Isame Load Balancer

A HTTP/HTTPS load balancer written in Go with TLS termination, multiple load balancing algorithms (RR, WRR, LC), circuit breaker, retry logic, rate limiting, health checking, Prometheus metrics.

Features

• Contains Round robin, weighted RR, least connections
• Has TLS/SSL termination with configurable versions (1.2/1.3)
• Has a circuit breaker pattern and exponential backoff retry
• Per-client rate limiting with sliding window
• Active monitoring with configurable thresholds
• Contains prometheus metrics and status endpoints

Prerequisites

• Go 1.22 or later
• Make (optional)

Quick Start

# Build
make build

# Run with example config
./bin/isame-lb -config=configs/example.yaml

# Run with HTTPS enabled
cd certs/dev && ./generate.sh  # Generate certificates
cd ../..
./bin/isame-lb -config=configs/dev-tls.yaml

Configuration Example

version: "2.0.0"
service: "my-load-balancer"

server:
  port: 8080

upstreams:
  - name: "web-servers"
    algorithm: "weighted_round_robin" # round_robin, weighted_round_robin, least_connections
    backends:
      - url: "http://localhost:3000"
        weight: 3
      - url: "http://localhost:3001"
        weight: 2
    rate_limit:
      enabled: true
      requests_per_ip: 100
      window_size: "1m"

health:
  enabled: true
  interval: "30s"
  timeout: "5s"
  path: "/health"
  unhealthy_threshold: 3
  healthy_threshold: 2

metrics:
  enabled: true
  port: 9090
  path: "/metrics"

circuit_breaker:
  enabled: true
  failure_threshold: 5
  timeout: "60s"

retry:
  enabled: true
  max_attempts: 3
  initial_backoff: "100ms"
  max_backoff: "2s"

tls:
  enabled: true
  cert_file: "certs/dev/server.crt"
  key_file: "certs/dev/server.key"
  min_version: "1.2"

API Endpoints

Load Balancer (Port 8080/8443)

• GET /health - Health check
• GET /status - Backend health status
• /* - Proxy to backend servers

Metrics Server (Port 9090)

• GET /metrics - Prometheus metrics

Usage Examples

# Check health
curl http://localhost:8080/health

# Check HTTPS
curl -k https://localhost:8443/health

# View status
curl http://localhost:8080/status

# View metrics
curl http://localhost:9090/metrics

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Demo

System Overview

Full system running with load balancer, backend servers, and monitoring:

Load Balancing in Action

Weighted round-robin algorithm distributing traffic across backends (3:2:1 ratio):

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Development

# Run tests
make test

# Run linter
make lint

# Format code
make fmt

License

See LICENSE file for details.