images

A distributed asynchronous image processing service.

A detailed guide is available which walks through the API endpoints and how to use them.

Highlighted Features

• Selectable storage implementation based on Spring profiles.
• Batched image processing - perform multiple operations in a single request.
• Horizontal image processing scalability via "worker" nodes.
• Robust mime type validation via Apache Tika.
• Authentication via JWT.
• All components are containerized and can be run locally for a great developer experience.
• OpenAPI specification and Swagger UI endpoints. See /api and /swagger respectively.

Forward Looking Statements

1. Blob Storage - The project supports easily adding multiple storage implementations. The current implementation uses the file system for simplicity. A more robust implementation would use a cloud storage provider such as AWS S3 for durability and subsequently AWS CloudFront as a CDN.
2. Supported Image Types - Additional image types can be supported by leveraging libraries such as Apache Batik to support SVG.
3. Authentication - The authentication is a simplified version of what should be used in a production environment. Here a JWT token is used to authenticate the user. In a production environment, a more robust solution should be used such as OAuth2.
4. API Documentation - The API should be versioned and documented via OpenAPI. This would ease supporting multiple languages by leveraging code generation for clients. This would also allow for robust contract testing.
5. Testing - The project has a few unit and integration tests but more are warranted before being considered ready for production. Additional unit and integration tests should be added as well as load tests.
6. Monitoring - The project includes basic logging but metrics and tracing should be added for production use.

Requirements

These are the requirements for running the project locally:

• Docker Compose
• curl

If you use IntelliJ IDEA, you can use the included test.http to exercise endpoints via the internal HTTP client.

How to build and test

See: CONTRIBUTING.md

How to run

From the root directory, run the following:

docker-compose up --build

To stop the containers, run the following:

docker-compose down

Architecture

Components

• api - async REST API server which serves as the entry point for the system. (Spring Boot w/Kotlin coroutines)
• blob storage - storage for images. (File system, S3, etc.)
• core - library which contains shared code between the api and worker. (Kotlin)
• db - relational database which stores image metadata. (PostgreSQL)
• message broker - messaging broker which is used for communication between the api and worker. (NATS)
• worker - worker which processes image processing jobs. (Spring Boot)