DynamoTableGlobalSecondaryIndexMonitoring ignores localAlarmNamePrefixOverride

[haljarrett]

Version

5.10.4

Steps and/or minimal code example to reproduce

Given two dynamo tables, each with identically named GSIs, adding alarms (such as addReadThrottledEventsCountAlarm) will create a construct id name collision:

Error: There is already a Construct with name '<globalPrefix>-<GSIName>-Throttled-Events-Warning' in AmazonMonitoringFacade [Monitoring]

This is not fixed by adding a localAlarmNamePrefixOverride.

If I get some time I'll put together a reproduction example.

Expected behavior

I would expect the localAlarmNamePrefixOverride to allow updating the local part of the alarm name (GSI name).

Actual behavior

Value is ignored.

Other details

This occurs because DynamoTableGlobalSecondaryIndexMonitoring calls createAlarmFactory on it's parent scope, MonitoringFacade, instead of on it's own superclass, Monitoring which handles the alarm local name override.

[haljarrett]

Simple reproduction:

#!/usr/bin/env node
import 'source-map-support/register';
import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';
import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';
import * as mc from 'cdk-monitoring-constructs';

class MonitoringBugStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Create first DynamoDB table with a GSI named "MyGSI"
    const table1 = new dynamodb.Table(this, 'Table1', {
      partitionKey: { name: 'id', type: dynamodb.AttributeType.STRING },
      billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
    });

    // Add a GSI to the first table
    table1.addGlobalSecondaryIndex({
      indexName: 'MyGSI',
      partitionKey: { name: 'gsiKey', type: dynamodb.AttributeType.STRING },
    });

    // Create second DynamoDB table with a GSI with the same name "MyGSI"
    const table2 = new dynamodb.Table(this, 'Table2', {
      partitionKey: { name: 'id', type: dynamodb.AttributeType.STRING },
      billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
    });

    // Add a GSI to the second table with the same name
    table2.addGlobalSecondaryIndex({
      indexName: 'MyGSI',
      partitionKey: { name: 'gsiKey', type: dynamodb.AttributeType.STRING },
    });

    // Create a monitoring facade
    const monitoring = new mc.MonitoringFacade(this, 'Monitoring', {
      alarmFactoryDefaults: {
        actionsEnabled: false,
        alarmNamePrefix: 'MonitoringBug',
      },
    });

    // Define throttling thresholds for alarms
    const throttlingThresholds = {
      Warning: {
        maxThrottledEventsThreshold: 0,
      },
    };

    // Add alarms for the GSIs on both tables
    // This will cause the error because both GSIs have the same name
    monitoring.monitorDynamoTableGlobalSecondaryIndex({
      table: table1,
      globalSecondaryIndexName: 'MyGSI',
      addReadThrottledEventsCountAlarm: throttlingThresholds,
    });

    // Even with localAlarmNamePrefixOverride, it will still fail
    monitoring.monitorDynamoTableGlobalSecondaryIndex({
      table: table2,
      globalSecondaryIndexName: 'MyGSI',
      localAlarmNamePrefixOverride: 'Table2-MyGSI',
      addReadThrottledEventsCountAlarm: throttlingThresholds,
    });
  }
}

const app = new cdk.App();
new MonitoringBugStack(app, 'MonitoringBugStack');