In order to get contributing, you're going to need to setup a development environment - a place where you can work on code where it can behave the same as everyone else's environment.

Many parts of BeeWare use the same tools: a specific version of Python, and virtual environment controls.

Python

Python is a scripting language, which is available on a number of different operating systems. However, depending on what system you are using, your version of Python is going to be different. Because of this reason, we specify exactly what version of Python we expect the code to work with.

For the following instructions, we're going to assume that you know exactly which version of Python you need to install. Normally this is listed in the README.md file or in the tutorial information. Our CI systems have to be told exactly what version of Python is required, too. So if you're really stuck, try looking at the .travis.yml or circle.yml file for the specific version you need.

pyenv

pyenv is a way to get multiple versions of Python working on your machine at the same time. It allows you to pick and choose whichever version you need for a particular project.

Once pyenv is installed, you need to install the specific Python version. This information is stored in a .python-version file, which means you can have different versions of Python used in different projects on your computer.

To install and set Python version:

$ cd /path/to/your/project
$ pyenv install 3.5.1
$ pyenv local 3.5.1

More information about pyenv is available on their website

virtualenv

Once Python is installed, you're going to want to be able to install different Python packages. Since you may have more than one project being worked on, and more than one version of Python, having a way to make sure that only specific Python packages are available at any one time is handy.

One way we can do this is via virtualenv.

Using pip, we can install virtualenv

$ pip install virtualenv

Then, we want to setup a virtualenv that we can then activate. Having more than one virtualenv is ok, but only one can be activated at a time. Make sure you have your Python selection done with pyenv, so that we know what version of Python to use

$ virtualenv -p $(pyenv which python) env

Then, we can activate the virtual environment.

$ source env/bin/activate

This will result in a little note in your command line letting you know you're in a virtual environment

(env) $

To disable your virtualenv:

$ deactivate