Rest API using AWS Lamda, Serverless and Nodejs

Prerequisite

AWS Lamda : If you are not aware of lamda function, please visit the following link.

http://www.fullstacktechnos.com/2017/11/what-is-aws-lamda.html

Serverless Framework : I am using serverless to deploy my aws infrastructure. Please visit the following article to setup the serverless in your local box. You don’t need to create any project though.

http://www.fullstacktechnos.com/2017/11/create-your-first-nodejs-lamda-function.html

Setup :

If you have configured serverless for aws successfully then verify the installations by typing the command in the terminal. Your version number may not match mine.

$node -v
v6.11.3
$sls -v
1.18.1
$aws — version
aws-cli/1.11.127 Python/3.6.2 Darwin/17.2.0 botocore/1.5.90
$cat ~/.aws/credentials
[default]
aws_access_key_id=*******************
aws_secret_access_key=*****************

I have already created the sample nodejs lamda project with serverless. Please find the following github link.

https://github.com/fullstacktechnos/serverless-lamda-test

Checkout the code :

git clone https://github.com/fullstacktechnos/serverless-lamda-test.git
handler.js : (lamda code goes here)

‘use strict’;
module.exports.helloWorld = (event, context, callback) => {
const response = {
statusCode: 200,
headers: {
‘Access-Control-Allow-Origin’: ‘*’, // Required for CORS support to work
},
body: JSON.stringify({
message: ‘Go Serverless v1.0! Your function executed successfully!’,
input: event,
}),
};

callback(null, response);
};

serverless.yml:

service: serverless-hello-world

provider:
name: aws
runtime: nodejs6.10

functions:
helloWorld:
handler: handler.helloWorld

events:
— http:
path: hello-world
method: get
cors: true

To define a rest endpoint we have to mention the method (get or post) and path inside events -> http.
cors: true will enable the cross.

To know more about it please visit the serverless.com (https://serverless.com/framework/docs/providers/aws/guide/events/)

If you want to push the same code to your aws environment then run the following command.

$sls deploy
Serverless: Packaging service…
Serverless: Excluding development dependencies…
Serverless: Uploading CloudFormation file to S3…
Serverless: Uploading artifacts…
Serverless: Uploading service .zip file to S3 (967 B)…
Serverless: Validating template…
Serverless: Updating Stack…
Serverless: Checking Stack update progress…
…………..
Serverless: Stack update finished…
Service Information
service: serverless-hello-world
stage: dev
region: us-east-1
api keys:
None
endpoints:
GET — https://l2krwp3ete.execute-api.us-east-1.amazonaws.com/dev/hello-world
functions:
helloWorld: serverless-hello-world-dev-helloWorld

Go to the browser and enter the GET endpoint URL. Your’s will be different than mine. Mine is for testing purpose. It wont be available for you.
You can see the event object that lamda return as a response in the browser.