Receipt Processor

Receipt Processor is a lightweight API backend built in Go that processes retail receipts to calculate reward points based on a set of business rules. The project is designed using an n‑tier architecture with separate layers for API handling, business logic, persistence, and middleware.

What This Project Does

• Process Receipts: Accepts a JSON payload of receipt data, validates it, and calculates reward points according to specific rules (e.g., points per alphanumeric character in the retailer name, bonus points for round totals, etc.).
• Retrieve Points: Provides an endpoint to look up the points awarded for a processed receipt via its unique ID.
• Duplicate Prevention: Uses a hash of the receipt data to prevent storing duplicate receipts.
• Rate Limiting: Implements a sliding window rate limiter (using Redis) to throttle incoming requests.
• Logging with Context: All logs include a unique request ID, making it easier to trace requests through the system.

Running the Application Using Docker

This project includes a Dockerfile and a Docker Compose configuration to simplify deployment. The Docker setup creates two services:

• receipt_processor: The Go API service.
• redis: A Redis service used for the rate limiter.

To run the application in Docker, use the following Makefile command:

make docker-run

This command will:

1. Tear down any existing Docker Compose stack (removing images if necessary).
2. Build and start the containers in detached mode.
3. You can then access the API at http://localhost:8080

Warning: Make sure both ports (8080 and 6379) are not in use.

Running Tests

The project includes a comprehensive set of unit and integration tests for the API, middleware, repository, and service layers. To run all tests, use:

make test

For a test coverage report (which generates a coverage.out file and an HTML report), run:

make test-coverage

Makefile Commands

The provided Makefile includes the following targets:

1. test

   Runs all tests in the project:

   make test

2. Coverage

   Runs tests with coverage and generates a coverage HTML report:

   make test-coverage

3. Run

   Builds and runs the Docker containers using Docker Compose:

   make docker-run