This document describes how to set up an environment for the development of the Glean Python bindings.
Instructions for installing a copy of the Glean Python bindings into your own environment for use in your project are described in adding Glean to your project.
Glean requires Python 3.7 or later.
Make sure it is installed on your system and accesible on the PATH
as python3
.
If you've already set up Rust for building Glean for Android or iOS, you already have everything you need and can skip this section.
Rust can be installed using rustup
, with the following commands:
curl https://sh.rustup.rs -sSf | sh
rustup update
It is recommended to do all Python development inside a virtual environment to make sure there are no interactions with other Python libraries installed on your system.
You may want to manage your own virtual environment if, for example, you are developing a library that is using Glean and you want to install Glean into it. If you are just developing Glean itself, however, Glean's Makefile
will handle the creation and use of a virtual environment automatically (though the Makefile
unfortunately does not work on Microsoft Windows).
The instructions below all have both the manual instructions and the Makefile
shortcuts.
The following instructions use the basic virtual environment functionality that comes in the Python standard library. Other higher level tools exist to manage virtual environments, such as pipenv and conda. These will work just as well, but are not documented here. Using an alternative tool would replace the instructions in this section only, but all other instructions below would remain the same.
To create a virtual environment, enter the following command, replacing <venv>
with the path to the virtual environment you want to create. You will need to do this only once.
$ python3 -m venv <venv>
Then activate the environment. You will need to do this for each new shell session when you want to develop Glean. The command to use depends on your shell environment.
Platform | Shell | Command to activate virtual environment |
---|---|---|
POSIX | bash/zsh | source <venv>/bin/activate |
fish | . <venv>/bin/activate.fish |
|
csh/tcsh | source <venv>bin/activate.csh |
|
PowerShell Core | <venv>/bin/Activate.ps1 |
|
Windows | cmd.exe | <venv>\Scripts\activate.bat |
PowerShell | <venv>\Scripts\Activate.ps1 |
Lastly, install Glean's Python development dependencies into the virtual environment.
cd glean-core/python
pip install -r requirements_dev.txt
$ make python-setup
Note: If you wish to change the location of the virtual environment that the
Makefile
uses, set theGLEAN_PYENV
environment variable.
First, rebuild the Rust core if any Rust changes were made:
$ cargo build # If there were Rust changes
$ cd glean-core/python
$ python setup.py install
This will implicitly setup the Python environment, rebuild the Rust core and then build the Python bindings.
$ make build-python
Make sure the Python bindings are built, then:
$ cd glean-core/python
$ py.test
The following will run the Python unit tests using py.test
:
$ make test-python
You can send extra parameters to the py.test
command by setting the PYTEST_ARGS
variable:
$ make test-python PYTEST_ARGS="-s --pdb"
The Glean Python bindings use the following tools:
$ cd glean-core/python
$ flake8 glean tests
$ black glean tests
$ mypy glean
To just check the lints:
$ make pythonlint
To reformat the Python files in-place:
$ make pythonfmt
The Python API docs are built using pdoc3.
$ python -m pdoc --html glean --force -o build/docs/python
$ make python-docs
Building on Linux using the above instructions will create Linux binaries that dynamically link against the version of libc
installed on your machine.
This generally will not be portable to other Linux distributions, and PyPI will not even allow it to be uploaded.
In order to create wheels that can be installed on the broadest range of Linux distributions, the Python Packaging Authority's manylinux project maintains a Docker image for building compatible Linux wheels.
The CircleCI configuration handles making these wheels from tagged releases.
If you need to reproduce this locally, see the CircleCI job pypi-linux-release
for an example of how this Docker image is used in practice.