feat: Use old configMap data with failure message in case APIs has error

pkg/exporter/configmap.go

@@ -25,7 +25,7 @@ var (
 	isImmutable = true
 )
 
-func (e *Exporter) CreateOrUpdateConfigMap(ctx context.Context, configMapName string, emissionForecast []client.EmissionsForecastDto) error {
+func (e *Exporter) CreateConfigMapFromEmissionForecast(ctx context.Context, configMapName string, emissionForecast []client.EmissionsForecastDto) error {
 	if emissionForecast == nil {
 		return errors.New("emission forecast cannot be nil")
 	}
@@ -41,33 +41,36 @@ func (e *Exporter) CreateOrUpdateConfigMap(ctx context.Context, configMapName st
 
 	minForecast, maxForeCast := getMinMaxForecast(ctx, forecast.ForecastData)
 
-	configMap := &corev1.ConfigMap{
-		ObjectMeta: v1.ObjectMeta{
-			Name:      configMapName,
-			Namespace: client.Namespace,
-		},
-		Immutable: &isImmutable,
-		Data: map[string]string{
+	return e.CreateConfigMapFromProperties(ctx, configMapName,
+		map[string]string{
 			ConfigMapLastHeartbeatTime: time.Now().String(),                      // The latest time that the data exporter controller sends the data.
 			ConfigMapMessage:           "",                                       // Additional information for user notification, if any.
 			ConfigMapNumOfRecords:      strconv.Itoa(len(forecast.ForecastData)), // The number can be any value between 0 (no records for the current location) and 24(hours) * 12(5 min interval per hour).
 			ConfigMapForecastDateTime:  forecast.DataStartAt.String(),            // The time when the data was started by the GSF SDK.
 			ConfigMapMinForecast:       fmt.Sprintf("%f", minForecast),           // min forecast in the forecastData.
 			ConfigMapMaxForecast:       fmt.Sprintf("%f", maxForeCast),           // max forecast in the forecastData.
+		}, binaryData)
+}
+
+func (e *Exporter) CreateConfigMapFromProperties(ctx context.Context, configMapName string, data map[string]string, binaryData []byte) error {
+	configMap := &corev1.ConfigMap{
+		ObjectMeta: v1.ObjectMeta{
+			Name:      configMapName,
+			Namespace: client.Namespace,
 		},
+		Immutable: &isImmutable,
+		Data:      data,
 		BinaryData: map[string][]byte{
-			"data": binaryData, // json marshal of the EmissionsData array.
+			BinaryData: binaryData, // json marshal of the EmissionsData array.
 		},
 	}
-
-	_, err = e.clusterClient.CoreV1().
+	_, err := e.clusterClient.CoreV1().
 		ConfigMaps(client.Namespace).
 		Create(ctx, configMap, v1.CreateOptions{})
 	if err != nil {
 		return err
 	}
 	klog.Infof("configMap %s has been created", configMapName)
-
 	return nil
 }
 
@@ -83,15 +86,16 @@ func (e *Exporter) GetGonfigMapWatch(ctx context.Context, configMapName string)
 	return watch
 }
 
-func (e *Exporter) DeleteConfigmap(ctx context.Context, configMapName string) error {
-	_, err := e.clusterClient.CoreV1().ConfigMaps(client.Namespace).Get(ctx, configMapName, v1.GetOptions{})
+func (e *Exporter) DeleteConfigMap(ctx context.Context, configMapName string) error {
+	currentConfigMap, err := e.GetConfigMap(ctx, configMapName)
 	if err != nil {
-		if apierrors.IsNotFound(err) { // if configMap is not found, no errors will be returned.
-			return nil
-		}
 		return err
 	}
 
+	if currentConfigMap == nil {
+		return nil // configMap is not found, delete will not be called.
+	}
+
 	err = e.clusterClient.CoreV1().
 		ConfigMaps(client.Namespace).
 		Delete(ctx, configMapName, v1.DeleteOptions{})
@@ -104,6 +108,18 @@ func (e *Exporter) DeleteConfigmap(ctx context.Context, configMapName string) er
 	return nil
 }
 
+func (e *Exporter) GetConfigMap(ctx context.Context, configMapName string) (*corev1.ConfigMap, error) {
+	currentConfigMap, err := e.clusterClient.CoreV1().ConfigMaps(client.Namespace).Get(ctx, configMapName, v1.GetOptions{})
+	if err != nil {
+		if apierrors.IsNotFound(err) { // if configMap is not found, no errors will be returned.
+			return nil, nil
+		}
+		return nil, err
+	}
+
+	return currentConfigMap, nil
+}
+
 func getMinMaxForecast(ctx context.Context, forecastData []client.EmissionsDataDto) (float64, float64) {
 	values := make([]float64, len(forecastData))
 	for index := range forecastData {

pkg/exporter/consts.go

@@ -14,5 +14,5 @@ const (
 	ConfigMapMinForecast       = "minForecast"
 	ConfigMapMaxForecast       = "maxForecast"
 
-	TimeLayout = "2006-01-02 15:04:05"
+	BinaryData = "data"
 )

pkg/exporter/exporter.go

@@ -105,19 +105,43 @@ func (e *Exporter) Run(ctx context.Context, configMapName, region string, patrol
 }
 
 func (e *Exporter) RefreshData(ctx context.Context, configMapName string, region string, stopChan <-chan struct{}) error {
-	err := e.DeleteConfigmap(ctx, configMapName)
+	// get current object (if any) in case we could not update the data.
+	currentConfigMap, err := e.GetConfigMap(ctx, configMapName)
+	if err != nil {
+		return err
+	}
+
+	err = e.DeleteConfigMap(ctx, configMapName)
 	if err != nil && !apierrors.IsNotFound(err) { // if configMap is not found,
 		return err
 	}
 
-	retry.OnError(constantBackoff, func(err error) bool {
+	var forecast []client.EmissionsForecastDto
+	err = retry.OnError(constantBackoff, func(err error) bool {
 		return true
 	}, func() error {
-		forecast, err := e.getCurrentForecastData(ctx, region, stopChan)
-		if err != nil {
+		forecast, err = e.getCurrentForecastData(ctx, region, stopChan)
+		return err
+	})
+	if err != nil {
+		if currentConfigMap != nil {
+			// return old data with failed message
+			return e.UseCurrentConfigMap(ctx, err.Error(), currentConfigMap)
+		} else {
+			e.recorder.Eventf(&corev1.ObjectReference{
+				Kind:      "Pod",
+				Namespace: client.Namespace,
+				Name:      client.PodName,
+			}, corev1.EventTypeWarning, "Cannot retrieve updated forecast data", "Error while retrieving updated forecast data")
+			klog.Errorf("an error has occurred while retrieving updated forecast data")
 			return err
 		}
-		return e.CreateOrUpdateConfigMap(ctx, configMapName, forecast)
+	}
+
+	err = retry.OnError(constantBackoff, func(err error) bool {
+		return true
+	}, func() error {
+		return e.CreateConfigMapFromEmissionForecast(ctx, configMapName, forecast)
 	})
 	if err != nil {
 		e.recorder.Eventf(&corev1.ObjectReference{
@@ -136,6 +160,25 @@ func (e *Exporter) RefreshData(ctx context.Context, configMapName string, region
 	return nil
 }
 
+func (e *Exporter) UseCurrentConfigMap(ctx context.Context, message string, currentConfigMap *corev1.ConfigMap) error {
+	if currentConfigMap.Data != nil {
+		currentConfigMap.Data[ConfigMapLastHeartbeatTime] = time.Now().String()
+		currentConfigMap.Data[ConfigMapMessage] = message
+	} else {
+		currentConfigMap.Data = map[string]string{
+			ConfigMapLastHeartbeatTime: time.Now().String(),
+			ConfigMapMessage:           message,
+		}
+	}
+	if currentConfigMap.BinaryData == nil {
+		currentConfigMap.BinaryData = map[string][]byte{
+			BinaryData: {},
+		}
+	}
+	return e.CreateConfigMapFromProperties(ctx, currentConfigMap.Name,
+		currentConfigMap.Data, currentConfigMap.BinaryData[BinaryData])
+}
+
 func (e *Exporter) getCurrentForecastData(ctx context.Context, region string, stopChan <-chan struct{}) ([]client.EmissionsForecastDto, error) {
 	opt := &client.CarbonAwareApiGetCurrentForecastDataOpts{
 		DataStartAt: optional.EmptyTime(),