Contributing to BioPsyKit

This document contains information for developers that want to contribute to BioPsyKit.

It includes further in-depth information on how to set up and use required tools and learn about programing methods used in the development of this project.

Contributing Guidelines

General Information

BioPsyKit is under active development and welcomes everyone to contribute to code improvements, documentation, testing, and new features! Why should I contribute?

The project is structured into different submodules that each are designed for specific purposes, such as signals, sleep, saliva, questionnaires, as well as overarching submodules used throughout the package, such as plotting, colors, and utils.

Before adding new features, please think about on where your features might suit best into the project structure to that other users can find them easily.

Additionally, please don’t forget to comment and document your code, as well as adding examples and unit tests (more on that below) to your code.

Git Workflow

As multiple people are expected to contribute to BioPsyKit at the same time, BioPsyKit implements a proper Git workflow to prevent possible issues.

Branching structure

In BioPsyKit we use a main + feature branches structure. This workflow is well explained here.

All changes to the main branch should be performed using feature branches. Before merging, the feature branches should be rebased onto the current main branch.

In summary, follow these steps:

Create a Pull Request

Create a new branch from the main branch. If you propose a new feature then name your branch something like <feature_feature-name> where feature-name roughly describes the purpose of the new feature. If you propose a bugfix, improvement, etc. then name your branch something like <fix_fix-name> where fix-name roughly describes the bugfix or improvement you propose.

Afterwards, create a Pull Request. Be sure to have a WIP: at the very beginning of its name. The source branch is the new branch you just created and the target branch is main.

In the description, write shortly what you are going to fix, add, or improve, then start working!

During Development

During development, remember to adhere to the general recommendations for feature branches.

As a reminder, feature branches…

  • …should be short-lived

  • …should be dedicated to a single feature

  • …should be worked on by a single person

  • …must be merged via a Pull Request and not manually

  • …must be reviewed before merging

  • …must pass the pipeline checks before merging

  • …should be rebased onto main if possible (remember to only rebase if you are the only person working on this branch!)

  • …should be pushed soon and often to allow everyone to see what you are working on

  • …should be associated with a Pull Request, which is used for discussions and code review.

  • …that are not ready to review, should have a Pull Request prefixed with WIP:

  • …should also close issues that they solve, once they are merged

Pushing Code

As soon as your new contribution to BioPsyKit is ready, it’s time to ensure your code passes all necessary checks, such as formatting, linting, building documentation, and performing tests. To run these checks more easily this project uses poethepoet, a task runner that runs well with poetry and that provides a cross-platform CLI for common tasks. More details on that are explained in a later Section.

Ask to Merge Pull Request

When you think your implementation is done and ready to be merged into the main branch, remove the WIP: prefix from the Pull Request’s name. Then, assign a reviewer to the Pull Request. This person will review your code, and, if the reviewer agrees with your proposed solution, he or she will merge your changes into main. Attempting to merge a Pull Request into main will trigger GitHub Actions that will again check if your code passes linting and tests and will afterwards build the documentation. Upon passing all checks, your changes will be automatically merged into main.

That’s it!

In summary, your Git workflow should look similar to this:

# Create a new branch
git checkout main
git pull origin main
git checkout -b new-branch-name
git push origin new-branch-name
# Go to GitHub and create a new pull request with WIP prefix

# Do your work. During commit and push your
git push origin new-branch-name

# In case there are important changes in main, rebase
git fetch origin main
git rebase origin/main
# resolve potential conflicts
git push origin new-branch-name --force-with-lease

# Create a pull request and merge via web interface

# Once branch is merged, delete it locally, start a new branch
git checkout main
git branch -D new-branch-name

# Start at top!

Implementing Large Features

When implementing large features it sometimes makes sense to split it into individual merge requests/sub-features. If each of these features are useful on their own, they should be merged directly into main. If the large feature requires multiple pull requests to be usable, it might make sense to create a long-lived feature branch, from which new branches for the sub-features can be created. It will act as a develop branch for just this feature.

Note: Remember to rebase this temporary develop branch onto main from time to time!

General Git Tips

  • Communicate with your Co-developers

  • Commit often

  • Commit in logical chunks

  • Don’t commit temp files

  • Write at least somewhat proper messages

    • Use the imperative mood in the subject line

    • Use the body to explain what and why vs. how

    • …more see link above

Development Tools

Project Setup and Poetry

BioPsyKit only supports Python 3.7 and newer. First, install a compatible version of Python. If you do not want to modify your system installation of Python you can use conda or pyenv. However, there are some issues with using conda. Please, check the trouble shooting guide below.

BioPsyKit uses poetry to manage its dependencies. Once you installed poetry, run the following commands to initialize a virtual env and install all development dependencies:

poetry install

This will create a new folder called .venv inside your project dir. It contains the python interpreter and all site packages. You can point your IDE to this folder to use this version of Python. For PyCharm you can find information about this here.

In case you encounter any issues (with this command or any command below), please check the section on trouble shooting.

To add new dependencies:

poetry add <package name>

# Or in case of a dev dependency
poetry add --dev <package name>

For more commands see the official documentation.

To update dependencies after the pyproject.toml file was changed (It is a good idea to run this after a git pull):

poetry install --no-root

# or (see differences below)
poetry update

Running poetry install will only install packages that are not yet installed. poetry update will also check if newer versions of already installed packages exist.

Tools used in BioPsyKit

To make it easier to run command-line tasks this project uses poethepoet to provide a cross-platform CLI for common tasks.

Install poethepoet into your project (so it works inside poetry shell):

poetry add --dev poethepoet

And into your default python environment (so it works outside of poetry shell)

pip install poethepoet

All commands need to be executed in the venv created by poetry. To list the available tasks, run:

$ poe
docs                 Build the html docs using Sphinx.
format               Reformat all files using black.
format_check         Check, but not change, formatting using black.
lint                 Lint all files with Prospector.
test                 Run Pytest with coverage.
update_version       Bump the version in pyproject.toml and biopsykit.__init__. Pass the options "major", "minor", or "patch" with the `-v` argument to bump the major, minor, or patch version, respectively.
register_ipykernel   Register a new IPython kernel named `biopsykit` linked to the virtual environment.  

To run one of the commands execute (e.g. the test command):

poe test

To execute format, lint, and test all together, run:

poe default

You should run this as often as possible! At least once before any git push.

To ensure that the whole library uses a consistent format, we use black to autoformat our code. Black can also be integrated into your editor, if you do not want to run it from the command line. Because, it is so easy, we also use black to format the test-suite.

For everything black can not handle, we use prospector to handle all other linting tasks. Prospector runs pylint, pep257, and pyflakes with custom rules to ensure consistent code and docstring style.

For documentation we follow the numpy doc-string guidelines and auto-build our API documentation using Sphinx. To make your life easier, you should also set your IDE tools to support the numpy docstring conventions.

Note: In order to build the documentation, you need to additionally install pandoc.

Testing and Test Data

BioPsyKit uses pytest for testing. Besides using the poe-command, you can also use an IDE integration available for most IDEs.

While all automated tests should go in the tests folder, it might be helpful to create some external test script from time to time.

For this you can simply install the package locally (using poetry install) and even get a Jupyter kernel with all dependencies installed (see IDE Config). Test data is available under example_data and you can import it directly using the get_... helper functions:

from biopsykit.example_data import get_sleep_imu_example

data, fs = get_sleep_imu_example()

Configure your IDE


Test runner: Set the default testrunner to pytest.

Black: Refer to this guide

Autoreload for the Python console:

You can instruct Pycharm to automatically reload modules upon changing by adding the following lines to “Settings -> Build, Excecution, Deployment -> Console -> Python Console” in the Starting Script:

%load_ext autoreload
%autoreload 2

Jupyter Lab/Notebooks

To set up a Jupyter environment that has BioPsyKit and all dependencies installed, run the following commands:

# poetry install including root!
poetry install
poetry run poe register_ipykernel

After this you can start Jupyter as always, but select “biopsykit” as a kernel when you want to run a notebook.

Remember to use the autoreload extension to make sure that Jupyter reloads BioPsyKit, when ever you change something in the library. Put this in your first cell of every Jupyter Notebook to activate it:

%load_ext autoreload  # Load the extension
%autoreload 2  # Autoreload all modules

Release Model

BioPsyKit follows typically semantic visioning: A.B.C (e.g. 1.3.5)

  • A is the major version, which will be updated once there were fundamental changes to the project

  • B is the minor version, which will be updated whenever new features are added

  • C is the patch version, which will be updated for bugfixes

As long as no new minor or major version is released, all changes should be interface compatible. This means that the user can update to a new patch version without changing any user code!

This means at any given time we need to support and work with two versions: The last minor release, which will get further patch releases until its end of life. The upcoming minor release for which new features are developed at the moment.

Note that we will not support old minor releases after the release of the next minor release to keep things simple. We expect users to update to the new minor release, if they want to get new features and bugfixes.

There is no fixed timeline for a release, but rather a list of features we will plan to include in every release. Releases can often happen and even with small added features.


poetry not found when using zsh as shell

If you have trouble installing poetry while using zsh as your shell, check this issue

Installation issues while using conda

Setting up poetry with conda as the main Python version can be a little tricky. First, make sure that you installed poetry in the recommended way using the PowerShell command.

Then you have 2 options to start using poetry for this package:

  1. Using a conda env instead of venv

    • Create a new conda env (using the required Python version for this project).

    • Activate the environment.

    • Run poetry install --no-root. Poetry will detect that you are already using a conda env and will use it, instead of creating a new one.

    • After running the poetry install command you should be able to use poetry without activating the conda env again.

    • Setup your IDE to use the conda env you created

  2. Using conda python and a venv

    • This only works, if your conda base env has a Python version supported by the project (>= 3.7)

    • Activate the base env

    • Run poetry install --no-root. Poetry will create a new venv in the folder .venv, because it detects and handles the conda base env different than other envs.

    • Everything else should work like you are not using conda

Warning/Error about outdated/missing dependencies in the lock file when running install or update

This happens when the pyproject.toml file was changed either by a git update or by manual editing. To resolve this issue, run the following and then rerun the command you wanted to run:

poetry update --lock

This will synchronise the lock file with the packages listed in pyproject.toml