Alerting: Return extra alertmanager config as a string for mimirtool (#106959)

pkg/services/ngalert/api/api_convert_prometheus.go

@@ -605,18 +605,14 @@ func (srv *ConvertPrometheusSrv) RouteConvertPrometheusGetAlertmanagerConfig(c *
 		return response.Error(http.StatusNotFound, "Alertmanager configuration not found", nil)
 	}
 
-	// Parse the configuration into our Gettable struct which will automatically
-	// sanitize secrets and exclude global settings when marshaled back to YAML.
-	var prometheusConfig amconfig.Config
-	if err := yaml.Unmarshal([]byte(extraCfg.AlertmanagerConfig), &prometheusConfig); err != nil {
+	sanitizedConfig, err := extraCfg.GetSanitizedAlertmanagerConfigYAML()
+	if err != nil {
 		return response.Error(http.StatusBadRequest, "Invalid Alertmanager configuration format", err)
 	}
 
-	respBody := apimodels.GettableAlertmanagerUserConfig{
-		AlertmanagerConfig: apimodels.GettableAlertmanagerConfig{
-			Config: prometheusConfig,
-		},
-		TemplateFiles: extraCfg.TemplateFiles,
+	respBody := apimodels.AlertmanagerUserConfig{
+		AlertmanagerConfig: sanitizedConfig,
+		TemplateFiles:      extraCfg.TemplateFiles,
 	}
 
 	resp := response.YAML(http.StatusOK, respBody)