BackupItemActionPlugin: handle nil updatedItem

Handle the case where a BackupItemAction may return nil for updatedItem,
meaning "no modifications to the item". The backupPVAction does this,
and we were panicking instead of accepting it.

Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>

pkg/backup/mocks/item_action.go

@@ -0,0 +1,65 @@
+// Code generated by mockery v1.0.0. DO NOT EDIT.
+package mocks
+
+import backup "github.com/heptio/ark/pkg/backup"
+import mock "github.com/stretchr/testify/mock"
+import runtime "k8s.io/apimachinery/pkg/runtime"
+import v1 "github.com/heptio/ark/pkg/apis/ark/v1"
+
+// ItemAction is an autogenerated mock type for the ItemAction type
+type ItemAction struct {
+	mock.Mock
+}
+
+// AppliesTo provides a mock function with given fields:
+func (_m *ItemAction) AppliesTo() (backup.ResourceSelector, error) {
+	ret := _m.Called()
+
+	var r0 backup.ResourceSelector
+	if rf, ok := ret.Get(0).(func() backup.ResourceSelector); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(backup.ResourceSelector)
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func() error); ok {
+		r1 = rf()
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+// Execute provides a mock function with given fields: item, _a1
+func (_m *ItemAction) Execute(item runtime.Unstructured, _a1 *v1.Backup) (runtime.Unstructured, []backup.ResourceIdentifier, error) {
+	ret := _m.Called(item, _a1)
+
+	var r0 runtime.Unstructured
+	if rf, ok := ret.Get(0).(func(runtime.Unstructured, *v1.Backup) runtime.Unstructured); ok {
+		r0 = rf(item, _a1)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(runtime.Unstructured)
+		}
+	}
+
+	var r1 []backup.ResourceIdentifier
+	if rf, ok := ret.Get(1).(func(runtime.Unstructured, *v1.Backup) []backup.ResourceIdentifier); ok {
+		r1 = rf(item, _a1)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).([]backup.ResourceIdentifier)
+		}
+	}
+
+	var r2 error
+	if rf, ok := ret.Get(2).(func(runtime.Unstructured, *v1.Backup) error); ok {
+		r2 = rf(item, _a1)
+	} else {
+		r2 = ret.Error(2)
+	}
+
+	return r0, r1, r2
+}

pkg/plugin/backup_item_action.go

@@ -171,24 +171,34 @@ func (s *BackupItemActionGRPCServer) Execute(ctx context.Context, req *proto.Exe
 		return nil, err
 	}
 
-	updatedItemJSON, err := json.Marshal(updatedItem.UnstructuredContent())
-	if err != nil {
-		return nil, err
+	// If the plugin implementation returned a nil updatedItem (meaning no modifications), reset updatedItem to the
+	// original item.
+	var updatedItemJSON []byte
+	if updatedItem == nil {
+		updatedItemJSON = req.Item
+	} else {
+		updatedItemJSON, err = json.Marshal(updatedItem.UnstructuredContent())
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	res := &proto.ExecuteResponse{
 		Item: updatedItemJSON,
 	}
 
-	for _, itm := range additionalItems {
-		val := proto.ResourceIdentifier{
-			Group:     itm.Group,
-			Resource:  itm.Resource,
-			Namespace: itm.Namespace,
-			Name:      itm.Name,
-		}
-		res.AdditionalItems = append(res.AdditionalItems, &val)
+	for _, item := range additionalItems {
+		res.AdditionalItems = append(res.AdditionalItems, backupResourceIdentifierToProto(item))
 	}
 
 	return res, nil
 }
+
+func backupResourceIdentifierToProto(id arkbackup.ResourceIdentifier) *proto.ResourceIdentifier {
+	return &proto.ResourceIdentifier{
+		Group:     id.Group,
+		Resource:  id.Resource,
+		Namespace: id.Namespace,
+		Name:      id.Name,
+	}
+}

pkg/plugin/backup_item_action_test.go

@@ -0,0 +1,190 @@
+/*
+Copyright 2018 the Heptio Ark contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package plugin
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/heptio/ark/pkg/apis/ark/v1"
+	"github.com/heptio/ark/pkg/backup"
+	"github.com/heptio/ark/pkg/backup/mocks"
+	proto "github.com/heptio/ark/pkg/plugin/generated"
+	"github.com/pkg/errors"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/net/context"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+func TestBackupItemActionGRPCServerExecute(t *testing.T) {
+	invalidItem := []byte("this is gibberish json")
+	validItem := []byte(`
+	{
+		"apiVersion": "v1",
+		"kind": "ConfigMap",
+		"metadata": {
+			"namespace": "myns",
+			"name": "myconfigmap"
+		},
+		"data": {
+			"key": "value"
+		}
+	}`)
+	var validItemObject unstructured.Unstructured
+	err := json.Unmarshal(validItem, &validItemObject)
+	require.NoError(t, err)
+
+	updatedItem := []byte(`
+		{
+			"apiVersion": "v1",
+			"kind": "ConfigMap",
+			"metadata": {
+				"namespace": "myns",
+				"name": "myconfigmap"
+			},
+			"data": {
+				"key": "changed!"
+			}
+		}`)
+	var updatedItemObject unstructured.Unstructured
+	err = json.Unmarshal(updatedItem, &updatedItemObject)
+	require.NoError(t, err)
+
+	invalidBackup := []byte("this is gibberish json")
+	validBackup := []byte(`
+	{
+		"apiVersion": "ark.heptio.com/v1",
+		"kind": "Backup",
+		"metadata": {
+			"namespace": "myns",
+			"name": "mybackup"
+		},
+		"spec": {
+			"includedNamespaces": ["*"],
+			"includedResources": ["*"],
+			"ttl": "60m"
+		}
+	}`)
+	var validBackupObject v1.Backup
+	err = json.Unmarshal(validBackup, &validBackupObject)
+	require.NoError(t, err)
+
+	tests := []struct {
+		name                string
+		backup              []byte
+		item                []byte
+		implUpdatedItem     runtime.Unstructured
+		implAdditionalItems []backup.ResourceIdentifier
+		implError           error
+		expectError         bool
+		skipMock            bool
+	}{
+		{
+			name:        "error unmarshaling item",
+			item:        invalidItem,
+			backup:      validBackup,
+			expectError: true,
+			skipMock:    true,
+		},
+		{
+			name:        "error unmarshaling backup",
+			item:        validItem,
+			backup:      invalidBackup,
+			expectError: true,
+			skipMock:    true,
+		},
+		{
+			name:        "error running impl",
+			item:        validItem,
+			backup:      validBackup,
+			implError:   errors.New("impl error"),
+			expectError: true,
+		},
+		{
+			name:   "nil updatedItem / no additionalItems",
+			item:   validItem,
+			backup: validBackup,
+		},
+		{
+			name:            "same updatedItem / some additionalItems",
+			item:            validItem,
+			backup:          validBackup,
+			implUpdatedItem: &validItemObject,
+			implAdditionalItems: []backup.ResourceIdentifier{
+				{
+					GroupResource: schema.GroupResource{Group: "v1", Resource: "pods"},
+					Namespace:     "myns",
+					Name:          "mypod",
+				},
+			},
+		},
+		{
+			name:            "different updatedItem",
+			item:            validItem,
+			backup:          validBackup,
+			implUpdatedItem: &updatedItemObject,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			itemAction := &mocks.ItemAction{}
+			defer itemAction.AssertExpectations(t)
+
+			if !test.skipMock {
+				itemAction.On("Execute", &validItemObject, &validBackupObject).Return(test.implUpdatedItem, test.implAdditionalItems, test.implError)
+			}
+
+			s := &BackupItemActionGRPCServer{impl: itemAction}
+
+			req := &proto.ExecuteRequest{
+				Item:   test.item,
+				Backup: test.backup,
+			}
+
+			resp, err := s.Execute(context.Background(), req)
+
+			// Verify error
+			assert.Equal(t, test.expectError, err != nil)
+			if test.expectError {
+				return
+			}
+
+			// Verify updated item
+			updatedItem := test.implUpdatedItem
+			if updatedItem == nil {
+				// If the impl returned nil for its updatedItem, we should expect the plugin to return the original item
+				updatedItem = &validItemObject
+			}
+
+			var respItem unstructured.Unstructured
+			err = json.Unmarshal(resp.Item, &respItem)
+			require.NoError(t, err)
+
+			assert.Equal(t, updatedItem, &respItem)
+
+			// Verify additional items
+			var expectedAdditionalItems []*proto.ResourceIdentifier
+			for _, item := range test.implAdditionalItems {
+				expectedAdditionalItems = append(expectedAdditionalItems, backupResourceIdentifierToProto(item))
+			}
+			assert.Equal(t, expectedAdditionalItems, resp.AdditionalItems)
+		})
+	}
+}