bygg 0.0.3

A small build system

Bygg

a Python build system that gets out of your way

Installation • Usage • Development

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Bygg is in early stage of development. It is usable and useful for its currently implemented use cases. Feel free to try it out, but also expect things to change and evolve. Feedback and bug reports are welcome!

Introduction

Bygg is a build system implemented in and configured using Python. It is general-purpose, but is aimed at those that use Python to glue together other systems.

Bygg tries to get out of your way and be as thin as possible, while still providing correctness and minimal rebuilds.

Basics

• Specify actions in pure Python.
• Actions can depend on other actions.
• An action will be executed if the digests of its source or output files have changed.

Installation

Bygg currently requires Python 3.11. Support for earlier versions should be straightforward but hasn't been prioritised; feel free to open an issue if you need it.

Install globally with

pip install bygg or pipx install bygg

or in a virtual environment.

Usage

Specify the actions in Byggfile.py in your source directory. Either wrap the action function using the @action decorator, or use the Action constructor directly.

# Decorator:

@action(
    "build1",
    inputs=["foo.in", "bar.in"],
    outputs=["foo.out", "bar.out"]
    is_entrypoint: True
)
def a_build_command(ctx: Context):
    # do stuff
    ...


# Separate function + Action constructor:

def also_a_build_command(ctx: Context):
    # do stuff
    ...

Action(
    "build2",
    inputs=["foo.in", "bar.in"],
    outputs=["foo.out", "bar.out"],
    dependencies=["another action"],
    command=also_a_build_command
    is_entrypoint=True
)

Bygg will check for the presence of Byggfile.py in the current directory. The actions above can be built with bygg build1 and bygg build2, respectively.

Settings file

There is also experimental support for declaring actions in a settings file (currently YAML). This is intended primarily for configuring static settings like which virtual environment to use, but can also be used for declaring simple actions. See examples/taskrunner/Byggfile.yml.

Getting a local copy

If you want to try out the examples or even develop Bygg itself, Bygg can be tried out and worked on without installing it globally:

First, clone this repo and cd into it, then execute the commands below. bootstrap.sh creates a virtual environment and installs Bygg into it together with its dependencies.

./bootstrap.sh
. .venv/bin/activate

Now you can try out one of the examples:

cd examples/trivial
bygg transform

In the above, bygg is the command to execute bygg, and transform is an action (much like a target in a Makefile). See examples/trivial/Byggfile.py for details.

The target can be cleaned with

bygg transform --clean` .

Development

Running tests

With Bygg's virtual environment activated per above, tests can be run from the root directory:

pytest

With the virtual environment deactivated, the full test suite (so far synonymous to just running pytest though) can be run with nox. Nox should be installed globally since it manages its own virtual environments:

pipx install nox

After that, run tests with

nox