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129 lines
4.6 KiB
ReStructuredText
.. _pip-virtualenv:
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Further Configuration of Pip and Virtualenv
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===========================================
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Requiring an active virtual environment for ``pip``
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---------------------------------------------------
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By now it should be clear that using virtual envirtonments is a great way to keep
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your development environment clean and keeping different projects' requirements
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separate.
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When you start working on many different projects, it can be hard to remember to
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activate the related virtual environment when you come back to a specific project.
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As a result of this, it is very easy to install packages globally while thinking
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that you are actually installing the package for the virtual environment of the
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project. Over time this can result in a messy global package list.
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In order to make sure that you install packages to your active virtual environment
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when you use ``pip install``, consider adding the following two lines to your
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:file:`~/.bashrc` file:
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.. code-block:: console
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export PIP_REQUIRE_VIRTUALENV=true
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After saving this change and sourcing the :file:`~/.bashrc` file with ``source ~/.bashrc``,
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pip will no longer let you install packages if you are not in a virtual environment.
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If you try to use ``pip install`` outside of a virtual environment pip will gently
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remind you that an activated virtual environment is needed to install packages.
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.. code-block:: console
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$ pip install requests
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Could not find an activated virtualenv (required).
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You can also do this configuration by editing your :file:`pip.conf` or :file:`pip.ini`
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file. :file:`pip.conf` is used by Unix and Mac OS X operating systems and it can be
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found at:
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.. code-block:: console
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$HOME/.pip/pip.conf
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Similarly, the :file:`pip.ini` file is used by Windows operating systems and it can
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be found at:
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.. code-block:: console
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%HOME%\pip\pip.ini
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If you don't have a :file:`pip.conf` or :file:`pip.ini` file at these locations, you can
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create a new file with the correct name for your operating system.
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If you already have a configuration file, just add the following line under the
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``[global]`` settings to require an active virtual environment:
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.. code-block:: console
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require-virtualenv = true
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If you did not have a configuration file, you will need to create a new one and
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add the following lines to this new file:
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.. code-block:: console
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[global]
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require-virtualenv = true
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You will of course need to install some packages globally (usually ones that you
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use across different projects consistenly) and this can be accomplished by adding
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the following to your :file:`~/.bashrc` file:
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.. code-block:: console
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gpip() {
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PIP_REQUIRE_VIRTUALENV="" pip "$@"
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}
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After saving the changes and sourcing your :file:`~/.bashrc` file you can now install
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packages globally by running ``gpip install``. You can change the name of the
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function to anything you like, just keep in mind that you will have to use that
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name when trying to install packages globally with pip.
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Caching packages for future use
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-------------------------------
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Every developer has preferred libraries and when you are working on a lot of
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different projects, you are bound to have some overlap between the libraries that
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you use. For example, you may be using the ``requests`` library in a lot of different
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projects.
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It is surely unnecessary to re-download the same packages/libraries each time you
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start working on a new project (and in a new virtual environmen as a result).
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Fortunately, you can configure pip in such a way that it tries to reuse already
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installed packages.
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On UNIX systems, you can add the following line to your :file:`.bashrc` or :file:`.bash_profile`
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file.
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.. code-block:: console
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export PIP_DOWNLOAD_CACHE=$HOME/.pip/cache
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You can set the path to anywhere you like (as long as you have write
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access). After adding this line, ``source`` your :file:`.bashrc` (or :file:`.bash_profile`)
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file and you will be all set.
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Another way of doing the same configuration is via the :file:`pip.conf` or :file:`pip.ini`
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files, depending on your system. If you are on Windows, you can add the following
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line to your :file:`pip.ini` file under ``[global]`` settings:
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.. code-block:: console
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download-cache = %HOME%\pip\cache
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Similarly, on UNIX systems you should simply add the following line to your
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:file:`pip.conf` file under ``[global]`` settings:
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.. code-block:: console
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download-cache = $HOME/.pip/cache
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Even though you can use any path you like to store your cache, it is recommended
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that you create a new folder *in* the folder where your :file:`pip.conf` or :file:`pip.ini`
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file lives. If you don't trust yourself with all of this path voodoo, just use
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the values provided here and you will be fine.
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