A snippet of a Lambda function that uses cfn-custom-resource to respond appropriately to CloudFormation when invoking a Lambda on deployment

cfn-custom-resource.yaml

# For more info, read:
## https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-custom-resources.html
## https://www.npmjs.com/package/cfn-custom-resource?activeTab=readme
AWS = require('aws-sdk');
const ECS = new AWS.ECS({ region: "us-west-2" });
const SM = new AWS.SecretsManager({ region: "us-west-2" })
const cfnCR = require('cfn-custom-resource');
const { sendSuccess, sendFailure, CREATE, UPDATE, DELETE } = cfnCR;

exports.handler = async (event, context) => {

  console.log(JSON.stringify(event, undefined, 2));
  if( event.RequestType === DELETE ) {
    return sendSuccess('runIndexer', {}, event)
  }

  let url;

  try {

    if( process.env.ENV == 'production' ) {
      url = 'https://docs.stackery.io'
    } else {
      url = `https://${process.env.CDN_DomainName}`
    }
  
    const config = {
    }
  
    var secretParams = {
      SecretId: process.env.SECRETS_NAMESPACE + 'ALGOLIA_API_KEY'
    };

    console.log('retrieving secretvalue')
    const secretresponse = await SM.getSecretValue(secretParams).promise()
    
    const taskParams = {
      taskDefinition: process.env.DOCKER_TASK_ARN,
      launchType: 'FARGATE',
      networkConfiguration: {
        awsvpcConfiguration: {
          subnets: process.env.DOCKER_TASK_SUBNETS.split(','),
          assignPublicIp: 'ENABLED',
        }
      },
      overrides: {
        containerOverrides: [
          {
            name: "0",
            environment: [
              {
                name: 'API_KEY',
                value: secretresponse.SecretString
              },
              {
                name: 'CONFIG',
                value: JSON.stringify(config)
              }
            ],
          }
        ]
      }
    };
    console.log('starting ECS.runtask')
    const taskresponse = await ECS.runTask(taskParams).promise()
    console.log('responding successful for ECS.runtask to CFN')
    const cfnCRSuccess = await sendSuccess('runIndexer', {}, event)
    console.log(JSON.stringify(taskresponse))
  } catch(err) {
    console.log(JSON.stringify(err, undefined, 2))
    const cfnCRFailure = await sendFailure('ECS task failed to invoke successfully', event);
  }
};