API-Gateway

Implementation A modern C++ API Gateway implementation featuring thread-safe request handling, LRU caching, and round-robin load balancing. Designed for high throughput and low latency in microservices architectures.

Architecture The gateway utilizes a thread pool for concurrent request processing and an LRU cache for response optimization. Core components include:

• Thread-safe request handling with configurable worker pool
• LRU caching with O(1) lookup performance
• Round-robin load balancing across backend servers
• Comprehensive performance monitoring

Implementation Details Key components:

• ThreadPool with std::condition_variable for efficient worker management
• LRUCache combining hash map and doubly-linked list for O(1) operations
• std::mutex protection for thread-safe concurrent access
• Performance metrics tracking for latency and cache effectiveness

Data Structures

• Cache: std::unordered_map<std::string, Node*> with linked list for LRU ordering
• Thread Pool: std::queue<std::function<void()>> for task management
• Backend Servers: std::vector<std::string> with round-robin selection

Features

• Thread-safe request processing
• Automatic response caching
• Load balancing across multiple backends
• Comprehensive performance monitoring
• Hardware-optimized thread pool sizing

Usage Example

// Initialize gateway with cache size and thread count
APIGateway gateway(1000, std::thread::hardware_concurrency());

// Process requests
std::string response = gateway.handleRequest("/api/users/1");

// Run performance tests
GatewayTester tester(gateway);
auto metrics = tester.runLoadTest(1000, 10);
metrics.print();

Requirements

• C++17 or later compiler
• Standard Template Library
• POSIX threads support

The implementation prioritizes thread safety and performance while maintaining clean code structure through careful synchronization and memory management practices.