all: Propagate errors from NamespacedKV (#6203)

As foretold by the prophecy, "once the database refactor is merged, then
shall appear a request to propagate errors from the store known
throughout the land as the NamedspacedKV, and it shall be good".

lib/stats/device.go

@@ -28,24 +28,30 @@ func NewDeviceStatisticsReference(ldb *db.Lowlevel, device string) *DeviceStatis
 	}
 }
 
-func (s *DeviceStatisticsReference) GetLastSeen() time.Time {
-	t, ok := s.ns.Time("lastSeen")
-	if !ok {
+func (s *DeviceStatisticsReference) GetLastSeen() (time.Time, error) {
+	t, ok, err := s.ns.Time("lastSeen")
+	if err != nil {
+		return time.Time{}, err
+	} else if !ok {
 		// The default here is 1970-01-01 as opposed to the default
 		// time.Time{} from s.ns
-		return time.Unix(0, 0)
+		return time.Unix(0, 0), nil
 	}
 	l.Debugln("stats.DeviceStatisticsReference.GetLastSeen:", s.device, t)
-	return t
+	return t, nil
 }
 
-func (s *DeviceStatisticsReference) WasSeen() {
+func (s *DeviceStatisticsReference) WasSeen() error {
 	l.Debugln("stats.DeviceStatisticsReference.WasSeen:", s.device)
-	s.ns.PutTime("lastSeen", time.Now())
+	return s.ns.PutTime("lastSeen", time.Now())
 }
 
-func (s *DeviceStatisticsReference) GetStatistics() DeviceStatistics {
-	return DeviceStatistics{
-		LastSeen: s.GetLastSeen(),
+func (s *DeviceStatisticsReference) GetStatistics() (DeviceStatistics, error) {
+	lastSeen, err := s.GetLastSeen()
+	if err != nil {
+		return DeviceStatistics{}, err
 	}
+	return DeviceStatistics{
+		LastSeen: lastSeen,
+	}, nil
 }