Civet

(Picture credit: Leendertz)

Civet precompiles Sass and CoffeeScript files in your Django project when you use the runserver command. It will also watch the file changes for you. Therefore, you can edit your Sass and CoffeeScript files and expect runserver to recompile those files upon save, just like it how restarts the app server when you make changes to your Python source code

Usage

In your settings.py, add Civet to your INSTALLED_APPS right after django.contrib.staticfiles:

INSTALLED_APPS = (
    # ...
    'django.contrib.staticfiles',
    'civet',
    # ...
)

Then add a CIVET_PRECOMPILED_ASSET_DIR setting that tells Civet where to put the precompiled assets. For example:

CIVET_PRECOMPILED_ASSET_DIR = os.path.join(BASE_DIR, 'precompiled_assets')

That's it. Once set up, each time you use manage.py runserver, Civet will first check to see if there are new Sass and CoffeeScript files that need precompiling. It will also start watch for file changes.

Sass and CoffeeScript Versions Supported

Civet is known to work with the following versions of Sass and CoffeeScript:

Sass 3.2.5+ and Compass 0.12.2+
CoffeeScript 1.6.3+

"But We Only Use Sass (or CoffeeScript)"

If your project doesn't use Sass and therefore doesn't contain any Sass files, Civet won't invoke the Sass compiler and therefore it's ok if you don't have Sass installed. The same rule applies to CoffeeScript files.

Customizable Options

By default, Civet looks for coffee and sass in your PATH environment varible. If you want to use specific paths, you can put these in your settings.py:

# The paths here are just examples
CIVET_COFFEE_BIN = '/opt/local/bin/coffee'
CIVET_SASS_BIN = '/opt/local/bin/sass'

For Sass, a lot of people use Bundler to manage their Ruby command-line tools. This can be especially useful if you also use libaries like Compass and want to lock down their versions. Bundler requires you to set up a Gemfile. To use Bundler to run Sass, add this in your settings.py:

CIVET_BUNDLE_GEMFILE = '/some/where/Gemfile'

Please note that CIVET_BUNDLE_GEMFILE and CIVET_SASS_BIN must not be set at the same time. If both are set, Civet will raise an error. Also, by default, Civet looks for the tool bundle in your PATH. If you want to use a specific path, set CIVET_BUNDLE_BIN in your settings.py.

Finally, if you want to use additional CoffeeScript or Sass compiling options, add these to your settings.py. Here are the default values Civet uses:

CIVET_COFFEE_SCRIPT_ARGUMENTS = ('--compile', '--map')
CIVET_SASS_ARGUMENTS = ()

If you want to, for example, use Compass with Sass, use:

CIVET_SASS_ARGUMENTS = ('--compass',)

You can also define patterns (files or directories) for Civet to ignore by setting:

# As an exmaple, this will cause Civet to ignore files with 'coffee' in the
# name or path.
CIVET_IGNORE_PATTERNS = ['coffee']

This gets extended into the ignore_patterns list defined in django.contrib.staticfiles.management.commands.collectstatic.

You can also define staticfile directories you want Civet to ignore by setting:

# This will cause Civet to ignore files located in 'bower_components' or
# 'node_modules' even if those folders are included in STATICFILES_DIRS.
CIVET_IGNORE_DIRS = ['bower_components', 'node_modules']

This is particularly useful when using a package manager such as Bower or NPM. These managers often install packages that include their own build systems, configurations, and files that are incompatible with how Civet compiles assets.

Recompile Everything

To recompile everything, just quit the server, delete the entire CIVET_PRECOMPILED_ASSET_DIR directory, and use the runserver command again.

Sample Project

We have included a sample project in testsite/ to demonstrate how Civet works with Django.

Motivation

We have developed Civet to solve the following problems:

It is too cumbersome to ask all our developers to remember using coffee -w and sass -w every time they use runserver.
We want our CoffeeScript and Sass assets to be precompiled. It makes no sense to compile them on the fly as we serve static assets. Plus, Sass files that have a lot of includes can take a long time to process. At one point we had a Sass file that took 6 seconds to compile. We don't want our developers to wait for 6 seconds every time they reload a page.
Django's static file layout requires Sass and CoffeeScript to watch for separate directories. We simply can't have them watch the top-level directory and call it a day. It is very cumbersome, however, to have Sass compiler watch multiple directories, and the option for multi-directory watch simply doesn't exist in the CoffeeScript compiler.
We have a lot of CoffeeScript files, and on OS X that number exceeds the default maximum number of files that node.js (on which the official CoffeeScript compiler is based on) can watch. (See this issue for details.)

About the Name

Civet is "a slender nocturnal carnivorous mammal" (according to New Oxford American Dictionary) that also produces kopi luwak by ingesting coffee beans. I was looking for a cheeky (sassy) project name that has to do with coffee, and this comes to mind. Disclaimer: I have no idea what kopi luwak tastes like, and no animal is harmed during the development of this plug-in.

tajmorton/civet