serverless-http-echo

Hello world from AWS Serverless (feat. serverless).

Rationale

I want to build more services with AWS Serverless model because I want to make a service with its backend but I don't want to server costs if there is no request from user.

This is a very basic example that how to build up a simple serverless application written by NodeJS and serverless framework.

Prerequisites

I don't like this way, but it can be convenience if you install serverless framework globally.

npm i -g serverless

Instruction

Initialize.

Create a directory for our service and initialize with serverless command.

$ mkdir serverless-http-echo
$ cd serverless-http-echo
$ serverless create --name serverless-http-echo --template aws-nodejs-typescript

Yes, I love TypeScript ;)

Then we can see these files.

.gitignore
handler.ts
package.json
serverless.yml
tsconfig.json
webpack.config.json

If we don't want to more complex works, we can concentrate only two files handler.ts and serverless.yml.

`serverless.yml`

service:
  name: serverless-http-echo

plugins:
  - serverless-webpack

provider:
  name: aws
  runtime: nodejs8.10

functions:
  hello:
    handler: handler.hello
    events:
      - http:
          method: get
          path: hello

If we want to more API, add some functions and chain events in this file. But it is not today, and not in this repository.

`handler.ts`

import { APIGatewayProxyHandler } from 'aws-lambda';
import 'source-map-support/register';

export const hello: APIGatewayProxyHandler = async (event, _context) => {
  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'Go Serverless Webpack (Typescript) v1.0! Your function executed successfully!',
      input: event,
    }),
  };
}

It already has a code that echoes its event that is an event from AWS API Gateway because it set at serverless.yml file.

So it's over ;)

Edit somethings.

I want to give more things about me to package.json.

And it is actually meaningless, but I fix a bug that a main file is handler.ts instead of handler.js because it is a TypeScript project.

📄 package.json

  {
    "name": "serverless-http-echo",
    "version": "1.0.0",
-   "description": "Serverless webpack example using Typescript",
-   "main": "handler.js",
+   "description": "Echo API Gateway's request with AWS Serverless",
+   "main": "handler.ts",
    "scripts": {
      "test": "echo \"Error: no test specified\" && exit 1"
    },
      "typescript": "^3.2.4",
      "webpack": "^4.29.0"
    },
-   "author": "The serverless webpack authors (https://github.com/elastic-coders/serverless-webpack)",
+   "author": "lactrious@gmail.com",
    "license": "MIT"
- }+ }

And give a region to serverless.yml to avoid to deploy a service into us-east-1 region.

📄 serverless.yml

  provider:
    name: aws
    runtime: nodejs8.10
+   region: ap-northeast-2
  
  functions:
    hello:

Deploy

Ok, we are ready to deploy. Please set aws credential configurations before deploying. If there is a profile to deploy, we can use a --aws--profile parameter of serverless cli.

$ serverless deploy

That's all. It is deadly simple :)

Serverless: Bundling with Webpack...
Time: 1480ms
Built at: 2019-03-16 17:06:09
Serverless: Packaging service...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service serverless-http-echo.zip file to S3 (68.71 KB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
..............................
Serverless: Stack update finished...
Service Information
service: serverless-http-echo
stage: dev
region: ap-northeast-2
stack: serverless-http-echo-dev
resources: 10
api keys:
  None
endpoints:
  GET - https://0000000000.execute-api.ap-northeast-2.amazonaws.com/dev/hello
functions:
  hello: serverless-http-echo-dev-hello
layers:
  None

Using curl, check if it works correctly.

$ curl https://0000000000.execute-api.ap-northeast-2.amazonaws.com/dev/hello
{"message":"Go Serverless Webpack (Typescript) v1.0! Your function executed successfully!","input":{"resource":"/hello","path":"/hello",...omitted...}}

If we want to see the deployed information, just use info command.

$ serverless info
Service Information
service: serverless-http-echo
stage: dev
...omitted...

So now, we can deploy some functions like RESTful API via the serverless world. :)