Automating Serverless Web App Deployment with CI/CD and AWS Lambda Functions

8 August 2024

Using Jenkins and AWS CloudFormation to Automate Deployments

When it comes to deploying serverless web applications, the process can be more complex than traditional deployments due to the use of cloud-based services like AWS Lambda. One way to simplify this process is by implementing Continuous Integration/Continuous Deployment (CI/CD) pipelines that automate the build, test, and deployment of your application.
In this article, we will explore how you can leverage Jenkins, a popular open-source automation server, in conjunction with AWS CloudFormation to create a CI/CD pipeline for deploying serverless web applications using AWS Lambda functions.

Setting Up Jenkins

The first step is setting up Jenkins on an EC2 instance. This involves installing Java and then downloading and running the Jenkins installation script from the official website. Once installed, configure Jenkins by adding an admin user and optionally setting up a mail server for notifications.

Configuring Jenkins to Use AWS Credentials

Next, you need to configure Jenkins to use your AWS credentials so that it can access your AWS account programmatically. This involves creating a new credential in Jenkins under Jenkins > Manage Jenkins > Configure Global Security and then adding a new AWS credential. The credential should contain your AWS Access Key ID and Secret Access Key.

Using AWS CloudFormation to Define Your Deployment Stack

AWS CloudFormation is a powerful service that allows you to define infrastructure resources as code, which makes it ideal for automating deployments. To use AWS CloudFormation with Jenkins, you first need to create a new template file (named serverless-stack.yaml) that defines your deployment stack:

Resources:
  LambdaFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      FunctionName: !Sub '${AWS::Region}-lambda-function'
      Runtime: nodejs14.x
      Handler: index.handler
      Role: !GetAtt 'LambdaExecutionRole.Arn'
      Code: S3Bucket: !Sub 's3://${S3_BUCKET_NAME}/${S3_KEY_NAME}'

In this example, the serverless-stack.yaml template defines a Lambda function with a specific runtime and handler.

Creating a Jenkinsfile to Automate Deployment

Once you have defined your deployment stack using AWS CloudFormation, you can create a Jenkinsfile that automates the deployment process. Here is an example of what the Jenkinsfile might look like:

pipeline {
    agent any
    stages {
        stage('Checkout') {
            steps {
                checkout scm
            }
        }
        stage('Build') {
            steps {
                sh 'npm install'
                sh 'npm run build'
            }
        }
        stage('Deploy') {
            steps {
                withAWS(credentials: 'aws-credentials') {
                    deployLambdaFunction()
                }
            }
        }
    }
}
def call() {
    sh 'echo "Deployment successful!"'
}
def deployLambdaFunction() {
    // Define a function to deploy the Lambda function using AWS CloudFormation
}

In this example, the Jenkinsfile defines three stages: Checkout, Build, and Deploy. The Deploy stage uses the withAWS function provided by the Jenkins AWS plugin to deploy the Lambda function.
By implementing a CI/CD pipeline with Jenkins and AWS CloudFormation, you can automate the deployment of your serverless web application using AWS Lambda functions. This process simplifies the complex workflow involved in deploying cloud-based services and makes it easier to manage your application’s infrastructure as code.

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