Monitor: wait once if timeout configured

charger/openwb.go

@@ -74,7 +74,7 @@ func NewOpenWB(log *util.Logger, mqttconf mqtt.Config, id int, topic string, p1p
 	}
 
 	// check if loadpoint configured
-	configured, err := to.BoolGetter(mq(openwb.ConfiguredTopic))
+	configured, err := provider.NewMqtt(log, client, fmt.Sprintf("%s/lp/%d/%s", topic, id, openwb.ConfiguredTopic), timeout).BoolGetter()
 	if err != nil {
 		return nil, err
 	}

charger/warp2.go

@@ -60,19 +60,19 @@ func NewWarp2FromConfig(other map[string]interface{}) (api.Charger, error) {
 	}
 
 	var currentPower, totalEnergy func() (float64, error)
-	if wb.hasFeature(cc.Topic, warp.FeatureMeter) {
+	if wb.hasFeature(cc.Topic, warp.FeatureMeter, cc.Timeout) {
 		currentPower = wb.currentPower
 		totalEnergy = wb.totalEnergy
 	}
 
 	var currents, voltages func() (float64, float64, float64, error)
-	if wb.hasFeature(cc.Topic, warp.FeatureMeterPhases) {
+	if wb.hasFeature(cc.Topic, warp.FeatureMeterPhases, cc.Timeout) {
 		currents = wb.currents
 		voltages = wb.voltages
 	}
 
 	var identity func() (string, error)
-	if wb.hasFeature(cc.Topic, warp.FeatureNfc) {
+	if wb.hasFeature(cc.Topic, warp.FeatureNfc, cc.Timeout) {
 		identity = wb.identify
 	}
 
@@ -160,14 +160,14 @@ func NewWarp2(mqttconf mqtt.Config, topic, emTopic string, timeout time.Duration
 	return wb, nil
 }
 
-func (wb *Warp2) hasFeature(root, feature string) bool {
+func (wb *Warp2) hasFeature(root, feature string, timeout time.Duration) bool {
 	if wb.features != nil {
 		return slices.Contains(wb.features, feature)
 	}
 
 	topic := fmt.Sprintf("%s/info/features", root)
 
-	if dataG, err := provider.NewMqtt(wb.log, wb.client, topic, 0).StringGetter(); err == nil {
+	if dataG, err := provider.NewMqtt(wb.log, wb.client, topic, timeout).StringGetter(); err == nil {
 		if data, err := dataG(); err == nil {
 			if err := json.Unmarshal([]byte(data), &wb.features); err == nil {
 				return slices.Contains(wb.features, feature)

meter/openwb.go

@@ -26,8 +26,8 @@ func NewOpenWBFromConfig(other map[string]interface{}) (api.Meter, error) {
 		Usage       string
 		capacity    `mapstructure:",squash"`
 	}{
-		Topic:   "openWB",
-		Timeout: 15 * time.Second,
+		Topic:   openwb.RootTopic,
+		Timeout: openwb.Timeout,
 	}
 
 	if err := util.DecodeOther(other, &cc); err != nil {
@@ -76,7 +76,8 @@ func NewOpenWBFromConfig(other map[string]interface{}) (api.Meter, error) {
 		currents = collectPhaseProviders(curr)
 
 	case "pv":
-		configuredG, err := to.BoolGetter(mq("%s/pv/1/%s", cc.Topic, openwb.PvConfigured)) // first pv
+		// first pv
+		configuredG, err := provider.NewMqtt(log, client, fmt.Sprintf("%s/pv/1/%s", cc.Topic, openwb.PvConfigured), cc.Timeout).BoolGetter()
 		if err != nil {
 			return nil, err
 		}
@@ -99,7 +100,7 @@ func NewOpenWBFromConfig(other map[string]interface{}) (api.Meter, error) {
 		}
 
 	case "battery":
-		configuredG, err := to.BoolGetter(mq("%s/housebattery/%s", cc.Topic, openwb.BatteryConfigured))
+		configuredG, err := provider.NewMqtt(log, client, fmt.Sprintf("%s/housebattery/%s", cc.Topic, openwb.BatteryConfigured), cc.Timeout).BoolGetter()
 		if err != nil {
 			return nil, err
 		}

util/monitor.go

@@ -64,9 +64,32 @@ func (m *Monitor[T]) GetFunc(get func(T)) error {
 		default:
 			return api.ErrOutdated
 		}
-	} else if time.Since(m.updated) > m.timeout {
+	}
+
+	if time.Since(m.updated) > m.timeout {
+		err := api.ErrOutdated
+
+		// wait once on very first call
+		if m.updated.IsZero() {
+			m.mu.RUnlock()
+
+			// mark as waited once
+			m.mu.Lock()
+			m.updated.Add(time.Nanosecond)
+			m.mu.Unlock()
+
+			select {
+			case <-m.done:
+				// got value and updated timestamp
+				err = nil
+			case <-time.After(m.timeout):
+			}
+
+			m.mu.RLock()
+		}
+
 		get(m.val)
-		return api.ErrOutdated
+		return err
 	}
 
 	get(m.val)