use poolKey as the pool map key to avoid multi dimensional maps

discovery/manager.go

@@ -52,10 +52,18 @@ type Discoverer interface {
 	Run(ctx context.Context, up chan<- []*config.TargetGroup)
 }
-// type pool struct {
-// 	cancel func()
-// 	tgroups []*config.TargetGroup
-// }
+type poolKey struct {
+	set      string
+	provider string
+}
+
+// byProvider implements sort.Interface for []poolKey based on the provider field.
+// Sorting is needed so that we can have predictable tests.
+type byProvider []poolKey
+
+func (a byProvider) Len() int           { return len(a) }
+func (a byProvider) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a byProvider) Less(i, j int) bool { return a[i].provider < a[j].provider }
 // NewManager is the Discovery Manager constructor
 func NewManager(logger log.Logger) *Manager {
@@ -63,20 +71,19 @@ func NewManager(logger log.Logger) *Manager {
 		logger:         logger,
 		actionCh:       make(chan func(context.Context)),
 		syncCh:         make(chan map[string][]*config.TargetGroup),
-		targets:        make(map[string]map[string][]*config.TargetGroup),
+		targets:        make(map[poolKey][]*config.TargetGroup),
 		discoverCancel: []context.CancelFunc{},
 	}
 }
 // Manager maintains a set of discovery providers and sends each update to a channel used by other packages.
-// The sync channels sends the updates in map[targetSetName] where targetSetName is the job value from the scrape config.
-// Targets pool is kept in a map with a format map[targetSetName]map[providerName].
 type Manager struct {
 	logger         log.Logger
-	syncCh         chan map[string][]*config.TargetGroup
 	actionCh       chan func(context.Context)
 	discoverCancel []context.CancelFunc
-	targets        map[string]map[string][]*config.TargetGroup
+	targets        map[poolKey][]*config.TargetGroup
+	// The sync channels sends the updates in map[targetSetName] where targetSetName is the job value from the scrape config.
+	syncCh chan map[string][]*config.TargetGroup
 }
 // Run starts the background processing
@@ -104,7 +111,7 @@ func (m *Manager) ApplyConfig(cfg *config.Config) error {
 		m.cancelDiscoverers()
 		for _, scfg := range cfg.ScrapeConfigs {
 			for provName, prov := range m.providersFromConfig(scfg.ServiceDiscoveryConfig) {
-				m.startProvider(ctx, scfg.JobName, provName, prov)
+				m.startProvider(ctx, poolKey{set: scfg.JobName, provider: provName}, prov)
 			}
 		}
 		close(err)
@@ -113,17 +120,17 @@ func (m *Manager) ApplyConfig(cfg *config.Config) error {
 	return <-err
 }
-func (m *Manager) startProvider(ctx context.Context, jobName, provName string, worker Discoverer) {
+func (m *Manager) startProvider(ctx context.Context, poolKey poolKey, worker Discoverer) {
 	ctx, cancel := context.WithCancel(ctx)
 	updates := make(chan []*config.TargetGroup)
 	m.discoverCancel = append(m.discoverCancel, cancel)
 	go worker.Run(ctx, updates)
-	go m.runProvider(ctx, provName, jobName, updates)
+	go m.runProvider(ctx, poolKey, updates)
 }
-func (m *Manager) runProvider(ctx context.Context, provName, jobName string, updates chan []*config.TargetGroup) {
+func (m *Manager) runProvider(ctx context.Context, poolKey poolKey, updates chan []*config.TargetGroup) {
 	for {
 		select {
 		case <-ctx.Done():
@@ -134,8 +141,8 @@ func (m *Manager) runProvider(ctx context.Context, provName, jobName string, upd
 			if !ok {
 				return
 			}
-			m.addGroup(jobName, provName, tgs)
-			m.syncCh <- m.allGroups(jobName)
+			m.addGroup(poolKey, tgs)
+			m.syncCh <- m.allGroups(poolKey)
 		}
 	}
 }
@@ -144,20 +151,16 @@ func (m *Manager) cancelDiscoverers() {
 	for _, c := range m.discoverCancel {
 		c()
 	}
-	m.targets = make(map[string]map[string][]*config.TargetGroup)
+	m.targets = make(map[poolKey][]*config.TargetGroup)
 	m.discoverCancel = nil
 }
-func (m *Manager) addGroup(tsName, provName string, tg []*config.TargetGroup) {
+func (m *Manager) addGroup(poolKey poolKey, tg []*config.TargetGroup) {
 	done := make(chan struct{})
 	m.actionCh <- func(ctx context.Context) {
-		if m.targets[tsName] == nil {
-			m.targets[tsName] = make(map[string][]*config.TargetGroup)
-		}
-
 		if tg != nil {
-			m.targets[tsName][provName] = tg
+			m.targets[poolKey] = tg
 		}
 		close(done)
@@ -165,31 +168,29 @@ func (m *Manager) addGroup(tsName, provName string, tg []*config.TargetGroup) {
 	<-done
 }
-func (m *Manager) allGroups(tsName string) map[string][]*config.TargetGroup {
-	tset := make(chan map[string][]*config.TargetGroup)
+func (m *Manager) allGroups(pk poolKey) map[string][]*config.TargetGroup {
+	tSets := make(chan map[string][]*config.TargetGroup)
 	m.actionCh <- func(ctx context.Context) {
-		tgAll := []*config.TargetGroup{}
-		// Sorting the providers is needed so that we can have predictable tests.
-		// Maps cannot be sorted so need to extract the keys to a slice and sort the string slice.
-		var providerNames []string
-		for providerName := range m.targets[tsName] {
-			providerNames = append(providerNames, providerName)
+		// Sorting by the poolKey is needed so that we can have predictable tests.
+		var pKeys []poolKey
+		for pk := range m.targets {
+			pKeys = append(pKeys, pk)
 		}
-		sort.Strings(providerNames)
-		for _, prov := range providerNames {
-			for _, tg := range m.targets[tsName][prov] {
+		sort.Sort(byProvider(pKeys))
+
+		tSetsAll := map[string][]*config.TargetGroup{}
+		for _, pk := range pKeys {
+			for _, tg := range m.targets[pk] {
 				if tg.Source != "" { // Don't add empty targets.
-					tgAll = append(tgAll, tg)
+					tSetsAll[pk.set] = append(tSetsAll[pk.set], tg)
 				}
 			}
 		}
-		t := make(map[string][]*config.TargetGroup)
-		t[tsName] = tgAll
-		tset <- t
+		tSets <- tSetsAll
 	}
-	return <-tset
+	return <-tSets
 }

discovery/manager_test.go

@@ -590,7 +590,7 @@ func TestDiscoveryManagerSyncCalls(t *testing.T) {
 		var totalUpdatesCount int
 		for tpName, update := range testCase.updates {
 			provider := newMockDiscoveryProvider(update)
-			discoveryManager.startProvider(ctx, strconv.Itoa(testIndex), tpName, provider)
+			discoveryManager.startProvider(ctx, poolKey{set: strconv.Itoa(testIndex), provider: tpName}, provider)
 			if len(update) > 0 {
 				totalUpdatesCount = totalUpdatesCount + len(update)
@@ -627,19 +627,15 @@ func TestDiscoveryManagerSyncCalls(t *testing.T) {
 }
 func TestTargetSetRecreatesTargetGroupsEveryRun(t *testing.T) {
-	verifyPresence := func(tSets map[string]map[string][]*config.TargetGroup, tSetName string, provName, label string, present bool) {
-		if _, ok := tSets[tSetName]; !ok {
-			t.Fatalf("'%s' should be present in TargetSets: %v", tSetName, tSets)
-			return
-		}
-		if _, ok := tSets[tSetName][provName]; !ok {
-			t.Fatalf("'%s' should be present in Discovery providers: %v", provName, tSets[tSetName])
+	verifyPresence := func(tSets map[poolKey][]*config.TargetGroup, poolKey poolKey, label string, present bool) {
+		if _, ok := tSets[poolKey]; !ok {
+			t.Fatalf("'%s' should be present in Pool keys: %v", poolKey, tSets)
 			return
 		}
 		match := false
 		var mergedTargets string
-		for _, targetGroup := range tSets[tSetName][provName] {
+		for _, targetGroup := range tSets[poolKey] {
 			for _, l := range targetGroup.Targets {
 				mergedTargets = mergedTargets + " " + l.String()
@@ -678,8 +674,8 @@ scrape_configs:
 	discoveryManager.ApplyConfig(cfg)
 	_ = <-discoveryManager.SyncCh()
-	verifyPresence(discoveryManager.targets, "prometheus", "static/0", "{__address__=\"foo:9090\"}", true)
-	verifyPresence(discoveryManager.targets, "prometheus", "static/0", "{__address__=\"bar:9090\"}", true)
+	verifyPresence(discoveryManager.targets, poolKey{set: "prometheus", provider: "static/0"}, "{__address__=\"foo:9090\"}", true)
+	verifyPresence(discoveryManager.targets, poolKey{set: "prometheus", provider: "static/0"}, "{__address__=\"bar:9090\"}", true)
 	sTwo := `
 scrape_configs:
@@ -693,8 +689,8 @@ scrape_configs:
 	discoveryManager.ApplyConfig(cfg)
 	_ = <-discoveryManager.SyncCh()
-	verifyPresence(discoveryManager.targets, "prometheus", "static/0", "{__address__=\"foo:9090\"}", true)
-	verifyPresence(discoveryManager.targets, "prometheus", "static/0", "{__address__=\"bar:9090\"}", false)
+	verifyPresence(discoveryManager.targets, poolKey{set: "prometheus", provider: "static/0"}, "{__address__=\"foo:9090\"}", true)
+	verifyPresence(discoveryManager.targets, poolKey{set: "prometheus", provider: "static/0"}, "{__address__=\"bar:9090\"}", false)
 }
 type update struct {