Extend functionality

The functionality of xk6-python can be extended with remote modules written in Starlark and built-in modules written in go.

By using remote modules

The functionality of xk6-python can be extended most easily with remote modules written in Starlark language. It is not necessary to modify the source code of the xk6-python extension, nor is it necessary to build a new k6 executable.

A Starlark module should be created and deployed on a static web server accessible via https protocol. The remote modules can be used on the developer’s machine with the http protocol by specifying the host 127.0.0.1.

load("https://grafana.github.io/k6pylib/welcome.py", "hello")

def default(_):
    hello("Joe")

See more in the Remote Modules section.

By using built-in modules

The built-in modules should be written in the go programming language. A custom k6 build is required to integrate them.

The built-in module is loaded by a loader function implemented by the module.

type BuiltinLoaderFunc func(string, *starlark.Thread, modules.VU) (starlark.StringDict, error)

The module loader function should be registered using the RegisterBuiltin() function during startup.

func RegisterBuiltin(loader BuiltinLoaderFunc, module string)

There are two options for placing the source code of the module:

1. By modifying the source of xk6-pyhon. The module should be placed in a subdirectory of the py/builtin directory and registered in the Bootstrap() function.

2. By creating a k6 extension. This k6 extension should be integrated into k6 and the module registration should be done in the init() function.

For example, it is worth looking at the built-in modules of xk6-python.