This content originally appeared on DEV Community and was authored by Janith Disanayake

Introdction

If you want to build a application but you don’t want to buy and maintain server the best option is Lambda. You still can use .zip file to create a Expressjs Lambda but that is not a best practice to do as a developer. In this scenario you can use Container Image to create a server.

Resources

• Base Image
• Documentation

Steps

Create Express app

1. Create Directory for application

mkdir lambda-express
cd lambda-express

1. Initialization

npm init

1. Install Express

npm install express

1. Install serverless-http

npm install serverless-http

Application implementation

1. app.js file => (lambda-express/app.js)

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

app.use(express.json());

app.get('/', (req, res) => {
        console.log("/ endpoint is reached");
        res.send('Hello World!');
});

app.get('/hello', (req, res) => {
        console.log("/ endpoint is reached");
        res.send('Hello from Lambda!');
});

module.exports.handler = serverless(app);

1. package.json => (lambda-express/app.js)

{
  "name": "example",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "start": "node app.js"
  },
  "author": "janith",
  "license": "ISC",
  "description": "",
  "dependencies": {
    "express": "^4.19.2",
    "serverless-http": "^3.2.0"
  }
}

1. Check all the npm packages are available or not

npm ls 

## result
example@1.0.0 /home/janith/TEST/example
├── express@4.19.2
└── serverless-http@3.2.0

Create a docker image

1. Docker file

# Use the official AWS Lambda Node.js base image
FROM amazon/aws-lambda-nodejs

# Copy function code
COPY package*.json ${LAMBDA_TASK_ROOT}
COPY node_modules ${LAMBDA_TASK_ROOT}
COPY app.js ${LAMBDA_TASK_ROOT}
RUN npm install

# Command to run the Lambda function
CMD ["app.handler"]

1. Confirm installation

npm install

1. Build the Image
2. make sure you are in the same directory that Dockerfile file is located

docker build -t lambda-express:latest . 

Upload Image to ECR

1. Create a ECR
2. ECR is Elastic Container Registory in AWS

3. go to ECR and create a private repository
   

4. Upload the Image that you build locally

5. go inside of the repository

6. click View push commands

1. Login first

aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin 144901196852.dkr.ecr.us-east-1.amazonaws.com

1. Tag the image

• you build the image previously no need to build it again if you use another name that different from this repostiry

docker tag lambda-express:latest 144901196852.dkr.ecr.us-east-1.amazonaws.com/lambda-express:latest

1. Push the image into ECR

docker push 144901196852.dkr.ecr.us-east-1.amazonaws.com/lambda-express:latest

Deploy Image on Lambda

1) Create a Lambda function

2) Select option as Container Image

3) Function Name

4) Container Image URI

• Click Browse images
  

• Select your private repository and Image that you created
  

5) Keep other settings as default and create the function

6) Goto configurations and create a Function URL

7) Make sure to select the Auth type as NONE

Congratulations Just now you deployed your app

click your Function URL and enjoy

happy coding !

This content originally appeared on DEV Community and was authored by Janith Disanayake