Contributing to Mars

Mars is an open-sourced project released under Apache License 2.0. We welcome and thanks for your contributions. Here are some guidelines you may find useful when you want to make some change of Mars.

General Guidelines

Mars hosts and maintains its code on Github. We provide a generalized guide for opening issues and pull requests.

Setting Up a Development Environment

Unless you want to develop or debug Mars under Windows, it is strongly recommended to develop Mars under MacOS or Linux, where you can test all functions of Mars. The steps listed below are applicable on MacOS and Linux.

Install in Conda

It is recommended to develop Mars with conda. When you want ot install Mars for development, use the following steps to create an environment and install Mars inside it:

git clone
cd mars
conda create -n mars-dev --file conda-spec.txt python=3.7
source activate mars-dev
conda install -c conda-forge pyarrow tiledb-py
pip install -e .

Change 3.7 into the version of Python you want to install, and mars-dev into your preferred environment name.

Other Python Distributions

Mars has a dev option for installation. When you want to install Mars for development, use the following steps:

pip install --upgrade setuptools pip
git clone
cd mars
pip install -e ".[dev]"

If you are using a system-wide Python installation and you only want to install Mars for you, you can add --user to the pip install commands.


After installing Mars, you can check if Mars is installed correctly by running

python -c "import mars; print(mars.__version__)"

If this command correctly outputs your Mars version, Mars is correctly installed.

Rebuilding Cython Code

Mars uses Cython to accelerate part of its code. After you change Cython source code, you need to compile them into binaries by executing the command below on the root of Mars project:

python build_ext -i

Running Tests

It is recommended to use pytest to run Mars tests. A simple command below will run all the tests of Mars:

pytest mars

If you want to generate a coverage report as well, you can run:

pytest --cov=mars --cov-report=html mars

Coverage report will be put into the directory htmlcov.

The command above does not contain coverage data for Cython files by default. To obtain coverage data about Cython files, you can run

CYTHON_TRACE=1 python build_ext -i --force

before running the pytest command mentioned above. After report is generated, it it recommended to remove all generated C files and binaries and rebuild without CYTHON_TRACE, as this option will reduce the performance of Mars.

Building Documentations

Mars uses sphinx to build documents. You need to install necessary packages with the command below to install these dependencies and build your documents into HTML.

pip install -r docs/doc-requirements.txt
cd docs
make html

The built documents are in docs/build/html directory.

When you want to create translations of Mars documents, you may append -l <locale> after the I18NSPHINXLANGS variable in Makefile. Currently only simplified Chinese is supported. After that, run the command below to generate portable files (*.po) for the documents, which are in docs/source/locale/<locale>/LC_MESSAGES:

cd docs
make gettext

After that you can translate Mars documents into your language. Note that when you run make gettext again, translations will be broken into a fixed-width text. For Chinese translators, you need to install jieba to get this effect.

When you finish translation, you can run

cd docs
# change LANG into the language you want to build
make -e SPHINXOPTS="-D language='LANG'" html

to build the document in the language you just translated into.