load-test-builder

Load Test Builder

Validate system performance under realistic and stress conditions.

Core Workflow

1. Define scenarios: User journeys and load patterns
2. Set thresholds: Performance requirements
3. Configure load: Ramp-up, peak, duration
4. Run tests: Execute load scenarios
5. Analyze results: Metrics and bottlenecks
6. Integrate CI: Automated performance gates

k6 Load Testing

Installation

# macOS
brew install k6

# Docker
docker pull grafana/k6

Basic Load Test

// load-tests/basic.js
import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

// Custom metrics
const errorRate = new Rate('errors');
const responseTime = new Trend('response_time');

// Test configuration
export const options = {
  stages: [
    { duration: '1m', target: 20 },   // Ramp up to 20 users
    { duration: '3m', target: 20 },   // Stay at 20 users
    { duration: '1m', target: 50 },   // Ramp up to 50 users
    { duration: '3m', target: 50 },   // Stay at 50 users
    { duration: '1m', target: 0 },    // Ramp down to 0
  ],
  thresholds: {
    http_req_duration: ['p(95)<500', 'p(99)<1000'],
    http_req_failed: ['rate<0.01'],
    errors: ['rate<0.05'],
  },
};

const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';

export default function () {
  // Homepage
  const homeResponse = http.get(`${BASE_URL}/`);

  check(homeResponse, {
    'homepage status is 200': (r) => r.status === 200,
    'homepage loads fast': (r) => r.timings.duration < 500,
  });

  responseTime.add(homeResponse.timings.duration);
  errorRate.add(homeResponse.status !== 200);

  sleep(1);

  // API request
  const apiResponse = http.get(`${BASE_URL}/api/users`);

  check(apiResponse, {
    'api status is 200': (r) => r.status === 200,
    'api returns array': (r) => Array.isArray(JSON.parse(r.body)),
  });

  errorRate.add(apiResponse.status !== 200);

  sleep(Math.random() * 3 + 1); // Random think time 1-4 seconds
}