Local Testing Guide

Overview

Test UltraBalancer on your local machine before deploying to production. This guide covers setting up test backends, validating configurations, and debugging.

Quick Start

Get testing in under 5 minutes

Multiple Backends

Set up test backend servers

Docker Testing

Test with Docker containers

Debug Mode

Verbose logging for debugging

Quick Start

Simple Test with Python

Create Test Backends

# Terminal 1: Start backend on port 3001
python3 -m http.server 3001

# Terminal 2: Start backend on port 3002
python3 -m http.server 3002

# Terminal 3: Start backend on port 3003
python3 -m http.server 3003

Start UltraBalancer

# Terminal 4: Start load balancer
ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  -b localhost:3003 \
  -a round-robin \
  -p 8080 \
  --log-level debug

Test Requests

# Make test requests
curl http://localhost:8080

# Watch distribution
for i in {1..10}; do
  curl -s http://localhost:8080 | head -n 1
  sleep 0.5
done

Backend Test Servers

Node.js Backend

const express = require('express');
const app = express();
const port = process.env.PORT || 3000;

// Health check endpoint
app.get('/health', (req, res) => {
  res.json({ status: 'healthy', port });
});

// Main endpoint
app.get('*', (req, res) => {
  res.json({
    message: `Response from backend on port ${port}`,
    timestamp: new Date().toISOString(),
    headers: req.headers
  });
});

app.listen(port, () => {
  console.log(`Backend running on port ${port}`);
});

Python Backend

backend.py

from flask import Flask, request, jsonify
import os
from datetime import datetime

app = Flask(__name__)
port = int(os.getenv('PORT', 3000))

@app.route('/health')
def health():
    return jsonify({
        'status': 'healthy',
        'port': port
    })

@app.route('/')
def index():
    return jsonify({
        'message': f'Response from backend on port {port}',
        'timestamp': datetime.now().isoformat(),
        'headers': dict(request.headers)
    })

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=port)

# Run multiple instances
PORT=3001 python backend.py &
PORT=3002 python backend.py &
PORT=3003 python backend.py &

# Start UltraBalancer
ultrabalancer -b localhost:3001 -b localhost:3002 -b localhost:3003

Go Backend

backend.go

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"
    "os"
    "time"
)

type Response struct {
    Message   string            `json:"message"`
    Port      string            `json:"port"`
    Timestamp string            `json:"timestamp"`
    Headers   map[string]string `json:"headers"`
}

func main() {
    port := os.Getenv("PORT")
    if port == "" {
        port = "3000"
    }

    http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
        json.NewEncoder(w).Encode(map[string]string{
            "status": "healthy",
            "port":   port,
        })
    })

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        headers := make(map[string]string)
        for k, v := range r.Header {
            headers[k] = v[0]
        }

        response := Response{
            Message:   fmt.Sprintf("Response from backend on port %s", port),
            Port:      port,
            Timestamp: time.Now().Format(time.RFC3339),
            Headers:   headers,
        }

        w.Header().Set("Content-Type", "application/json")
        json.NewEncoder(w).Encode(response)
    })

    log.Printf("Backend listening on port %s\n", port)
    log.Fatal(http.ListenAndServe(":"+port, nil))
}

Docker Testing

Docker Compose Setup

docker-compose.test.yml

version: '3.8'

services:
  ultrabalancer:
    image: ultrabalancer/ultrabalancer:latest
    ports:
      - "8080:8080"
    command: >
      -b backend1:80
      -b backend2:80
      -b backend3:80
      -a round-robin
      --log-level debug
    depends_on:
      - backend1
      - backend2
      - backend3

  backend1:
    image: nginx:alpine
    volumes:
      - ./backend1:/usr/share/nginx/html:ro

  backend2:
    image: nginx:alpine
    volumes:
      - ./backend2:/usr/share/nginx/html:ro

  backend3:
    image: nginx:alpine
    volumes:
      - ./backend3:/usr/share/nginx/html:ro

# Create test content
mkdir -p backend1 backend2 backend3
echo "Backend 1" > backend1/index.html
echo "Backend 2" > backend2/index.html
echo "Backend 3" > backend3/index.html

# Start services
docker-compose -f docker-compose.test.yml up

# Test
curl http://localhost:8080

Testing Different Algorithms

Round Robin
Least Connections
IP Hash
Weighted

ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  -b localhost:3003 \
  -a round-robin \
  -p 8080

# Test distribution
for i in {1..9}; do
  curl -s http://localhost:8080 | grep port
done
# Should see: 3001, 3002, 3003, 3001, 3002, 3003, ...

ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  -b localhost:3003 \
  -a least-connections \
  -p 8080

# Test with concurrent connections
ab -n 100 -c 10 http://localhost:8080/

ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  -b localhost:3003 \
  -a ip-hash \
  -p 8080

# Same client should hit same backend
for i in {1..10}; do
  curl -s http://localhost:8080 | grep port
done
# Should see same port repeated

ultrabalancer \
  -b localhost:3001:200 \
  -b localhost:3002:100 \
  -b localhost:3003:50 \
  -a weighted \
  -p 8080

# Backend 1 should get 2x traffic of backend 2
# Backend 2 should get 2x traffic of backend 3
for i in {1..100}; do
  curl -s http://localhost:8080 | grep port
done | sort | uniq -c

Health Check Testing

Test Health Check Failover

# Start backends
PORT=3001 python backend.py &
PORT=3002 python backend.py &
PORT=3003 python backend.py &

# Start UltraBalancer with aggressive health checks
ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  -b localhost:3003 \
  --health-check-interval 2000 \
  --health-check-fails 2 \
  --log-level debug

# Kill one backend
kill $(lsof -ti:3002)

# Watch logs - should see:
# WARN Backend localhost:3002 health check failed (1/2)
# WARN Backend localhost:3002 health check failed (2/2)
# WARN Backend localhost:3002 marked DOWN

# Requests should continue working
while true; do curl http://localhost:8080 && sleep 1; done

Configuration Testing

Validate Configuration

# Create test config
cat > test-config.yaml << 'EOF'
listen_address: "127.0.0.1"
listen_port: 8080
algorithm: "round-robin"

backends:
  - host: "localhost"
    port: 3001
  - host: "localhost"
    port: 3002

health_check:
  enabled: true
  interval_ms: 5000
EOF

# Validate
ultrabalancer validate -c test-config.yaml

# Run with config
ultrabalancer -c test-config.yaml

Debug Mode

Enable Verbose Logging

# Maximum verbosity
ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  --log-level trace \
  --log-format text

# Output shows:
# TRACE Request received: GET / HTTP/1.1
# TRACE Selected backend: localhost:3001
# TRACE Forwarding request...
# TRACE Backend response: 200 OK
# TRACE Sent response to client

Monitoring During Tests

Check Metrics

# Start UltraBalancer
ultrabalancer -b localhost:3001 -b localhost:3002 -p 8080

# Generate traffic
ab -n 1000 -c 10 http://localhost:8080/

# Check metrics
curl http://localhost:8080/metrics | jq

# Watch metrics in real-time
watch -n 1 'curl -s http://localhost:8080/metrics | jq'

Automated Testing

Test Script

test.sh

#!/bin/bash

echo "Starting UltraBalancer test suite..."

# Start test backends
echo "Starting backends..."
PORT=3001 python3 -m http.server 3001 > /dev/null 2>&1 &
PID1=$!
PORT=3002 python3 -m http.server 3002 > /dev/null 2>&1 &
PID2=$!
PORT=3003 python3 -m http.server 3003 > /dev/null 2>&1 &
PID3=$!

sleep 2

# Start UltraBalancer
echo "Starting UltraBalancer..."
ultrabalancer \
  -b localhost:3001 \
  -b localhost:3002 \
  -b localhost:3003 \
  -p 8080 \
  > /tmp/ultrabalancer.log 2>&1 &
LB_PID=$!

sleep 2

# Run tests
echo "Running tests..."

# Test 1: Basic connectivity
echo -n "Test 1: Basic connectivity... "
if curl -sf http://localhost:8080 > /dev/null; then
    echo "PASS"
else
    echo "FAIL"
    exit 1
fi

# Test 2: Load distribution
echo -n "Test 2: Load distribution... "
RESPONSES=$(for i in {1..30}; do curl -s http://localhost:8080 & done | wait | wc -l)
if [ $RESPONSES -eq 30 ]; then
    echo "PASS"
else
    echo "FAIL (got $RESPONSES/30)"
    exit 1
fi

# Test 3: Health check
echo -n "Test 3: Health check... "
kill $PID2  # Kill one backend
sleep 6     # Wait for health check
if curl -sf http://localhost:8080 > /dev/null; then
    echo "PASS"
else
    echo "FAIL"
    exit 1
fi

# Cleanup
echo "Cleaning up..."
kill $PID1 $PID3 $LB_PID 2>/dev/null
echo "All tests passed!"

Load Testing

Performance testing with ab, wrk, k6

Benchmarks

Performance benchmarks

Configuration

Configuration reference

Troubleshooting

Debug production issues

Getting Started

Concepts

Configuration

Deployment

Testing

API

Advanced

Overview

Quick Start

Multiple Backends

Docker Testing

Debug Mode

Quick Start

Simple Test with Python

Backend Test Servers

Node.js Backend

Python Backend

Go Backend

Docker Testing

Docker Compose Setup

Testing Different Algorithms

Health Check Testing

Test Health Check Failover

Configuration Testing

Validate Configuration

Debug Mode

Enable Verbose Logging

Monitoring During Tests

Check Metrics

Automated Testing

Test Script

Load Testing

Benchmarks

Configuration

Troubleshooting

Getting Started

Concepts

Configuration

Deployment

Testing

API

Advanced

​Overview

Quick Start

Multiple Backends

Docker Testing

Debug Mode

​Quick Start

​Simple Test with Python

​Backend Test Servers

​Node.js Backend

​Python Backend

​Go Backend

​Docker Testing

​Docker Compose Setup

​Testing Different Algorithms

​Health Check Testing

​Test Health Check Failover

​Configuration Testing

​Validate Configuration

​Debug Mode

​Enable Verbose Logging

​Monitoring During Tests

​Check Metrics

​Automated Testing

​Test Script

​Related Topics

Load Testing

Benchmarks

Configuration

Troubleshooting

Overview

Quick Start

Simple Test with Python

Backend Test Servers

Node.js Backend

Python Backend

Go Backend

Docker Testing

Docker Compose Setup

Testing Different Algorithms

Health Check Testing

Test Health Check Failover

Configuration Testing

Validate Configuration

Debug Mode

Enable Verbose Logging

Monitoring During Tests

Check Metrics

Automated Testing

Test Script

Related Topics