add ignoreNullValues for AWS CloudWatch Scaler

CHANGELOG.md

@@ -67,6 +67,7 @@ Here is an overview of all new **experimental** features:
 - **General**: Add GRPC Healthchecks ([#5590](https://github.com/kedacore/keda/issues/5590))
 - **General**: Add OPENTELEMETRY flag in e2e test YAML ([#5375](https://github.com/kedacore/keda/issues/5375))
 - **General**: Add support for cross tenant/cloud authentication when using Azure Workload Identity for TriggerAuthentication ([#5441](https://github.com/kedacore/keda/issues/5441))
+- **AWS CloudWatch Scaler**: Add support for ignoreNullValues ([#5352](https://github.com/kedacore/keda/issues/5352))
 - **GCP Stackdriver Scaler**: Add missing parameters 'rate' and 'count' for GCP Stackdriver Scaler alignment ([#5633](https://github.com/kedacore/keda/issues/5633))
 - **Metrics API Scaler**: Add support for various formats: json, xml, yaml, prometheus ([#2633](https://github.com/kedacore/keda/issues/2633))
 - **MongoDB Scaler**: Add scheme field support srv record ([#5544](https://github.com/kedacore/keda/issues/5544))

pkg/scalers/aws_cloudwatch_scaler.go

@@ -3,6 +3,7 @@ package scalers
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"strconv"
 	"strings"
 	"time"
@@ -42,6 +43,7 @@ type awsCloudwatchMetadata struct {
 	targetMetricValue           float64
 	activationTargetMetricValue float64
 	minMetricValue              float64
+	ignoreNullValues            bool
 
 	metricCollectionTime int64
 	metricStat           string
@@ -115,7 +117,6 @@ func getFloatMetadataValue(metadata map[string]string, key string, required bool
 
 func createCloudwatchClient(ctx context.Context, metadata *awsCloudwatchMetadata) (*cloudwatch.Client, error) {
 	cfg, err := awsutils.GetAwsConfig(ctx, metadata.awsRegion, metadata.awsAuthorization)
-
 	if err != nil {
 		return nil, err
 	}
@@ -189,6 +190,12 @@ func parseAwsCloudwatchMetadata(config *scalersconfig.ScalerConfig) (*awsCloudwa
 	}
 	meta.minMetricValue = minMetricValue
 
+	ignoreNullValues, err := getParameterFromConfigV2(config, "ignoreNullValues", reflect.TypeOf(true), IsOptional(true), UseMetadata(true), WithDefaultVal(true))
+	if err != nil {
+		return nil, err
+	}
+	meta.ignoreNullValues, _ = ignoreNullValues.(bool)
+
 	meta.metricStat = defaultMetricStat
 	if val, ok := config.TriggerMetadata["metricStat"]; ok && val != "" {
 		meta.metricStat = val
@@ -213,8 +220,8 @@ func parseAwsCloudwatchMetadata(config *scalersconfig.ScalerConfig) (*awsCloudwa
 	}
 	meta.metricCollectionTime = metricCollectionTime
 
-	if meta.metricCollectionTime < 0 || meta.metricCollectionTime%meta.metricStatPeriod != 0 {
-		return nil, fmt.Errorf("metricCollectionTime must be greater than 0 and a multiple of metricStatPeriod(%d), %d is given", meta.metricStatPeriod, meta.metricCollectionTime)
+	if err = checkMetricCollectionTime(meta.metricCollectionTime, meta.metricStatPeriod); err != nil {
+		return nil, err
 	}
 
 	metricEndTimeOffset, err := getIntMetadataValue(config.TriggerMetadata, "metricEndTimeOffset", false, defaultMetricEndTimeOffset)
@@ -284,6 +291,14 @@ func checkMetricStatPeriod(period int64) error {
 	return nil
 }
 
+func checkMetricCollectionTime(metricCollectionTime, metricStatPeriod int64) error {
+	if metricCollectionTime < 0 || metricCollectionTime%metricStatPeriod != 0 {
+		return fmt.Errorf("metricCollectionTime must be greater than 0 and a multiple of metricStatPeriod(%d), %d is given", metricStatPeriod, metricCollectionTime)
+	}
+
+	return nil
+}
+
 func computeQueryWindow(current time.Time, metricPeriodSec, metricEndTimeOffsetSec, metricCollectionTimeSec int64) (startTime, endTime time.Time) {
 	endTime = current.Add(time.Second * -1 * time.Duration(metricEndTimeOffsetSec)).Truncate(time.Duration(metricPeriodSec) * time.Second)
 	startTime = endTime.Add(time.Second * -1 * time.Duration(metricCollectionTimeSec))
@@ -292,7 +307,6 @@ func computeQueryWindow(current time.Time, metricPeriodSec, metricEndTimeOffsetS
 
 func (s *awsCloudwatchScaler) GetMetricsAndActivity(ctx context.Context, metricName string) ([]external_metrics.ExternalMetricValue, bool, error) {
 	metricValue, err := s.GetCloudwatchMetrics(ctx)
-
 	if err != nil {
 		s.logger.Error(err, "Error getting metric value")
 		return []external_metrics.ExternalMetricValue{}, false, err
@@ -375,20 +389,28 @@ func (s *awsCloudwatchScaler) GetCloudwatchMetrics(ctx context.Context) (float64
 	}
 
 	output, err := s.cwClient.GetMetricData(ctx, &input)
-
 	if err != nil {
 		s.logger.Error(err, "Failed to get output")
 		return -1, err
 	}
 
 	s.logger.V(1).Info("Received Metric Data", "data", output)
+
+	// If no metric data results or the first result has no values, and ignoreNullValues is false,
+	// the scaler should return an error to prevent any further scaling actions.
+	if len(output.MetricDataResults) > 0 && len(output.MetricDataResults[0].Values) == 0 && !s.metadata.ignoreNullValues {
+		emptyMetricsErrMsg := "empty metric data received, ignoreNullValues is false, returning error"
+		s.logger.Error(nil, emptyMetricsErrMsg)
+		return -1, fmt.Errorf(emptyMetricsErrMsg)
+	}
+
 	var metricValue float64
+
 	if len(output.MetricDataResults) > 0 && len(output.MetricDataResults[0].Values) > 0 {
 		metricValue = output.MetricDataResults[0].Values[0]
 	} else {
 		s.logger.Info("empty metric data received, returning minMetricValue")
 		metricValue = s.metadata.minMetricValue
 	}
-
 	return metricValue, nil
 }