relates to discussion kedacore#6565 (comment)

the final semaphore acquisition was still missing, which resulted in loop not waiting until all metrics were gathered from each metrics API server

Signed-off-by: julian GUINARD <[email protected]>

Author: julianguinard

pkg/scalers/metrics_api_scaler.go

@@ -224,6 +224,7 @@ func getValueFromPrometheusResponse(body []byte, valueLocation string) (float64,
 // getValueFromJSONResponse uses provided valueLocation to access the numeric value in provided body using GJSON
 func getValueFromJSONResponse(body []byte, valueLocation string) (float64, error) {
 	r := gjson.GetBytes(body, valueLocation)
+
 	if r.Type == gjson.String {
 		v, err := resource.ParseQuantity(r.String())
 		if err != nil {
@@ -400,6 +401,7 @@ func (s *metricsAPIScaler) aggregateMetricsFromMultipleEndpoints(ctx context.Con
 	var err error
 	var firstMetricEncountered bool
 	var aggregation float64
+	s.logger.V(1).Info(fmt.Sprintf("start iterating %d endpoint urls", len(endpointsUrls)))
 	for _, endpointURL := range endpointsUrls {
 		if err := sem.Acquire(ctx, 1); err != nil {
 			s.logger.Error(err, "Failed to acquire semaphore")
@@ -437,6 +439,11 @@ func (s *metricsAPIScaler) aggregateMetricsFromMultipleEndpoints(ctx context.Con
 			}
 		}(endpointURL)
 	}
+	// Wait that all goroutines have released their semaphore acquisition
+	if err := sem.Acquire(ctx, maxGoroutines); err != nil {
+		s.logger.V(1).Error(err, "final semaphore acquisition failed")
+	}
+	s.logger.V(1).Info(fmt.Sprintf("ENDED iterating %d endpoint urls, aggregation is now %v", len(endpointsUrls), aggregation))
 
 	if nbErrors > 0 && nbErrors == len(endpointsUrls) {
 		err = fmt.Errorf("could not get any metric successfully from the %d provided endpoints", len(endpointsUrls))
@@ -470,6 +477,7 @@ func (s *metricsAPIScaler) getMetricValueFromURL(ctx context.Context, url *strin
 		return 0, err
 	}
 	v, err := GetValueFromResponse(b, s.metadata.ValueLocation, s.metadata.Format)
+
 	if err != nil {
 		return 0, err
 	}