add an option for passing custom k8s rest config

modules/k8s/client.go

@@ -34,6 +34,9 @@ func GetKubernetesClientFromOptionsE(t testing.TestingT, options *KubectlOptions
 			return nil, err
 		}
 		logger.Log(t, "Configuring Kubernetes client to use the in-cluster serviceaccount token")
+	} else if options.RestConfig != nil {
+		config = options.RestConfig
+		logger.Log(t, "Configuring Kubernetes client to use provided rest config object set with API server address: %s", config.Host)
 	} else {
 		kubeConfigPath, err := options.GetConfigPath(t)
 		if err != nil {

modules/k8s/kubectl_options.go

@@ -3,6 +3,7 @@ package k8s
 import (
 	"github.com/gruntwork-io/terratest/modules/logger"
 	"github.com/gruntwork-io/terratest/modules/testing"
+	"k8s.io/client-go/rest"
 )
 
 // KubectlOptions represents common options necessary to specify for all Kubectl calls
@@ -12,6 +13,7 @@ type KubectlOptions struct {
 	Namespace     string
 	Env           map[string]string
 	InClusterAuth bool
+	RestConfig    *rest.Config
 	Logger        *logger.Logger
 }
 
@@ -32,6 +34,14 @@ func NewKubectlOptionsWithInClusterAuth() *KubectlOptions {
 	}
 }
 
+// NewKubectlOptionsWithRestConfig will return a pointer to a new instance of KubectlOptions with pre-built config object
+func NewKubectlOptionsWithRestConfig(config *rest.Config, namespace string) *KubectlOptions {
+	return &KubectlOptions{
+		Namespace:  namespace,
+		RestConfig: config,
+	}
+}
+
 // GetConfigPath will return a sensible default if the config path is not set on the options.
 func (kubectlOptions *KubectlOptions) GetConfigPath(t testing.TestingT) (string, error) {
 	// We predeclare `err` here so that we can update `kubeConfigPath` in the if block below. Otherwise, go complains

test/kubernetes_rest_config_example_test.go

@@ -0,0 +1,71 @@
+//go:build kubeall || kubernetes
+// +build kubeall kubernetes
+
+// NOTE: we have build tags to differentiate kubernetes tests from non-kubernetes tests. This is done because minikube
+// is heavy and can interfere with docker related tests in terratest. Specifically, many of the tests start to fail with
+// `connection refused` errors from `minikube`. To avoid overloading the system, we run the kubernetes tests and helm
+// tests separately from the others. This may not be necessary if you have a sufficiently powerful machine.  We
+// recommend at least 4 cores and 16GB of RAM if you want to run all the tests together.
+
+package test
+
+import (
+	"fmt"
+	"os/user"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"k8s.io/client-go/tools/clientcmd"
+
+	"github.com/gruntwork-io/terratest/modules/k8s"
+	"github.com/gruntwork-io/terratest/modules/random"
+)
+
+func TestKubernetesRestConfigBasicExampleConfig(t *testing.T) {
+	t.Parallel()
+
+	// website::tag::1::Path to the Kubernetes resource config we will test
+	kubeResourcePath, err := filepath.Abs("../examples/kubernetes-basic-example/nginx-deployment.yml")
+	require.NoError(t, err)
+
+	// To ensure we can reuse the resource config on the same cluster to test different scenarios, we setup a unique
+	// namespace for the resources for this test.
+	// Note that namespaces must be lowercase.
+	namespaceName := fmt.Sprintf("kubernetes-basic-example-%s", strings.ToLower(random.UniqueId()))
+
+	usr, err := user.Current()
+	if err != nil {
+		require.NoError(t, err)
+	}
+
+	// Construct the path to the kubeconfig file
+	kubeconfigPath := filepath.Join(usr.HomeDir, ".kube", "config")
+
+	// Generate rest.Config from kubeconfig file
+	config, err := clientcmd.BuildConfigFromFlags("", kubeconfigPath)
+	if err != nil {
+		panic(err.Error())
+	}
+
+	// website::tag::2:: Setup the kubectl config and context.
+	options := k8s.NewKubectlOptionsWithRestConfig(config, namespaceName)
+
+	k8s.CreateNamespace(t, options, namespaceName)
+	// website::tag::5::Make sure to delete the namespace at the end of the test
+	defer k8s.DeleteNamespace(t, options, namespaceName)
+
+	// website::tag::6::At the end of the test, run `kubectl delete -f RESOURCE_CONFIG` to clean up any resources that were created.
+	defer k8s.KubectlDelete(t, options, kubeResourcePath)
+
+	// website::tag::3::Apply kubectl with 'kubectl apply -f RESOURCE_CONFIG' command.
+	// This will run `kubectl apply -f RESOURCE_CONFIG` and fail the test if there are any errors
+	k8s.KubectlApply(t, options, kubeResourcePath)
+
+	// website::tag::4::Check if NGINX service was deployed successfully.
+	// This will get the service resource and verify that it exists and was retrieved successfully. This function will
+	// fail the test if the there is an error retrieving the service resource from Kubernetes.
+	service := k8s.GetService(t, options, "nginx-service")
+	require.Equal(t, service.Name, "nginx-service")
+}