simplify naming and API.

cmd/prometheus/main.go

@@ -236,7 +236,7 @@ func main() {
 		ctxRule                       = context.Background()
 		notifier         = notifier.New(&cfg.notifier, log.With(logger, "component", "notifier"))
-		discoveryManager = discovery.NewDiscoveryManager(ctxDiscovery, log.With(logger, "component", "discovery manager"))
+		discoveryManager = discovery.NewManager(ctxDiscovery, log.With(logger, "component", "discovery manager"))
 		scrapeManager    = retrieval.NewScrapeManager(log.With(logger, "component", "scrape manager"), fanoutStorage)
 		queryEngine      = promql.NewEngine(fanoutStorage, &cfg.queryEngine)
 		ruleManager      = rules.NewManager(&rules.ManagerOptions{Appendable: fanoutStorage,

discovery/manager.go

@@ -36,15 +36,15 @@ import (
 	"github.com/prometheus/prometheus/discovery/zookeeper"
 )
-// DiscoveryProvider provides information about target groups. It maintains a set
+// Discoverer provides information about target groups. It maintains a set
 // of sources from which TargetGroups can originate. Whenever a discovery provider
-// detects a potential change, it sends the TargetGroup through its provided channel.
+// detects a potential change, it sends the TargetGroup through its channel.
 //
-// The DiscoveryProvider does not have to guarantee that an actual change happened.
+// Discoverer does not know if an actual change happened.
 // It does guarantee that it sends the new TargetGroup whenever a change happens.
 //
-// DiscoveryProviders should initially send a full set of all discoverable TargetGroups.
-type DiscoveryProvider interface {
+// Discoverers should initially send a full set of all discoverable TargetGroups.
+type Discoverer interface {
 	// Run hands a channel to the discovery provider(consul,dns etc) through which it can send
 	// updated target groups.
 	// Must returns if the context gets canceled. It should not close the update
@@ -52,33 +52,35 @@ type DiscoveryProvider interface {
 	Run(ctx context.Context, up chan<- []*config.TargetGroup)
 }
-type targetSetProvider struct {
-	cancel  func()
-	tgroups []*config.TargetGroup
-}
-// NewDiscoveryManager is the DiscoveryManager constructor
-func NewDiscoveryManager(ctx context.Context, logger log.Logger) *DiscoveryManager {
-	return &DiscoveryManager{
-		ctx:                ctx,
-		logger:             logger,
-		actionCh:           make(chan func()),
-		syncCh:             make(chan map[string][]*config.TargetGroup),
-		targetSetProviders: make(map[string]map[string]*targetSetProvider),
+// type pool struct {
+// 	cancel func()
+// 	tgroups []*config.TargetGroup
+// }
+// NewManager is the Discovery Manager constructor
+func NewManager(ctx context.Context, logger log.Logger) *Manager {
+	return &Manager{
+		ctx:            ctx,
+		logger:         logger,
+		actionCh:       make(chan func()),
+		syncCh:         make(chan map[string][]*config.TargetGroup),
+		endpoints:      make(map[string]map[string][]*config.TargetGroup),
+		discoverCancel: []context.CancelFunc{},
 	}
 }
-// DiscoveryManager maintains a set of discovery providers and sends each update to a channel used by other packages.
-type DiscoveryManager struct {
-	ctx                context.Context
-	logger             log.Logger
-	syncCh             chan map[string][]*config.TargetGroup // map[targetSetName]
-	actionCh           chan func()
-	targetSetProviders map[string]map[string]*targetSetProvider // map[targetSetName]map[providerName]
+// Manager maintains a set of discovery providers and sends each update to a channel used by other packages.
+type Manager struct {
+	ctx            context.Context
+	logger         log.Logger
+	syncCh         chan map[string][]*config.TargetGroup // map[targetSetName]
+	actionCh       chan func()
+	discoverCancel []context.CancelFunc
+	endpoints      map[string]map[string][]*config.TargetGroup // map[targetSetName]map[providerName]
 }
 // Run starts the background processing
-func (m *DiscoveryManager) Run() error {
+func (m *Manager) Run() error {
 	for {
 		select {
 		case f := <-m.actionCh:
@@ -90,27 +92,27 @@ func (m *DiscoveryManager) Run() error {
 }
 // SyncCh returns a read only channel used by all DiscoveryProviders targetSet updates
-func (m *DiscoveryManager) SyncCh() <-chan map[string][]*config.TargetGroup {
+func (m *Manager) SyncCh() <-chan map[string][]*config.TargetGroup {
 	return m.syncCh
 }
 // ApplyConfig removes all running discovery providers and starts new ones using the provided config.
-func (m *DiscoveryManager) ApplyConfig(cfg *config.Config) error {
+func (m *Manager) ApplyConfig(cfg *config.Config) error {
 	err := make(chan error)
 	m.actionCh <- func() {
-		m.cancelDiscoveryProviders()
+		m.cancelDiscoverers()
 		for _, scfg := range cfg.ScrapeConfigs {
 			for provName, prov := range m.providersFromConfig(scfg.ServiceDiscoveryConfig) {
 				ctx, cancel := context.WithCancel(m.ctx)
 				updates := make(chan []*config.TargetGroup)
-				m.createProvider(cancel, scfg.JobName, provName)
+				m.discoverCancel = append(m.discoverCancel, cancel)
 				go prov.Run(ctx, updates)
 				go func(provName string) {
 					select {
 					case <-ctx.Done():
-						// First set of all targets the provider knows.
+						// First set of all endpoints the provider knows.
 					case tgs, ok := <-updates:
 						// Handle the case that a target provider exits and closes the channel
 						// before the context is done.
@@ -146,35 +148,29 @@ func (m *DiscoveryManager) ApplyConfig(cfg *config.Config) error {
 	return <-err
 }
-func (m *DiscoveryManager) cancelDiscoveryProviders() {
-	for targetSetName, targetSetProviders := range m.targetSetProviders {
-		for _, discoveryProvider := range targetSetProviders {
-			discoveryProvider.cancel()
-		}
-		delete(m.targetSetProviders, targetSetName)
+func (m *Manager) cancelDiscoverers() {
+	for _, c := range m.discoverCancel {
+		c()
 	}
+	m.endpoints = make(map[string]map[string][]*config.TargetGroup)
+	m.discoverCancel = []context.CancelFunc{}
 }
-func (m *DiscoveryManager) createProvider(cancel context.CancelFunc, tsName, provName string) {
-	if m.targetSetProviders[tsName] == nil {
-		m.targetSetProviders[tsName] = make(map[string]*targetSetProvider)
+// mergeGroups adds a new target group for a given discovery provider and returns all target groups for a given target set
+func (m *Manager) mergeGroups(tsName, provName string, tg []*config.TargetGroup) map[string][]*config.TargetGroup {
+	if m.endpoints[tsName] == nil {
+		m.endpoints[tsName] = make(map[string][]*config.TargetGroup)
 	}
-	m.targetSetProviders[tsName][provName] = &targetSetProvider{
-		cancel:  cancel,
-		tgroups: []*config.TargetGroup{},
-	}
-}
-// mergeGroups adds a new target group for a named discovery provider and returns all target groups for a given target set
-func (m *DiscoveryManager) mergeGroups(tsName, provName string, tg []*config.TargetGroup) map[string][]*config.TargetGroup {
+	m.endpoints[tsName][provName] = []*config.TargetGroup{}
 	tset := make(chan map[string][]*config.TargetGroup)
 	m.actionCh <- func() {
 		if tg != nil {
-			m.targetSetProviders[tsName][provName].tgroups = tg
+			m.endpoints[tsName][provName] = tg
 		}
 		var tgAll []*config.TargetGroup
-		for _, prov := range m.targetSetProviders[tsName] {
-			for _, tg := range prov.tgroups {
+		for _, prov := range m.endpoints[tsName] {
+			for _, tg := range prov {
 				tgAll = append(tgAll, tg)
 			}
 		}
@@ -185,10 +181,10 @@ func (m *DiscoveryManager) mergeGroups(tsName, provName string, tg []*config.Tar
 	return <-tset
 }
-func (m *DiscoveryManager) providersFromConfig(cfg config.ServiceDiscoveryConfig) map[string]DiscoveryProvider {
-	providers := map[string]DiscoveryProvider{}
-	app := func(mech string, i int, tp DiscoveryProvider) {
+func (m *Manager) providersFromConfig(cfg config.ServiceDiscoveryConfig) map[string]Discoverer {
+	providers := map[string]Discoverer{}
+	app := func(mech string, i int, tp Discoverer) {
 		providers[fmt.Sprintf("%s/%d", mech, i)] = tp
 	}
@@ -280,7 +276,7 @@ func NewStaticProvider(groups []*config.TargetGroup) *StaticProvider {
 	return &StaticProvider{groups}
 }
-// Run implements the DiscoveryProvider interface.
+// Run implements the Worker interface.
 func (sd *StaticProvider) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	// We still have to consider that the consumer exits right away in which case
 	// the context will be canceled.