Alerting: Move alertmanager default config to UnifiedAlertingSettings (#39597) (#39714)

(cherry picked from commit 05eb30e323)

Co-authored-by: Yuriy Tseretyan <yuriy.tseretyan@grafana.com>
Co-authored-by: Sofia Papagiannaki <sofia@grafana.com>

pkg/services/ngalert/notifier/alertmanager.go

@@ -55,29 +55,6 @@ const (
 	defaultResolveTimeout = 5 * time.Minute
 	// memoryAlertsGCInterval is the interval at which we'll remove resolved alerts from memory.
 	memoryAlertsGCInterval = 30 * time.Minute
-	// To start, the alertmanager needs at least one route defined.
-	// TODO: we should move this to Grafana settings and define this as the default.
-	alertmanagerDefaultConfiguration = `
-{
-	"alertmanager_config": {
-		"route": {
-			"receiver": "grafana-default-email"
-		},
-		"receivers": [{
-			"name": "grafana-default-email",
-			"grafana_managed_receiver_configs": [{
-				"uid": "",
-				"name": "email receiver",
-				"type": "email",
-				"isDefault": true,
-				"settings": {
-					"addresses": "<example@email.com>"
-				}
-			}]
-		}]
-	}
-}
-`
 )
 
 type ClusterPeer interface {
@@ -252,19 +229,19 @@ func (am *Alertmanager) SaveAndApplyDefaultConfig() error {
 	defer am.reloadConfigMtx.Unlock()
 
 	cmd := &ngmodels.SaveAlertmanagerConfigurationCmd{
-		AlertmanagerConfiguration: alertmanagerDefaultConfiguration,
+		AlertmanagerConfiguration: am.Settings.UnifiedAlerting.DefaultConfiguration,
 		Default:                   true,
 		ConfigurationVersion:      fmt.Sprintf("v%d", ngmodels.AlertConfigurationVersion),
 		OrgID:                     am.orgID,
 	}
 
-	cfg, err := Load([]byte(alertmanagerDefaultConfiguration))
+	cfg, err := Load([]byte(am.Settings.UnifiedAlerting.DefaultConfiguration))
 	if err != nil {
 		return err
 	}
 
 	err = am.Store.SaveAlertmanagerConfigurationWithCallback(cmd, func() error {
-		if err := am.applyConfig(cfg, []byte(alertmanagerDefaultConfiguration)); err != nil {
+		if err := am.applyConfig(cfg, []byte(am.Settings.UnifiedAlerting.DefaultConfiguration)); err != nil {
 			return err
 		}
 		return nil

pkg/services/ngalert/notifier/multiorg_alertmanager_test.go

@@ -33,7 +33,7 @@ func TestMultiOrgAlertmanager_SyncAlertmanagersForOrgs(t *testing.T) {
 	m := metrics.NewNGAlert(reg)
 	cfg := &setting.Cfg{
 		DataPath:        tmpDir,
-		UnifiedAlerting: setting.UnifiedAlertingSettings{AlertmanagerConfigPollInterval: 3 * time.Minute}, // do not poll in tests.
+		UnifiedAlerting: setting.UnifiedAlertingSettings{AlertmanagerConfigPollInterval: 3 * time.Minute, DefaultConfiguration: setting.GetAlertmanagerDefaultConfiguration()}, // do not poll in tests.
 	}
 	mam, err := NewMultiOrgAlertmanager(cfg, configStore, orgStore, kvStore, m.GetMultiOrgAlertmanagerMetrics(), log.New("testlogger"))
 	require.NoError(t, err)