migrate-clientset-to-client

name

migrate-clientset-to-client

description

Migrates Kubernetes typed clientset (e.g. client-go kubernetes.Interface or custom clientsets) in test code to the controller-runtime client.Client interface. Use when refactoring test files that call K8sClient.CoreV1().Pods().Get/Create/UpdateStatus typed APIs, replacing them with fake.NewClientBuilder + client.Client.Get/Create/Status().Update patterns. Triggered when the user mentions "replace clientset", "migrate client", or "use controller-runtime client".

Migrate Clientset to controller-runtime client.Client

Migrates typed clientset usage in test code to client.Client from sigs.k8s.io/controller-runtime/pkg/client.

Migration Patterns

Import Changes

Remove:

"github.com/openkruise/agents/pkg/sandbox-manager/clients"
// or any other typed clientset packages

Add:

"k8s.io/apimachinery/pkg/runtime"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
clientgoscheme "k8s.io/client-go/kubernetes/scheme"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/controller-runtime/pkg/client/fake"

Also import and register any custom CRD schemes (e.g. agentsv1alpha1) if needed.

---

Building a Fake Client

Before (typed clientset):

client := clients.NewFakeClientSet(t)

After (controller-runtime fake client):

// Initialize scheme at the top of the test function (or outside sub-tests for sharing)
scheme := runtime.NewScheme()
utilruntime.Must(clientgoscheme.AddToScheme(scheme))
utilruntime.Must(agentsv1alpha1.AddToScheme(scheme)) // if CRD support needed

// Build fakeClient in each sub-test
fakeClient := fake.NewClientBuilder().
    WithScheme(scheme).
    WithStatusSubresource(&corev1.Pod{}). // declare types that support status subresource
    Build()

Important: WithStatusSubresource must declare every type that needs .Status().Update(), otherwise the status field will not be persisted.

---

Creating Resources

Before:

createdPod, err := client.K8sClient.CoreV1().Pods("default").Create(ctx, pod, metav1.CreateOptions{})

After:

err := fakeClient.Create(ctx, pod)

---

Updating Status

Before:

createdPod.Status = pod.Status
_, err = client.K8sClient.CoreV1().Pods("default").UpdateStatus(ctx, createdPod, metav1.UpdateOptions{})

After:

// After Create, the original object already has ResourceVersion populated — update status directly on it
pod.Status = corev1.PodStatus{...}
err = fakeClient.Status().Update(ctx, pod)

---

Reading Resources

Before:

pod, err := client.K8sClient.CoreV1().Pods(namespace).Get(ctx, name, metav1.GetOptions{})

After:

var pod corev1.Pod
err := c.Get(ctx, types.NamespacedName{Namespace: namespace, Name: name}, &pod)

Important: Avoid naming the parameter client — it conflicts with the client package name. Use c instead.

---

Function Signature Migration

Before:

func waitForXxx(ctx context.Context, client *SomeClientSet, ...) error {
    pod, err := client.K8sClient.CoreV1().Pods(ns).Get(ctx, name, metav1.GetOptions{})

After:

func waitForXxx(ctx context.Context, c client.Client, ...) error {
    var pod corev1.Pod
    if err := c.Get(ctx, types.NamespacedName{Namespace: ns, Name: name}, &pod); err != nil {

---

Full Migration Example

Real migration in this project: pkg/sandbox-manager/infra/sandboxcr/claim_test.go

// Before (TestWaitForPodResizeState)
client := clients.NewFakeClientSet(t)
createdPod, err := client.K8sClient.CoreV1().Pods("default").Create(t.Context(), pod, metav1.CreateOptions{})
createdPod.Status = pod.Status
_, err = client.K8sClient.CoreV1().Pods("default").UpdateStatus(t.Context(), createdPod, metav1.UpdateOptions{})
err = waitForPodResizeState(t.Context(), client, ...)

// After
scheme := runtime.NewScheme()
utilruntime.Must(clientgoscheme.AddToScheme(scheme))
fakeClient := fake.NewClientBuilder().WithScheme(scheme).WithStatusSubresource(&corev1.Pod{}).Build()
err := fakeClient.Create(t.Context(), pod)
pod.Status = corev1.PodStatus{...}
err = fakeClient.Status().Update(t.Context(), pod)
err = waitForPodResizeState(t.Context(), fakeClient, ...)

---

Verification

After migration, run:

go vet ./pkg/...
go test ./pkg/<your-package>/ -count=1 -timeout 120s