[MM-11861] Design & implement a better way for plugins to update their own configuration (#9712)

* [MM-11861] Design & implement a better way for plugins to update their own configuration

Added GetPluginConfig and SavePluginConfig plugin APIs.
Added test cases for testing new APIs.

* Fixed gofmt error

* Minor changes requested in PR

plugin/api.go

@@ -34,6 +34,16 @@ type API interface {
 	// SaveConfig sets the given config and persists the changes
 	SaveConfig(config *model.Config) *model.AppError
 
+	// GetPluginConfig fetches the currently persisted config of plugin
+	//
+	// Minimum server version: 5.6
+	GetPluginConfig() map[string]interface{}
+
+	// SavePluginConfig sets the given config for plugin and persists the changes
+	//
+	// Minimum server version: 5.6
+	SavePluginConfig(config map[string]interface{}) *model.AppError
+
 	// GetServerVersion return the current Mattermost server version
 	//
 	// Minimum server version: 5.4

plugin/client_rpc_generated.go

@@ -656,6 +656,61 @@ func (s *apiRPCServer) SaveConfig(args *Z_SaveConfigArgs, returns *Z_SaveConfigR
 	return nil
 }
 
+type Z_GetPluginConfigArgs struct {
+}
+
+type Z_GetPluginConfigReturns struct {
+	A map[string]interface{}
+}
+
+func (g *apiRPCClient) GetPluginConfig() map[string]interface{} {
+	_args := &Z_GetPluginConfigArgs{}
+	_returns := &Z_GetPluginConfigReturns{}
+	if err := g.client.Call("Plugin.GetPluginConfig", _args, _returns); err != nil {
+		log.Printf("RPC call to GetPluginConfig API failed: %s", err.Error())
+	}
+	return _returns.A
+}
+
+func (s *apiRPCServer) GetPluginConfig(args *Z_GetPluginConfigArgs, returns *Z_GetPluginConfigReturns) error {
+	if hook, ok := s.impl.(interface {
+		GetPluginConfig() map[string]interface{}
+	}); ok {
+		returns.A = hook.GetPluginConfig()
+	} else {
+		return encodableError(fmt.Errorf("API GetPluginConfig called but not implemented."))
+	}
+	return nil
+}
+
+type Z_SavePluginConfigArgs struct {
+	A map[string]interface{}
+}
+
+type Z_SavePluginConfigReturns struct {
+	A *model.AppError
+}
+
+func (g *apiRPCClient) SavePluginConfig(config map[string]interface{}) *model.AppError {
+	_args := &Z_SavePluginConfigArgs{config}
+	_returns := &Z_SavePluginConfigReturns{}
+	if err := g.client.Call("Plugin.SavePluginConfig", _args, _returns); err != nil {
+		log.Printf("RPC call to SavePluginConfig API failed: %s", err.Error())
+	}
+	return _returns.A
+}
+
+func (s *apiRPCServer) SavePluginConfig(args *Z_SavePluginConfigArgs, returns *Z_SavePluginConfigReturns) error {
+	if hook, ok := s.impl.(interface {
+		SavePluginConfig(config map[string]interface{}) *model.AppError
+	}); ok {
+		returns.A = hook.SavePluginConfig(args.A)
+	} else {
+		return encodableError(fmt.Errorf("API SavePluginConfig called but not implemented."))
+	}
+	return nil
+}
+
 type Z_GetServerVersionArgs struct {
 }
 

plugin/plugintest/api.go

@@ -581,6 +581,20 @@ func (_m *API) GetConfig() *model.Config {
 	return r0
 }
 
+// GetPluginConfig provides a mock function with given fields:
+func (_m *API) GetPluginConfig() map[string]interface{} {
+	ret := _m.Called()
+
+	var r0 map[string]interface{}
+	if rf, ok := ret.Get(0).(func() map[string]interface{}); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(map[string]interface{})
+	}
+
+	return r0
+}
+
 // GetDirectChannel provides a mock function with given fields: userId1, userId2
 func (_m *API) GetDirectChannel(userId1 string, userId2 string) (*model.Channel, *model.AppError) {
 	ret := _m.Called(userId1, userId2)
@@ -1819,6 +1833,22 @@ func (_m *API) SaveConfig(config *model.Config) *model.AppError {
 	return r0
 }
 
+// SavePluginConfig provides a mock function with given fields: pluginConfig
+func (_m *API) SavePluginConfig(pluginConfig map[string]interface{}) *model.AppError {
+	ret := _m.Called(pluginConfig)
+
+	var r0 *model.AppError
+	if rf, ok := ret.Get(0).(func(map[string]interface{}) *model.AppError); ok {
+		r0 = rf(pluginConfig)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*model.AppError)
+		}
+	}
+
+	return r0
+}
+
 // SearchChannels provides a mock function with given fields: teamId, term
 func (_m *API) SearchChannels(teamId string, term string) (*model.ChannelList, *model.AppError) {
 	ret := _m.Called(teamId, term)