Deploy Express JS container image on Lambda AWS

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

2) Initialization

npm init

3) Install Express

npm install express

4) 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);

2) package.json => (lambda-express/package.json)

{
  "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"
  }
}

3) 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"]

2) Confirm installation

npm install

3) Build the Image

• 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

• ECR is Elastic Container Registory in AWS
• go to ECR and create a private repository

2) Upload the Image that you build locally

• go inside of the repository
• click View push commands

3) 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

4) 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

5) 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 !

Comments

[Pruthuvi de Silva]

Great article, Janith! Your explanation of deploying Express.js with Docker on AWS Lambda is clear and practical. It would be helpful to include tips on handling environment variables and reducing cold start delays. Thanks for this valuable guide!