feat(cloudwatch): Support 'datapointsToAlarm' on Alarms

Adds support for settingt the `dataPointsToAlarm` property of the CloudWatch `Alarm`s (also via the `Metric`s). Fixes #1626
aws · Jan 29, 2019 · 5b47ebe · 5b47ebe
1 parent 6a8e010
commit 5b47ebe
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Showing 5 changed files with 30 additions and 6 deletions.
diff --git a/packages/@aws-cdk/aws-cloudwatch/lib/alarm.ts b/packages/@aws-cdk/aws-cloudwatch/lib/alarm.ts
@@ -68,6 +68,15 @@ export interface AlarmProps {
    * @default true
    */
   actionsEnabled?: boolean;
+
+  /**
+   * The number of datapoints that must be breaching to trigger the alarm. This is used only if you are setting an "M
+   * out of N" alarm. In that case, this value is the M. For more information, see Evaluating an Alarm in the Amazon
+   * CloudWatch User Guide.
+   *
+   * @default ``evaluationPeriods``
+   */
+  datapointsToAlarm?: number;
 }
 
 /**
@@ -153,6 +162,7 @@ export class Alarm extends Construct {
       // Evaluation
       comparisonOperator,
       threshold: props.threshold,
+      datapointsToAlarm: props.datapointsToAlarm,
       evaluateLowSampleCountPercentile: props.evaluateLowSampleCountPercentile,
       evaluationPeriods: props.evaluationPeriods,
       treatMissingData: props.treatMissingData,

diff --git a/packages/@aws-cdk/aws-cloudwatch/lib/metric.ts b/packages/@aws-cdk/aws-cloudwatch/lib/metric.ts
@@ -157,6 +157,7 @@ export class Metric {
       alarmName: props.alarmName,
       alarmDescription: props.alarmDescription,
       comparisonOperator: props.comparisonOperator,
+      datapointsToAlarm: props.datapointsToAlarm,
       threshold: props.threshold,
       evaluationPeriods: props.evaluationPeriods,
       evaluateLowSampleCountPercentile: props.evaluateLowSampleCountPercentile,
@@ -372,6 +373,15 @@ export interface NewAlarmProps {
    * @default true
    */
   actionsEnabled?: boolean;
+
+  /**
+   * The number of datapoints that must be breaching to trigger the alarm. This is used only if you are setting an "M
+   * out of N" alarm. In that case, this value is the M. For more information, see Evaluating an Alarm in the Amazon
+   * CloudWatch User Guide.
+   *
+   * @default ``evaluationPeriods``
+   */
+  datapointsToAlarm?: number;
 }
 
 function ifUndefined<T>(x: T | undefined, def: T | undefined): T | undefined {

diff --git a/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-and-dashboard.expected.json b/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-and-dashboard.expected.json
@@ -8,10 +8,8 @@
       "Properties": {
         "ComparisonOperator": "GreaterThanOrEqualToThreshold",
         "EvaluationPeriods": 3,
-        "MetricName": "ApproximateNumberOfMessagesVisible",
-        "Namespace": "AWS/SQS",
-        "Period": 300,
         "Threshold": 100,
+        "DatapointsToAlarm": 2,
         "Dimensions": [
           {
             "Name": "QueueName",
@@ -23,6 +21,9 @@
             }
           }
         ],
+        "MetricName": "ApproximateNumberOfMessagesVisible",
+        "Namespace": "AWS/SQS",
+        "Period": 300,
         "Statistic": "Average"
       }
     },

diff --git a/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-and-dashboard.ts b/packages/@aws-cdk/aws-cloudwatch/test/integ.alarm-and-dashboard.ts
@@ -21,7 +21,8 @@ const metric = new cloudwatch.Metric({
 
 const alarm = metric.newAlarm(stack, 'Alarm', {
   threshold: 100,
-  evaluationPeriods: 3
+  evaluationPeriods: 3,
+  datapointsToAlarm: 2,
 });
 
 const dashboard = new cloudwatch.Dashboard(stack, 'Dash');

diff --git a/packages/@aws-cdk/aws-cloudwatch/test/test.alarm.ts b/packages/@aws-cdk/aws-cloudwatch/test/test.alarm.ts
@@ -17,13 +17,15 @@ export = {
     new Alarm(stack, 'Alarm', {
       metric: testMetric,
       threshold: 1000,
-      evaluationPeriods: 2
+      evaluationPeriods: 3,
+      datapointsToAlarm: 2,
     });
 
     // THEN
     expect(stack).to(haveResource('AWS::CloudWatch::Alarm', {
       ComparisonOperator: "GreaterThanOrEqualToThreshold",
-      EvaluationPeriods: 2,
+      EvaluationPeriods: 3,
+      DatapointsToAlarm: 2,
       MetricName: "Metric",
       Namespace: "CDK/Test",
       Period: 300,