a/retrieval/targetmanager.go
+++ b/retrieval/targetmanager.go
@@ -446,19 +446,6 @@ func (tm *TargetManager) targetsFromGroup(tg *config.TargetGroup, cfg *config.Sc
 
 	targets := make([]*Target, 0, len(tg.Targets))
 	for i, labels := range tg.Targets {
-		addr := string(labels[model.AddressLabel])
-		// If no port was provided, infer it based on the used scheme.
-		if !strings.Contains(addr, ":") {
-			switch cfg.Scheme {
-			case "http":
-				addr = fmt.Sprintf("%s:80", addr)
-			case "https":
-				addr = fmt.Sprintf("%s:443", addr)
-			default:
-				panic(fmt.Errorf("targetsFromGroup: invalid scheme %q", cfg.Scheme))
-			}
-			labels[model.AddressLabel] = model.LabelValue(addr)
-		}
 		for k, v := range cfg.Params {
 			if len(v) > 0 {
 				labels[model.LabelName(model.ParamLabelPrefix+k)] = model.LabelValue(v[0])
@@ -496,6 +483,19 @@ func (tm *TargetManager) targetsFromGroup(tg *config.TargetGroup, cfg *config.Sc
 		if labels == nil {
 			continue
 		}
+		// If no port was provided, infer it based on the used scheme.
+		addr := string(labels[model.AddressLabel])
+		if !strings.Contains(addr, ":") {
+			switch labels[model.SchemeLabel] {
+			case "http", "":
+				addr = fmt.Sprintf("%s:80", addr)
+			case "https":
+				addr = fmt.Sprintf("%s:443", addr)
+			default:
+				panic(fmt.Errorf("targetsFromGroup: invalid scheme %q", cfg.Scheme))
+			}
+			labels[model.AddressLabel] = model.LabelValue(addr)
+		}
 		if err = config.CheckTargetAddress(labels[model.AddressLabel]); err != nil {
 			return nil, err
 		}
diff --git a/retrieval/targetmanager_test.go b/retrieval/targetmanager_test.go
index 654083d3e..85abdd31e 100644
--- a/retrieval/targetmanager_test.go
+++ b/retrieval/targetmanager_test.go
@@ -211,7 +211,7 @@ func TestTargetManagerConfigUpdate(t *testing.T) {
 		TargetGroups: []*config.TargetGroup{{
 			Targets: []model.LabelSet{
 				{model.AddressLabel: "example.org:80"},
-				{model.AddressLabel: "example.com:80"},
+				{model.AddressLabel: "example.com"},
 			},
 		}},
 		RelabelConfigs: []*config.RelabelConfig{
@@ -223,6 +223,13 @@ func TestTargetManagerConfigUpdate(t *testing.T) {
 				Replacement:  "$1",
 				Action:       config.RelabelReplace,
 			},
+			{
+				// The port number is added after relabeling, so
+				// this relabel rule should have no effect.
+				SourceLabels: model.LabelNames{model.AddressLabel},
+				Regex:        config.MustNewRegexp("example.com:80"),
+				Action:       config.RelabelDrop,
+			},
 		},
 	}
 	testJob2 := &config.ScrapeConfig{