Code samples for A templated guide to AWS serverless development with CDK

README.md

If you're looking for a quick and painless entry into AWS serverless development with CDK, either of these two links is preferable to reading excerpts from this gist.

Article: https://www.industrialcuriosity.com//2020/06/a-templated-guide-to-aws-serverless.html

Source repository: https://github.com/therightstuff/aws-cdk-js-dev-guide

bin-aws-cdk-js-dev-guide.ts

// this configuration results in the creation of AwsStack-dev,
// AwsStack-prod-us, AwsStack-test-eu and AwsStack-test-us
let stages:stagesType = {
    prod: ["us"],
    test: ["eu", "us"],
    dev: [""]
}

for (let name in stages) {
    let stage:string[] = stages[name];
    for (let i in stage) {
        let region = stage[i];
        if (region.length == 0) {
            // deploy region-agnostic when no region is specified
            new AwsStack(app, `AwsStack-${name}`);
        } else {
            new AwsStack(app, `AwsStack-${name}-${region}`, { env: regions[region] });
        }
    }
}

cdk-deploy.out

Outputs:
AwsStack-dev.layerapiEndpointXXXXXXXX = https://XXXXXXXXXX.execute-api.us-east-1.amazonaws.com/prod/
AwsStack-dev.dynamodbapiEndpointXXXXXXXX = https://XXXXXXXXXX.execute-api.us-east-1.amazonaws.com/prod/
AwsStack-dev.simpleapiEndpointXXXXXXXX = https://XXXXXXXXXX.execute-api.us-east-1.amazonaws.com/prod/

Stack ARN:
arn:aws:cloudformation:us-east-1:XXXXXXXXXXXX:stack/AwsStack-dev/a0b1c2d3-a0b1-a0b1-a0b1-a0b1c2d3e4f5

lambda-promise-resolution.js

exports.handler = async (event) => {
    const promise = new Promise(function(resolve, reject) {
        // randomly return success or failure with the appropriate status code
        let success = Math.floor(Math.random() * 2) == 1;
        let statusCode = (success ? 200 : 500)
        let returnObject = {
            "success": success
        };

        resolve({
            "isBase64Encoded": false,
            "statusCode": statusCode,
            "headers": {},
            "body": JSON.stringify(returnObject)
        });
    });
    return promise;
}

lambda-response-format.js

{
    "isBase64Encoded": false,
    "statusCode": 200,
    "headers": {},
    "body": JSON.stringify(returnObject)
}

lib-aws-cdk-js-dev-guide-stack.ts

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

    // simple test function
    const simpleFunction = new Function(this, 'simple-function', {
      runtime: Runtime.NODEJS_12_X,
      handler: 'index.handler',
      code: Code.asset('./handlers/simple'),
      environment: {
        GREETING: "Hello, World!"
      },
    });

    const simpleApi = new RestApi(this, 'simple-api', {
      restApiName: 'Simple API sample',
      description: "Simple API sample with no dependencies"
    });

    simpleApi.root.addMethod('GET', new LambdaIntegration(simpleFunction));

    ...

lib-regions.json

{
    "eu": {
        "region": "eu-west-1",
        "account": "XXXXXXXXXXXX"
    },
    "us": {
        "region": "us-east-1",
        "account": "XXXXXXXXXXXX"
    }
}