AWS CI/CD Pipeline with GitHub Actions practice

This project demonstrates how to build an AWS CI/CD pipeline using GitHub Actions, AWS CDK (TypeScript), AWS Lambda (Python), and DynamoDB . It automates infrastructure deployment while incorporating AWS Lambda and DynamoDB to track and store website visits.

📚 Key Concepts Practiced

• ✅ AWS CDK: Defines infrastructure as code using TypeScript.
• ✅ GitHub Actions: Automates deployments and version updates.
• ✅ AWS Lambda: Runs a Python function for visit tracking.
• ✅ DynamoDB: Stores visit counts as a NoSQL database.
• ✅ Git Hooks: Automatically increments version numbers.

⚙️ Setting Up the Project

• Install AWS CLI and configure your AWS credentials: aws configure
• Install Node.js and AWS CDK globally: npm install -g aws-cdk
• Ensure Python 3.9+ is installed for the Lambda function.
• Enable GitHub Actions by adding AWS credentials as secrets in GitHub.

Building and Deploying the Project

1️⃣ Initialize a New AWS CDK Project

using typescript for example

cdk init app --language typescript

2️⃣ Define AWS Resources in CDK

In cicd-aws-stack.ts, define a Lambda function with DynamoDB access:

const lambdaFunction = new lambda.Function(this, "LambdaFunction", {
    runtime: lambda.Runtime.PYTHON_3_9,
    code: lambda.Code.fromAsset("lambda"), 
    handler: "main.handler",
    environment: {
        VERSION: process.env.VERSION || "0.0",
        TABLE_NAME: table.tableName,
    }
});

Define a DynamoDB table for visit tracking:

const table = new dynamodb.Table(this, "VisitorTimeTable", {
    partitionKey: { name: "key", type: dynamodb.AttributeType.STRING },
    billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
});

3️⃣ Enable Function URL for Direct HTTP Requests

lambdaFunction.addFunctionUrl({
    authType: lambda.FunctionUrlAuthType.NONE,
});

4️⃣ Deploy the CDK Stack

cdk bootstrap --region us-west-2
cdk synth
cdk deploy

---

Configuring GitHub Actions for CI/CD

Create the GitHub Actions Workflow

Workflows must be inside .github/workflows/. This setup:

• Caches dependencies for faster builds.
• Deploys the CDK stack using AWS credentials.
• Automatically updates the version.

To enable GitHub Actions deployment, add AWS credentials in GitHub:

GitHub Repo -> Settings -> Secrets and variables -> Actions -> New Repository Secret

Automating Versioning with a Git Hook

1️⃣ Enable Git Hooks

Since .git is hidden, enable it and navigate to the hooks directory.

2️⃣ Create a Pre-Commit Hook

Copy and rename pre-commit.sample to pre-commit, then add this script:

#!/bin/sh 

VERSION=$(sed -n 's/VERSION="\([^"]*\)"/\1/p' .env)

if [[ -n $VERSION ]]; then
    IFS='.' read -ra ADDR <<< $VERSION 
    last_index=$((${#ADDR[@]} - 1))
    ADDR[$last_index]=$((${ADDR[$last_index]} + 1))
    NEW_VERSION=$(IFS=.; echo "${ADDR[*]}")

    perl -pi -e "s/$VERSION/$NEW_VERSION/g" .env
    echo "NEW version: $NEW_VERSION"
    git add .env
fi 

3️⃣ Make the Script Executable

chmod +x .git/hooks/pre-commit

---

Connecting Lambda to DynamoDB

In the Lambda function, use Boto3 to interact with DynamoDB:

import boto3
import os

dynamodb = boto3.resource("dynamodb")
table = dynamodb.Table(os.environ["TABLE_NAME"])

def handler(event, context):
    table.update_item(
        Key={"key": "visitor_count"},
        UpdateExpression="ADD visit_count :inc",
        ExpressionAttributeValues={":inc": 1}
    )
    return {"statusCode": 200, "body": "Visit count updated!"}

Filtering Out Unwanted Paths

Ensure only root paths increase the visit count:

if event["rawPath"] != "/":
    return {"statusCode": 404, "body": "Not Found"}

---

📜 Credit

Inspired by this tutorial.