Use Component for start/shutdown of the Scraper (#2187)

In a followup PR, after #2186 is merged, use component helper.

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

receiver/hostmetricsreceiver/hostmetrics_receiver_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/stretchr/testify/require"
 	"go.uber.org/zap"
 
+	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/consumer/consumertest"
 	"go.opentelemetry.io/collector/consumer/pdata"
@@ -212,9 +213,9 @@ func (m *mockFactory) CreateMetricsScraper(context.Context, *zap.Logger, interna
 	return args.Get(0).(receiverhelper.MetricsScraper), args.Error(1)
 }
 
-func (m *mockScraper) Name() string                     { return "" }
-func (m *mockScraper) Initialize(context.Context) error { return nil }
-func (m *mockScraper) Close(context.Context) error      { return nil }
+func (m *mockScraper) Name() string                                { return "" }
+func (m *mockScraper) Start(context.Context, component.Host) error { return nil }
+func (m *mockScraper) Shutdown(context.Context) error              { return nil }
 func (m *mockScraper) Scrape(context.Context, string) (pdata.MetricSlice, error) {
 	return pdata.NewMetricSlice(), errors.New("err1")
 }
@@ -228,9 +229,9 @@ func (m *mockResourceFactory) CreateResourceMetricsScraper(context.Context, *zap
 	return args.Get(0).(receiverhelper.ResourceMetricsScraper), args.Error(1)
 }
 
-func (m *mockResourceScraper) Name() string                     { return "" }
-func (m *mockResourceScraper) Initialize(context.Context) error { return nil }
-func (m *mockResourceScraper) Close(context.Context) error      { return nil }
+func (m *mockResourceScraper) Name() string                                { return "" }
+func (m *mockResourceScraper) Start(context.Context, component.Host) error { return nil }
+func (m *mockResourceScraper) Shutdown(context.Context) error              { return nil }
 func (m *mockResourceScraper) Scrape(context.Context, string) (pdata.ResourceMetricsSlice, error) {
 	return pdata.NewResourceMetricsSlice(), errors.New("err2")
 }

receiver/receiverhelper/scraper.go

@@ -17,6 +17,7 @@ package receiverhelper
 import (
 	"context"
 
+	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/consumer/pdata"
 	"go.opentelemetry.io/collector/obsreport"
 )
@@ -39,16 +40,10 @@ type Close func(ctx context.Context) error
 type ScraperOption func(*baseScraper)
 
 type BaseScraper interface {
+	component.Component
+
 	// Name returns the scraper name
 	Name() string
-
-	// Initialize performs any timely initialization tasks such as
-	// setting up performance counters for initial collection.
-	Initialize(ctx context.Context) error
-
-	// Close should clean up any unmanaged resources such as
-	// performance counter handles.
-	Close(ctx context.Context) error
 }
 
 // MetricsScraper is an interface for scrapers that scrape metrics.
@@ -75,14 +70,14 @@ func (b baseScraper) Name() string {
 	return b.name
 }
 
-func (b baseScraper) Initialize(ctx context.Context) error {
+func (b baseScraper) Start(ctx context.Context, _ component.Host) error {
 	if b.initialize == nil {
 		return nil
 	}
 	return b.initialize(ctx)
 }
 
-func (b baseScraper) Close(ctx context.Context) error {
+func (b baseScraper) Shutdown(ctx context.Context) error {
 	if b.close == nil {
 		return nil
 	}

receiver/receiverhelper/scrapercontroller.go

@@ -138,9 +138,11 @@ func NewScraperControllerReceiver(
 }
 
 // Start the receiver, invoked during service start.
-func (sc *scraperController) Start(ctx context.Context, _ component.Host) error {
-	if err := sc.initializeScrapers(ctx); err != nil {
-		return err
+func (sc *scraperController) Start(ctx context.Context, host component.Host) error {
+	for _, scraper := range sc.resourceMetricScrapers {
+		if err := scraper.Start(ctx, host); err != nil {
+			return err
+		}
 	}
 
 	sc.initialized = true
@@ -157,24 +159,13 @@ func (sc *scraperController) Shutdown(ctx context.Context) error {
 		<-sc.terminated
 	}
 
-	var errors []error
-
-	if err := sc.closeScrapers(ctx); err != nil {
-		errors = append(errors, err)
-	}
-
-	return componenterror.CombineErrors(errors)
-}
-
-// initializeScrapers initializes all the scrapers
-func (sc *scraperController) initializeScrapers(ctx context.Context) error {
+	var errs []error
 	for _, scraper := range sc.resourceMetricScrapers {
-		if err := scraper.Initialize(ctx); err != nil {
-			return err
+		if err := scraper.Shutdown(ctx); err != nil {
+			errs = append(errs, err)
 		}
 	}
-
-	return nil
+	return componenterror.CombineErrors(errs)
 }
 
 // startScraping initiates a ticker that calls Scrape based on the configured
@@ -232,19 +223,6 @@ func (sc *scraperController) stopScraping() {
 	close(sc.done)
 }
 
-// closeScrapers closes all the scrapers
-func (sc *scraperController) closeScrapers(ctx context.Context) error {
-	var errs []error
-
-	for _, scraper := range sc.resourceMetricScrapers {
-		if err := scraper.Close(ctx); err != nil {
-			errs = append(errs, err)
-		}
-	}
-
-	return componenterror.CombineErrors(errs)
-}
-
 var _ ResourceMetricsScraper = (*multiMetricScraper)(nil)
 
 type multiMetricScraper struct {
@@ -255,19 +233,19 @@ func (mms *multiMetricScraper) Name() string {
 	return ""
 }
 
-func (mms *multiMetricScraper) Initialize(ctx context.Context) error {
+func (mms *multiMetricScraper) Start(ctx context.Context, host component.Host) error {
 	for _, scraper := range mms.scrapers {
-		if err := scraper.Initialize(ctx); err != nil {
+		if err := scraper.Start(ctx, host); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-func (mms *multiMetricScraper) Close(ctx context.Context) error {
+func (mms *multiMetricScraper) Shutdown(ctx context.Context) error {
 	var errs []error
 	for _, scraper := range mms.scrapers {
-		if err := scraper.Close(ctx); err != nil {
+		if err := scraper.Shutdown(ctx); err != nil {
 			errs = append(errs, err)
 		}
 	}