Update To Go 1.15.0

[seanmalloy]

As part of the k8s 1.19 release cycle the Go version is being bumped to
1.15.0. Updating the descheduler to use Go 1.15 prior to the descheduler
v0.19.0 release.

See below issues for reference:

• Golang 1.15 updates kubernetes/release#1421
• go1.15.0 / k8s 1.19 tracker kubernetes/kubernetes#93484

[seanmalloy]

/hold

We should wait until the k/k repo is successfully updated to use Go 1.15.0. Also, the descheduler test-infra jobs for the master branch should be updated to use Go 1.15.0.

[seanmalloy]

The k/k repo has been updated with Go 1.15.0: kubernetes/kubernetes#93939. I believe this plan for the k8s 1.19 release is still to use Go 1.15.0.

I believe all that needs to be done now for the descheduler is to update test-infra jobs to use Go 1.15. Then this PR can be retested and merged.

[seanmalloy]

Created PR kubernetes/test-infra#18836 to update the descheduler test-intra jobs to use Go 1.15.

[ingvagabund]

@seanmalloy is the code currently vendored in the descheduler buildable with go1.15?

[seanmalloy]

@seanmalloy is the code currently vendored in the descheduler buildable with go1.15?

Yes, I was able to compile with go 1.15 and run "go mod vendor" and "go mod tidy". No changes to the vendor directory were made when updating from go 1.14 to go 1.15.

[seanmalloy]

I did notice that make verify fails with Go 1.15. I will have to figure out how to fix this before we can merge this.

Error details:

make verify
./hack/verify-gofmt.sh
./hack/verify-vendor.sh
Vendor Verified.
Removing ./hack/../_tmp/kube-vendor.3Zn7Ec
./_output/bin/golangci-lint run
WARN [runner/gosimple] Can't run megacheck because of compilation errors in packages [sigs.k8s.io/descheduler/pkg/apis/componentconfig sigs.k8s.io/descheduler/pkg/apis/componentconfig/v1alpha1 sigs.k8s.io/descheduler/pkg/api sigs.k8s.io/descheduler/pkg/api/v1alpha1 sigs.k8s.io/descheduler/pkg/descheduler/scheme sigs.k8s.io/descheduler/cmd/descheduler/app/options sigs.k8s.io/descheduler/pkg/descheduler/client sigs.k8s.io/descheduler/pkg/descheduler/evictions/utils sigs.k8s.io/descheduler/pkg/utils sigs.k8s.io/descheduler/cmd/descheduler/app sigs.k8s.io/descheduler/test sigs.k8s.io/descheduler/pkg/descheduler [sigs.k8s.io/descheduler/pkg/descheduler.test] sigs.k8s.io/descheduler/pkg/descheduler/evictions [sigs.k8s.io/descheduler/pkg/descheduler/evictions.test] sigs.k8s.io/descheduler/pkg/descheduler/node [sigs.k8s.io/descheduler/pkg/descheduler/node.test] sigs.k8s.io/descheduler/pkg/descheduler/pod [sigs.k8s.io/descheduler/pkg/descheduler/pod.test] sigs.k8s.io/descheduler/pkg/descheduler/strategies [sigs.k8s.io/descheduler/pkg/descheduler/strategies.test] sigs.k8s.io/descheduler/test/e2e [sigs.k8s.io/descheduler/test/e2e.test]]: pkg/apis/componentconfig/doc.go:1: /Users/foo/tech/go/src/fmt/scan.go:334:15: RuneLen not declared by package utf8 and 1988 more errors: run `golangci-lint run --no-config --disable-all -E typecheck` to see all errors
helm lint ./charts/descheduler
==> Linting ./charts/descheduler

1 chart(s) linted, 0 chart(s) failed

[seanmalloy]

I got a little bit closer. I had to update golangci-lint to 1.30.0 to make it work with Go 1.15. But now the new version of golangci-lint is failing with the below errors:

./_output/bin/golangci-lint run
pkg/descheduler/strategies/lownodeutilization_test.go:817:27: copylocks: literal copies lock value from *fakePtr: k8s.io/client-go/testing.Fake (govet)
				&fake.Clientset{Fake: *fakePtr},
				                      ^
pkg/descheduler/strategies/lownodeutilization_test.go:825:50: copylocks: literal copies lock value from *fakePtr: k8s.io/client-go/testing.Fake (govet)
			LowNodeUtilization(ctx, &fake.Clientset{Fake: *fakePtr}, strategy, item.nodes, podEvictor)
			                                              ^
make: *** [Makefile:89: lint] Error 1

@ingvagabund @lixiang233 @damemi any ideas what I need to change to make the new version of golangci-lint happy?

[lixiang233]

pkg/descheduler/strategies/lownodeutilization_test.go:817:27: copylocks: literal copies lock value from *fakePtr: k8s.io/client-go/testing.Fake (govet)

@seanmalloy This error haapens because Fake contains sync.RWMutex and we are passing a copy of Fake which may cause dead lock(it should be referred to through a pointer).

I think we can refactor newFake to create a fake.Clientset just like NewSimpleClientset. E.g.

func newFakeClient(objects ...runtime.Object) *fake.Clientset {
	...

	fakeClient := &fake.Clientset{}
	fakeClient.AddReactor("list", "pods", func(action core.Action) (bool, runtime.Object, error) {
		...
	})
	fakeClient.AddReactor("*", "*", core.ObjectReaction(o))
	fakeClient.AddWatchReactor("*", core.DefaultWatchReactor(watch.NewFake(), nil))

	return fakeClient
}

[ingvagabund]

@lixiang233 @seanmalloy let's drop the fake completely: #385

[seanmalloy]

I will rebase this PR after #385 is merged. Then I think it might work.

[ingvagabund]

/retest

[ingvagabund]

/retest

[seanmalloy]

/hold cancel
/assign @damemi @ingvagabund

[ingvagabund]

/lgtm

[damemi]

/approve

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