Zig Database Server

This project is a basic in-memory database server implemented in the Zig programming language. It mimics a simplified Redis-like architecture, supporting basic commands like SET, GET, and PING. The server uses multithreading to handle client connections and includes a custom hashmap implementation for storing key-value pairs.

Features

• In-memory Key-Value Store:

  • Stores keys and values in memory using DBhashmap, a structure built around std.StringHashMap.
  • Provides thread-safe access with read-write locks.

• Basic Commands:

  • PING: Responds with a "PONG".
  • SET key value: Adds or updates a key-value pair.
  • GET key: Retrieves the value associated with a key.

• Thread-Safe Multithreading:

  • Uses std.Thread for handling multiple client connections concurrently.
  • Includes thread-safe management for active client and thread pools.

• Signal Handling:

  • Gracefully handles signals like SIGINT to allow clean shutdowns.

• Memory Management:

  • Supports custom allocators for debugging and performance.
  • Tracks memory allocation during tests to ensure no memory leaks.

• Cross-Platform Compatibility:

  • Runs on Linux, macOS, and Windows.

Project Structure

Source Files

• src/db.zig:

  • Implements DBhashmap, the core data structure for storing key-value pairs.
  • Includes add, get, and initialization/de-initialization functions.

• src/handle_client.zig:

  • Handles client commands by tokenizing input and executing appropriate functions.
  • Includes functions for PING, SET, and GET.

• src/main.zig:

  • The entry point of the application.
  • Sets up the server, initializes resources, and manages the main event loop.

• src/my_server.zig:

  • Encapsulates server operations, including accepting connections and shutting down.
  • Provides OS-specific handling for shutting down sockets.

• src/signal_handle.zig:

  • Implements signal handling for graceful shutdowns on Linux and Windows.

Test Files

• src/tests/test_db_hashmap.zig:

  • Tests DBhashmap for functionality and memory safety.

• src/tests/test_set.zig:

  • Tests the SET command functionality.

• src/test.zig:

  • Runs all tests defined in the project.

Running the Server

1. Build the Project:

   zig build

2. Run the Server:

   zig-out/bin/server

3. Connect to the Server: Use tools like telnet or a custom client to connect to 127.0.0.1:6379 and issue commands:

   telnet 127.0.0.1 6379

Commands

• PING: Test server responsiveness.

  > PING
  < +PONG
  

• SET key value: Store a key-value pair.

  > SET mykey myvalue
  < +OK
  

• GET key: Retrieve the value of a key.

  > GET mykey
  < $7
  < myvalue
  

Testing

Run the included tests to ensure functionality and memory safety:

zig test src/test.zig

Memory Debugging

The project supports memory tracking during debug builds using std.heap.GeneralPurposeAllocator. In non-debug builds, it uses the faster std.heap.raw_c_allocator.

Future Enhancements

• Support for more commands (e.g., DELETE, EXISTS).
• Persistent storage for data across server restarts.
• Optimizations for multithreaded performance.
• Improved client protocol handling for more robust communication.

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Enjoy exploring this lightweight and extensible database server in Zig! 🎉