Alerting: fix the migrated silence file content (#39557)

pkg/services/sqlstore/migrations/ualert/silences.go

@@ -47,13 +47,22 @@ func (m *migration) addSilence(da dashAlert, rule *alertRule) error {
 		ExpiresAt: time.Now().Add(365 * 20 * time.Hour), // 1 year.
 	}
 
-	m.silences = append(m.silences, s)
+	_, ok := m.silences[da.OrgId]
+	if !ok {
+		m.silences[da.OrgId] = make([]*pb.MeshSilence, 0)
+	}
+	m.silences[da.OrgId] = append(m.silences[da.OrgId], s)
 	return nil
 }
 
 func (m *migration) writeSilencesFile(orgID int64) error {
 	var buf bytes.Buffer
-	for _, e := range m.silences {
+	orgSilences, ok := m.silences[orgID]
+	if !ok {
+		return nil
+	}
+
+	for _, e := range orgSilences {
 		if _, err := pbutil.WriteDelimited(&buf, e); err != nil {
 			return err
 		}

pkg/services/sqlstore/migrations/ualert/ualert.go

@@ -61,6 +61,7 @@ func AddDashAlertMigration(mg *migrator.Migrator) {
 			seenChannelUIDs:           make(map[string]struct{}),
 			migratedChannelsPerOrg:    make(map[int64]map[*notificationChannel]struct{}),
 			portedChannelGroupsPerOrg: make(map[int64]map[string]string),
+			silences:                  make(map[int64][]*pb.MeshSilence),
 		})
 	case !ngEnabled && migrationRun:
 		// Remove the migration entry that creates unified alerting data. This is so when the feature
@@ -101,6 +102,7 @@ func RerunDashAlertMigration(mg *migrator.Migrator) {
 			seenChannelUIDs:           make(map[string]struct{}),
 			migratedChannelsPerOrg:    make(map[int64]map[*notificationChannel]struct{}),
 			portedChannelGroupsPerOrg: make(map[int64]map[string]string),
+			silences:                  make(map[int64][]*pb.MeshSilence),
 		})
 
 	case !ngEnabled && migrationRun:
@@ -150,7 +152,7 @@ type migration struct {
 
 	seenChannelUIDs           map[string]struct{}
 	migratedChannelsPerOrg    map[int64]map[*notificationChannel]struct{}
-	silences                  []*pb.MeshSilence
+	silences                  map[int64][]*pb.MeshSilence
 	portedChannelGroupsPerOrg map[int64]map[string]string // Org -> Channel group key -> receiver name.
 	lastReceiverID            int                         // For the auto generated receivers.
 }