projectenv

The easiest way to create virtual environments for your python projects.

Installation

See the INSTALL file.

Configuring a virtualenv for your project

cd path/to/your/project
projectenv init
vi environment.py # configure to your heart's content
projectenv sync # This could take a while

At this point, a virtualenv for your project has been created and all of the packages you specified have been installed. The virtualenv will be active and ready for you to use.

Activating the virtualenv for a project

cd path/to/your/project
projectenv on

Deactivating the virtualenv for a project

projectenv off # works anywhere

The environment.py file

The environment.py file is where you specify the packages you want installed in your virtualenv as well as the environment variables that should be present and their values. When you run projectenv init an empty environment.py file is generated for you with two variables present: the environment_vars dict and the required_libs list.

Once you have created your environment.py file, you must run projectenv sync to setup the virtualenv for your project. The sync commands installs all of the python packages listed in required_libs and generates scripts to setup and restore your shell's environment whenever you run projectenv on or projectenv off. Any time you change your environment.py file, you should run projectenv sync to ensure that your project's virtualenv stays up to date.

environment_vars

The environment_vars dict allows you to specify environment variables that you want available in your project's virtualenv. projectenv is careful to save and restore your current shell environment when you run projectenv on|off, so it is safe to specify anything here. Here is a simple example of an environment_vars specification:

environment_vars = {
    'FOO': 'bar'
    'PYTHONPATH': '$HOME/python/my_unreleased_lib'
}

Notice that you can even use environment variables from your normal shell environment in your virtual environment.

required_libs

The required_libs list allows you to specifiy which packages are installed and in which order they are installed. If a package has dependencies specified in its setup.py file, projectenv will install those dependencies automatically so you don't need to specify those. Also, if you have a package you want to install that is not hosted on a pypi server but is available as a git repository, you can install the package directly from the git repositiory.

Here is an example required_libs specification:

required_libs = [
  'nose',
  'simplejson>=2.1.2,<2.2',
  ('readline', {'install_with': 'easy_install'}),
  ('customlib', {
     'git': 'git://github.com/jbgo/customlib.git',
     'ref': 'experimental'
  })
] + read_requirements()

By default, you just need to specify a package name and the latest version on pypi will be installed. You can also specify specific versions. projectenv uses pip as the default installer, but you can specify a custom install command with the install_with option. Installing from a git repo requires the git option specifying the absolute URL of the repo. You can also specify a particular branch, tag, or commit with the ref option. Also, if you have a requirements.txt file for your project, you can include those automatically by calling the read_requirements() function.

Predefined values

The following variables are available for you to use in your environment.py file:

VIRTUAL_ENV - The path to your project's virtual environment.

PROJECTENV_HOME - ~/.projectenv

SITE_PACKAGES - The path to your project's virtual site-packages directory.

Helper functions

The following helper functions are available for you to use in your environment.py file.

read_requirements(path='requirements.txt') - Returns an array of requirements from your project's requirements.txt file.

*install_src_dir(rel_path) - Appends path components to the source directory for packages installed from a git repository and returns the absolute path. For example, install_src_dir('customlib', 'VERSION') returns /home/you/.projectenv/src/customlib/VERSION.

*site_packages_dir(rel_path) - Appends path components to the site-packages directory for your virtualenv. For example, site_packages_dir('some-package.egg', 'configure.py') returns /home/you/.projectenv/your-project/lib/python2.6/site-packages/some-package.egg/configure.py'.

Installing packages from alternate python servers

If you have packages hosted on a local or internal pypi server, and you have configured your ~/.pypirc file to include those servers, projectenv will automatically detect those servers and install packages from them. For example, if you had the following ~/.pypirc file, projectenv will attempt to install packages from pypi.internal.com:6789:

[distutils]
index-servers =
    pypi
    internal

[internal]
repository:http://pypi.internal.com:6789