kubernetes/vendor/go.uber.org/goleak
Patrick Ohly f131cabfa0 test: use go-uber/goleak for strict leak checking
It provides more readable output and has additional APIs for using it inside a
unit test. goleak.IgnoreCurrent is needed to filter out the goroutine that gets
started when importing go.opencensus.io/stats/view.

In order to handle background goroutines that get created on demand and cannot
be stopped (like the one for LogzHealth), a helper function ensures that those
are running before calling goleak.IgnoreCurrent. Keeping those goroutines
running is not a problem and thus not worth the effort of adding new APIs to
stop them.

Other goroutines are genuine leaks for which no fix is available. Those get
suppressed via IgnoreTopFunction, which works as long as that function
is unique enough.

Example output for the leak fixed in https://github.com/kubernetes/kubernetes/pull/115423:

    E0202 09:30:51.641841   74789 etcd.go:205] "EtcdMain goroutine check" err=<
        found unexpected goroutines:
        [Goroutine 4889 in state chan receive, with k8s.io/apimachinery/pkg/watch.(*Broadcaster).loop on top of the stack:
        goroutine 4889 [chan receive]:
        k8s.io/apimachinery/pkg/watch.(*Broadcaster).loop(0xc0076183c0)
        	/nvme/gopath/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/watch/mux.go:268 +0x65
        created by k8s.io/apimachinery/pkg/watch.NewBroadcaster
        	/nvme/gopath/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/watch/mux.go:77 +0x116
    >
2023-02-14 12:11:37 +01:00
..
internal/stack
.gitignore test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
CHANGELOG.md test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
doc.go test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
glide.yaml test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
leaks.go test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
LICENSE test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
Makefile
options.go test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
README.md test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
testmain.go test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00
tracestack_new.go test: use go-uber/goleak for strict leak checking 2023-02-14 12:11:37 +01:00

goleak GoDoc Build Status Coverage Status

Goroutine leak detector to help avoid Goroutine leaks.

Installation

You can use go get to get the latest version:

go get -u go.uber.org/goleak

goleak also supports semver releases.

Note that go-leak only supports the two most recent minor versions of Go.

Quick Start

To verify that there are no unexpected goroutines running at the end of a test:

func TestA(t *testing.T) {
	defer goleak.VerifyNone(t)

	// test logic here.
}

Instead of checking for leaks at the end of every test, goleak can also be run at the end of every test package by creating a TestMain function for your package:

func TestMain(m *testing.M) {
	goleak.VerifyTestMain(m)
}

Determine Source of Package Leaks

When verifying leaks using TestMain, the leak test is only run once after all tests have been run. This is typically enough to ensure there's no goroutines leaked from tests, but when there are leaks, it's hard to determine which test is causing them.

You can use the following bash script to determine the source of the failing test:

# Create a test binary which will be used to run each test individually
$ go test -c -o tests

# Run each test individually, printing "." for successful tests, or the test name
# for failing tests.
$ for test in $(go test -list . | grep -E "^(Test|Example)"); do ./tests -test.run "^$test\$" &>/dev/null && echo -n "." || echo -e "\n$test failed"; done

This will only print names of failing tests which can be investigated individually. E.g.,

.....
TestLeakyTest failed
.......

Stability

goleak is v1 and follows SemVer strictly.

No breaking changes will be made to exported APIs before 2.0.