constructor()

in src/constructs/cloudwatch/ec2-alarms.ts [89:113]

• 22 lines of code
• 2 McCabe index (conditional complexity)

  constructor(scope: GuStack, props: GuUnhealthyInstancesAlarmProps) {
    const alarmName = `Unhealthy instances for ${props.app} in ${scope.stage}`;

    const period = Duration.minutes(1);
    const evaluationPeriods = 60;
    const evaluationInterval = Duration.minutes(period.toMinutes() * evaluationPeriods).toHumanString();

    const alarmDescription = `${props.app}'s instances have failed healthchecks several times over the last ${evaluationInterval}.
      This typically results in the AutoScaling Group cycling instances and can lead to problems with deployment,
      scaling or handling traffic spikes.

      Check ${props.app}'s application logs or ssh onto an unhealthy instance in order to debug these problems.`;
    const alarmProps: GuAlarmProps = {
      ...props,
      alarmName: alarmName,
      alarmDescription: alarmDescription,
      metric: props.targetGroup.metrics.unhealthyHostCount().with({ period, statistic: Statistic.MAXIMUM }),
      treatMissingData: TreatMissingData.NOT_BREACHING,
      threshold: 1,
      comparisonOperator: ComparisonOperator.GREATER_THAN_OR_EQUAL_TO_THRESHOLD,
      datapointsToAlarm: 30,
      evaluationPeriods,
    };
    super(scope, AppIdentity.suffixText(props, "UnhealthyInstancesAlarm"), alarmProps);
  }