PLT-8131 (part2) Add plugin key value store support (#7902)

* Add plugin key value store support

* Add localization strings

* Updates per feedback

4 files changed, 150 insertions, 7 deletions

diff --git a/plugin/api.go b/plugin/api.go
index 8d27bc794..4bcfd112b 100644
--- a/plugin/api.go
+++ b/plugin/api.go
@@ -79,6 +79,20 @@ type API interface {
 	// GetPost gets a post.
 	GetPost(postId string) (*model.Post, *model.AppError)
 
-	// Update post updates a post.
+	// UpdatePost updates a post.
 	UpdatePost(post *model.Post) (*model.Post, *model.AppError)
+
+	// KeyValueStore returns an object for accessing the persistent key value storage.
+	KeyValueStore() KeyValueStore
+}
+
+type KeyValueStore interface {
+	// Set will store a key-value pair, unique per plugin.
+	Set(key string, value []byte) *model.AppError
+
+	// Get will retrieve a value based on the key. Returns nil for non-existent keys.
+	Get(key string) ([]byte, *model.AppError)
+
+	// Delete will remove a key-value pair. Returns nil for non-existent keys.
+	Delete(key string) *model.AppError
 }
diff --git a/plugin/plugintest/api.go b/plugin/plugintest/api.go
index c0e77648b..37052b4cf 100644
--- a/plugin/plugintest/api.go
+++ b/plugin/plugintest/api.go
@@ -12,9 +12,15 @@ import (
 
 type API struct {
 	mock.Mock
+	Store *KeyValueStore
+}
+
+type KeyValueStore struct {
+	mock.Mock
 }
 
 var _ plugin.API = (*API)(nil)
+var _ plugin.KeyValueStore = (*KeyValueStore)(nil)
 
 func (m *API) LoadPluginConfiguration(dest interface{}) error {
 	return m.Called(dest).Error(0)
@@ -235,3 +241,35 @@ func (m *API) UpdatePost(post *model.Post) (*model.Post, *model.AppError) {
 	err, _ := ret.Get(1).(*model.AppError)
 	return postOut, err
 }
+
+func (m *API) KeyValueStore() plugin.KeyValueStore {
+	return m.Store
+}
+
+func (m *KeyValueStore) Set(key string, value []byte) *model.AppError {
+	ret := m.Called(key, value)
+	if f, ok := ret.Get(0).(func(string, []byte) *model.AppError); ok {
+		return f(key, value)
+	}
+	err, _ := ret.Get(0).(*model.AppError)
+	return err
+}
+
+func (m *KeyValueStore) Get(key string) ([]byte, *model.AppError) {
+	ret := m.Called(key)
+	if f, ok := ret.Get(0).(func(string) ([]byte, *model.AppError)); ok {
+		return f(key)
+	}
+	psv, _ := ret.Get(0).([]byte)
+	err, _ := ret.Get(1).(*model.AppError)
+	return psv, err
+}
+
+func (m *KeyValueStore) Delete(key string) *model.AppError {
+	ret := m.Called(key)
+	if f, ok := ret.Get(0).(func(string) *model.AppError); ok {
+		return f(key)
+	}
+	err, _ := ret.Get(0).(*model.AppError)
+	return err
+}
diff --git a/plugin/rpcplugin/api.go b/plugin/rpcplugin/api.go
index 98333b1d9..f2068e815 100644
--- a/plugin/rpcplugin/api.go
+++ b/plugin/rpcplugin/api.go
@@ -259,6 +259,41 @@ func (api *LocalAPI) UpdatePost(args *model.Post, reply *APIPostReply) error {
 	return nil
 }
 
+type APIKeyValueStoreReply struct {
+	Value []byte
+	Error *model.AppError
+}
+
+type APIKeyValueStoreSetArgs struct {
+	Key   string
+	Value []byte
+}
+
+func (api *LocalAPI) KeyValueStoreSet(args *APIKeyValueStoreSetArgs, reply *APIErrorReply) error {
+	err := api.api.KeyValueStore().Set(args.Key, args.Value)
+	*reply = APIErrorReply{
+		Error: err,
+	}
+	return nil
+}
+
+func (api *LocalAPI) KeyValueStoreGet(args string, reply *APIKeyValueStoreReply) error {
+	v, err := api.api.KeyValueStore().Get(args)
+	*reply = APIKeyValueStoreReply{
+		Value: v,
+		Error: err,
+	}
+	return nil
+}
+
+func (api *LocalAPI) KeyValueStoreDelete(args string, reply *APIErrorReply) error {
+	err := api.api.KeyValueStore().Delete(args)
+	*reply = APIErrorReply{
+		Error: err,
+	}
+	return nil
+}
+
 func ServeAPI(api plugin.API, conn io.ReadWriteCloser, muxer *Muxer) {
 	server := rpc.NewServer()
 	server.Register(&LocalAPI{
@@ -269,11 +304,17 @@ func ServeAPI(api plugin.API, conn io.ReadWriteCloser, muxer *Muxer) {
 }
 
 type RemoteAPI struct {
-	client *rpc.Client
-	muxer  *Muxer
+	client        *rpc.Client
+	muxer         *Muxer
+	keyValueStore *RemoteKeyValueStore
+}
+
+type RemoteKeyValueStore struct {
+	api *RemoteAPI
 }
 
 var _ plugin.API = (*RemoteAPI)(nil)
+var _ plugin.KeyValueStore = (*RemoteKeyValueStore)(nil)
 
 func (api *RemoteAPI) LoadPluginConfiguration(dest interface{}) error {
 	var config []byte
@@ -467,13 +508,47 @@ func (api *RemoteAPI) UpdatePost(post *model.Post) (*model.Post, *model.AppError
 	return reply.Post, reply.Error
 }
 
+func (api *RemoteAPI) KeyValueStore() plugin.KeyValueStore {
+	return api.keyValueStore
+}
+
+func (s *RemoteKeyValueStore) Set(key string, value []byte) *model.AppError {
+	var reply APIErrorReply
+	if err := s.api.client.Call("LocalAPI.KeyValueStoreSet", &APIKeyValueStoreSetArgs{Key: key, Value: value}, &reply); err != nil {
+		return model.NewAppError("RemoteAPI.KeyValueStoreSet", "plugin.rpcplugin.invocation.error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+	return reply.Error
+}
+
+func (s *RemoteKeyValueStore) Get(key string) ([]byte, *model.AppError) {
+	var reply APIKeyValueStoreReply
+	if err := s.api.client.Call("LocalAPI.KeyValueStoreGet", key, &reply); err != nil {
+		return nil, model.NewAppError("RemoteAPI.KeyValueStoreGet", "plugin.rpcplugin.invocation.error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+	return reply.Value, reply.Error
+}
+
+func (s *RemoteKeyValueStore) Delete(key string) *model.AppError {
+	var reply APIErrorReply
+	if err := s.api.client.Call("LocalAPI.KeyValueStoreDelete", key, &reply); err != nil {
+		return model.NewAppError("RemoteAPI.KeyValueStoreDelete", "plugin.rpcplugin.invocation.error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+	return reply.Error
+}
+
 func (h *RemoteAPI) Close() error {
 	return h.client.Close()
 }
 
 func ConnectAPI(conn io.ReadWriteCloser, muxer *Muxer) *RemoteAPI {
-	return &RemoteAPI{
-		client: rpc.NewClient(conn),
-		muxer:  muxer,
+	remoteKeyValueStore := &RemoteKeyValueStore{}
+	remoteApi := &RemoteAPI{
+		client:        rpc.NewClient(conn),
+		muxer:         muxer,
+		keyValueStore: remoteKeyValueStore,
 	}
+
+	remoteKeyValueStore.api = remoteApi
+
+	return remoteApi
 }
diff --git a/plugin/rpcplugin/api_test.go b/plugin/rpcplugin/api_test.go
index 080f2825f..0c7321162 100644
--- a/plugin/rpcplugin/api_test.go
+++ b/plugin/rpcplugin/api_test.go
@@ -34,7 +34,8 @@ func testAPIRPC(api plugin.API, f func(plugin.API)) {
 }
 
 func TestAPI(t *testing.T) {
-	var api plugintest.API
+	keyValueStore := &plugintest.KeyValueStore{}
+	api := plugintest.API{Store: keyValueStore}
 	defer api.AssertExpectations(t)
 
 	type Config struct {
@@ -199,5 +200,20 @@ func TestAPI(t *testing.T) {
 		post, err = remote.UpdatePost(testPost)
 		assert.Equal(t, testPost, post)
 		assert.Nil(t, err)
+
+		api.KeyValueStore().(*plugintest.KeyValueStore).On("Set", "thekey", []byte("thevalue")).Return(nil).Once()
+		err = remote.KeyValueStore().Set("thekey", []byte("thevalue"))
+		assert.Nil(t, err)
+
+		api.KeyValueStore().(*plugintest.KeyValueStore).On("Get", "thekey").Return(func(key string) ([]byte, *model.AppError) {
+			return []byte("thevalue"), nil
+		}).Once()
+		ret, err := remote.KeyValueStore().Get("thekey")
+		assert.Nil(t, err)
+		assert.Equal(t, []byte("thevalue"), ret)
+
+		api.KeyValueStore().(*plugintest.KeyValueStore).On("Delete", "thekey").Return(nil).Once()
+		err = remote.KeyValueStore().Delete("thekey")
+		assert.Nil(t, err)
 	})
 }