Step 2: Simple API - solargis/cdk-workshop GitHub Wiki

In this step we will create simple API handled by Lambda function, which will return only hello message with current timestamp.

We will have simple web and simple API deployed in the cloud, but separated for now.

Fast-forward to this step (optional)

git checkout step-2/simple-api
npm install

NOTE: if you have uncommited work in project repository it is not possible to checkout new Git branch, you have 3 options:

git stash - move all local changes into a 'drawer', more info here

git commit -a -m "my change" - commit all changes to local branch

git reset --hard HEAD - remove all local changes

Preparation

Add npm dependencies:

npm install --save @aws-cdk/aws-apigateway @aws-cdk/aws-lambda aws-lambda
npm install --save-dev @types/aws-lambda

2.1 Create simple API

Add Lambda handler code: ./lib/api/hello-lambda.ts

import { APIGatewayProxyEvent, Context, Callback } from 'aws-lambda';

export function handler(event: APIGatewayProxyEvent, context: Context, callback: Callback) {
  console.log('*** hello ***', event);
  callback(null, {
    statusCode: 200,
    body: JSON.stringify({ message: `Hello from CDK Lambda, ${Date.now()}` })
  });
}

Add TypeScript config for API code: ./lib/tsconfig.api.json

{
  "extends": "../tsconfig.json",
  "compilerOptions": {
    "outDir": "../dist/api",
    "declaration": false
  },
  "include": ["api"],
  "exclude": ["node_modules/**", "web*"]
}

Add build script for API: ./package.json

"scripts": {
  "api:build": "tsc -p lib/tsconfig.api.json"
}

Build API code:

npm run api:build

Check the compiled code in ./dist/api

Define cloud resources for API: ./cdk/cdk-workshop-stack.ts

import { LambdaIntegration, RestApi } from '@aws-cdk/aws-apigateway';
import { Code, Function, Runtime } from '@aws-cdk/aws-lambda';
// ...

// reference to compiled API code
const apiCode = Code.fromAsset('dist/api');

// Lambda handler definition
const helloHandler = new Function(this, 'HelloHandler', {
  code: apiCode,
  runtime: Runtime.NODEJS_10_X,
  handler: 'hello-lambda.handler',
});

// API Gateway
const api = new RestApi(this, `CdkWorkshopAPI_${props.userName}`);

// API resource on /hello path
const helloApi = api.root.addResource('hello');
// GET /hello
helloApi.addMethod('GET', new LambdaIntegration(helloHandler));

Check stack changes:

cdk diff

Deploy simple API:

cdk deploy

Test