Remove Pyroscope scrape loops for no longer active targets (#1833)

CHANGELOG.md

@@ -35,6 +35,8 @@ Main (unreleased)
 
 - Fixed a bug in `import.git` which caused a `"non-fast-forward update"` error message. (@ptodev)
 
+- `pyroscope.scrape` no longer tries to scrape endpoints which are not active targets anymore. (@wildum @mattdurham @dehaansa @ptodev)
+
 ### Other changes
 
 - Small fix in UI stylesheet to fit more content into visible table area. (@defanator)

internal/component/pyroscope/scrape/manager.go

@@ -112,6 +112,14 @@ func (m *Manager) reload() {
 			wg.Done()
 		}(m.targetsGroups[setName], groups)
 	}
+
+	for tgName, sp := range m.targetsGroups {
+		if _, ok := m.targetSets[tgName]; !ok {
+			sp.stop()
+			delete(m.targetsGroups, tgName)
+		}
+	}
+
 	wg.Wait()
 }
 

internal/component/pyroscope/scrape/manager_test.go

@@ -11,9 +11,12 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 	"github.com/prometheus/prometheus/model/labels"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/goleak"
 )
 
 func TestManager(t *testing.T) {
+	defer goleak.VerifyNone(t, goleak.IgnoreTopFunction("go.opencensus.io/stats/view.(*worker).start"))
+
 	reloadInterval = time.Millisecond
 
 	m := NewManager(Options{}, pyroscope.AppendableFunc(func(ctx context.Context, labels labels.Labels, samples []*pyroscope.RawSample) error {
@@ -62,6 +65,8 @@ func TestManager(t *testing.T) {
 		return len(m.TargetsActive()["group2"]) == 10
 	}, time.Second, 10*time.Millisecond)
 
+	require.Equal(t, 1, len(m.targetsGroups))
+
 	for _, ts := range m.targetsGroups {
 		require.Equal(t, 1*time.Second, ts.config.ScrapeInterval)
 	}