Fix test goroutine leaks in ./cmd/collector/app/ (#5292)

## Which problem is this PR solving?

Solves part of #5006.

## Description of the changes

I introduced `testutils.VerifyGoLeaks(m)` and then ensured all leaked
goroutines were stopped.

## How was this change tested?

`make lint` and `make test`

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [ ] I have added unit tests for the new functionality
- [ ] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `yarn lint` and `yarn test`

Signed-off-by: Will Sewell <[email protected]>

cmd/collector/app/collector.go

@@ -218,9 +218,15 @@ func (c *Collector) Close() error {
 	}
 
 	// watchers actually never return errors from Close
-	_ = c.tlsGRPCCertWatcherCloser.Close()
-	_ = c.tlsHTTPCertWatcherCloser.Close()
-	_ = c.tlsZipkinCertWatcherCloser.Close()
+	if c.tlsGRPCCertWatcherCloser != nil {
+		_ = c.tlsGRPCCertWatcherCloser.Close()
+	}
+	if c.tlsHTTPCertWatcherCloser != nil {
+		_ = c.tlsHTTPCertWatcherCloser.Close()
+	}
+	if c.tlsZipkinCertWatcherCloser != nil {
+		_ = c.tlsZipkinCertWatcherCloser.Close()
+	}
 
 	return nil
 }

cmd/collector/app/collector_test.go

@@ -52,6 +52,7 @@ func TestNewCollector(t *testing.T) {
 	hc := healthcheck.New()
 	logger := zap.NewNop()
 	baseMetrics := metricstest.NewFactory(time.Hour)
+	defer baseMetrics.Backend.Stop()
 	spanWriter := &fakeSpanWriter{}
 	strategyStore := &mockStrategyStore{}
 	tm := &tenancy.Manager{}
@@ -78,6 +79,7 @@ func TestCollector_StartErrors(t *testing.T) {
 			hc := healthcheck.New()
 			logger := zap.NewNop()
 			baseMetrics := metricstest.NewFactory(time.Hour)
+			defer baseMetrics.Backend.Stop()
 			spanWriter := &fakeSpanWriter{}
 			strategyStore := &mockStrategyStore{}
 			tm := &tenancy.Manager{}
@@ -94,6 +96,7 @@ func TestCollector_StartErrors(t *testing.T) {
 			err := c.Start(options)
 			require.Error(t, err)
 			assert.Contains(t, err.Error(), expErr)
+			require.NoError(t, c.Close())
 		})
 	}
 
@@ -131,7 +134,9 @@ func TestCollector_PublishOpts(t *testing.T) {
 	hc := healthcheck.New()
 	logger := zap.NewNop()
 	baseMetrics := metricstest.NewFactory(time.Second)
+	defer baseMetrics.Backend.Stop()
 	forkFactory := metricstest.NewFactory(time.Second)
+	defer forkFactory.Backend.Stop()
 	metricsFactory := fork.New("internal", forkFactory, baseMetrics)
 	spanWriter := &fakeSpanWriter{}
 	strategyStore := &mockStrategyStore{}
@@ -168,6 +173,7 @@ func TestAggregator(t *testing.T) {
 	hc := healthcheck.New()
 	logger := zap.NewNop()
 	baseMetrics := metricstest.NewFactory(time.Hour)
+	defer baseMetrics.Backend.Stop()
 	spanWriter := &fakeSpanWriter{}
 	strategyStore := &mockStrategyStore{}
 	agg := &mockAggregator{}

cmd/collector/app/metrics_test.go

@@ -29,6 +29,7 @@ import (
 
 func TestProcessorMetrics(t *testing.T) {
 	baseMetrics := metricstest.NewFactory(time.Hour)
+	defer baseMetrics.Backend.Stop()
 	serviceMetrics := baseMetrics.Namespace(jaegerM.NSOptions{Name: "service", Tags: nil})
 	hostMetrics := baseMetrics.Namespace(jaegerM.NSOptions{Name: "host", Tags: nil})
 	spm := NewSpanProcessorMetrics(serviceMetrics, hostMetrics, []processor.SpanFormat{processor.SpanFormat("scruffy")})
@@ -63,6 +64,7 @@ func TestProcessorMetrics(t *testing.T) {
 
 func TestNewTraceCountsBySvc(t *testing.T) {
 	baseMetrics := metricstest.NewFactory(time.Hour)
+	defer baseMetrics.Backend.Stop()
 	metrics := newTraceCountsBySvc(baseMetrics, "not_on_my_level", 3)
 
 	metrics.countByServiceName("fry", false, model.SamplerTypeUnrecognized)
@@ -95,6 +97,7 @@ func TestNewTraceCountsBySvc(t *testing.T) {
 
 func TestNewSpanCountsBySvc(t *testing.T) {
 	baseMetrics := metricstest.NewFactory(time.Hour)
+	defer baseMetrics.Backend.Stop()
 	metrics := newSpanCountsBySvc(baseMetrics, "not_on_my_level", 3)
 	metrics.countByServiceName("fry", false)
 	metrics.countByServiceName("leela", false)

cmd/collector/app/package_test.go

@@ -0,0 +1,14 @@
+// Copyright (c) 2024 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package app
+
+import (
+	"testing"
+
+	"github.com/jaegertracing/jaeger/pkg/testutils"
+)
+
+func TestMain(m *testing.M) {
+	testutils.VerifyGoLeaks(m)
+}

cmd/collector/app/span_handler_builder_test.go

@@ -61,6 +61,7 @@ func TestNewSpanHandlerBuilder(t *testing.T) {
 	assert.NotNil(t, spanHandlers.JaegerBatchesHandler)
 	assert.NotNil(t, spanHandlers.GRPCHandler)
 	assert.NotNil(t, spanProcessor)
+	require.NoError(t, spanProcessor.Close())
 }
 
 func TestDefaultSpanFilter(t *testing.T) {

cmd/collector/app/span_processor_test.go

@@ -83,6 +83,7 @@ func TestBySvcMetrics(t *testing.T) {
 
 	for _, test := range tests {
 		mb := metricstest.NewFactory(time.Hour)
+		defer mb.Backend.Stop()
 		logger := zap.NewNop()
 		serviceMetrics := mb.Namespace(metrics.NSOptions{Name: "service", Tags: nil})
 		hostMetrics := mb.Namespace(metrics.NSOptions{Name: "host", Tags: nil})
@@ -258,6 +259,7 @@ func TestSpanProcessorErrors(t *testing.T) {
 		err: fmt.Errorf("some-error"),
 	}
 	mb := metricstest.NewFactory(time.Hour)
+	defer mb.Backend.Stop()
 	serviceMetrics := mb.Namespace(metrics.NSOptions{Name: "service", Tags: nil})
 	p := NewSpanProcessor(w,
 		nil,
@@ -342,6 +344,7 @@ func TestSpanProcessorBusy(t *testing.T) {
 
 func TestSpanProcessorWithNilProcess(t *testing.T) {
 	mb := metricstest.NewFactory(time.Hour)
+	defer mb.Backend.Stop()
 	serviceMetrics := mb.Namespace(metrics.NSOptions{Name: "service", Tags: nil})
 
 	w := &fakeSpanWriter{}
@@ -440,6 +443,7 @@ func TestSpanProcessorCountSpan(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			mb := metricstest.NewFactory(time.Hour)
+			defer mb.Backend.Stop()
 			m := mb.Namespace(metrics.NSOptions{})
 
 			w := &fakeSpanWriter{}
@@ -606,6 +610,7 @@ func TestStartDynQueueSizeUpdater(t *testing.T) {
 	}
 
 	assert.EqualValues(t, 104857, p.queue.Capacity())
+	require.NoError(t, p.Close())
 }
 
 func TestAdditionalProcessors(t *testing.T) {

internal/metricstest/local.go

@@ -392,3 +392,7 @@ func (l *Factory) Namespace(scope metrics.NSOptions) metrics.Factory {
 		Backend:   l.Backend,
 	}
 }
+
+func (l *Factory) Stop() {
+	l.Backend.Stop()
+}