Fixed a cloudwatch-metric-publisher issue where very small values would result in a failure calling cloudwatch.

Author: millems

metric-publishers/cloudwatch-metric-publisher/src/main/java/software/amazon/awssdk/metrics/publishers/cloudwatch/internal/transform/MetricCollectionAggregator.java

@@ -150,7 +150,7 @@ private MetricDatum detailedMetricDatum(Instant timeBucket,
                                                        .limit(maxElements);
 
         boundedMetrics.forEach(detailedMetrics -> {
-            values.add(detailedMetrics.metricValue());
+            values.add(MetricValueNormalizer.normalize(detailedMetrics.metricValue()));
             counts.add((double) detailedMetrics.metricCount());
         });
 
@@ -167,9 +167,9 @@ private MetricDatum detailedMetricDatum(Instant timeBucket,
     private MetricDatum summaryMetricDatum(Instant timeBucket,
                                            SummaryMetricAggregator metric) {
         StatisticSet stats = StatisticSet.builder()
-                                         .minimum(metric.min())
-                                         .maximum(metric.max())
-                                         .sum(metric.sum())
+                                         .minimum(MetricValueNormalizer.normalize(metric.min()))
+                                         .maximum(MetricValueNormalizer.normalize(metric.max()))
+                                         .sum(MetricValueNormalizer.normalize(metric.sum()))
                                          .sampleCount((double) metric.count())
                                          .build();
         return MetricDatum.builder()

metric-publishers/cloudwatch-metric-publisher/src/main/java/software/amazon/awssdk/metrics/publishers/cloudwatch/internal/transform/MetricValueNormalizer.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.metrics.publishers.cloudwatch.internal.transform;
+
+import software.amazon.awssdk.annotations.SdkInternalApi;
+
+@SdkInternalApi
+class MetricValueNormalizer {
+    /**
+     * Really small values (close to 0) result in CloudWatch failing with an "unsupported value" error. Make sure that we floor
+     * those values to 0 to prevent that error.
+     */
+    private static final double ZERO_THRESHOLD = 0.0001;
+
+    private MetricValueNormalizer() {
+    }
+
+    /**
+     * Normalizes a metric value so that it won't upset CloudWatch when it is uploaded.
+     */
+    public static double normalize(double value) {
+        if (value > ZERO_THRESHOLD) {
+            return value;
+        }
+
+        if (value < -ZERO_THRESHOLD) {
+            return value;
+        }
+
+        return 0;
+    }
+}

metric-publishers/cloudwatch-metric-publisher/src/main/java/software/amazon/awssdk/metrics/publishers/cloudwatch/internal/transform/TimeBucketedMetrics.java

@@ -120,7 +120,7 @@ private void aggregateMetrics(MetricCollection metrics, Map<MetricAggregatorKey,
             MetricAggregatorKey aggregatorKey = new MetricAggregatorKey(metricRecord.metric(), dimensions);
             valueFor(metricRecord).ifPresent(metricValue -> {
                 bucket.computeIfAbsent(aggregatorKey, m -> newAggregator(aggregatorKey))
-                      .addMetricValue(metricValue);
+                      .addMetricValue(MetricValueNormalizer.normalize(metricValue));
             });
         });
     }

metric-publishers/cloudwatch-metric-publisher/src/test/java/software/amazon/awssdk/metrics/publishers/cloudwatch/internal/transform/MetricCollectionAggregatorTest.java

@@ -82,6 +82,55 @@ private void validateValuesCount(PutMetricDataRequest request, int valuesExpecte
             .hasSize(valuesExpected);
     }
 
+    @Test
+    public void smallValuesAreNormalizedToZeroWithSummaryMetrics() {
+        // Really small values (close to 0) result in CloudWatch failing with an "unsupported value" error. Make sure that we
+        // floor those values to 0 to prevent that error.
+
+        MetricCollectionAggregator aggregator = defaultAggregator();
+
+        MetricCollector collector = collector();
+        SdkMetric<Double> metric = someMetric(Double.class);
+        collector.reportMetric(metric, -1E-10);
+        collector.reportMetric(metric, 1E-10);
+        aggregator.addCollection(collectToFixedTime(collector));
+
+        assertThat(aggregator.getRequests()).hasOnlyOneElementSatisfying(request -> {
+            assertThat(request.metricData()).hasOnlyOneElementSatisfying(metricData -> {
+                StatisticSet stats = metricData.statisticValues();
+                assertThat(stats.minimum()).isEqualTo(0.0);
+                assertThat(stats.maximum()).isEqualTo(0.0);
+                assertThat(stats.sum()).isEqualTo(0.0);
+                assertThat(stats.sampleCount()).isEqualTo(2.0);
+            });
+        });
+    }
+
+    @Test
+    public void smallValuesAreNormalizedToZeroWithDetailedMetrics() {
+        // Really small values (close to 0) result in CloudWatch failing with an "unsupported value" error. Make sure that we
+        // floor those values to 0 to prevent that error.
+
+        SdkMetric<Double> metric = someMetric(Double.class);
+        MetricCollectionAggregator aggregator = aggregatorWithCustomDetailedMetrics(metric);
+
+        MetricCollector collector = collector();
+        collector.reportMetric(metric, -1E-10);
+        collector.reportMetric(metric, 1E-10);
+        aggregator.addCollection(collectToFixedTime(collector));
+
+        assertThat(aggregator.getRequests()).hasOnlyOneElementSatisfying(request -> {
+            assertThat(request.metricData()).hasOnlyOneElementSatisfying(metricData -> {
+                assertThat(metricData.values()).hasOnlyOneElementSatisfying(metricValue -> {
+                    assertThat(metricValue).isEqualTo(0.0);
+                });
+                assertThat(metricData.counts()).hasOnlyOneElementSatisfying(metricCount -> {
+                    assertThat(metricCount).isEqualTo(2.0);
+                });
+            });
+        });
+    }
+
     @Test
     public void dimensionOrderInCollectionDoesNotMatter() {
         MetricCollectionAggregator aggregator = defaultAggregator();