Amtal

To know a thing well, know its limits. Only when pushed beyond its tolerances will true nature be seen. – The Amtal Rule

Simple load testing tool done out of sheer desperation to load test Sapho (Yes, we're Frank Herbert's Dune enthusiasts).

Aimed at easy scripting of real-world API usage

When use Amtal

If you want to write a complex test script of REST API simulating real service usage, are not afraid of little Javascript, if you want to run the script on your infrastructure and not pay a dime for the tool, Amtal is for you.

If you want to record web app usage and then just replay it, or smash a few resources as hard as you can with no logic involved, there are lot of tools out there, probably better suited for the task.

Basic Usage

let amtal = require('amtal');

let scenario = user =>
    Promise.resolve()
    // Sequential requests with tink time in between:
    .then(user.POST("Submit Login","/api/login", {user: "tom", "password": "123"})) // POST, PUT: request name, path, data [, options]
    .then(user.wait(2))
    .then(user.GET("Get Main Data", "/api/data"), {processResponse: true}) // GET: request name, path [, options]
    // Parallel requests
    .then(response => Promise.all(
        JSON.parse(response.body).links.map(link => 
            user.GET("Get " + link.name, link.url)())));

let configuration = {
    host: "api.acme.com"
};

let rampup = { 
    0: 0, // minute => number of running users
    '1:30': 5, // or 'h:m:s' => number of running users
    2: 5,
    5: 50,
    10: 50
}

amtal
    .run(scenario, configuration, rampup)
    .then(amtal.exportResults({dir:"results"}))

Promises Cookbook

• Start with Proimise.resolve().
• Chain synchronous requests with .then(user.METHOD(...)).then(user.METHOD(...)).
• To process response syncronously, set the processResponse option to true and chain .then(data => new Promise((resolve, reject) => { /* work with data (raw response)*/; resolve(); }))
• To fire parallel requests (and wait for all to complete), do .then(() => Promise.all([user.GET(...)(), user.POST(...)()])) - notice the METHOD functions are executed here! You're chaining a function returning a promise of array, not array of promises!
• To add a result processing in the parallel part, instead of single user.GET(...)(), do Promise.resolve().then(user.METHOD(...)).then(data => new Promise((resolve, reject) => {})) - same as the top level promise chain

User Context

The user instance holds a context hash (user.context) that can be used to store values and use them in path interpolation.

To use the context values in path interpolation, use ${this.foo} in second (path) argument of user.METHOD shortcut methods. ${this.foo} will be resolved to value of user.context.foo when the request is initiated.