MM-22235: Fixing stop/start behavior on Elasticsearch engine (#13887)

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

app/app_iface.go

@@ -43,7 +43,7 @@ type AppIface interface {
 	AddConfigListener(listener func(*model.Config, *model.Config)) string
 	AddCursorIdsForPostList(originalList *model.PostList, afterPost, beforePost string, since int64, page, perPage int)
 	AddDirectChannels(teamId string, user *model.User) *model.AppError
-	AddLicenseListener(listener func()) string
+	AddLicenseListener(listener func(oldLicense, newLicense *model.License)) string
 	AddNotificationEmailToBatch(user *model.User, post *model.Post, team *model.Team) *model.AppError
 	AddPublicKey(name string, key io.Reader) *model.AppError
 	AddSamlIdpCertificate(fileData *multipart.FileHeader) *model.AppError

app/license.go

@@ -13,8 +13,6 @@ import (
 )
 
 func (a *App) LoadLicense() {
-	a.SetLicense(nil)
-
 	licenseId := ""
 	props, err := a.Srv().Store.System().Get()
 	if err == nil {
@@ -37,6 +35,7 @@ func (a *App) LoadLicense() {
 	record, err := a.Srv().Store.License().Get(licenseId)
 	if err != nil {
 		mlog.Info("License key from https://mattermost.com required to unlock enterprise features.")
+		a.SetLicense(nil)
 		return
 	}
 
@@ -108,9 +107,15 @@ func (a *App) License() *model.License {
 }
 
 func (a *App) SetLicense(license *model.License) bool {
+	oldLicense := a.Srv().licenseValue.Load()
+
 	defer func() {
 		for _, listener := range a.Srv().licenseListeners {
-			listener()
+			if oldLicense == nil {
+				listener(nil, license)
+			} else {
+				listener(oldLicense.(*model.License), license)
+			}
 		}
 	}()
 
@@ -169,13 +174,13 @@ func (a *App) RemoveLicense() *model.AppError {
 	return nil
 }
 
-func (s *Server) AddLicenseListener(listener func()) string {
+func (s *Server) AddLicenseListener(listener func(oldLicense, newLicense *model.License)) string {
 	id := model.NewId()
 	s.licenseListeners[id] = listener
 	return id
 }
 
-func (a *App) AddLicenseListener(listener func()) string {
+func (a *App) AddLicenseListener(listener func(oldLicense, newLicense *model.License)) string {
 	id := model.NewId()
 	a.Srv().licenseListeners[id] = listener
 	return id

app/server.go

@@ -82,7 +82,7 @@ type Server struct {
 
 	licenseValue       atomic.Value
 	clientLicenseValue atomic.Value
-	licenseListeners   map[string]func()
+	licenseListeners   map[string]func(*model.License, *model.License)
 
 	timezones *timezones.Timezones
 
@@ -143,7 +143,7 @@ func NewServer(options ...Option) (*Server, error) {
 	s := &Server{
 		goroutineExitSignal: make(chan struct{}, 1),
 		RootRouter:          rootRouter,
-		licenseListeners:    map[string]func(){},
+		licenseListeners:    map[string]func(*model.License, *model.License){},
 		clientConfig:        make(map[string]string),
 	}
 
@@ -776,14 +776,14 @@ func (s *Server) StartElasticsearch() {
 		}
 	})
 
-	s.AddLicenseListener(func() {
-		if s.License() != nil {
+	s.AddLicenseListener(func(oldLicense, newLicense *model.License) {
+		if oldLicense == nil && newLicense != nil {
 			s.Go(func() {
 				if err := s.Elasticsearch.Start(); err != nil {
 					mlog.Error(err.Error())
 				}
 			})
-		} else {
+		} else if oldLicense != nil && newLicense == nil {
 			s.Go(func() {
 				if err := s.Elasticsearch.Stop(); err != nil {
 					mlog.Error(err.Error())

app/server_app_adapters.go

@@ -39,7 +39,7 @@ func (s *Server) RunOldAppInitialization() error {
 			s.FakeApp().Publish(message)
 		})
 	})
-	s.FakeApp().Srv().licenseListenerId = s.FakeApp().AddLicenseListener(func() {
+	s.FakeApp().Srv().licenseListenerId = s.FakeApp().AddLicenseListener(func(oldLicense, newLicense *model.License) {
 		s.FakeApp().configOrLicenseListener()
 
 		message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_LICENSE_CHANGED, "", "", "", nil)