k6-stress-test-demo.js

import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate } from 'k6/metrics';
import { htmlReport } from "https://raw.githubusercontent.com/benc-uk/k6-reporter/main/dist/bundle.js";
import { textSummary } from "https://jslib.k6.io/k6-summary/0.0.1/index.js";

// Custom metric to track failure rate
const failureRate = new Rate('check_failure_rate');

export const options = {
  // Stress test configuration with stages
  stages: [
    { duration: '30s', target: 25 },    // Ramp up to 25 users
    { duration: '30s', target: 50 },    // Ramp up to 50 users
    { duration: '30s', target: 100 },   // Ramp up to 100 users
    { duration: '30s', target: 200 },   // Peak at 200 users
    { duration: '30s', target: 0 },     // Ramp down to 0 users (recovery)
  ],
  thresholds: {
    // We set higher thresholds for stress test as we expect degradation
    'http_req_duration': [
      'p(95)<2000',  // 95% of requests should be below 2s
      'p(99)<3000',  // 99% of requests should be below 3s
    ],
    'http_req_failed': ['rate<0.15'],      // Allow up to 15% failure rate during stress
    'check_failure_rate': ['rate<0.15'],    // Same threshold for our custom check
  },
};

export default function () {
  const url = 'http://localhost:5127/mostborrowedbook';
  
  // Send GET request with custom tags for better metrics
  const response = http.get(url, {
    tags: { name: 'MostBorrowedBook' },
  });

  // Define checks
  const checks = check(response, {
    'status is 200': (r) => r.status === 200,
    'response time < 2000ms': (r) => r.timings.duration < 2000,
    'valid response body': (r) => r.body.length > 0,
  });

  // Update custom metric
  failureRate.add(!checks);

  // Log if we see a non-200 response
  if (response.status !== 200) {
    console.log(`Got non-200 response: ${response.status}, body: ${response.body}`);
  }

  // Random sleep between 1s and 3s to add variability
  sleep(Math.random() * 2 + 1); // Random sleep between 1-3s
}

export function handleSummary(data) {
  return {
    "stress-test-results.html": htmlReport(data),
    stdout: textSummary(data, { indent: " ", enableColors: true }),
  };
}