Today I'm showing how to Build and deploy an express/Node Rest API using serverless lambda.

We know Serverless is growing so fastly and a lot of companies are saving money by using Serverless computing.

Amazon web services offer us wide variety of services to build and deploy Small-scale to Large-Scale Applications.

What is Aws Lambda?

AWS Lambda runs your code without provisioning or managing servers it means you don't need to buy or manage a server. You only pay whenever your code runs or whenever a user visits your site.

What are Requirements?

• Aws Free Tier Account

• Nodejs v8+

I'm using the serverless framework Cli to create and deploy apps.

Open your terminal

npm install -g serverless

sls login // SLS is a shortcut of serverless

After sls login, You need to configure Your Aws Credentials with a serverless framework.

Get Aws Credentials

Once It is done Your are good to go.

Creating and Deploying the Rest API endpoints

Create a Template in Your Working Directory

serverless create --template aws-nodejs

The above command generates the boilerplate.

Now we need to initialize the Package.json file and install
some dependencies.

npm init -y // generates package.json file

npm i -s body-parser cors express mongoose serverless-http

Open Your app folder in your Favourite code editor.

Create an app.js file and import the requirements for the database i'm using the mongodb.

We need to create a Model for the MongoDB database.

create a data.js file.

const mongoose = require('mongoose');

const Users = mongoose.Schema({
    name: String,
    age: Number,
})

const User = mongoose.model('User', Users);

module.exports = User;

This is our simple User model.

Open your serveless.yml and add the below code.

• runtime nodejs8.10 why because Aws lambda currently supports v8.10.
• handler: we need to define the app.handler it means please look into app.js file.
• serverless-offline plugin helps us to run your app into the local environment.

Open your Terminal and run.

sls offline start // to run the code in local environment

Wow, our code is running without any errors.

How to deploy the Code into Aws Lambda?

• It is very easy serverless framework does all things in the background

Open your terminal and run.

sls deploy 

Once you run above command after some time your API endpoints are visible in your terminal.

How to Test the API Endpoints?

• I'm using the Postman to test the API endpoints.

Post Method

Get Method

How to deploy your existing rest API?

1. Open your app.js file or main.js file and add these export.

const serverless = require('serverless-http');
const express = require('express');
const app = express();

*express code*

module.exports.handler = serverless(app);

2.Setup your serverless.yml

How to Monitor and Track your Lamda Invocations?

For monitoring, Debugging and error detection of lambdas we are using Dashbird

Why Dashbird?

• Dashbird helps us actively monitoring the health and errors.

• One main thing about Dashbird is its user-friendly Interface.

• Dashbird visualizes all your AWS Lambda metrics like
  memory utilization, invocation count, and execution duration.

DashBird Interface

Hope you guys enjoyed if you have any doubts feel free to ask.

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