Alerting: Support for simplified notification settings in rule API (#81011)

* Add notification settings to storage\domain and API models. Settings are a slice to workaround XORM mapping
* Support validation of notification settings when rules are updated

* Implement route generator for Alertmanager configuration. That fetches all notification settings.
* Update multi-tenant Alertmanager to run the generator before applying the configuration.

* Add notification settings labels to state calculation
* update the Multi-tenant Alertmanager to provide validation for notification settings

* update GET API so only admins can see auto-gen

pkg/services/ngalert/api/api_ruler.go

@@ -16,10 +16,12 @@ import (
 	"github.com/grafana/grafana/pkg/services/auth/identity"
 	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
 	"github.com/grafana/grafana/pkg/services/dashboards"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/ngalert/accesscontrol"
 	apimodels "github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
 	"github.com/grafana/grafana/pkg/services/ngalert/eval"
 	ngmodels "github.com/grafana/grafana/pkg/services/ngalert/models"
+	"github.com/grafana/grafana/pkg/services/ngalert/notifier"
 	"github.com/grafana/grafana/pkg/services/ngalert/provisioning"
 	"github.com/grafana/grafana/pkg/services/ngalert/store"
 	"github.com/grafana/grafana/pkg/services/quota"
@@ -33,6 +35,14 @@ type ConditionValidator interface {
 	Validate(ctx eval.EvaluationContext, condition ngmodels.Condition) error
 }
 
+type AMConfigStore interface {
+	GetLatestAlertmanagerConfiguration(ctx context.Context, orgID int64) (*ngmodels.AlertConfiguration, error)
+}
+
+type AMRefresher interface {
+	ApplyConfig(ctx context.Context, orgId int64, dbConfig *ngmodels.AlertConfiguration) error
+}
+
 type RulerSrv struct {
 	xactManager        provisioning.TransactionManager
 	provenanceStore    provisioning.ProvisioningStore
@@ -42,6 +52,10 @@ type RulerSrv struct {
 	cfg                *setting.UnifiedAlertingSettings
 	conditionValidator ConditionValidator
 	authz              RuleAccessControlService
+
+	amConfigStore  AMConfigStore
+	amRefresher    AMRefresher
+	featureManager featuremgmt.FeatureToggles
 }
 
 var (
@@ -283,8 +297,11 @@ func (srv RulerSrv) checkGroupLimits(group apimodels.PostableRuleGroupConfig) er
 
 // updateAlertRulesInGroup calculates changes (rules to add,update,delete), verifies that the user is authorized to do the calculated changes and updates database.
 // All operations are performed in a single transaction
+//
+//nolint:gocyclo
 func (srv RulerSrv) updateAlertRulesInGroup(c *contextmodel.ReqContext, groupKey ngmodels.AlertRuleGroupKey, rules []*ngmodels.AlertRuleWithOptionals) response.Response {
 	var finalChanges *store.GroupDelta
+	var dbConfig *ngmodels.AlertConfiguration
 	err := srv.xactManager.InTransaction(c.Req.Context(), func(tranCtx context.Context) error {
 		userNamespace, id := c.SignedInUser.GetNamespacedID()
 		logger := srv.log.New("namespace_uid", groupKey.NamespaceUID, "group",
@@ -309,6 +326,24 @@ func (srv RulerSrv) updateAlertRulesInGroup(c *contextmodel.ReqContext, groupKey
 			return err
 		}
 
+		newOrUpdatedNotificationSettings := groupChanges.NewOrUpdatedNotificationSettings()
+		if len(newOrUpdatedNotificationSettings) > 0 {
+			dbConfig, err = srv.amConfigStore.GetLatestAlertmanagerConfiguration(c.Req.Context(), groupChanges.GroupKey.OrgID)
+			if err != nil {
+				return fmt.Errorf("failed to get latest configuration: %w", err)
+			}
+			cfg, err := notifier.Load([]byte(dbConfig.AlertmanagerConfiguration))
+			if err != nil {
+				return fmt.Errorf("failed to parse configuration: %w", err)
+			}
+			validator := notifier.NewNotificationSettingsValidator(&cfg.AlertmanagerConfig)
+			for _, s := range newOrUpdatedNotificationSettings {
+				if err := validator.Validate(s); err != nil {
+					return errors.Join(ngmodels.ErrAlertRuleFailedValidation, err)
+				}
+			}
+		}
+
 		if err := verifyProvisionedRulesNotAffected(c.Req.Context(), srv.provenanceStore, c.SignedInUser.GetOrgID(), groupChanges); err != nil {
 			return err
 		}
@@ -392,6 +427,15 @@ func (srv RulerSrv) updateAlertRulesInGroup(c *contextmodel.ReqContext, groupKey
 		}
 		return ErrResp(http.StatusInternalServerError, err, "failed to update rule group")
 	}
+
+	if srv.featureManager.IsEnabled(c.Req.Context(), featuremgmt.FlagAlertingSimplifiedRouting) && dbConfig != nil {
+		// This isn't strictly necessary since the alertmanager config is periodically synced.
+		err := srv.amRefresher.ApplyConfig(c.Req.Context(), groupKey.OrgID, dbConfig)
+		if err != nil {
+			srv.log.Warn("Failed to refresh Alertmanager config for org after change in notification settings", "org", c.SignedInUser.GetOrgID(), "error", err)
+		}
+	}
+
 	return changesToResponse(finalChanges)
 }
 
@@ -440,23 +484,25 @@ func toGettableExtendedRuleNode(r ngmodels.AlertRule, provenanceRecords map[stri
 	if prov, exists := provenanceRecords[r.ResourceID()]; exists {
 		provenance = prov
 	}
+
 	gettableExtendedRuleNode := apimodels.GettableExtendedRuleNode{
 		GrafanaManagedAlert: &apimodels.GettableGrafanaRule{
-			ID:              r.ID,
-			OrgID:           r.OrgID,
-			Title:           r.Title,
-			Condition:       r.Condition,
-			Data:            ApiAlertQueriesFromAlertQueries(r.Data),
-			Updated:         r.Updated,
-			IntervalSeconds: r.IntervalSeconds,
-			Version:         r.Version,
-			UID:             r.UID,
-			NamespaceUID:    r.NamespaceUID,
-			RuleGroup:       r.RuleGroup,
-			NoDataState:     apimodels.NoDataState(r.NoDataState),
-			ExecErrState:    apimodels.ExecutionErrorState(r.ExecErrState),
-			Provenance:      apimodels.Provenance(provenance),
-			IsPaused:        r.IsPaused,
+			ID:                   r.ID,
+			OrgID:                r.OrgID,
+			Title:                r.Title,
+			Condition:            r.Condition,
+			Data:                 ApiAlertQueriesFromAlertQueries(r.Data),
+			Updated:              r.Updated,
+			IntervalSeconds:      r.IntervalSeconds,
+			Version:              r.Version,
+			UID:                  r.UID,
+			NamespaceUID:         r.NamespaceUID,
+			RuleGroup:            r.RuleGroup,
+			NoDataState:          apimodels.NoDataState(r.NoDataState),
+			ExecErrState:         apimodels.ExecutionErrorState(r.ExecErrState),
+			Provenance:           apimodels.Provenance(provenance),
+			IsPaused:             r.IsPaused,
+			NotificationSettings: AlertRuleNotificationSettingsFromNotificationSettings(r.NotificationSettings),
 		},
 	}
 	forDuration := model.Duration(r.For)