feat: use one minute granularity for 5XX alarms (#454)

guardian · Apr 16, 2021 · b46f749 · b46f749
1 parent e79b15c
commit b46f749
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Showing 3 changed files with 8 additions and 6 deletions.
diff --git a/src/constructs/cloudwatch/__snapshots__/ec2-alarms.test.ts.snap b/src/constructs/cloudwatch/__snapshots__/ec2-alarms.test.ts.snap
@@ -170,7 +170,7 @@ Object {
                 "MetricName": "HTTPCode_ELB_5XX_Count",
                 "Namespace": "AWS/ApplicationELB",
               },
-              "Period": 300,
+              "Period": 60,
               "Stat": "Sum",
             },
             "ReturnData": false,
@@ -193,7 +193,7 @@ Object {
                 "MetricName": "HTTPCode_Target_5XX_Count",
                 "Namespace": "AWS/ApplicationELB",
               },
-              "Period": 300,
+              "Period": 60,
               "Stat": "Sum",
             },
             "ReturnData": false,
@@ -216,7 +216,7 @@ Object {
                 "MetricName": "RequestCount",
                 "Namespace": "AWS/ApplicationELB",
               },
-              "Period": 300,
+              "Period": 60,
               "Stat": "Sum",
             },
             "ReturnData": false,

diff --git a/src/constructs/cloudwatch/ec2-alarms.test.ts b/src/constructs/cloudwatch/ec2-alarms.test.ts
@@ -62,7 +62,7 @@ describe("The Gu5xxPercentageAlarm construct", () => {
     const alb = new GuApplicationLoadBalancer(stack, "ApplicationLoadBalancer", { ...app, vpc });
     const props = {
       tolerated5xxPercentage: 1,
-      numberOfFiveMinutePeriodsToEvaluate: 3,
+      numberOfMinutesAboveThresholdBeforeAlarm: 3,
       snsTopicName: "test-topic",
     };
     new Gu5xxPercentageAlarm(stack, "test", { ...app, loadBalancer: alb, ...props });

diff --git a/src/constructs/cloudwatch/ec2-alarms.ts b/src/constructs/cloudwatch/ec2-alarms.ts
@@ -1,5 +1,6 @@
 import { ComparisonOperator, MathExpression, TreatMissingData } from "@aws-cdk/aws-cloudwatch";
 import { HttpCodeElb, HttpCodeTarget } from "@aws-cdk/aws-elasticloadbalancingv2";
+import { Duration } from "@aws-cdk/core";
 import type { GuStack } from "../core";
 import type { AppIdentity } from "../core/identity";
 import type { GuApplicationLoadBalancer } from "../loadbalancing";
@@ -14,7 +15,7 @@ export interface Gu5xxPercentageMonitoringProps
   extends Omit<GuAlarmProps, "evaluationPeriods" | "metric" | "period" | "threshold" | "treatMissingData">,
     AppIdentity {
   tolerated5xxPercentage: number;
-  numberOfFiveMinutePeriodsToEvaluate?: number;
+  numberOfMinutesAboveThresholdBeforeAlarm?: number;
   noMonitoring?: false;
 }
 
@@ -32,6 +33,7 @@ export class Gu5xxPercentageAlarm extends GuAlarm {
         m3: props.loadBalancer.metricRequestCount(),
       },
       label: `% of 5XX responses served for ${props.app} (load balancer and instances combined)`,
+      period: Duration.minutes(1),
     });
     const defaultAlarmName = `High 5XX error % from ${props.app} in ${scope.stage}`;
     const defaultDescription = `${props.app} exceeded ${props.tolerated5xxPercentage}% error rate`;
@@ -43,7 +45,7 @@ export class Gu5xxPercentageAlarm extends GuAlarm {
       comparisonOperator: ComparisonOperator.GREATER_THAN_THRESHOLD,
       alarmName: props.alarmName ?? defaultAlarmName,
       alarmDescription: props.alarmDescription ?? defaultDescription,
-      evaluationPeriods: props.numberOfFiveMinutePeriodsToEvaluate ?? 1,
+      evaluationPeriods: props.numberOfMinutesAboveThresholdBeforeAlarm ?? 1,
     };
     super(scope, id, alarmProps);
   }