126 lines
2.7 KiB
Go
126 lines
2.7 KiB
Go
package gather
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"time"
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"github.com/influxdata/influxdb"
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"github.com/influxdata/influxdb/nats"
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"go.uber.org/zap"
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)
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// nats subjects
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const (
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MetricsSubject = "metrics"
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promTargetSubject = "promTarget"
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)
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// Scheduler is struct to run scrape jobs.
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type Scheduler struct {
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Targets influxdb.ScraperTargetStoreService
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// Interval is between each metrics gathering event.
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Interval time.Duration
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// Timeout is the maxisium time duration allowed by each TCP request
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Timeout time.Duration
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// Publisher will send the gather requests and gathered metrics to the queue.
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Publisher nats.Publisher
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Logger *zap.Logger
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gather chan struct{}
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}
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// NewScheduler creates a new Scheduler and subscriptions for scraper jobs.
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func NewScheduler(
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numScrapers int,
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l *zap.Logger,
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targets influxdb.ScraperTargetStoreService,
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p nats.Publisher,
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s nats.Subscriber,
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interval time.Duration,
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timeout time.Duration,
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) (*Scheduler, error) {
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if interval == 0 {
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interval = 60 * time.Second
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}
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if timeout == 0 {
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timeout = 30 * time.Second
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}
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scheduler := &Scheduler{
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Targets: targets,
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Interval: interval,
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Timeout: timeout,
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Publisher: p,
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Logger: l,
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gather: make(chan struct{}, 100),
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}
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for i := 0; i < numScrapers; i++ {
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err := s.Subscribe(promTargetSubject, "metrics", &handler{
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Scraper: new(prometheusScraper),
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Publisher: p,
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Logger: l,
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})
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if err != nil {
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return nil, err
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}
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}
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return scheduler, nil
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}
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// Run will retrieve scraper targets from the target storage,
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// and publish them to nats job queue for gather.
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func (s *Scheduler) Run(ctx context.Context) error {
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go func(s *Scheduler, ctx context.Context) {
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for {
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select {
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case <-ctx.Done():
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return
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case <-time.After(s.Interval): // TODO: change to ticker because of garbage collection
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s.gather <- struct{}{}
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}
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}
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}(s, ctx)
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return s.run(ctx)
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}
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func (s *Scheduler) run(ctx context.Context) error {
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for {
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select {
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case <-ctx.Done():
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return nil
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case <-s.gather:
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ctx, cancel := context.WithTimeout(ctx, s.Timeout)
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defer cancel()
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targets, err := s.Targets.ListTargets(ctx)
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if err != nil {
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s.Logger.Error("cannot list targets", zap.Error(err))
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continue
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}
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for _, target := range targets {
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if err := requestScrape(target, s.Publisher); err != nil {
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s.Logger.Error("json encoding error", zap.Error(err))
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}
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}
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}
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}
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}
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func requestScrape(t influxdb.ScraperTarget, publisher nats.Publisher) error {
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buf := new(bytes.Buffer)
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err := json.NewEncoder(buf).Encode(t)
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if err != nil {
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return err
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}
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switch t.Type {
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case influxdb.PrometheusScraperType:
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return publisher.Publish(promTargetSubject, buf)
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}
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return fmt.Errorf("unsupported target scrape type: %s", t.Type)
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}
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