✨ Allow setting "UseExistingCluster" via environment

pkg/envtest/server.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
@@ -34,6 +35,7 @@ var log = logf.RuntimeLog.WithName("test-env")
 
 // Default binary path for test framework
 const (
+	envUseExistingCluster  = "USE_EXISTING_CLUSTER"
 	envKubeAPIServerBin    = "TEST_ASSET_KUBE_APISERVER"
 	envEtcdBin             = "TEST_ASSET_ETCD"
 	envKubectlBin          = "TEST_ASSET_KUBECTL"
@@ -87,7 +89,7 @@ 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
@@ -105,7 +107,7 @@ 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()
@@ -122,7 +124,8 @@ 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 {
+	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
@@ -225,3 +228,11 @@ 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
+}