influxdb/gather/scheduler.go

137 lines
3.1 KiB
Go

package gather
import (
"context"
"sync"
"time"
"github.com/influxdata/influxdb/v2"
"github.com/influxdata/influxdb/v2/storage"
"go.uber.org/zap"
)
// Scheduler is struct to run scrape jobs.
type Scheduler struct {
Targets influxdb.ScraperTargetStoreService
// Interval is between each metrics gathering event.
Interval time.Duration
log *zap.Logger
scrapeRequest chan *influxdb.ScraperTarget
done chan struct{}
wg sync.WaitGroup
writer storage.PointsWriter
}
// NewScheduler creates a new Scheduler and subscriptions for scraper jobs.
func NewScheduler(
log *zap.Logger,
scrapeQueueLength int,
scrapesInProgress int,
targets influxdb.ScraperTargetStoreService,
writer storage.PointsWriter,
interval time.Duration,
) (*Scheduler, error) {
if interval == 0 {
interval = 60 * time.Second
}
scheduler := &Scheduler{
Targets: targets,
Interval: interval,
log: log,
scrapeRequest: make(chan *influxdb.ScraperTarget, scrapeQueueLength),
done: make(chan struct{}),
writer: writer,
}
scheduler.wg.Add(1)
scraperPool := make(chan *prometheusScraper, scrapesInProgress)
for i := 0; i < scrapesInProgress; i++ {
scraperPool <- newPrometheusScraper()
}
go func() {
defer scheduler.wg.Done()
for {
select {
case req := <-scheduler.scrapeRequest:
select {
// Each request much acquire a scraper from the (limited) pool to run the scrape,
// then return it to the pool
case scraper := <-scraperPool:
scheduler.doScrape(scraper, req, func(s *prometheusScraper) {
scraperPool <- s
})
case <-scheduler.done:
return
}
case <-scheduler.done:
return
}
}
}()
scheduler.wg.Add(1)
go func() {
defer scheduler.wg.Done()
ticker := time.NewTicker(scheduler.Interval)
defer ticker.Stop()
for {
select {
case <-scheduler.done:
return
case <-ticker.C:
scheduler.doGather()
}
}
}()
return scheduler, nil
}
func (s *Scheduler) doScrape(scraper *prometheusScraper, req *influxdb.ScraperTarget, releaseScraper func(s *prometheusScraper)) {
s.wg.Add(1)
go func() {
defer s.wg.Done()
defer releaseScraper(scraper)
logger := s.log.With(zap.String("scraper-name", req.Name))
if req == nil {
return
}
ms, err := scraper.Gather(*req)
if err != nil {
logger.Error("Unable to gather", zap.Error(err))
return
}
ps, err := ms.MetricsSlice.Points()
if err != nil {
logger.Error("Unable to gather list of points", zap.Error(err))
}
err = s.writer.WritePoints(context.Background(), ms.OrgID, ms.BucketID, ps)
if err != nil {
logger.Error("Unable to write gathered points", zap.Error(err))
}
}()
}
func (s *Scheduler) doGather() {
targets, err := s.Targets.ListTargets(context.Background(), influxdb.ScraperTargetFilter{})
if err != nil {
s.log.Error("Cannot list targets", zap.Error(err))
return
}
for i := range targets {
select {
case s.scrapeRequest <- &targets[i]:
default:
s.log.Warn("Skipping scrape due to scraper backlog", zap.String("target", targets[i].Name))
}
}
}
func (s *Scheduler) Close() {
close(s.done)
s.wg.Wait()
}