This is a starting point for OCaml solutions to the "Build Your Own Redis" Challenge.

In this challenge, you'll build a toy Redis clone that's capable of handling basic commands like PING, SET and GET. Along the way we'll learn about event loops, the Redis protocol and more.

Note: If you're viewing this repo on GitHub, head over to codecrafters.io to try the challenge.

Passing the first stage

The entry point for your Redis implementation is in src/main.ml. Study and uncomment the relevant code, and push your changes to pass the first stage:

git commit -am "pass 1st stage" # any msg
git push origin master

That's all!

Stage 2 & beyond

Note: This section is for stages 2 and beyond.

1. Ensure you have dune installed locally
2. Run ./your_program.sh to run your Redis server, which is implemented in src/main.ml.
3. Commit your changes and run git push origin master to submit your solution to CodeCrafters. Test output will be streamed to your terminal.

Features

This Redis implementation supports:

• Basic commands: PING, ECHO, GET, SET (with PX/EX expiry)
• Replication: Master-replica configuration, PSYNC, REPLCONF
• Command propagation: Automatic propagation to replicas with batching
• WAIT command: Synchronous replication with configurable timeout
• Key expiry: Time-based expiration with lazy cleanup

Architecture

The codebase is organized into focused modules:

• resp.ml - RESP protocol parsing and serialization
• command.ml - Command parsing and validation
• storage.ml - In-memory key-value store with expiry support
• database.ml - Core database logic and command execution
• replica_manager.ml - Replication state and replica coordination
• protocol.ml - Network protocol handling
• main.ml - Server entry point

Tests

Comprehensive unit tests (130+ tests across 4 test suites) using the Alcotest framework.

To run tests: dune runtest

Contributing Documentation

When adding new documentation:

1. Create markdown files in this docs/ directory
2. Add entry to this README with brief description
3. Follow existing documentation structure and style
4. Include code examples where helpful
5. Keep documentation in sync with code changes