Casky – Lightweight C Key-Value Engine with Crash Recovery
Description
Casky is a lightweight, crash-safe key-value store written in C, designed for fast storage and retrieval of data with a minimal footprint. Built using Test-Driven Development (TDD), Casky ensures reliability while keeping the codebase clean and maintainable. It is inspired by Bitcask and aims to provide a simple, embeddable storage engine that can be integrated into microservices, IoT devices, and other C-based applications.
Objectives:
- Implement a minimal key-value store with append-only file storage.
- Support crash-safe persistence and recovery.
- Expose a simple public API: store(key, value), load(key), delete(key).
- Follow TDD methodology for robust and testable code.
- Provide a foundation for future extensions, such as in-memory caching, compaction, and eventual integration with vector-based databases like PixelDB.
Why This Project is Interesting:
Casky combines low-level C programming with modern database concepts, making it an ideal playground to explore storage engines, crash safety, and performance optimization. It’s small enough to complete during Hackweek, yet it provides a solid base for future experiments and more complex projects.
Goals
- Working prototype with append-only storage and memtable.
- TDD test suite covering core functionality and recovery.
- Demonstration of basic operations: insert, load, delete.
- Optional bonus: LRU caching, file compaction, performance benchmarks.
Future Directions:
After Hackweek, Casky can evolve into a backend engine for projects like PixelDB, supporting vector storage and approximate nearest neighbor search, combining low-level performance with cutting-edge AI retrieval applications.
Resources
The Bitcask paper: https://riak.com/assets/bitcask-intro.pdf The Casky repository: https://github.com/thesp0nge/casky
Day 1
[0.10.0] - 2025-12-01
Added
- Core in-memory KeyDir and EntryNode structures
- API functions: caskyopen, caskyclose, caskyput, caskyget, casky_delete
- Hash function: caskydjb2hash_xor
- Error handling via casky_errno
- Unit tests for all APIs using standard asserts
- Test cleanup of temporary files
Changed
- None (first MVP)
Fixed
- None (first MVP)
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This project is part of:
Hack Week 25
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