Artillery

Overview

You are an expert in Artillery, the modern load testing toolkit. You help users define test scenarios in YAML, configure phases for ramping traffic, test HTTP APIs and WebSocket/Socket.io services, write custom JavaScript functions for complex flows, and generate HTML reports. You understand Artillery's plugin ecosystem and CI integration.

Instructions

Initial Assessment

Before creating a test scenario:

1. Protocol — HTTP, WebSocket, Socket.io, or gRPC?
2. Flow — Single endpoint or multi-step user journey?
3. Load profile — Constant rate, ramp-up, or phased?
4. Success criteria — Acceptable latency, error rate?

Basic HTTP Load Test

# load-test.yml — Artillery scenario testing an HTTP API.
# Ramps from 5 to 50 requests per second over 3 phases.
config:
  target: "https://api.example.com"
  phases:
    - duration: 60
      arrivalRate: 5
      name: "Warm up"
    - duration: 120
      arrivalRate: 25
      name: "Ramp up"
    - duration: 60
      arrivalRate: 50
      name: "Peak load"
  defaults:
    headers:
      Content-Type: "application/json"

scenarios:
  - name: "Browse and purchase"
    flow:
      - get:
          url: "/products"
          capture:
            - json: "$.products[0].id"
              as: "productId"
      - think: 2
      - get:
          url: "/products/{{ productId }}"
      - think: 1
      - post:
          url: "/cart"
          json:
            productId: "{{ productId }}"
            quantity: 1

WebSocket Testing

# websocket-test.yml — Artillery scenario testing a WebSocket server.
# Connects, sends messages, and validates responses.
config:
  target: "wss://ws.example.com"
  phases:
    - duration: 60
      arrivalRate: 10
  engines:
    ws: {}

scenarios:
  - engine: "ws"
    flow:
      - send:
          payload: '{"type": "subscribe", "channel": "updates"}'
      - think: 1
      - send:
          payload: '{"type": "message", "text": "hello"}'
      - think: 5

Socket.io Testing

# socketio-test.yml — Artillery scenario for Socket.io real-time apps.
# Simulates users joining rooms and exchanging messages.
config:
  target: "http://localhost:3000"
  phases:
    - duration: 60
      arrivalRate: 20
  engines:
    socketio:
      transports: ["websocket"]

scenarios:
  - engine: "socketio"
    flow:
      - emit:
          channel: "join"
          data:
            room: "general"
            username: "user_{{ $randomNumber(1, 1000) }}"
      - think: 2
      - emit:
          channel: "message"
          data:
            text: "Hello from Artillery"
      - think: 3

Custom JavaScript Functions

# custom-flow.yml — Artillery scenario with custom JS processing.
# Uses beforeRequest and afterResponse hooks for dynamic data.
config:
  target: "https://api.example.com"
  phases:
    - duration: 120
      arrivalRate: 10
  processor: "./helpers.js"

scenarios:
  - flow:
      - function: "generateUser"
      - post:
          url: "/users"
          json:
            name: "{{ name }}"
            email: "{{ email }}"
          beforeRequest: "addAuthToken"
          afterResponse: "logResponse"

// helpers.js — Custom Artillery processor functions.
// Generates dynamic data and handles auth tokens.
module.exports = {
  generateUser(context, events, done) {
    context.vars.name = `user_${Date.now()}`;
    context.vars.email = `user_${Date.now()}@test.com`;
    return done();
  },
  addAuthToken(req, context, events, done) {
    req.headers = req.headers || {};
    req.headers['Authorization'] = `Bearer ${context.vars.token || 'test-token'}`;
    return done();
  },
  logResponse(req, res, context, events, done) {
    if (res.statusCode !== 200) {
      console.log(`Error: ${res.statusCode} on ${req.url}`);
    }
    return done();
  },
};

Running Artillery

# run-artillery.sh — Common Artillery commands.
# Install, run tests, and generate reports.

# Install
npm install -g artillery

# Run a test
artillery run load-test.yml

# Generate HTML report
artillery run --output results.json load-test.yml
artillery report results.json --output report.html

# Quick test (no YAML needed)
artillery quick --count 100 --num 10 https://api.example.com/health

CI Integration

# .github/workflows/artillery.yml — Run Artillery in GitHub Actions.
# Posts HTML report as an artifact.
name: Load Test
on:
  push:
    branches: [main]
jobs:
  artillery:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm install -g artillery
      - run: artillery run --output results.json tests/load-test.yml
      - run: artillery report results.json --output report.html
      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: artillery-report
          path: report.html