Redez - A Simple Redis Clone in Go

Description

Redez is a basic implementation of a Redis-like in-memory key-value store built with Go. This project serves as an educational tool to understand the core concepts behind Redis, including the Redis Serialization Protocol (RESP), command handling, concurrency, and persistence mechanisms like AOF.

Features

• TCP Server: Listens for client connections on port 6969. (Note: The current main.go accepts only a single connection after startup; a loop is needed for true concurrent handling).
• RESP Implementation: Includes a parser for handling basic RESP data types: Arrays, Bulk Strings, Simple Strings, Errors, and Integers. Also includes functions for serializing responses back into RESP format.
• Command Handling: Supports a subset of Redis commands: PING, ECHO, SET, GET.
• In-Memory Storage: Utilizes a thread-safe map[string]string protected by a sync.RWMutex for storing key-value data.
• AOF Persistence: Implements Append-Only File (AOF) persistence. Successful SET commands are appended to the redez.aof file.
• Basic CLI Client: A command-line client is included (./cli) for interacting with the Redez server.

Getting Started

Prerequisites

• Go (latest stable version recommended)

Building

1. Build & Run the Server:

   cd /path/to/redez # Navigate to the project root
   make run

2. Build & Run the Client: Open another terminal window:

   cd /path/to/redez # Navigate to the project root
   make run-cli

You can now type Redis commands (like PING, SET key value, GET key) into the client terminal. Type QUIT or EXIT to close the client.

Implemented Commands

• PING [message] - Responds with PONG if no message is provided, or echoes the message if one is given.
• ECHO message - Responds with the provided message.
• SET key value - Stores the key and value. This command is logged to the AOF file. Responds with OK on success.
• GET key - Retrieves the value associated with the key. Responds with the value as a bulk string, or (nil) if the key does not exist.

Future Work / TODOs

• Implement a proper connection loop in main.go to handle multiple concurrent clients.
• Implement the logic to load existing data from the AOF file upon server startup (aof.go).
• Expand command support (e.g., DEL, EXISTS, List commands, Hash commands).
• Add support for key expiration (EX option for SET, TTL command).
• Enhance error handling throughout the application.
• Improve the client's RESP response parser to handle complex types like nested arrays correctly (cli/main.go).
• Consider adding configuration options (e.g., port, AOF filename).
• Implement periodic fsync for the AOF file to improve data durability (aof.go).