Azure Application Insights: Add option to ignore null values

CHANGELOG.md

@@ -66,6 +66,7 @@ Here is an overview of all new **experimental** features:
 - **General**: Add a warning when KEDA run outside supported k8s versions ([#4130](https://github.com/kedacore/keda/issues/4130))
 - **General**: Use (self-signed) certificates for all the communications (internals and externals) ([#3931](https://github.com/kedacore/keda/issues/3931))
 - **General**: Use TLS1.2 as minimum TLS version ([#4193](https://github.com/kedacore/keda/issues/4193))
+- **Azure Application Insights Scaler**: Add ignoreNullValues to ignore errors when the data returned has null in its values ([#4316](https://github.com/kedacore/keda/issues/4316))
 - **Azure Pipelines Scaler**: Improve error logging for `validatePoolID` ([#3996](https://github.com/kedacore/keda/issues/3996))
 - **Azure Pipelines Scaler**: New configuration parameter `requireAllDemands` to scale only if jobs request all demands provided by the scaling definition ([#4138](https://github.com/kedacore/keda/issues/4138))
 - **Hashicorp Vault**: Add support to secrets backend version 1 ([#2645](https://github.com/kedacore/keda/issues/2645))

pkg/scalers/azure/azure_app_insights.go

@@ -89,7 +89,7 @@ func extractAppInsightValue(info AppInsightsInfo, metric ApplicationInsightsMetr
 		}
 		floatVal = val.(float64)
 	} else {
-		return -1, fmt.Errorf("metric %s did not containe aggregation type %s", info.MetricID, info.AggregationType)
+		return -1, fmt.Errorf("metric %s did not contain aggregation type %s", info.MetricID, info.AggregationType)
 	}
 
 	azureAppInsightsLog.V(2).Info("value extracted from metric request", "metric type", info.AggregationType, "metric value", floatVal)
@@ -115,7 +115,7 @@ func queryParamsForAppInsightsRequest(info AppInsightsInfo) (map[string]interfac
 }
 
 // GetAzureAppInsightsMetricValue returns the value of an Azure App Insights metric, rounded to the nearest int
-func GetAzureAppInsightsMetricValue(ctx context.Context, info AppInsightsInfo, podIdentity kedav1alpha1.AuthPodIdentity) (float64, error) {
+func GetAzureAppInsightsMetricValue(ctx context.Context, info AppInsightsInfo, podIdentity kedav1alpha1.AuthPodIdentity, ignoreNullValues bool) (float64, error) {
 	config := getAuthConfig(ctx, info, podIdentity)
 	authorizer, err := config.Authorizer()
 	if err != nil {
@@ -154,5 +154,9 @@ func GetAzureAppInsightsMetricValue(ctx context.Context, info AppInsightsInfo, p
 		return -1, err
 	}
 
-	return extractAppInsightValue(info, *metric)
+	val, err := extractAppInsightValue(info, *metric)
+	if err != nil && ignoreNullValues {
+		return 0.0, nil
+	}
+	return val, err
 }

pkg/scalers/azure_app_insights_scaler.go

@@ -24,13 +24,23 @@ const (
 	azureAppInsightsMetricAggregationTypeName     = "metricAggregationType"
 	azureAppInsightsMetricFilterName              = "metricFilter"
 	azureAppInsightsTenantIDName                  = "tenantId"
+	azureAppInsightsIgnoreNullValues              = "ignoreNullValues"
+)
+
+var (
+	azureAppInsightsDefaultIgnoreNullValues = true
 )
 
 type azureAppInsightsMetadata struct {
 	azureAppInsightsInfo  azure.AppInsightsInfo
 	targetValue           float64
 	activationTargetValue float64
 	scalerIndex           int
+	// sometimes we should consider there is an error we can accept
+	// default value is true/t, to ignore the null value returned from prometheus
+	// change to false/f if you can not accept prometheus returning null values
+	// https://github.com/kedacore/keda/issues/4316
+	ignoreNullValues bool
 }
 
 type azureAppInsightsScaler struct {
@@ -139,6 +149,16 @@ func parseAzureAppInsightsMetadata(config *ScalerConfig, logger logr.Logger) (*a
 	}
 	meta.azureAppInsightsInfo.ActiveDirectoryEndpoint = activeDirectoryEndpoint
 
+	meta.ignoreNullValues = azureAppInsightsDefaultIgnoreNullValues
+	if val, ok := config.TriggerMetadata[azureAppInsightsIgnoreNullValues]; ok && val != "" {
+		azureAppInsightsIgnoreNullValues, err := strconv.ParseBool(val)
+		if err != nil {
+			return nil, fmt.Errorf("err incorrect value for azureAppInsightsIgnoreNullValues given: %s, "+
+				"please use true or false", val)
+		}
+		meta.ignoreNullValues = azureAppInsightsIgnoreNullValues
+	}
+
 	// Required authentication parameters below
 
 	val, err = getParameterFromConfig(config, azureAppInsightsAppIDName, true)
@@ -182,7 +202,7 @@ func (s *azureAppInsightsScaler) GetMetricSpecForScaling(context.Context) []v2.M
 
 // GetMetricsAndActivity returns value for a supported metric and an error if there is a problem getting the metric
 func (s *azureAppInsightsScaler) GetMetricsAndActivity(ctx context.Context, metricName string) ([]external_metrics.ExternalMetricValue, bool, error) {
-	val, err := azure.GetAzureAppInsightsMetricValue(ctx, s.metadata.azureAppInsightsInfo, s.podIdentity)
+	val, err := azure.GetAzureAppInsightsMetricValue(ctx, s.metadata.azureAppInsightsInfo, s.podIdentity, s.metadata.ignoreNullValues)
 	if err != nil {
 		s.logger.Error(err, "error getting azure app insights metric")
 		return []external_metrics.ExternalMetricValue{}, false, err