Plugin code refactoring

The plugin code has been refactored to
implement a common interface.
This will allow us to do plugin validation
at loadtime of the plugin instead of at runtime.
This also makes the code calling the plugins cleaner
and easier to read.

Issue-ID: MULTICLOUD-557
Change-Id: Ice2bcc9b850d7c0e1707dcc42132c63dd77472a7
Signed-off-by: Kiran Kamineni <kiran.k.kamineni@intel.com>

2 files changed, 104 insertions, 62 deletions

diff --git a/src/k8splugin/plugins/namespace/plugin.go b/src/k8splugin/plugins/namespace/plugin.go
index 6f823918..2d5d2ab8 100644
--- a/src/k8splugin/plugins/namespace/plugin.go
+++ b/src/k8splugin/plugins/namespace/plugin.go
@@ -16,39 +16,42 @@ package main
 import (
 	"log"
 
-	"k8s.io/client-go/kubernetes"
-
 	pkgerrors "github.com/pkg/errors"
-
 	coreV1 "k8s.io/api/core/v1"
 	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 
 	utils "k8splugin/internal"
+	"k8splugin/internal/helm"
+	"k8splugin/internal/plugin"
 )
 
+// ExportedVariable is what we will look for when calling the plugin
+var ExportedVariable namespacePlugin
+
+type namespacePlugin struct {
+}
+
 // Create a namespace object in a specific Kubernetes cluster
-func Create(data *utils.ResourceData, client kubernetes.Interface) (string, error) {
-	namespace := &coreV1.Namespace{
+func (p namespacePlugin) Create(yamlFilePath string, namespace string, client plugin.KubernetesConnector) (string, error) {
+	namespaceObj := &coreV1.Namespace{
 		ObjectMeta: metaV1.ObjectMeta{
-			Name: data.Namespace,
+			Name: namespace,
 		},
 	}
-	_, err := client.CoreV1().Namespaces().Create(namespace)
+	_, err := client.GetStandardClient().CoreV1().Namespaces().Create(namespaceObj)
 	if err != nil {
 		return "", pkgerrors.Wrap(err, "Create Namespace error")
 	}
-	log.Printf("Namespace (%s) created", data.Namespace)
+	log.Printf("Namespace (%s) created", namespace)
 
-	return data.Namespace, nil
+	return namespace, nil
 }
 
 // Get an existing namespace hosted in a specific Kubernetes cluster
-func Get(name string, namespace string, client kubernetes.Interface) (string, error) {
+func (p namespacePlugin) Get(resource helm.KubernetesResource, namespace string, client plugin.KubernetesConnector) (string, error) {
 	opts := metaV1.GetOptions{}
-	opts.APIVersion = "apps/v1"
-	opts.Kind = "Deployment"
-
-	ns, err := client.CoreV1().Namespaces().Get(name, opts)
+	ns, err := client.GetStandardClient().CoreV1().Namespaces().Get(resource.Name, opts)
 	if err != nil {
 		return "", pkgerrors.Wrap(err, "Get Namespace error")
 	}
@@ -57,14 +60,14 @@ func Get(name string, namespace string, client kubernetes.Interface) (string, er
 }
 
 // Delete an existing namespace hosted in a specific Kubernetes cluster
-func Delete(name string, namespace string, client kubernetes.Interface) error {
+func (p namespacePlugin) Delete(resource helm.KubernetesResource, namespace string, client plugin.KubernetesConnector) error {
 	deletePolicy := metaV1.DeletePropagationForeground
 	opts := &metaV1.DeleteOptions{
 		PropagationPolicy: &deletePolicy,
 	}
 
-	log.Println("Deleting namespace: " + name)
-	if err := client.CoreV1().Namespaces().Delete(name, opts); err != nil {
+	log.Println("Deleting namespace: " + resource.Name)
+	if err := client.GetStandardClient().CoreV1().Namespaces().Delete(resource.Name, opts); err != nil {
 		return pkgerrors.Wrap(err, "Delete namespace error")
 	}
 
@@ -72,23 +75,30 @@ func Delete(name string, namespace string, client kubernetes.Interface) error {
 }
 
 // List of existing namespaces hosted in a specific Kubernetes cluster
-func List(namespace string, client kubernetes.Interface) ([]string, error) {
+// This plugin ignores both gvk and namespace arguments
+func (p namespacePlugin) List(gvk schema.GroupVersionKind, namespace string, client plugin.KubernetesConnector) ([]helm.KubernetesResource, error) {
 	opts := metaV1.ListOptions{
 		Limit: utils.ResourcesListLimit,
 	}
-	opts.APIVersion = "apps/v1"
-	opts.Kind = "Namespace"
 
-	list, err := client.CoreV1().Namespaces().List(opts)
+	list, err := client.GetStandardClient().CoreV1().Namespaces().List(opts)
 	if err != nil {
 		return nil, pkgerrors.Wrap(err, "Get Namespace list error")
 	}
 
-	result := make([]string, 0, utils.ResourcesListLimit)
+	result := make([]helm.KubernetesResource, 0, utils.ResourcesListLimit)
 	if list != nil {
-		for _, deployment := range list.Items {
-			log.Printf("%v", deployment.Name)
-			result = append(result, deployment.Name)
+		for _, ns := range list.Items {
+			log.Printf("%v", ns.Name)
+			result = append(result,
+				helm.KubernetesResource{
+					GVK: schema.GroupVersionKind{
+						Group:   "",
+						Version: "v1",
+						Kind:    "Namespace",
+					},
+					Name: ns.Name,
+				})
 		}
 	}
 
diff --git a/src/k8splugin/plugins/namespace/plugin_test.go b/src/k8splugin/plugins/namespace/plugin_test.go
index 0019df1c..9e57b971 100644
--- a/src/k8splugin/plugins/namespace/plugin_test.go
+++ b/src/k8splugin/plugins/namespace/plugin_test.go
@@ -18,36 +18,54 @@ import (
 	"strings"
 	"testing"
 
-	utils "k8splugin/internal"
+	"k8splugin/internal/helm"
 
 	coreV1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
 	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	testclient "k8s.io/client-go/kubernetes/fake"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/dynamic"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/fake"
 )
 
+type TestKubernetesConnector struct {
+	object runtime.Object
+}
+
+func (t TestKubernetesConnector) GetMapper() meta.RESTMapper {
+	return nil
+}
+
+func (t TestKubernetesConnector) GetDynamicClient() dynamic.Interface {
+	return nil
+}
+
+func (t TestKubernetesConnector) GetStandardClient() kubernetes.Interface {
+	return fake.NewSimpleClientset(t.object)
+}
+
 func TestCreateNamespace(t *testing.T) {
-	namespace := "test1"
 	testCases := []struct {
 		label          string
-		input          *utils.ResourceData
-		clientOutput   *coreV1.Namespace
+		input          string
+		object         *coreV1.Namespace
 		expectedResult string
 		expectedError  string
 	}{
 		{
-			label: "Successfully create a namespace",
-			input: &utils.ResourceData{
-				Namespace: namespace,
-			},
-			clientOutput:   &coreV1.Namespace{},
-			expectedResult: namespace,
+			label:          "Successfully create a namespace",
+			input:          "test1",
+			object:         &coreV1.Namespace{},
+			expectedResult: "test1",
 		},
 	}
 
 	for _, testCase := range testCases {
-		client := testclient.NewSimpleClientset(testCase.clientOutput)
+		client := TestKubernetesConnector{testCase.object}
 		t.Run(testCase.label, func(t *testing.T) {
-			result, err := Create(testCase.input, client)
+			result, err := namespacePlugin{}.Create("", testCase.input, client)
 			if err != nil {
 				if testCase.expectedError == "" {
 					t.Fatalf("Create method return an un-expected (%s)", err)
@@ -72,39 +90,47 @@ func TestCreateNamespace(t *testing.T) {
 }
 
 func TestListNamespace(t *testing.T) {
-	namespace := "test1"
 	testCases := []struct {
 		label          string
 		input          string
-		clientOutput   *coreV1.NamespaceList
-		expectedResult []string
+		object         *coreV1.NamespaceList
+		expectedResult []helm.KubernetesResource
 	}{
 		{
 			label:          "Sucessfully to display an empty namespace list",
-			input:          namespace,
-			clientOutput:   &coreV1.NamespaceList{},
-			expectedResult: []string{},
+			input:          "",
+			object:         &coreV1.NamespaceList{},
+			expectedResult: []helm.KubernetesResource{},
 		},
 		{
 			label: "Sucessfully to display a list of existing namespaces",
-			input: namespace,
-			clientOutput: &coreV1.NamespaceList{
+			input: "test1",
+			object: &coreV1.NamespaceList{
 				Items: []coreV1.Namespace{
 					coreV1.Namespace{
 						ObjectMeta: metaV1.ObjectMeta{
-							Name: namespace,
+							Name: "test1",
 						},
 					},
 				},
 			},
-			expectedResult: []string{namespace},
+			expectedResult: []helm.KubernetesResource{
+				{
+					Name: "test1",
+					GVK:  schema.GroupVersionKind{Group: "", Version: "v1", Kind: "Namespace"},
+				},
+			},
 		},
 	}
 
 	for _, testCase := range testCases {
-		client := testclient.NewSimpleClientset(testCase.clientOutput)
+		client := TestKubernetesConnector{testCase.object}
 		t.Run(testCase.label, func(t *testing.T) {
-			result, err := List(testCase.input, client)
+			result, err := namespacePlugin{}.List(schema.GroupVersionKind{
+				Group:   "",
+				Version: "v1",
+				Kind:    "Namespace",
+			}, testCase.input, client)
 			if err != nil {
 				t.Fatalf("List method returned an error (%s)", err)
 			} else {
@@ -113,7 +139,7 @@ func TestListNamespace(t *testing.T) {
 				}
 				if !reflect.DeepEqual(testCase.expectedResult, result) {
 
-					t.Fatalf("List method returned: \n%v\n and it was expected: \n%v", result, testCase.expectedResult)
+					t.Fatalf("List method returned: \n%+v\n and it was expected: \n%+v", result, testCase.expectedResult)
 				}
 			}
 		})
@@ -122,14 +148,14 @@ func TestListNamespace(t *testing.T) {
 
 func TestDeleteNamespace(t *testing.T) {
 	testCases := []struct {
-		label        string
-		input        map[string]string
-		clientOutput *coreV1.Namespace
+		label  string
+		input  map[string]string
+		object *coreV1.Namespace
 	}{
 		{
 			label: "Sucessfully to delete an existing namespace",
 			input: map[string]string{"name": "test-name", "namespace": "test-namespace"},
-			clientOutput: &coreV1.Namespace{
+			object: &coreV1.Namespace{
 				ObjectMeta: metaV1.ObjectMeta{
 					Name: "test-name",
 				},
@@ -138,9 +164,12 @@ func TestDeleteNamespace(t *testing.T) {
 	}
 
 	for _, testCase := range testCases {
-		client := testclient.NewSimpleClientset(testCase.clientOutput)
+		client := TestKubernetesConnector{testCase.object}
 		t.Run(testCase.label, func(t *testing.T) {
-			err := Delete(testCase.input["name"], testCase.input["namespace"], client)
+			err := namespacePlugin{}.Delete(helm.KubernetesResource{
+				GVK:  schema.GroupVersionKind{Group: "", Version: "v1", Kind: "Namespace"},
+				Name: testCase.input["name"],
+			}, testCase.input["namespace"], client)
 			if err != nil {
 				t.Fatalf("Delete method returned an error (%s)", err)
 			}
@@ -152,14 +181,14 @@ func TestGetNamespace(t *testing.T) {
 	testCases := []struct {
 		label          string
 		input          map[string]string
-		clientOutput   *coreV1.Namespace
+		object         *coreV1.Namespace
 		expectedResult string
 		expectedError  string
 	}{
 		{
 			label: "Sucessfully to get an existing namespace",
 			input: map[string]string{"name": "test-name", "namespace": "test-namespace"},
-			clientOutput: &coreV1.Namespace{
+			object: &coreV1.Namespace{
 				ObjectMeta: metaV1.ObjectMeta{
 					Name: "test-name",
 				},
@@ -169,7 +198,7 @@ func TestGetNamespace(t *testing.T) {
 		{
 			label: "Fail to get an non-existing namespace",
 			input: map[string]string{"name": "test-name", "namespace": "test-namespace"},
-			clientOutput: &coreV1.Namespace{
+			object: &coreV1.Namespace{
 				ObjectMeta: metaV1.ObjectMeta{
 					Name: "test-name2",
 				},
@@ -179,9 +208,12 @@ func TestGetNamespace(t *testing.T) {
 	}
 
 	for _, testCase := range testCases {
-		client := testclient.NewSimpleClientset(testCase.clientOutput)
+		client := TestKubernetesConnector{testCase.object}
 		t.Run(testCase.label, func(t *testing.T) {
-			result, err := Get(testCase.input["name"], testCase.input["namespace"], client)
+			result, err := namespacePlugin{}.Get(helm.KubernetesResource{
+				GVK:  schema.GroupVersionKind{Group: "", Version: "v1", Kind: "Namespace"},
+				Name: testCase.input["name"],
+			}, testCase.input["namespace"], client)
 			if err != nil {
 				if testCase.expectedError == "" {
 					t.Fatalf("Get method return an un-expected (%s)", err)