fix(cloudwatch): metric label not rendered into Alarms (#13070)

Cloudwatch allows adding labels to metrics. These can be seen when viewing alarms. Currently labels only work for math expression metrics. This change will fix it to work for single alarm metrics too. ---- *By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*
aws · Mar 3, 2021 · cbcc712 · robo-sk · Mar 8, 2021 · cbcc712
1 parent 6f7cebd
commit cbcc712
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Showing 3 changed files with 116 additions and 12 deletions.
diff --git a/packages/@aws-cdk/aws-cloudwatch/lib/alarm.ts b/packages/@aws-cdk/aws-cloudwatch/lib/alarm.ts
@@ -227,18 +227,40 @@ export class Alarm extends AlarmBase {
   private renderMetric(metric: IMetric) {
     const self = this;
     return dispatchMetric(metric, {
-      withStat(st) {
-        self.validateMetricStat(st, metric);
-
-        return dropUndefined({
-          dimensions: st.dimensions,
-          namespace: st.namespace,
-          metricName: st.metricName,
-          period: st.period?.toSeconds(),
-          statistic: renderIfSimpleStatistic(st.statistic),
-          extendedStatistic: renderIfExtendedStatistic(st.statistic),
-          unit: st.unitFilter,
-        });
+      withStat(stat, conf) {
+        self.validateMetricStat(stat, metric);
+
+        if (conf.renderingProperties?.label == undefined) {
+          return dropUndefined({
+            dimensions: stat.dimensions,
+            namespace: stat.namespace,
+            metricName: stat.metricName,
+            period: stat.period?.toSeconds(),
+            statistic: renderIfSimpleStatistic(stat.statistic),
+            extendedStatistic: renderIfExtendedStatistic(stat.statistic),
+            unit: stat.unitFilter,
+          });
+        }
+
+        return {
+          metrics: [
+            {
+              metricStat: {
+                metric: {
+                  metricName: stat.metricName,
+                  namespace: stat.namespace,
+                  dimensions: stat.dimensions,
+                },
+                period: stat.period.toSeconds(),
+                stat: stat.statistic,
+                unit: stat.unitFilter,
+              },
+              id: stat.metricName,
+              label: conf.renderingProperties?.label,
+              returnData: true,
+            } as CfnAlarm.MetricDataQueryProperty,
+          ],
+        };
       },
 
       withExpression() {

diff --git a/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-with-label.expected.json b/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-with-label.expected.json
@@ -0,0 +1,50 @@
+{
+    "Resources": {
+        "Alarm1F9009D71": {
+            "Type": "AWS::CloudWatch::Alarm",
+            "Properties": {
+                "Metrics": [
+                    {
+                        "Id": "Metric",
+                        "Label": "Metric [AVG: ${AVG}]",
+                        "MetricStat": {
+                            "Metric": {
+                                "MetricName": "Metric",
+                                "Namespace": "CDK/Test"
+                            },
+                            "Period": 300,
+                            "Stat": "Average"
+                        },
+                        "ReturnData": true
+                    }
+                ],
+                "ComparisonOperator": "GreaterThanOrEqualToThreshold",
+                "EvaluationPeriods": 3,
+                "Threshold": 100
+            }
+        },
+        "Alarm2A7122E13": {
+            "Type": "AWS::CloudWatch::Alarm",
+            "Properties": {
+                "Metrics": [
+                    {
+                        "Id": "Metric",
+                        "Label": "Metric [AVG: ${AVG}]",
+                        "MetricStat": {
+                            "Metric": {
+                                "MetricName": "Metric",
+                                "Namespace": "CDK/Test"
+                            },
+                            "Period": 300,
+                            "Stat": "Average"
+                        },
+                        "ReturnData": true
+                    }
+                ],
+                "ComparisonOperator": "GreaterThanOrEqualToThreshold",
+                "EvaluationPeriods": 3,
+                "Threshold": 100
+            }
+        }
+    }
+}
diff --git a/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-with-label.ts b/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-with-label.ts
@@ -0,0 +1,32 @@
+import { App, Stack, StackProps } from '@aws-cdk/core';
+import { Alarm, Metric } from '../lib';
+
+class AlarmWithLabelIntegrationTest extends Stack {
+
+  constructor(scope: App, id: string, props?: StackProps) {
+    super(scope, id, props);
+
+    const testMetric = new Metric({
+      namespace: 'CDK/Test',
+      metricName: 'Metric',
+      label: 'Metric [AVG: ${AVG}]',
+    });
+
+    new Alarm(this, 'Alarm1', {
+      metric: testMetric,
+      threshold: 100,
+      evaluationPeriods: 3,
+    });
+
+    testMetric.createAlarm(this, 'Alarm2', {
+      threshold: 100,
+      evaluationPeriods: 3,
+    });
+  }
+}
+
+const app = new App();
+
+new AlarmWithLabelIntegrationTest(app, 'AlarmWithLabelIntegrationTest');
+
+app.synth();