go.mod

module foo

go 1.21.1

require (
	k8s.io/api v0.28.1
	k8s.io/client-go v0.28.1
	sigs.k8s.io/controller-runtime v0.16.1
)

require (
	github.com/davecgh/go-spew v1.1.1 // indirect
	github.com/emicklei/go-restful/v3 v3.9.0 // indirect
	github.com/evanphx/json-patch v5.6.0+incompatible // indirect
	github.com/evanphx/json-patch/v5 v5.6.0 // indirect
	github.com/go-logr/logr v1.2.4 // indirect
	github.com/go-openapi/jsonpointer v0.19.6 // indirect
	github.com/go-openapi/jsonreference v0.20.2 // indirect
	github.com/go-openapi/swag v0.22.3 // indirect
	github.com/gogo/protobuf v1.3.2 // indirect
	github.com/golang/protobuf v1.5.3 // indirect
	github.com/google/gnostic-models v0.6.8 // indirect
	github.com/google/go-cmp v0.5.9 // indirect
	github.com/google/gofuzz v1.2.0 // indirect
	github.com/google/uuid v1.3.0 // indirect
	github.com/josharian/intern v1.0.0 // indirect
	github.com/json-iterator/go v1.1.12 // indirect
	github.com/mailru/easyjson v0.7.7 // indirect
	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
	github.com/modern-go/reflect2 v1.0.2 // indirect
	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
	github.com/pkg/errors v0.9.1 // indirect
	golang.org/x/net v0.13.0 // indirect
	golang.org/x/oauth2 v0.8.0 // indirect
	golang.org/x/sys v0.11.0 // indirect
	golang.org/x/term v0.10.0 // indirect
	golang.org/x/text v0.11.0 // indirect
	golang.org/x/time v0.3.0 // indirect
	google.golang.org/appengine v1.6.7 // indirect
	google.golang.org/protobuf v1.30.0 // indirect
	gopkg.in/inf.v0 v0.9.1 // indirect
	gopkg.in/yaml.v2 v2.4.0 // indirect
	gopkg.in/yaml.v3 v3.0.1 // indirect
	k8s.io/apimachinery v0.28.1 // indirect
	k8s.io/klog/v2 v2.100.1 // indirect
	k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9 // indirect
	k8s.io/utils v0.0.0-20230406110748-d93618cff8a2 // indirect
	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
	sigs.k8s.io/yaml v1.3.0 // indirect
)

main.go

package main

import (
	"context"
	"fmt"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/client-go/kubernetes/scheme"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/client/fake"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

func main() {
	// Create a new fake client.
	scheme := scheme.Scheme
	cl := fake.NewClientBuilder().WithScheme(scheme).Build()

	// Create a Pod object.
	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "example-pod",
			Namespace: "default",
		},
		Spec: corev1.PodSpec{
			Containers: []corev1.Container{
				{
					Name:  "nginx",
					Image: "nginx:latest",
				},
			},
		},
	}

	// Create the Pod on the fake client.
	err := cl.Create(context.Background(), pod)
	if err != nil {
		fmt.Printf("Error creating Pod: %v\n", err)
		return
	}

	// Simulate some changes to the Pod's status.
	pod.Status.Phase = corev1.PodRunning

	// Update the Pod on the fake client.
	// !!!!! not using cl.Status().Update !!!!
	err = cl.Update(context.Background(), pod)
	if err != nil {
		fmt.Printf("Error updating Pod: %v\n", err)
		return
	}

	// Get the Pod back from the fake client.
	updatedPod := &corev1.Pod{}
	err = cl.Get(context.Background(), client.ObjectKey{Namespace: "default", Name: "example-pod"}, updatedPod)
	if err != nil {
		fmt.Printf("Error getting Pod: %v\n", err)
		return
	}

	// Print the updated Pod's status.
	fmt.Printf("Updated Pod Status: %v\n", updatedPod.Status)
}