feat: fix the matchselector issue and some little typos

README.md

@@ -29,6 +29,14 @@ kubernetes-labels-migrator \
 
 ![Screenshot of a terminal with all the execution](.github/docs/demo.png "CLI demo")
 
+## Tutorial
+
+Let's say you are managing your application with the gitops's philosohpy ([ArgoCD](https://argo-cd.readthedocs.io/en/stable/) is really great to do the job). You want to add or edit a label. This difference has already been done by your code but ArgoCD refused to sync because of the "immutable field" error. Then following this:
+- ⚠️ First of all, nothing intervene during the operation! `kubernetes-labels-migrator` should be free until the end. If you have tools like ArgoCD that synchronize your resources, **please** ensure this feature is **disabled**.
+- You can commit the changes on the resource and observe the difference
+- Launch the script and watch the magic happens
+- According your changes, the difference should have been resolved
+
 ## Motivation
 
 Deployment's labels are immutable. That means, if you have to edit, rename or add labels to a deployed application, you have to delete the deployment. On a production application, it is very annoying.

logs.go

@@ -20,6 +20,7 @@ func logBlocking(msg string) {
 	magenta := color.New(color.Bold, color.FgHiMagenta).SprintFunc()
 	fmt.Println(magenta(fmt.Sprintf("⌛️ %s", msg)))
 }
+
 func logBlockingDot() {
 	magenta := color.New(color.Bold, color.FgHiMagenta).SprintFunc()
 	fmt.Print(magenta("."))

main.go

@@ -28,8 +28,8 @@ func main() {
 	var labelToChangeValue = ""
 	var goalOfOperationIsToRemoveLabel = false
 
-	flag.StringVar(&deploymentName, "deployment", "" , "Name of the deployment to edit label")
-	flag.StringVar(&namespace, "namespace", "" , "Namespace of the deployment to edit label")
+	flag.StringVar(&deploymentName, "deployment", "", "Name of the deployment to edit label")
+	flag.StringVar(&namespace, "namespace", "", "Namespace of the deployment to edit label")
 	flag.BoolVar(&goalOfOperationIsToRemoveLabel, "remove-label", false, "If true, the label will be removed instead of be added/edited")
 	flag.StringVar(&labelToChangeKey, "label", "app.kubernetes.io/name", "Name of the label")
 	flag.StringVar(&labelToChangeValue, "value", "", "Value of the label")
@@ -62,7 +62,7 @@ func main() {
 		os.Exit(0)
 	}
 
-	Step1(
+	MigrationWorkflow(
 		namespace,
 		clientset,
 		deploymentName,

steps.go

@@ -11,7 +11,7 @@ import (
 	"k8s.io/client-go/kubernetes"
 )
 
-func Step1(
+func MigrationWorkflow(
 	namespace string,
 	clientset *kubernetes.Clientset,
 	deploymentName string,
@@ -33,7 +33,7 @@ func Step1(
 	// It's required because an error is thrown, we can not create a deployment with this property provided
 	temporalDeployment.ResourceVersion = ""
 
-	_, err = clientset.AppsV1().Deployments(namespace).Create(context.TODO(), &temporalDeployment, metav1.CreateOptions{});
+	_, err = clientset.AppsV1().Deployments(namespace).Create(context.TODO(), &temporalDeployment, metav1.CreateOptions{})
 	if err != nil {
 		if strings.Contains(err.Error(), "already exists, the server was not able to generate a unique name for the object") {
 			logWarning("1. Temporary deployment already created. Continue...")
@@ -45,7 +45,7 @@ func Step1(
 	logInfo("2. Updating the service...")
 	var temporalService = *currentService
 	delete(temporalService.Spec.Selector, changingLabelKey)
-	_, err = clientset.CoreV1().Services(namespace).Update(context.TODO(), &temporalService, metav1.UpdateOptions{});
+	_, err = clientset.CoreV1().Services(namespace).Update(context.TODO(), &temporalService, metav1.UpdateOptions{})
 	check(err)
 	logSuccess("2. Service updated")
 
@@ -54,9 +54,9 @@ func Step1(
 	for !areAllPodReady {
 		logBlockingDot()
 		time.Sleep(1 * time.Second)
-		areAllPodReady = 
-			waitUntilAllPodAreReady(clientset, namespace, "api") && 
-			waitUntilAllPodAreReady(clientset, namespace, fmt.Sprintf("%s-%s", currentDeployment.Name, "changing-label-tmp"))
+		areAllPodReady =
+			waitUntilAllPodAreReady(clientset, namespace, currentDeployment.Name) &&
+				waitUntilAllPodAreReady(clientset, namespace, fmt.Sprintf("%s-%s", currentDeployment.Name, "changing-label-tmp"))
 	}
 	fmt.Println("")
 
@@ -78,12 +78,17 @@ func Step1(
 	if removeLabel {
 		delete(futureOfficialDeployment.ObjectMeta.Labels, changingLabelKey)
 		delete(futureOfficialDeployment.Spec.Template.ObjectMeta.Labels, changingLabelKey)
-		} else {
+		delete(futureOfficialDeployment.Spec.Selector.MatchLabels, changingLabelKey)
+	} else {
+		// Label of the deployment
 		futureOfficialDeployment.ObjectMeta.Labels[changingLabelKey] = changingLabelValue
+		// Label of the pod created by the deployment
 		futureOfficialDeployment.Spec.Template.ObjectMeta.Labels[changingLabelKey] = changingLabelValue
+		// Then we must include the label in the matchSelector for the deployment to find pods
+		futureOfficialDeployment.Spec.Selector.MatchLabels[changingLabelKey] = changingLabelValue
 	}
 
-	_, err = clientset.AppsV1().Deployments(namespace).Create(context.TODO(), &futureOfficialDeployment, metav1.CreateOptions{});
+	_, err = clientset.AppsV1().Deployments(namespace).Create(context.TODO(), &futureOfficialDeployment, metav1.CreateOptions{})
 	if err != nil {
 		if strings.Contains(err.Error(), "already exists, the server was not able to generate a unique name for the object") {
 			fmt.Println("⚠️  Temporary deployment already created. Continue...")
@@ -97,7 +102,7 @@ func Step1(
 	for !areAllPodReady {
 		logBlockingDot()
 		time.Sleep(1 * time.Second)
-		areAllPodReady = waitUntilAllPodAreReady(clientset, namespace, "api")
+		areAllPodReady = waitUntilAllPodAreReady(clientset, namespace, currentDeployment.Name)
 	}
 	fmt.Println("")
 
@@ -109,7 +114,7 @@ func Step1(
 	logSuccess("7. Temporary deployment deleted")
 }
 
-func AddLabelToServiceSelector (
+func AddLabelToServiceSelector(
 	namespace string,
 	clientset *kubernetes.Clientset,
 	applicationName string,
@@ -123,7 +128,6 @@ func AddLabelToServiceSelector (
 	currentService, err := clientset.CoreV1().Services(namespace).Get(context.TODO(), applicationName, metav1.GetOptions{})
 	check(err)
 
-
 	var futureService = *currentService
 	if removeLabel {
 		// Update the value of the label

summary.go

@@ -18,8 +18,8 @@ func displaySummary(
 	t := table.NewWriter()
 	t.SetOutputMirror(os.Stdout)
 	t.AppendHeader(table.Row{"Parameter", "Value"})
-	t.AppendRows([]table.Row{{"Deployement name", namespace}})
-	t.AppendRows([]table.Row{{"Namespace", deploymentName}})
+	t.AppendRows([]table.Row{{"Deployment name", deploymentName}})
+	t.AppendRows([]table.Row{{"Namespace", namespace}})
 	if goalOfOperationIsToRemoveLabel {
 		t.AppendRows([]table.Row{{"Label", labelToChangeKey}})
 	} else {

version.go

@@ -7,8 +7,8 @@ import (
 	"github.com/fatih/color"
 )
 
-const Version string = "0.1.1"
-const BuildDate string = "2024-03-24"
+const Version string = "0.1.2"
+const BuildDate string = "2024-04-11"
 
 func cliCommandDisplayHelp(args []string) {
 	displayVersion := stringInSlice("-v", args[1:]) || stringInSlice("--version", args[1:])