Pip requirements.txt tip

Everybody loves requirements.txt files, right? You can list your dependencies, and then together with pip and virtualenv reproduce your application's environment complete with all dependencies in several machines.

This file is also known as pipscript.txt. in case you don't know, requirements.txt is a file containing a list of packages in this format:

    Django==1.4.4
    Fabric>=1.0
    OtherPackage==6.0
    -e git://some.git/repo/containing/package

It's very simple to use. You just have to use the command pip install -r <requirements file>. For this reason, it makes it very easy to automate a deployment step.

Splitting your requirements

In case your application needs to split requirement files for some reason, you can do that! Just add this line in a pip file:

    -r some/requirements.txt

To include another requirements file.

The requirements listed in the included file will get installed too.

I found out about this trick in this heroku doc page . It makes a lot of sense, seeing that requirements.txt represents a pip install command for each line. We get -e, why not -r?

This is very useful for Django, where you need a different package set in production and development.