[MM-35077] Add basic support for plugin intra-cluster communication (#17495)

* Add basic support for plugin intra-cluster communication

* Some renaming for added clarity

* Allow sending cluster event to specific nodes

* Improve naming and documentation

* Improve logging

plugin/api.go

@@ -1050,6 +1050,16 @@ type API interface {
 	// @tag SlashCommand
 	// Minimum server version: 5.28
 	DeleteCommand(commandID string) error
+
+	// PublishPluginClusterEvent broadcasts a plugin event to all other running instances of
+	// the calling plugin that are present in the cluster.
+	//
+	// This method is used to allow plugin communication in a High-Availability cluster.
+	// The receiving side should implement the OnPluginClusterEvent hook
+	// to receive events sent through this method.
+	//
+	// Minimum server version: 5.36
+	PublishPluginClusterEvent(ev model.PluginClusterEvent, opts model.PluginClusterEventSendOptions) error
 }
 
 var handshake = plugin.HandshakeConfig{

plugin/api_timer_layer_generated.go

@@ -1113,3 +1113,10 @@ func (api *apiTimerLayer) DeleteCommand(commandID string) error {
 	api.recordTime(startTime, "DeleteCommand", _returnsA == nil)
 	return _returnsA
 }
+
+func (api *apiTimerLayer) PublishPluginClusterEvent(ev model.PluginClusterEvent, opts model.PluginClusterEventSendOptions) error {
+	startTime := timePkg.Now()
+	_returnsA := api.apiImpl.PublishPluginClusterEvent(ev, opts)
+	api.recordTime(startTime, "PublishPluginClusterEvent", _returnsA == nil)
+	return _returnsA
+}

plugin/client_rpc_generated.go

@@ -532,6 +532,40 @@ func (s *hooksRPCServer) ReactionHasBeenRemoved(args *Z_ReactionHasBeenRemovedAr
 	return nil
 }
 
+func init() {
+	hookNameToId["OnPluginClusterEvent"] = OnPluginClusterEventID
+}
+
+type Z_OnPluginClusterEventArgs struct {
+	A *Context
+	B model.PluginClusterEvent
+}
+
+type Z_OnPluginClusterEventReturns struct {
+}
+
+func (g *hooksRPCClient) OnPluginClusterEvent(c *Context, ev model.PluginClusterEvent) {
+	_args := &Z_OnPluginClusterEventArgs{c, ev}
+	_returns := &Z_OnPluginClusterEventReturns{}
+	if g.implemented[OnPluginClusterEventID] {
+		if err := g.client.Call("Plugin.OnPluginClusterEvent", _args, _returns); err != nil {
+			g.log.Error("RPC call OnPluginClusterEvent to plugin failed.", mlog.Err(err))
+		}
+	}
+
+}
+
+func (s *hooksRPCServer) OnPluginClusterEvent(args *Z_OnPluginClusterEventArgs, returns *Z_OnPluginClusterEventReturns) error {
+	if hook, ok := s.impl.(interface {
+		OnPluginClusterEvent(c *Context, ev model.PluginClusterEvent)
+	}); ok {
+		hook.OnPluginClusterEvent(args.A, args.B)
+	} else {
+		return encodableError(fmt.Errorf("Hook OnPluginClusterEvent called but not implemented."))
+	}
+	return nil
+}
+
 type Z_RegisterCommandArgs struct {
 	A *model.Command
 }
@@ -4906,3 +4940,33 @@ func (s *apiRPCServer) DeleteCommand(args *Z_DeleteCommandArgs, returns *Z_Delet
 	}
 	return nil
 }
+
+type Z_PublishPluginClusterEventArgs struct {
+	A model.PluginClusterEvent
+	B model.PluginClusterEventSendOptions
+}
+
+type Z_PublishPluginClusterEventReturns struct {
+	A error
+}
+
+func (g *apiRPCClient) PublishPluginClusterEvent(ev model.PluginClusterEvent, opts model.PluginClusterEventSendOptions) error {
+	_args := &Z_PublishPluginClusterEventArgs{ev, opts}
+	_returns := &Z_PublishPluginClusterEventReturns{}
+	if err := g.client.Call("Plugin.PublishPluginClusterEvent", _args, _returns); err != nil {
+		log.Printf("RPC call to PublishPluginClusterEvent API failed: %s", err.Error())
+	}
+	return _returns.A
+}
+
+func (s *apiRPCServer) PublishPluginClusterEvent(args *Z_PublishPluginClusterEventArgs, returns *Z_PublishPluginClusterEventReturns) error {
+	if hook, ok := s.impl.(interface {
+		PublishPluginClusterEvent(ev model.PluginClusterEvent, opts model.PluginClusterEventSendOptions) error
+	}); ok {
+		returns.A = hook.PublishPluginClusterEvent(args.A, args.B)
+		returns.A = encodableError(returns.A)
+	} else {
+		return encodableError(fmt.Errorf("API PublishPluginClusterEvent called but not implemented."))
+	}
+	return nil
+}

plugin/hooks.go

@@ -35,6 +35,7 @@ const (
 	UserHasBeenCreatedID     = 17
 	ReactionHasBeenAddedID   = 18
 	ReactionHasBeenRemovedID = 19
+	OnPluginClusterEventID   = 20
 	TotalHooksID             = iota
 )
 
@@ -209,4 +210,13 @@ type Hooks interface {
 	//
 	// Minimum server version: 5.30
 	ReactionHasBeenRemoved(c *Context, reaction *model.Reaction)
+
+	// OnPluginClusterEvent is invoked when an intra-cluster plugin event is received.
+	//
+	// This is used to allow communication between multiple instances of the same plugin
+	// that are running on separate nodes of the same High-Availability cluster.
+	// This hook receives events sent by a call to PublishPluginClusterEvent.
+	//
+	// Minimum server version: 5.36
+	OnPluginClusterEvent(c *Context, ev model.PluginClusterEvent)
 }

plugin/hooks_timer_layer_generated.go

@@ -162,3 +162,9 @@ func (hooks *hooksTimerLayer) ReactionHasBeenRemoved(c *Context, reaction *model
 	hooks.hooksImpl.ReactionHasBeenRemoved(c, reaction)
 	hooks.recordTime(startTime, "ReactionHasBeenRemoved", true)
 }
+
+func (hooks *hooksTimerLayer) OnPluginClusterEvent(c *Context, ev model.PluginClusterEvent) {
+	startTime := timePkg.Now()
+	hooks.hooksImpl.OnPluginClusterEvent(c, ev)
+	hooks.recordTime(startTime, "OnPluginClusterEvent", true)
+}

plugin/plugintest/api.go

@@ -2682,6 +2682,20 @@ func (_m *API) PluginHTTP(request *http.Request) *http.Response {
 	return r0
 }
 
+// PublishPluginClusterEvent provides a mock function with given fields: ev, opts
+func (_m *API) PublishPluginClusterEvent(ev model.PluginClusterEvent, opts model.PluginClusterEventSendOptions) error {
+	ret := _m.Called(ev, opts)
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(model.PluginClusterEvent, model.PluginClusterEventSendOptions) error); ok {
+		r0 = rf(ev, opts)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
 // PublishUserTyping provides a mock function with given fields: userID, channelId, parentId
 func (_m *API) PublishUserTyping(userID string, channelId string, parentId string) *model.AppError {
 	ret := _m.Called(userID, channelId, parentId)

plugin/plugintest/hooks.go

@@ -194,6 +194,11 @@ func (_m *Hooks) OnDeactivate() error {
 	return r0
 }
 
+// OnPluginClusterEvent provides a mock function with given fields: c, ev
+func (_m *Hooks) OnPluginClusterEvent(c *plugin.Context, ev model.PluginClusterEvent) {
+	_m.Called(c, ev)
+}
+
 // ReactionHasBeenAdded provides a mock function with given fields: c, reaction
 func (_m *Hooks) ReactionHasBeenAdded(c *plugin.Context, reaction *model.Reaction) {
 	_m.Called(c, reaction)