From 8fa9ec278be58bf1f9ae7a5128f85a248d9d6361 Mon Sep 17 00:00:00 2001
From: Fabian Reinartz <fab.reinartz@gmail.com>
Date: Fri, 14 Aug 2015 14:24:31 +0200
Subject: [PATCH] Add application labels as meta labels

Removes built-in conditional scraping based on application's
'prometheus' label.
---
 retrieval/discovery/marathon/constants.go  | 15 ++++---
 retrieval/discovery/marathon/conversion.go | 50 +++++++---------------
 retrieval/discovery/marathon_test.go       | 34 ---------------
 3 files changed, 25 insertions(+), 74 deletions(-)

diff --git a/retrieval/discovery/marathon/constants.go b/retrieval/discovery/marathon/constants.go
index 7b761a660..41764cc3f 100644
--- a/retrieval/discovery/marathon/constants.go
+++ b/retrieval/discovery/marathon/constants.go
@@ -1,16 +1,19 @@
 package marathon
 
 import (
-	"github.com/prometheus/client_golang/model"
+	clientmodel "github.com/prometheus/client_golang/model"
 )
 
 const (
+	// metaLabelPrefix is the meta prefix used for all meta labels in this discovery.
+	metaLabelPrefix = clientmodel.MetaLabelPrefix + "marathon_"
+	// appLabelPrefix is the prefix for the application labels.
+	appLabelPrefix = metaLabelPrefix + "app_label_"
+
 	// AppLabel is used for the name of the app in Marathon.
-	AppLabel model.LabelName = "__meta_marathon_app"
-
+	appLabel clientmodel.LabelName = metaLabelPrefix + "app"
 	// ImageLabel is the label that is used for the docker image running the service.
-	ImageLabel model.LabelName = "__meta_marathon_image"
-
+	imageLabel clientmodel.LabelName = metaLabelPrefix + "image"
 	// TaskLabel contains the mesos task name of the app instance.
-	TaskLabel model.LabelName = "__meta_marathon_task"
+	taskLabel clientmodel.LabelName = metaLabelPrefix + "task"
 )
diff --git a/retrieval/discovery/marathon/conversion.go b/retrieval/discovery/marathon/conversion.go
index c6405e2f7..4acf499b9 100644
--- a/retrieval/discovery/marathon/conversion.go
+++ b/retrieval/discovery/marathon/conversion.go
@@ -2,7 +2,6 @@ package marathon
 
 import (
 	"fmt"
-	"strings"
 
 	clientmodel "github.com/prometheus/client_golang/model"
 
@@ -13,10 +12,8 @@ import (
 func AppsToTargetGroups(apps *AppList) map[string]*config.TargetGroup {
 	tgroups := map[string]*config.TargetGroup{}
 	for _, a := range apps.Apps {
-		if isValidApp(&a) {
-			group := createTargetGroup(&a)
-			tgroups[group.Source] = group
-		}
+		group := createTargetGroup(&a)
+		tgroups[group.Source] = group
 	}
 	return tgroups
 }
@@ -24,18 +21,24 @@ func AppsToTargetGroups(apps *AppList) map[string]*config.TargetGroup {
 func createTargetGroup(app *App) *config.TargetGroup {
 	var (
 		targets = targetsForApp(app)
-		source  = targetGroupName(app)
-		appName = clientmodel.LabelValue(sanitizeName(app.ID))
-		image   = clientmodel.LabelValue(imageName(app))
+		appName = clientmodel.LabelValue(app.ID)
+		image   = clientmodel.LabelValue(app.Container.Docker.Image)
 	)
-	return &config.TargetGroup{
+	tg := &config.TargetGroup{
 		Targets: targets,
 		Labels: clientmodel.LabelSet{
-			AppLabel:   appName,
-			ImageLabel: image,
+			appLabel:   appName,
+			imageLabel: image,
 		},
-		Source: source,
+		Source: app.ID,
 	}
+
+	for ln, lv := range app.Labels {
+		ln = appLabelPrefix + ln
+		tg.Labels[clientmodel.LabelName(ln)] = clientmodel.LabelValue(lv)
+	}
+
+	return tg
 }
 
 func targetsForApp(app *App) []clientmodel.LabelSet {
@@ -44,33 +47,12 @@ func targetsForApp(app *App) []clientmodel.LabelSet {
 		target := targetForTask(&t)
 		targets = append(targets, clientmodel.LabelSet{
 			clientmodel.AddressLabel: clientmodel.LabelValue(target),
-			TaskLabel:                clientmodel.LabelValue(sanitizeName(t.ID)),
+			taskLabel:                clientmodel.LabelValue(t.ID),
 		})
 	}
 	return targets
 }
 
-func imageName(app *App) string {
-	return app.Container.Docker.Image
-}
-
 func targetForTask(task *Task) string {
 	return fmt.Sprintf("%s:%d", task.Host, task.Ports[0])
 }
-
-func isValidApp(app *App) bool {
-	if app.RunningTasks > 0 {
-		_, ok := app.Labels["prometheus"]
-		return ok
-	}
-	return false
-}
-
-func targetGroupName(app *App) string {
-	return sanitizeName(app.ID)
-}
-
-func sanitizeName(id string) string {
-	trimID := strings.TrimLeft(id, " -/.")
-	return strings.Replace(trimID, "/", "-", -1)
-}
diff --git a/retrieval/discovery/marathon_test.go b/retrieval/discovery/marathon_test.go
index fcf11562c..7a1bbf9b1 100644
--- a/retrieval/discovery/marathon_test.go
+++ b/retrieval/discovery/marathon_test.go
@@ -104,40 +104,6 @@ func TestMarathonSDSendGroup(t *testing.T) {
 	}
 }
 
-func TestMarathonSDNoLabel(t *testing.T) {
-	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
-		return marathonTestAppList(map[string]string{}, 1), nil
-	})
-	go func() {
-		select {
-		case tg := <-ch:
-			t.Fatalf("Got group: %s", tg)
-		default:
-		}
-	}()
-	err := md.updateServices(ch)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-}
-
-func TestMarathonSDNotRunning(t *testing.T) {
-	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
-		return marathonTestAppList(marathonValidLabel, 0), nil
-	})
-	go func() {
-		select {
-		case tg := <-ch:
-			t.Fatalf("Got group: %s", tg)
-		default:
-		}
-	}()
-	err := md.updateServices(ch)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-}
-
 func TestMarathonSDRemoveApp(t *testing.T) {
 	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
 		return marathonTestAppList(marathonValidLabel, 1), nil