recompute backup_last_successful_timestamp metric during resync

Signed-off-by: Steve Kriss <krisss@vmware.com>

pkg/controller/backup_controller.go

@@ -148,12 +148,36 @@ func NewBackupController(
 }
 
 func (c *backupController) resync() {
+	// recompute backup_total metric
 	backups, err := c.lister.List(labels.Everything())
 	if err != nil {
 		c.logger.Error(err, "Error computing backup_total metric")
 	} else {
 		c.metrics.SetBackupTotal(int64(len(backups)))
 	}
+
+	// recompute backup_last_successful_timestamp metric for each
+	// schedule (including the empty schedule, i.e. ad-hoc backups)
+	lastSuccessBySchedule := map[string]time.Time{}
+	for _, backup := range backups {
+		if backup.Status.Phase != velerov1api.BackupPhaseCompleted {
+			continue
+		}
+		if backup.Status.CompletionTimestamp == nil {
+			continue
+		}
+
+		schedule := backup.Labels[velerov1api.ScheduleNameLabel]
+		timestamp := backup.Status.CompletionTimestamp.Time
+
+		if timestamp.After(lastSuccessBySchedule[schedule]) {
+			lastSuccessBySchedule[schedule] = timestamp
+		}
+	}
+
+	for schedule, timestamp := range lastSuccessBySchedule {
+		c.metrics.SetBackupLastSuccessfulTimestamp(schedule, timestamp)
+	}
 }
 
 func (c *backupController) processBackup(key string) error {

pkg/metrics/metrics.go

@@ -297,9 +297,9 @@ func (m *ServerMetrics) SetBackupTarballSizeBytesGauge(backupSchedule string, si
 }
 
 // SetBackupLastSuccessfulTimestamp records the last time a backup ran successfully, Unix timestamp in seconds
-func (m *ServerMetrics) SetBackupLastSuccessfulTimestamp(backupSchedule string) {
+func (m *ServerMetrics) SetBackupLastSuccessfulTimestamp(backupSchedule string, time time.Time) {
 	if g, ok := m.metrics[backupLastSuccessfulTimestamp].(*prometheus.GaugeVec); ok {
-		g.WithLabelValues(backupSchedule).Set(float64(time.Now().Unix()))
+		g.WithLabelValues(backupSchedule).Set(float64(time.Unix()))
 	}
 }
 
@@ -322,7 +322,7 @@ func (m *ServerMetrics) RegisterBackupSuccess(backupSchedule string) {
 	if c, ok := m.metrics[backupSuccessTotal].(*prometheus.CounterVec); ok {
 		c.WithLabelValues(backupSchedule).Inc()
 	}
-	m.SetBackupLastSuccessfulTimestamp(backupSchedule)
+	m.SetBackupLastSuccessfulTimestamp(backupSchedule, time.Now())
 }
 
 // RegisterBackupPartialFailure records a partially failed backup.