From 2060a0a15b93fd2cb7e44d03edb4f0e0a6a0529f Mon Sep 17 00:00:00 2001
From: Fabian Reinartz <fab.reinartz@gmail.com>
Date: Sun, 28 Feb 2016 20:03:44 +0100
Subject: [PATCH] Turn target group members into plain lists.

As the scrape pool deduplicates targets now, it is no longer necessary
to store a hash map for members of each group.
---
 retrieval/targetmanager.go | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/retrieval/targetmanager.go b/retrieval/targetmanager.go
index 5e590e44a..6daa708fc 100644
--- a/retrieval/targetmanager.go
+++ b/retrieval/targetmanager.go
@@ -176,7 +176,7 @@ type targetSet struct {
 	mtx sync.RWMutex
 
 	// Sets of targets by a source string that is unique across target providers.
-	tgroups   map[string]map[uint64]*Target
+	tgroups   map[string][]*Target
 	providers map[string]TargetProvider
 
 	scrapePool *scrapePool
@@ -189,7 +189,7 @@ type targetSet struct {
 
 func newTargetSet(cfg *config.ScrapeConfig, app storage.SampleAppender) *targetSet {
 	ts := &targetSet{
-		tgroups:    map[string]map[uint64]*Target{},
+		tgroups:    map[string][]*Target{},
 		scrapePool: newScrapePool(cfg, app),
 		syncCh:     make(chan struct{}, 1),
 		config:     cfg,
@@ -247,13 +247,11 @@ Loop:
 }
 
 func (ts *targetSet) sync() {
-	targets := []*Target{}
-	for _, tgroup := range ts.tgroups {
-		for _, t := range tgroup {
-			targets = append(targets, t)
-		}
+	var all []*Target
+	for _, targets := range ts.tgroups {
+		all = append(all, targets...)
 	}
-	ts.scrapePool.sync(targets)
+	ts.scrapePool.sync(all)
 }
 
 func (ts *targetSet) runProviders(ctx context.Context, providers map[string]TargetProvider) {
@@ -394,8 +392,8 @@ func providersFromConfig(cfg *config.ScrapeConfig) map[string]TargetProvider {
 }
 
 // targetsFromGroup builds targets based on the given TargetGroup and config.
-func targetsFromGroup(tg *config.TargetGroup, cfg *config.ScrapeConfig) (map[uint64]*Target, error) {
-	targets := make(map[uint64]*Target, len(tg.Targets))
+func targetsFromGroup(tg *config.TargetGroup, cfg *config.ScrapeConfig) ([]*Target, error) {
+	targets := make([]*Target, 0, len(tg.Targets))
 
 	for i, labels := range tg.Targets {
 		for k, v := range cfg.Params {
@@ -464,8 +462,7 @@ func targetsFromGroup(tg *config.TargetGroup, cfg *config.ScrapeConfig) (map[uin
 			labels[model.InstanceLabel] = labels[model.AddressLabel]
 		}
 
-		tr := NewTarget(labels, preRelabelLabels, cfg.Params)
-		targets[tr.hash()] = tr
+		targets = append(targets, NewTarget(labels, preRelabelLabels, cfg.Params))
 	}
 
 	return targets, nil