test/integration: goroutine leak check

go.mod

@@ -74,6 +74,7 @@ require (
 	go.opentelemetry.io/otel/sdk v1.10.0
 	go.opentelemetry.io/otel/trace v1.10.0
 	go.opentelemetry.io/proto/otlp v0.19.0
+	go.uber.org/goleak v1.2.1
 	go.uber.org/zap v1.19.0
 	golang.org/x/crypto v0.1.0
 	golang.org/x/net v0.5.0

go.sum

@@ -762,7 +762,8 @@ go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/goleak v1.1.10/go.mod h1:8a7PlsEVH3e/a/GLqe5IIrQx6GzcnRmZEufDUTk4A7A=
-go.uber.org/goleak v1.2.0 h1:xqgm/S+aQvhWFTtR0XK3Jvg7z8kGV8P4X14IzwN3Eqk=
+go.uber.org/goleak v1.2.1 h1:NBol2c7O1ZokfZ0LEU9K6Whx/KnwvepVetCUhtKja4A=
+go.uber.org/goleak v1.2.1/go.mod h1:qlT2yGI9QafXHhZZLxlSuNsMw3FFLxBr+tBRlmO1xH4=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4=
 go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=

staging/src/k8s.io/component-base/go.mod

@@ -62,7 +62,7 @@ require (
 	go.opentelemetry.io/otel/metric v0.31.0 // indirect
 	go.opentelemetry.io/proto/otlp v0.19.0 // indirect
 	go.uber.org/atomic v1.7.0 // indirect
-	go.uber.org/goleak v1.2.0 // indirect
+	go.uber.org/goleak v1.2.1 // indirect
 	go.uber.org/multierr v1.6.0 // indirect
 	golang.org/x/net v0.5.0 // indirect
 	golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b // indirect

test/integration/framework/etcd.go

@@ -29,10 +29,10 @@ import (
 	"syscall"
 	"time"
 
+	"go.uber.org/goleak"
 	"google.golang.org/grpc/grpclog"
 	"k8s.io/klog/v2"
 
-	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/kubernetes/pkg/util/env"
 )
 
@@ -182,37 +182,48 @@ func EtcdMain(tests func() int) {
 	// Bail out early when -help was given as parameter.
 	flag.Parse()
 
-	before := runtime.NumGoroutine()
+	// Must be called *before* creating new goroutines.
+	goleakOpts := IgnoreBackgroundGoroutines()
+
+	goleakOpts = append(goleakOpts,
+		// lumberjack leaks a goroutine:
+		// https://github.com/natefinch/lumberjack/issues/56 This affects tests
+		// using --audit-log-path (like
+		// ./test/integration/apiserver/admissionwebhook/reinvocation_test.go).
+		// In normal production that should be harmless. We don't know here
+		// whether the test is using that, so we have to suppress reporting
+		// this leak for all tests.
+		//
+		// Both names occurred in practice.
+		goleak.IgnoreTopFunction("k8s.io/kubernetes/vendor/gopkg.in/natefinch/lumberjack%2ev2.(*Logger).millRun"),
+		goleak.IgnoreTopFunction("gopkg.in/natefinch/lumberjack%2ev2.(*Logger).millRun"),
+	)
+
 	stop, err := startEtcd()
 	if err != nil {
 		klog.Fatalf("cannot run integration tests: unable to start etcd: %v", err)
 	}
 	result := tests()
 	stop() // Don't defer this. See os.Exit documentation.
-
-	checkNumberOfGoroutines := func() (bool, error) {
-		// We leave some room for leaked goroutines as there are
-		// still some leaks, mostly:
-		// - leak from lumberjack package we're vendoring
-		// - leak from apiserve healthz
-		// - leak from opencensus library
-		// Once fixed, we should be able to bring it down to zero.
-		if dg := runtime.NumGoroutine() - before; dg <= 3 {
-			return true, nil
+	klog.StopFlushDaemon()
+
+	// Several tests don't wait for goroutines to stop. goleak.Find retries
+	// internally, but not long enough. 5 seconds seemed to be enough for
+	// most tests, even when testing in the CI.
+	timeout := 5 * time.Second
+	start := time.Now()
+	for {
+		err := goleak.Find(goleakOpts...)
+		if err == nil {
+			break
+		}
+		if time.Now().Sub(start) >= timeout {
+			klog.ErrorS(err, "EtcdMain goroutine check")
+			result = 1
+			break
 		}
-		// Allow goroutines to schedule and die off.
-		runtime.Gosched()
-		return false, nil
 	}
 
-	// It generally takes visibly less than 1s to finish all goroutines.
-	// But we keep the limit higher to account for cpu-starved environments.
-	if err := wait.Poll(100*time.Millisecond, 5*time.Second, checkNumberOfGoroutines); err != nil {
-		after := runtime.NumGoroutine()
-		stacktraces := make([]byte, 1<<20)
-		runtime.Stack(stacktraces, true)
-		klog.Fatalf("unexpected number of goroutines: before: %d after %d\n%sd", before, after, string(stacktraces))
-	}
 	os.Exit(result)
 }
 

test/integration/framework/goleak.go

@@ -0,0 +1,36 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package framework
+
+import (
+	"go.uber.org/goleak"
+	"k8s.io/apiserver/pkg/server/healthz"
+)
+
+// IgnoreBackgroundGoroutines returns options for goleak.Find
+// which ignore goroutines created by "go test" and init functions,
+// like the one from go.opencensus.io/stats/view/worker.go.
+//
+// Goroutines that normally get created later when using the apiserver
+// get created already when calling this function, therefore they
+// also get ignored.
+func IgnoreBackgroundGoroutines() []goleak.Option {
+	// Ensure that on-demand goroutines are running.
+	_ = healthz.LogHealthz.Check(nil)
+
+	return []goleak.Option{goleak.IgnoreCurrent()}
+}