async

xk6-async

A k6 extension that provides async-compatible group() and check() functions.

Build

xk6 build --with github.com/agostone/xk6-async

Usage

group

import { group } from 'k6/x/async';
import http from 'k6/http';

export default async function () {
  await group('My Async Group', async () => {
    const response = await http.asyncRequest('GET', 'https://test.k6.io');
    console.log('Response status:', response.status);
  });
}

check

import { check } from 'k6/x/async';
import http from 'k6/http';

export default async function () {
  const response = await http.asyncRequest('GET', 'https://test.k6.io');
  
  await check(response, {
    'status is 200': (r) => r.status === 200,
    'async validation': async (r) => {
      // Perform async validation
      return r.status < 400;
    }
  });
}

Features

group

• ✅ Supports async functions
• ✅ Correctly measures group duration including async operations
• ✅ Properly manages group tags across async boundaries
• ✅ Emits group_duration metrics
• ✅ Works with both sync and async callbacks

check

• ✅ Supports async functions in checks
• ✅ Handles mixed sync and async checks
• ✅ Emits checks metrics after async operations complete
• ✅ Works with custom tags
• ✅ Compatible with all check features from built-in check()

Difference from built-in functions

group vs group()

The built-in group() function doesn't support async functions. This extension provides an async-compatible group() which:

• Accepts async functions as callbacks
• Waits for Promises to resolve before emitting metrics
• Ensures group tags are correctly restored after async operations complete

check vs check()

The built-in check() function doesn't support async functions. This extension provides an async-compatible check() which:

• Accepts async functions in check definitions
• Waits for all Promises to resolve before emitting check metrics
• Supports mixed sync and async checks in the same call