Identify potential memory leaks in our goroutines using uber-go/goleak

[shaun-nx]

As a maintainer of the NGINX Ingress Controller, I would like to know if there are any potential memory leaks in our go routines.

UACs:

• Identify all g routines in our code base
• Create at least one unit test that targets each go routine
• use uber-go/goleak in each test to identify a potential leak

Resources:
https://github.com/uber-go/goleak
https://medium.com/@hatronix/title-demystifying-gos-runtime-numgoroutine-93fddbb67527#:~:text=NumGoroutine()%20is%20a%20simple,the%20concurrency%20of%20your%20application.

[github-actions]

Hi @shaun-nx thanks for reporting!

Be sure to check out the docs and the Contributing Guidelines while you wait for a human to take a look at this 🙂

Cheers!

[shaun-nx]

List of known goroutines

This will be a list of which .go file which contains a goroutune covers that goroutine with a test

File	Total goroutines	Goroutines covered by tests
cmd/nginx-ingress/main.go	7	0
internal/certmanager/cm_controller.go	4	0
internal/externalcnd/controller.go	2	0
internal/k8s/controller.go	15	0
internal/k8s/task_queue.go	1	0
internal/metrics/syslog_listener.go	1	0
internal/nginx/manager.go	4	0
internal/pkg/client/informers/externalversions/factory.go	1	0

Detailed list of known goroutines

kubernetes-ingress  (35 usages found)
            cmd/nginx-ingress  (7 usages found)
                main.go  (7 usages found)
                    90 go updateSelfWithVersionInfo(kubeClient, version, appProtectVersion, agentVersion, nginxVersion, 10, time.Second*5)
                    222 go func() {
                    230 go handleTermination(lbc, nginxManager, syslogListener, process)
                    722 go metrics.RunPrometheusListenerForNginxPlus(*prometheusMetricsListenPort, plusCollector, registry, prometheusSecret)
                    726 go metrics.RunPrometheusListenerForNginx(*prometheusMetricsListenPort, client, registry, constLabels, prometheusSecret)
                    734 go syslogListener.Run()
                    754 go healthcheck.RunHealthCheck(*serviceInsightListenPort, plusClient, cnf, serviceInsightSecret)
            internal/certmanager  (4 usages found)
                cm_controller.go  (4 usages found)
                    255 go c.runWorker(ctx)
                    266 go nsi.vsSharedInformerFactory.Start(nsi.stopCh)
                    267 go nsi.cmSharedInformerFactory.Start(nsi.stopCh)
                    268 go nsi.kubeSharedInformerFactory.Start(nsi.stopCh)
            internal/externaldns  (2 usages found)
                controller.go  (2 usages found)
                    132 go c.runWorker(ctx)
                    143 go nsi.sharedInformerFactory.Start(nsi.stopCh)
            internal/k8s  (16 usages found)
                controller.go  (15 usages found)
                    691 go lbc.namespaceWatcherController.Run(lbc.ctx.Done())
                    703 go func() { time.Sleep(time.Second * 30); timeoutch <- true }()
                    711 go func() {
                    724 go lbc.certManagerController.Run(lbc.ctx.Done())
                    727 go lbc.externalDNSController.Run(lbc.ctx.Done())
                    731 go lbc.leaderElector.Run(lbc.ctx)
                    735 go func(ctx context.Context) {
                    750 go lbc.configMapController.Run(lbc.ctx.Done())
                    754 go lbc.globalConfigurationController.Run(lbc.ctx.Done())
                    757 go lbc.ingressLinkInformer.Run(lbc.ctx.Done())
                    776 go lbc.syncQueue.Run(time.Second, lbc.ctx.Done())
                    790 go nsi.sharedInformerFactory.Start(nsi.stopCh)
                    793 go nsi.secretInformerFactory.Start(nsi.stopCh)
                    797 go nsi.confSharedInformerFactory.Start(nsi.stopCh)
                    801 go nsi.dynInformerFactory.Start(nsi.stopCh)
                task_queue.go  (1 usage found)
                    80 go func(t task, after time.Duration) {
            internal/metrics  (1 usage found)
                syslog_listener.go  (1 usage found)
                    52 go l.collector.RecordLatency(string(buffer[:n]))
            internal/nginx  (4 usages found)
                manager.go  (4 usages found)
                    305 go func() {
                    508 go func() {
                    569 go func() {
                    591 go func() {
            pkg/client/informers/externalversions  (1 usage found)
                factory.go  (1 usage found)
                    116 go func() {