Configure AWS CloudWatch Events to trigger lambda (Cron)

Applicable when

• We need to execute some logic on a regular basis

Implementation

Lambda handler:

import { ScheduledEvent } from 'aws-lambda';

export async function handler(event: ScheduledEvent): Promise<void> {
  // Some logic here that needs to be executed as a cron job
}

CDK configuration:

import { Rule, Schedule } from '@aws-cdk/aws-events';
import { LambdaFunction as TargetLambdaFunction } from '@aws-cdk/aws-events-targets';
import { Function as LambdaFunction } from '@aws-cdk/aws-lambda';

export class LambdaCron extends Construct {
  constructor(scope: Construct) {
    super(scope, 'Cron');

    this.stopModels();
  }

  private stopModels(): void {
    // configure lambda
    const lambda = new LambdaFunction(this, lambdaName, {
      handler: lambdaHandlerPath,
      functionName: lambdaName,
      runtime: Runtime.NODEJS_12_X,
      code: Code.fromAsset(LAMBDA_CODE_PATH),
      timeout: Duration.minutes(FIVE),
    });

    // Run every day at 7PM UTC
    const rule = new Rule(this, 'StopModelsRule', {
      schedule: Schedule.cron({ minute: '0', hour: '19' }),
    });

    rule.addTarget(new TargetLambdaFunction(lambda));
  }
}