[chore] Fix small nits in scrapercontroller (#11652)

Signed-off-by: Bogdan Drutu <[email protected]>

Author: bogdandrutu

receiver/scraperhelper/scrapercontroller.go

@@ -5,7 +5,7 @@ package scraperhelper // import "go.opentelemetry.io/collector/receiver/scraperh
 
 import (
 	"context"
-	"errors"
+	"sync"
 	"time"
 
 	"go.uber.org/multierr"
@@ -63,12 +63,10 @@ type controller struct {
 
 	tickerCh <-chan time.Time
 
-	initialized bool
-	done        chan struct{}
-	terminated  chan struct{}
+	done chan struct{}
+	wg   sync.WaitGroup
 
-	obsrecv      *receiverhelper.ObsReport
-	recvSettings receiver.Settings
+	obsrecv *receiverhelper.ObsReport
 }
 
 // NewScraperControllerReceiver creates a Receiver with the configured options, that can control multiple scrapers.
@@ -78,10 +76,6 @@ func NewScraperControllerReceiver(
 	nextConsumer consumer.Metrics,
 	options ...ScraperControllerOption,
 ) (component.Component, error) {
-	if cfg.CollectionInterval <= 0 {
-		return nil, errors.New("collection_interval must be a positive duration")
-	}
-
 	obsrecv, err := receiverhelper.NewObsReport(receiverhelper.ObsReportSettings{
 		ReceiverID:             set.ID,
 		Transport:              "",
@@ -99,9 +93,7 @@ func NewScraperControllerReceiver(
 		timeout:            cfg.Timeout,
 		nextConsumer:       nextConsumer,
 		done:               make(chan struct{}),
-		terminated:         make(chan struct{}),
 		obsrecv:            obsrecv,
-		recvSettings:       set,
 	}
 
 	for _, op := range options {
@@ -110,14 +102,11 @@ func NewScraperControllerReceiver(
 
 	sc.obsScrapers = make([]*obsReport, len(sc.scrapers))
 	for i, scraper := range sc.scrapers {
-		scrp, err := newScraper(obsReportSettings{
+		sc.obsScrapers[i], err = newScraper(obsReportSettings{
 			ReceiverID:             sc.id,
 			Scraper:                scraper.ID(),
-			ReceiverCreateSettings: sc.recvSettings,
+			ReceiverCreateSettings: set,
 		})
-
-		sc.obsScrapers[i] = scrp
-
 		if err != nil {
 			return nil, err
 		}
@@ -134,20 +123,15 @@ func (sc *controller) Start(ctx context.Context, host component.Host) error {
 		}
 	}
 
-	sc.initialized = true
 	sc.startScraping()
 	return nil
 }
 
 // Shutdown the receiver, invoked during service shutdown.
 func (sc *controller) Shutdown(ctx context.Context) error {
-	sc.stopScraping()
-
-	// wait until scraping ticker has terminated
-	if sc.initialized {
-		<-sc.terminated
-	}
-
+	// Signal the goroutine to stop.
+	close(sc.done)
+	sc.wg.Wait()
 	var errs error
 	for _, scraper := range sc.scrapers {
 		errs = multierr.Append(errs, scraper.Shutdown(ctx))
@@ -159,12 +143,13 @@ func (sc *controller) Shutdown(ctx context.Context) error {
 // startScraping initiates a ticker that calls Scrape based on the configured
 // collection interval.
 func (sc *controller) startScraping() {
+	sc.wg.Add(1)
 	go func() {
+		defer sc.wg.Done()
 		if sc.initialDelay > 0 {
 			select {
 			case <-time.After(sc.initialDelay):
 			case <-sc.done:
-				sc.terminated <- struct{}{}
 				return
 			}
 		}
@@ -184,7 +169,6 @@ func (sc *controller) startScraping() {
 			case <-sc.tickerCh:
 				sc.scrapeMetricsAndReport()
 			case <-sc.done:
-				sc.terminated <- struct{}{}
 				return
 			}
 		}
@@ -222,11 +206,6 @@ func (sc *controller) scrapeMetricsAndReport() {
 	sc.obsrecv.EndMetricsOp(ctx, "", dataPointCount, err)
 }
 
-// stopScraping stops the ticker
-func (sc *controller) stopScraping() {
-	close(sc.done)
-}
-
 // withScrapeContext will return a context that has no deadline if timeout is 0
 // which implies no explicit timeout had occurred, otherwise, a context
 // with a deadline of the provided timeout is returned.

receiver/scraperhelper/scrapercontroller_test.go

@@ -76,7 +76,6 @@ type metricsTestCase struct {
 	scrapers                  int
 	scraperControllerSettings *ControllerConfig
 	scrapeErr                 error
-	expectedNewErr            string
 	expectScraped             bool
 
 	initialize    bool
@@ -95,12 +94,6 @@ func TestScrapeController(t *testing.T) {
 			scrapers:      2,
 			expectScraped: true,
 		},
-		{
-			name:                      "AddMetricsScrapersWithCollectionInterval_InvalidCollectionIntervalError",
-			scrapers:                  2,
-			scraperControllerSettings: &ControllerConfig{CollectionInterval: -time.Millisecond},
-			expectedNewErr:            "collection_interval must be a positive duration",
-		},
 		{
 			name:      "AddMetricsScrapers_ScrapeError",
 			scrapers:  2,
@@ -146,10 +139,6 @@ func TestScrapeController(t *testing.T) {
 			}
 
 			mr, err := NewScraperControllerReceiver(cfg, receiver.Settings{ID: receiverID, TelemetrySettings: tt.TelemetrySettings(), BuildInfo: component.NewDefaultBuildInfo()}, sink, options...)
-			if test.expectedNewErr != "" {
-				assert.EqualError(t, err, test.expectedNewErr)
-				return
-			}
 			require.NoError(t, err)
 
 			err = mr.Start(context.Background(), componenttest.NewNopHost())