djc.recipe 0.3

Options

The options of this recipe are not fixed, as many of those are used exclusively within the settings template file (see Templating).

Here we present the options that have an impact on the recipe aswell:

project

This identifies a python module (in dotted notation) that can serve as project package. The bare minimum for a project package is to contain a urls.py file and a templates directory. It is mandatory unless both the urlconf and templates option are defined.

urlconf

Identifies the module that contains the url definition: if omitted the file urls.py inside the module given as project is used.

templates

Identifies the templates directory. If omitted, the directory named templates located in the module given as project is used.

media-directory

Identifies the folder into which static content (images, CSS and Javascripts) will go. Relatives path are considered relative to the buildout directory. The directory will be created if not present, and nothing will be done if it already exists. If omitted, defaults to static.

settings-template

If specified, the given template is used to generate the settings.py file, if not provided, the default template will be used. See Templating for more details.

settings-template-extension

If specified, the given template is appended to the template specified by settings template or to the default one.

media-origin

If specified, defines directories from which to copy the static files that have to go in media-directory: see Media origin for more details.

base-settings

A settings module (only absolute imports) that is extended by the current settings. If specified, the defaults for apps, middleware and template-loaders becomes an empty string (resulting into them not being written at all).

wsgi

Defaults to false. If set to true (or on or 1) creates a script in parts/$partname named $partname.wsgi.py that can be used as WSGI script in Apache or other WSGI enabled webserver.

Templating

The settings.py file is generated by interpolating the options of the buildout section with a template, be it the default one or the one provided by the settings-template option.

The template must be a valid Tempita template, to which the whole options of the current buildout section is passed as namespace, integrated as follow:

1. In the options name, all minuses (-) are converted to underscores (_)

2. The option name and secret are added, respectively mapping to the buildout section name and to a randomly-generated secret [1].

3. A serie of functions is added to the namespace to simplify the handling of some situations, see below for more details.

Example usage

As first thing, we need to have a Django project egg around. We have made a very simple one just for testing and we have created a source distribution for it located in packages.

This is of course not the only way you can distribute and obtain the project egg: for example, during developement, it is recommended to use mr.developer for that.

That cleared, we create the most simple buildout conceivable using this recipe

>>> write('buildout.cfg',
... """
... [buildout]
... parts = django
... offline = false
... index = http://pypi.python.org/simple/
... find-links = packages
...
... [django]
... recipe = djc.recipe
... project = dummydjangoprj
... """)

And run it

>>> print "start\n", system(buildout)
start
...
Installing django.
django: Specified project 'dummydjangoprj' not found, attempting install
Getting distribution for 'dummydjangoprj'.
...
django: Generating settings in ...
django: Making empty media directory ...
django: Creating script at ...
Generated script ...
<BLANKLINE>

This generated some files and directories for us:

1. A Django manage.py wrapper located at bin/django

2. A media directory (empty) at static (default option)

3. A settings file located in parts/django/settings.py

So, as we can see, we have a static directory in the root, a bin/django script and a parts/django part

>>> ls(sample_buildout)
-  .installed.cfg
-  .secret.cfg
d  bin
-  buildout.cfg
d  develop-eggs
d  eggs
d  packages
d  parts
d  src
d  static
>>> ls('bin')
-  buildout
-  django
>>> ls('parts')
d  django

Let’s look at this first

>>> ls('parts', 'django')
-  settings.py
>>> cat('parts', 'django', 'settings.py')
ADMINS = (
<BLANKLINE>
    ('John Smith', 'root@localhost'),
)
MANAGERS = ADMINS
<BLANKLINE>
<BLANKLINE>
DATABASE_ENGINE = 'sqlite3'
DATABASE_NAME = 'storage.db'
DATABASE_USER = ''
DATABASE_PASSWORD = ''
DATABASE_HOST = ''
DATABASE_PORT = ''
<BLANKLINE>
TIME_ZONE = 'America/Chicago'
<BLANKLINE>
LANGUAGE_CODE = 'en-us'
<BLANKLINE>
MEDIA_ROOT = '.../static'
<BLANKLINE>
MEDIA_URL = '/media/'
<BLANKLINE>
ADMIN_MEDIA_PREFIX = '/admin_media/'
<BLANKLINE>
SECRET_KEY = '...'
MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.middleware.doc.XViewMiddleware',
)
<BLANKLINE>
ROOT_URLCONF = 'dummydjangoprj.urls'
INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.admin',
)
<BLANKLINE>
TEMPLATE_LOADERS = (
    'django.template.loaders.filesystem.load_template_source',
    'django.template.loaders.app_directories.load_template_source',
)
<BLANKLINE>
TEMPLATE_DIRS = (
    '.../dummydjangoprj/templates',
)
<BLANKLINE>
EMAIL_HOST = 'localhost'
EMAIL_PORT = 25
EMAIL_USE_TLS = False
<BLANKLINE>
CACHE_BACKEND = 'locmem:///'
CACHE_TIMEOUT = 60*5
CACHE_PREFIX = 'Z'

As you can see, this is pretty much the standard Django settings.py as created by Django’s django-admin. It has the peculiarity of not residing in a module, however, but is loaded at run time into the appropriate manage script as a ghost module named _django_settings.

Let’s have a look at the manage script

>>> cat('bin', 'django')
#!...
<BLANKLINE>
import sys
sys.path[0:0] = [
  ...
  ]
<BLANKLINE>
import djc.recipe.manage
<BLANKLINE>
if __name__ == '__main__':
    djc.recipe.manage.main('.../parts/django/settings.py')

As we can see, the main() function of the manage module is called, passing in the file with the settings as only argument.

>>> write('template-extension.py.in',
... """
... # Here we can extend the template, using variables pulled in from the
... # buildout section, with the dashes converted to underscores
... MY_CONFIG_VARIABLE = '{{config_variable_one}}'
... """)
>>> write('buildout.cfg',
... """
... [buildout]
... parts = django
... offline = false
... index = http://pypi.python.org/simple/
... find-links = packages
...
... [django]
... recipe = djc.recipe
... project = dummydjangoprj
... settings-template-extension = template-extension.py.in
... config-variable-one = test
... """)

>>> print system(buildout)
Uninstalling django.
Installing django.
...
Generated script ...
<BLANKLINE>
>>> cat('parts', 'django', 'settings.py')
ADMINS = (
<BLANKLINE>
    ('John Smith', 'root@localhost'),
)
MANAGERS = ADMINS
<BLANKLINE>
<BLANKLINE>
DATABASE_ENGINE = 'sqlite3'
DATABASE_NAME = 'storage.db'
DATABASE_USER = ''
DATABASE_PASSWORD = ''
DATABASE_HOST = ''
DATABASE_PORT = ''
<BLANKLINE>
TIME_ZONE = 'America/Chicago'
<BLANKLINE>
LANGUAGE_CODE = 'en-us'
<BLANKLINE>
MEDIA_ROOT = '.../static'
<BLANKLINE>
MEDIA_URL = '/media/'
<BLANKLINE>
ADMIN_MEDIA_PREFIX = '/admin_media/'
<BLANKLINE>
SECRET_KEY = '...'
MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.middleware.doc.XViewMiddleware',
)
<BLANKLINE>
ROOT_URLCONF = 'dummydjangoprj.urls'
INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.admin',
)
<BLANKLINE>
TEMPLATE_LOADERS = (
    'django.template.loaders.filesystem.load_template_source',
    'django.template.loaders.app_directories.load_template_source',
)
<BLANKLINE>
TEMPLATE_DIRS = (
    '.../dummydjangoprj/templates',
)
<BLANKLINE>
EMAIL_HOST = 'localhost'
EMAIL_PORT = 25
EMAIL_USE_TLS = False
<BLANKLINE>
CACHE_BACKEND = 'locmem:///'
CACHE_TIMEOUT = 60*5
CACHE_PREFIX = 'Z'
<BLANKLINE>
<BLANKLINE>
# Extension template %s
<BLANKLINE>
<BLANKLINE>
# Here we can extend the template, using variables pulled in from the
# buildout section, with the dashes converted to underscores
MY_CONFIG_VARIABLE = 'test'

>>> write('template.py.in',
... """
... # Total override
... FOODS = (
...     {{join(listify(foods), "',\\n    '", "'", "',")}}
... )
... """)
>>> write('buildout.cfg',
... """
... [buildout]
... parts = django
... offline = false
... index = http://pypi.python.org/simple/
... find-links = packages
...
... [django]
... recipe = djc.recipe
... project = dummydjangoprj
... settings-template = template.py.in
... foods =
...     spam
...     spam
...     eggs
...     spam
... """)

>>> print system(buildout)
Uninstalling django.
Installing django.
...
Generated script ...
<BLANKLINE>
>>> cat('parts', 'django', 'settings.py')
# Total override
FOODS = (
    'spam',
    'spam',
    'eggs',
    'spam',
)

Media origin

Static files are generally not served through Django, but instead the front-end web server takes care to serve them by exposing a directory on the filesystem to the web.

However, many static files (think .js or .css) are part of the functionality of a project or application, and would be interesting to be able to distribute them alongside the code.

The relevant resources can be included in the distributed package and use of the media-origin option will allow them to be copied into the media-directory folder (see Options).

media-origin can contain a list of static file sources, and each item of the list can be either in the form package:directory or package:directory:destination; package being the full dotted name of the importable module, directory the path to the directory inside the module containing static data, and destination an optional subdirectory inside media-directory where to copy the files.

Let’s then begin from the first, simple case, with a single source of static data.

The source of static data is the package dummydjangoapp1, residing as a developement package inside src.

>>> ls('src', 'dummydjangoapp1', 'dummydjangoapp1', 'static')
-  lib1.js
-  main.css
>>> cat('src', 'dummydjangoapp1', 'dummydjangoapp1', 'static', 'main.css')
body { font-family: "Helvetica" "Arial" sans-serif; }

Let’s create a buildout config and run it

>>> write('buildout.cfg',
... """
... [buildout]
... parts = django
... offline = false
... index = http://pypi.python.org/simple/
... find-links = packages
... develop = src/dummydjangoapp1
... eggs = dummydjangoapp1
...
... [django]
... recipe = djc.recipe
... project = dummydjangoprj
... media-directory = static
... media-origin = dummydjangoapp1:static
... """)
>>> rmdir('static')
>>> print system(buildout)
Develop: '.../dummydjangoapp1'
...
Uninstalling django.
Installing django.
...
django: Making media directory '.../static'
...
Generated script ...
<BLANKLINE>

And now let’s see what’s in static

>>> ls('static')
-  lib1.js
-  main.css
>>> cat('static', 'main.css')
body { font-family: "Helvetica" "Arial" sans-serif; }

Let’s now try using two sources: the second is another dummy app, named dummydjangoapp2, that like the first one resides in src.

Let’s see what’s in its static for us:

>>> ls('src', 'dummydjangoapp2', 'dummydjangoapp2', 'static')
-  lib2.js
-  main.css

It seems this app too defines a main.css, so let’s look at the content:

>>> cat('src', 'dummydjangoapp2', 'dummydjangoapp2', 'static', 'main.css')
h1 { color: #92B8D8; }

But this poses a problem! What happens when I put this as second source, and both define main.css? Well, the intuitive thing to do here is probably to override the file, so that the source at the bottom is the top skin layer.

So if we have this buildout

>>> write('buildout.cfg',
... """
... [buildout]
... parts = django
... offline = false
... index = http://pypi.python.org/simple/
... find-links = packages
... develop =
...     src/dummydjangoapp1
...     src/dummydjangoapp2
... eggs =
...     dummydjangoapp1
...     dummydjangoapp2
...
... [django]
... recipe = djc.recipe
... project = dummydjangoprj
... media-directory = static
... media-origin =
...     dummydjangoapp1:static
...     dummydjangoapp2:static
... """)

It is reasonable to expect that, after running it, the content of the main.css file is the one provided by the version held by dummydjangoapp2 rather than the one held by dummydjangoapp2.

A quick run and inspect confirms this:

>>> rmdir('static')
>>> print system(buildout)
Develop: '.../dummydjangoapp1'
...
Uninstalling django.
Installing django.
...
django: Making media directory '.../static'
...
Generated script ...
<BLANKLINE>
>>> ls('static')
-  lib1.js
-  lib2.js
-  main.css
>>> cat('static', 'main.css')
h1 { color: #92B8D8; }

However, I might not want the main.css override to happen, or any other clash between applications, for that matter. That is easily solved by a buildout written like this

>>> write('buildout.cfg',
... """
... [buildout]
... parts = django
... offline = false
... index = http://pypi.python.org/simple/
... find-links = packages
... develop =
...     src/dummydjangoapp1
...     src/dummydjangoapp2
... eggs =
...     dummydjangoapp1
...     dummydjangoapp2
...
... [django]
... recipe = djc.recipe
... project = dummydjangoprj
... media-directory = static
... media-origin =
...     dummydjangoapp1:static:app1
...     dummydjangoapp2:static:app2
... """)

It is to be noticed that the media-origin values have now three elements, the latter being the destination directory, which is defined as a subdirectory of static: in this case, both apps live in their subdirectory and no clash happens

>>> rmdir('static')
>>> print system(buildout)
Develop: '.../dummydjangoapp1'
...
Uninstalling django.
Installing django.
...
django: Making media directory '.../static'
...
Generated script ...
<BLANKLINE>
>>> ls('static')
d  app1
d  app2
>>> ls('static', 'app1')
-  lib1.js
-  main.css
>>> cat('static', 'app1', 'main.css')
body { font-family: "Helvetica" "Arial" sans-serif; }
>>> ls('static', 'app2')
-  lib2.js
-  main.css
>>> cat('static', 'app2', 'main.css')
h1 { color: #92B8D8; }

Of course, this behaviour is not usefol only in this case: an application might actually require you to put the static files in a precise subdirectory irrespective of the fact that other apps might be present or a clash occur.

0.3 (2010-05-19)

• Added multiple media-origin support [Simone Deponti]

• Added fixture-dirs support [Simone Deponti]

0.2 (2010-05-17)

• First public release [Simone Deponti]

0.1 (2010-04-22)

• Created package [Simone Deponti]