✨ make UseExistingCluster a pointer to support explicitly opt-out in …

…the code

pkg/envtest/server.go

@@ -90,7 +90,7 @@ type Environment struct {
 	// UseExisting indicates that this environments should use an
 	// existing kubeconfig, instead of trying to stand up a new control plane.
 	// This is useful in cases that need aggregated API servers and the like.
-	UseExistingCluster bool
+	UseExistingCluster *bool
 
 	// ControlPlaneStartTimeout is the maximum duration each controlplane component
 	// may take to start. It defaults to the KUBEBUILDER_CONTROLPLANE_START_TIMEOUT
@@ -113,7 +113,7 @@ type Environment struct {
 
 // Stop stops a running server
 func (te *Environment) Stop() error {
-	if te.UseExistingCluster {
+	if te.UseExistingCluster != nil && *te.UseExistingCluster {
 		return nil
 	}
 	return te.ControlPlane.Stop()
@@ -130,11 +130,8 @@ func (te Environment) getAPIServerFlags() []string {
 
 // Start starts a local Kubernetes server and updates te.ApiserverPort with the port it is listening on
 func (te *Environment) Start() (*rest.Config, error) {
-	if !te.UseExistingCluster {
-		// Check USE_EXISTING_CLUSTER env then
-		te.UseExistingCluster = strings.ToLower(os.Getenv(envUseExistingCluster)) == "true"
-	}
-	if te.UseExistingCluster {
+	useExistingCluster := te.useExistingCluster()
+	if useExistingCluster {
 		log.V(1).Info("using existing cluster")
 		if te.Config == nil {
 			// we want to allow people to pass in their own config, so
@@ -256,3 +253,11 @@ func (te *Environment) defaultTimeouts() error {
 	}
 	return nil
 }
+
+func (te *Environment) useExistingCluster() bool {
+	if te.UseExistingCluster == nil {
+		useExistingCluster := strings.ToLower(os.Getenv(envUseExistingCluster)) == "true"
+		te.UseExistingCluster = &useExistingCluster
+	}
+	return *te.UseExistingCluster == true
+}