🦀 CrabbyLB — A High-Performance HTTP Server & Load Balancer in C++

CrabbyLB is a high-performance HTTP server and load balancer implemented in C++. It leverages raw socket programming (netinet) to handle HTTP requests and distributes them across multiple backend servers using a round-robin load balancing algorithm.

Designed for performance and concurrency, CrabbyLB efficiently handles high loads, making it an excellent tool for learning about HTTP servers, load balancing, and low-level networking concepts.

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🚀 Features

✅ Basic HTTP Server to handle incoming client requests.
✅ Multi-threaded Server for handling requests concurrently.
✅ Thread Pool Server for efficient request handling.
✅ Round Robin Load Balancing for backend server distribution.
✅ Backend Health Monitoring with automatic failover and recovery.
✅ High Concurrency with per-request threading.
✅ Graceful Handling of Backend Failures and Recovery.

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🛠️ Usage

To run CrabbyLB, first make the script executable:

chmod +x run_crabbyLB.sh

Then, use the script to run CrabbyLB:

./run_crabbyLB.sh -m <mode> [-b <backend_addresses>]

Modes:

• basic: Run the basic single-threaded HTTP server.
• multi_thread: Run the multi-threaded server (one thread per request).
• thread_pool: Run the server with a thread pool.
• load_balancer: Run the load balancer with health checks.

Examples:

• Run Basic Mode:

  ./run_crabbyLB.sh -m basic

• Run Load Balancer Mode with backend addresses:

  ./run_crabbyLB.sh -m load_balancer -b 127.0.0.1:8081,127.0.0.1:8082

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🔄 Stress Test

To perform a stress test on CrabbyLB, you can use the wrk tool:

wrk -t4 -c100 -d5s http://localhost:8080/

This command runs a stress test with 4 threads, 100 connections, for a duration of 5 seconds against the server running on localhost at port 8080.

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