mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-15 16:30:55 +01:00
282 lines
7.9 KiB
Go
282 lines
7.9 KiB
Go
package consulagent
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import (
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"context"
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"encoding/json"
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"errors"
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"flag"
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"fmt"
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"net/url"
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"sync"
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"time"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discovery/consul"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
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"github.com/VictoriaMetrics/metrics"
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)
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// SDCheckInterval is check interval for Consul Agent service discovery.
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var SDCheckInterval = flag.Duration("promscrape.consulagentSDCheckInterval", 30*time.Second, "Interval for checking for changes in Consul Agent. "+
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"This works only if consulagent_sd_configs is configured in '-promscrape.config' file. "+
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"See https://docs.victoriametrics.com/sd_configs.html#consulagent_sd_configs for details")
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// consulAgentWatcher is a watcher for consul api, updates services map in background with long-polling.
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type consulAgentWatcher struct {
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client *discoveryutils.Client
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servicesQueryArgs string
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watchServices []string
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watchDatacenter string
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// servicesLock protects services
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servicesLock sync.Mutex
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services map[string]*serviceWatcher
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stoppedCh chan struct{}
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}
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type serviceWatcher struct {
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serviceName string
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serviceNodes []consul.ServiceNode
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stoppedCh chan struct{}
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requestCtx context.Context
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requestCancel context.CancelFunc
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}
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// newConsulAgentWatcher creates new watcher and starts background service discovery for Consul.
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func newConsulAgentWatcher(client *discoveryutils.Client, sdc *SDConfig, datacenter, namespace string) *consulAgentWatcher {
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var qv = url.Values{}
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if namespace != "" {
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qv.Set("ns", namespace)
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}
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if len(sdc.Filter) > 0 {
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qv.Set("filter", sdc.Filter)
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}
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cw := &consulAgentWatcher{
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client: client,
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servicesQueryArgs: "?" + qv.Encode(),
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watchServices: sdc.Services,
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watchDatacenter: datacenter,
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services: make(map[string]*serviceWatcher),
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stoppedCh: make(chan struct{}),
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}
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initCh := make(chan struct{})
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go func() {
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cw.watchForServicesUpdates(initCh)
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close(cw.stoppedCh)
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}()
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// wait for initialization to complete
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<-initCh
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return cw
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}
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func (cw *consulAgentWatcher) mustStop() {
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cw.client.Stop()
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<-cw.stoppedCh
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}
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func (cw *consulAgentWatcher) updateServices(serviceNames []string) {
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var initWG sync.WaitGroup
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// Start watchers for new services.
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cw.servicesLock.Lock()
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for _, serviceName := range serviceNames {
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if _, ok := cw.services[serviceName]; ok {
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// The watcher for serviceName already exists.
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continue
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}
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ctx, cancel := context.WithCancel(cw.client.Context())
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sw := &serviceWatcher{
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serviceName: serviceName,
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stoppedCh: make(chan struct{}),
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requestCtx: ctx,
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requestCancel: cancel,
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}
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cw.services[serviceName] = sw
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serviceWatchersCreated.Inc()
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initWG.Add(1)
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go func() {
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serviceWatchersCount.Inc()
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sw.watchForServiceNodesUpdates(cw, &initWG)
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serviceWatchersCount.Dec()
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close(sw.stoppedCh)
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}()
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}
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// Stop watchers for removed services.
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newServiceNamesMap := make(map[string]struct{}, len(serviceNames))
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for _, serviceName := range serviceNames {
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newServiceNamesMap[serviceName] = struct{}{}
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}
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var swsStopped []*serviceWatcher
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for serviceName, sw := range cw.services {
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if _, ok := newServiceNamesMap[serviceName]; ok {
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continue
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}
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sw.requestCancel()
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delete(cw.services, serviceName)
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swsStopped = append(swsStopped, sw)
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}
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cw.servicesLock.Unlock()
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// Wait until deleted service watchers are stopped.
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for _, sw := range swsStopped {
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<-sw.stoppedCh
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serviceWatchersStopped.Inc()
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}
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// Wait until added service watchers are initialized.
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initWG.Wait()
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}
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// watchForServicesUpdates watches for new services and updates it in cw.
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//
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// watchForServicesUpdates closes the initCh once the initialization is complete and first discovery iteration is done.
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func (cw *consulAgentWatcher) watchForServicesUpdates(initCh chan struct{}) {
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apiServer := cw.client.APIServer()
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f := func() {
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serviceNames, err := cw.getServiceNames()
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if err != nil {
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if !errors.Is(err, context.Canceled) {
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logger.Errorf("cannot obtain Consul Agent services from %q: %s", apiServer, err)
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}
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return
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}
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cw.updateServices(serviceNames)
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}
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logger.Infof("started Consul Agent service watcher for %q", apiServer)
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f()
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// send signal that initialization is complete
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close(initCh)
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ticker := time.NewTicker(getCheckInterval())
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defer ticker.Stop()
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stopCh := cw.client.Context().Done()
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for {
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select {
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case <-ticker.C:
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f()
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case <-stopCh:
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logger.Infof("stopping Consul Agent service watchers for %q", apiServer)
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startTime := time.Now()
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var swsStopped []*serviceWatcher
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cw.servicesLock.Lock()
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for _, sw := range cw.services {
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sw.requestCancel()
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swsStopped = append(swsStopped, sw)
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}
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cw.servicesLock.Unlock()
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for _, sw := range swsStopped {
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<-sw.stoppedCh
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serviceWatchersStopped.Inc()
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}
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logger.Infof("stopped Consul Agent service watcher for %q in %.3f seconds", apiServer, time.Since(startTime).Seconds())
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return
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}
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}
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}
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var (
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serviceWatchersCreated = metrics.NewCounter("vm_promscrape_discovery_consulagent_service_watchers_created_total")
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serviceWatchersStopped = metrics.NewCounter("vm_promscrape_discovery_consulagent_service_watchers_stopped_total")
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serviceWatchersCount = metrics.NewCounter("vm_promscrape_discovery_consulagent_service_watchers")
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)
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// getServiceNames obtains serviceNames via request to Consul Agent.
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//
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// It returns an empty serviceNames list if response contains the same index.
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func (cw *consulAgentWatcher) getServiceNames() ([]string, error) {
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path := "/v1/agent/services" + cw.servicesQueryArgs
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data, err := cw.client.GetAPIResponse(path)
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if err != nil {
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return nil, fmt.Errorf("cannot perform Consul Agent API request at %q: %w", path, err)
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}
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var m map[string]consul.Service
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if err := json.Unmarshal(data, &m); err != nil {
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return nil, fmt.Errorf("cannot parse response from %q: %w; data=%q", path, err, data)
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}
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serviceNames := make([]string, 0, len(m))
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for _, service := range m {
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serviceName := service.Service
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if service.Datacenter != cw.watchDatacenter {
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continue
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}
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if !consul.ShouldCollectServiceByName(cw.watchServices, serviceName) {
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continue
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}
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serviceNames = append(serviceNames, serviceName)
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}
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return serviceNames, nil
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}
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// watchForServiceNodesUpdates watches for Consul serviceNode changes for the given serviceName.
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//
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// watchForServiceNodesUpdates calls initWG.Done() once the initialization is complete and the first discovery iteration is done.
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func (sw *serviceWatcher) watchForServiceNodesUpdates(cw *consulAgentWatcher, initWG *sync.WaitGroup) {
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apiServer := cw.client.APIServer()
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path := "/v1/agent/health/service/name/" + sw.serviceName
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f := func() {
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data, err := cw.client.GetAPIResponseWithParamsCtx(sw.requestCtx, path, nil, nil)
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if err != nil {
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if !errors.Is(err, context.Canceled) {
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logger.Errorf("cannot obtain Consul Agent serviceNodes for serviceName=%q from %q: %s", sw.serviceName, apiServer, err)
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}
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return
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}
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sns, err := consul.ParseServiceNodes(data)
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if err != nil {
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logger.Errorf("cannot parse Consul Agent serviceNodes response for serviceName=%q from %q: %s", sw.serviceName, apiServer, err)
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return
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}
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cw.servicesLock.Lock()
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sw.serviceNodes = sns
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cw.servicesLock.Unlock()
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}
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f()
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// Notify caller that initialization is complete
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initWG.Done()
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ticker := time.NewTicker(getCheckInterval())
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defer ticker.Stop()
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stopCh := sw.requestCtx.Done()
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for {
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select {
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case <-ticker.C:
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f()
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case <-stopCh:
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return
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}
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}
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}
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// getServiceNodesSnapshot returns a snapshot of discovered ServiceNodes.
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func (cw *consulAgentWatcher) getServiceNodesSnapshot() map[string][]consul.ServiceNode {
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cw.servicesLock.Lock()
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sns := make(map[string][]consul.ServiceNode, len(cw.services))
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for svc, sw := range cw.services {
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sns[svc] = sw.serviceNodes
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}
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cw.servicesLock.Unlock()
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return sns
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}
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func getCheckInterval() time.Duration {
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d := *SDCheckInterval
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if d <= time.Second {
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return time.Second
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}
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return d
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}
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