Go TLS Echo Server with Rate Limiting and Prometheus Metrics

A secure TLS echo server written in Go that demonstrates advanced networking concepts, including:

Features

• TLS Encryption: All client-server communications are encrypted using TLS.
• Connection Limiting: Enforces a maximum number of concurrent connections using channels and mutexes.
• Prometheus Metrics: Exposes runtime metrics (total connections and active connections) on a dedicated HTTP endpoint for monitoring.
• Graceful Shutdown: Handles system signals to gracefully shut down the server.
• Rate Limiting: Prevents the server from being overwhelmed by too many requests.
• Basic Authentication: Restricts access to the server using username and password.

Prerequisites

• Go 1.16 or later
• Prometheus (if you wish to scrape the metrics)

Installation

1. Clone the Repository:

   cd go-tls-echo-server

2. Build the Server:

   go build -o echo-server

Usage

Run the server with default parameters:

./echo-server

You can also specify flags:

./echo-server -port=20080 -bufferSize=512 -certFile=server.crt -keyFile=server.key -maxConn=100 -rateLimit=10 -metricsAddr=":9090"

Metrics

The server exposes Prometheus metrics on the /metrics endpoint (by default at http://localhost:9090/metrics). Monitor total connections and active connections in real time.

Graceful Shutdown

The server listens for SIGINT and SIGTERM signals. Use Ctrl+C to gracefully shut down the server.

Testing

Run the test cases with:

go test -v

This will execute the provided test for the echo functionality, ensuring the server echoes messages correctly.