Open Graph Social Media Image Generator

This project generates Open Graph images for social media sharing. It uses a Go-based Lambda function to create images dynamically based on provided title and description parameters. The infrastructure is managed using AWS CDK.

Architecture

The project consists of the following main components:

• Lambda Function (Go): Generates the Open Graph image. It uses the gg and imaging Go libraries to create and manipulate images. It downloads assets from S3 on cold start.
• Infrastructure as Code (AWS CDK): Defines and deploys the AWS infrastructure required for the project, including the Lambda function, API Gateway, S3 bucket, and CloudFront distribution.
• S3 Bucket: Stores assets such as background images and fonts used by the Lambda function.
• API Gateway: Provides an HTTP endpoint to trigger the Lambda function.
• CloudFront: A content delivery network (CDN) that caches the generated images for faster delivery and provides a custom domain with SSL certificate.

Prerequisites

Before you can deploy this project, you need to have the following tools installed:

• Node.js (v18 or later)
• AWS CDK Toolkit
• Go (v1.21 or later)
• AWS CLI
• An AWS account

Setup

1. Configure AWS Credentials: Configure your AWS credentials using the AWS CLI.

   aws configure

2. Install Dependencies: Navigate to the infra directory and install the necessary Node.js dependencies.

   cd infra
   npm install

3. Set Environment Variables: Configure the following environment variables, either in your shell or in your CI/CD environment:
   • CDK_DEFAULT_ACCOUNT: Your AWS account ID.
   • AWS_DEFAULT_REGION: The AWS region you want to deploy to (e.g., us-east-1).
   • AWS_ACCESS_KEY_ID: Your AWS access key ID.
   • AWS_SECRET_ACCESS_KEY: Your AWS secret access key. You can set these variables in your .bashrc or .zshrc file, or pass them directly to the make command.

Deployment

The project includes a Makefile to simplify the build and deployment process. To deploy the project, run the following command:

make deploy

This command will:

1. Build the Go Lambda function.
2. Package the Lambda function into a ZIP file.
3. Deploy the AWS infrastructure using CDK.

Usage

After successful deployment, you can access the Open Graph image generator through the CloudFront distribution's domain name.

To generate an image, send a GET request to the API endpoint with the title and description query parameters: https://your-cloudfront-domain/prod?title=Your%20Page%20Title&description=Your%20Page%20Description

Replace your-cloudfront-domain with the actual domain name of your CloudFront distribution.

Customization

• Lambda Function: You can modify the Go code in the functions directory to customize the image generation process.
• Infrastructure: You can modify the CDK code in the open-graph-infra-stack.ts file to adjust the AWS infrastructure configuration.
• Assets: Replace the files in the S3 bucket to change the background, fonts, logo, etc.

Makefile commands

• make build: Builds the Go Lambda function and packages it into a ZIP file.
• make deploy: Builds the Lambda function, installs the CDK dependencies, and deploys the infrastructure.

This file defines a GitHub Actions workflow that automates the build and deployment process. It is triggered on workflow dispatch.