Lambda Scheduling & Event Filtering with EventBridge using Serverless Framework

Application Stack:

Serverless Framework
AWS EventBridge
AWS Lambda
NodeJs

In this post, We will take a look at a use-case that allows us to schedule lambda function call and custom event pattern matching based lambda function call with EventBridge using Serverless Framework.

AWS Architecture:

Above is an AWS Serverless architecture diagram showing EventBridge calling Lambda, using scheduled rules, and filtering lambda calls using custom even pattern matching rules.

1. Install Serverless Framework



npm install -g serverless

2. Create basic NodeJs type template project using Serverless Framework



serverless create --template aws-nodejs

By default it will generate a folder structure like this:

handler.js
serverless.yml

Default serverless.yml will have below IaC code:



service: default-aws-nodejs
frameworkVersion: '2'
provider:
  name: aws
  runtime: nodejs12.x
  lambdaHashingVersion: 20201221

functions:
  hello:
    handler: handler.hello

Default handler.js will have below NodeJs code:



'use strict';

module.exports.hello = async (event) => {

  return {

    statusCode: 200,

    body: JSON.stringify(

      {

        message: 'Go Serverless v1.0! Your function executed successfully!',

        input: event,

      },

      null,

      2

    ),

  };

};

Modify serverless.yml Infrastructure as code to provision needful Lambda functions with EventBridge as Event Source




service: sls-eventbridge

frameworkVersion: '2'

provider:

  name: aws

  runtime: nodejs12.x

  lambdaHashingVersion: 20201221

  stage: dev

  region: ap-south-1

functions:

  scheduledService:

    handler: handler.scheduledService

    events:

      - schedule: rate(1 minute)

invoiceService:

    handler: handler.invoiceService

    events:

      - cloudwatchEvent:

          event:


            detail:

              operation:

                - invoice-service

rewardService:

    handler: handler.rewardService

    events:

      - cloudwatchEvent:

          event:


            detail:

              operation:

                - reward-service

Modify handler.js with below sample demo code




'use strict';

const scheduledService = async (event) => {

  console.log(event);

  return {

    statusCode: 200,

    body: JSON.stringify(

      {

        message: 'scheduledService lambda function call through EventBridge scheduling rule!',

        input: event,

      },

      null,

      2

    ),

  };

};

const invoiceService = async (event) => {

  console.log(event);

  return {

    statusCode: 200,

    body: JSON.stringify(

      {

        message: 'invoiceService lambda function call through EventBridge custom pattern matching!',

        input: event,

      },

      null,

      2

    ),

  };

};

const rewardService = async (event) => {

  console.log(event);

  return {

    statusCode: 200,

    body: JSON.stringify(

      {

        message: 'rewardService lambda function call through EventBridge custom pattern matching!',

        input: event,

      },

      null,

      2

    ),

  };

};

module.exports = {

  scheduledService,

  invoiceService,

  rewardService

};

Create AWS IAM user with programmatic access and give needful permission that allows Serverless Framework to provision resources

The Serverless Framework needs access to your cloud provider account so that it can create and manage resources on your behalf.

During Creating AWS IAM user copy API Key & Secret.

6. Configure AWS Credentials for Serverless Framework Deployment



serverless config credentials --provider aws --key xxxxx --secret xxxxx

Deploy using Serverless Framework




serverless deploy



> serverless deploy

Serverless: Packaging service...

Serverless: Excluding development dependencies...

Serverless: Service files not changed. Skipping deployment...

Service Information

service: sls-eventbridge

stage: dev

region: ap-south-1

stack: sls-eventbridge-dev

resources: 18

api keys:

  None

endpoints:

  None

functions:

  scheduledService: sls-eventbridge-dev-scheduledService

  invoiceService: sls-eventbridge-dev-invoiceService

  rewardService: sls-eventbridge-dev-rewardService

layers:

  None