Escritura de scripts básicos de k6

Welcome to writing k6 scripts! k6 uses JavaScript to define your load tests, making it familiar for many developers.

A k6 script describes what your virtual users will do and how the load should be simulated.

• Define user actions like visiting pages or logging in.
• Specify the number of virtual users (VUs) and test duration.
• Validate server responses to ensure correctness.

Every k6 script typically has two main parts:

• The options object: Here you configure test-wide settings like virtual users (VUs) and test duration.
• The default function: This is where your virtual users' actions are defined. It's executed repeatedly by each VU.

Think of the default function as the "main loop" for each virtual user.

The most common action in a performance test is sending an HTTP request. k6 provides the k6/http module for this.

To send a simple GET request, you'll use http.get('URL'). This simulates a browser fetching a web page or an API endpoint.

Remember to import the http module at the top of your script.

Let's write our first k6 script to make a GET request to example.com. Copy and run this script using the k6 CLI.

k6 run your_script.js

In k6, a Virtual User (VU) simulates a real user interacting with your system. Each VU executes the default function independently.

If you have 10 VUs, it's like 10 people simultaneously using your application. k6 efficiently manages these VUs.

By controlling the number of VUs, you can simulate different levels of load on your application.

The options object is crucial for defining your test scenario. It sits at the top level of your script.

Two key options are:

• vus: The total number of virtual users to run concurrently.
• duration: How long the test should run (e.g., '30s', '5m', '2h').

These settings tell k6 how to distribute and execute your default function.

This script runs with 5 virtual users for a duration of 10 seconds, hitting the test website repeatedly.

Observe how k6 reports the VUs and duration when you run this script.

Beyond GET, you often need to send data to the server, like submitting a form or creating a resource. For this, you use http.post().

The http.post() function takes three arguments:

• The URL.
• The request body (usually a JSON string or form data).
• Optional parameters like headers.

Here's an example of a POST request sending JSON data. Notice how we specify the Content-Type header to tell the server we're sending JSON.

Which of the following statements about basic k6 scripting are TRUE?

Great job! You've learned the fundamentals of writing k6 scripts:

• The basic structure with options and the default function.
• How to send simple HTTP GET and POST requests using k6/http.
• Configuring test load with vus and duration.

In the next lesson, we'll dive into validating responses with Checks and setting performance targets with Thresholds!