fake.clientset doesn't behave properly on Apply

[miguescri]

What I'm trying to do: use the fake.Clientset mock to unit test a declarative Apply operation.
Expected behavior: if the declarative resource doesn't refer to an existing object, create it; else, patch it.
Actual behavior: when the declarative resource doesn't refer to an existing object, returns error "Not found".

Minimal reproducible test:

package clientest_bug

import (
	"context"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	applyv1 "k8s.io/client-go/applyconfigurations/core/v1"
	"k8s.io/client-go/kubernetes/fake"
	"testing"
)

func TestClientsetApply(t *testing.T) {
	clientset := fake.NewSimpleClientset()
	namespaceClient := clientset.CoreV1().Namespaces()

	namespace := applyv1.Namespace("test-namespace")
	_, err := namespaceClient.Apply(context.TODO(), namespace, v1.ApplyOptions{FieldManager: "test"})
	if err != nil {
		t.Fatalf("Error: %s", err)
	}
}

go test output:

/usr/lib/go-1.18/bin/go tool test2json -t /tmp/GoLand/___go_test_clientest_bug.test -test.v -test.paniconexit0
=== RUN   TestClientsetApply
    main_test.go:18: Error: namespaces "test-namespace" not found
--- FAIL: TestClientsetApply (0.00s)

FAIL

Process finished with the exit code 1

[vietanhduong]

Not only apply, I think this happens with all other verbs and CRDs.

[therealmitchconnors]

I was able to work around this with a Deployment reactor. A smarter man than myself might combine this with a restmapper and scheme to work for any type until the client-go library is fixed.

f := fake.NewSimpleClientset(objects...)
f.PrependReactor(
"patch",
"deployments",
func(action clienttesting.Action) (handled bool, ret runtime.Object, err error) {
	pa := action.(clienttesting.PatchAction)
	if pa.GetPatchType() == types.ApplyPatchType {
		// Apply patches are supposed to upsert, but fake client fails if the object doesn't exist,
		// if an apply patch occurs for a deployment that doesn't yet exist, create it.
		// However, we already hold the fakeclient lock, so we can't use the front door.
		rfunc := clienttesting.ObjectReaction(f.Tracker())
		_, obj, err := rfunc(
			clienttesting.NewGetAction(pa.GetResource(), pa.GetNamespace(), pa.GetName()),
		)
		if kerrors.IsNotFound(err) || obj == nil {
			_, _, _ = rfunc(
				clienttesting.NewCreateAction(
					pa.GetResource(),
					pa.GetNamespace(),
					&appsv1.Deployment{
						ObjectMeta: metav1.ObjectMeta{
							Name:      pa.GetName(),
							Namespace: pa.GetNamespace(),
						},
					},
				),
			)
		}
		return rfunc(clienttesting.NewPatchAction(
			pa.GetResource(),
			pa.GetNamespace(),
			pa.GetName(),
			types.StrategicMergePatchType,
			pa.GetPatch()))
	}
	return false, nil, nil
},
)

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/lifecycle stale

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/lifecycle rotten

[k8s-triage-robot]

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/close not-planned

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue, marking it as "Not Planned".

In response to this:

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

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/close not-planned

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[paulopiriquito]

/reopen

[k8s-ci-robot]

@paulopiriquito: You can't reopen an issue/PR unless you authored it or you are a collaborator.

In response to this:

/reopen

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[paulopiriquito]

/remove-lifecycle rotten