invoke config listeners when app.UpdateConfig is used (#7773)

app/app.go

@@ -253,7 +253,9 @@ func (a *App) Config() *model.Config {
 }
 
 func (a *App) UpdateConfig(f func(*model.Config)) {
+	old := utils.Cfg.Clone()
 	f(utils.Cfg)
+	utils.InvokeGlobalConfigListeners(old, utils.Cfg)
 }
 
 func (a *App) PersistConfig() {

app/app_test.go

@@ -10,6 +10,9 @@ import (
 
 	l4g "github.com/alecthomas/log4go"
 
+	"github.com/stretchr/testify/assert"
+
+	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/store/storetest"
 	"github.com/mattermost/mattermost-server/utils"
 )
@@ -49,3 +52,23 @@ func TestAppRace(t *testing.T) {
 		a.Shutdown()
 	}
 }
+
+func TestUpdateConfig(t *testing.T) {
+	th := Setup()
+	defer th.TearDown()
+
+	prev := *th.App.Config().ServiceSettings.SiteURL
+	defer th.App.UpdateConfig(func(cfg *model.Config) {
+		*cfg.ServiceSettings.SiteURL = prev
+	})
+
+	listener := utils.AddConfigListener(func(old, current *model.Config) {
+		assert.Equal(t, prev, *old.ServiceSettings.SiteURL)
+		assert.Equal(t, "foo", *current.ServiceSettings.SiteURL)
+	})
+	defer utils.RemoveConfigListener(listener)
+
+	th.App.UpdateConfig(func(cfg *model.Config) {
+		*cfg.ServiceSettings.SiteURL = "foo"
+	})
+}

utils/config.go

@@ -414,13 +414,17 @@ func LoadGlobalConfig(fileName string) *model.Config {
 	SetDefaultRolesBasedOnConfig()
 	SetSiteURL(*Cfg.ServiceSettings.SiteURL)
 
-	for _, listener := range cfgListeners {
+	InvokeGlobalConfigListeners(&oldConfig, config)
-		listener(&oldConfig, config)
-	}
 
 	return config
 }
 
+func InvokeGlobalConfigListeners(old, current *model.Config) {
+	for _, listener := range cfgListeners {
+		listener(old, current)
+	}
+}
+
 func RegenerateClientConfig() {
 	ClientCfg = getClientConfig(Cfg)
 }