van.static 0.4

Tools for managing Pyramid static files on a CDN

Serving static files from a CDN

Rationale

This tool aids in implementing a very specific workflow using static files and pyramid:

• During development static files are stored in subversion and are configured as normal in Pyramid applications.

• Before deployment, the static files are extracted from the eggs by the system administrator and uploaded to a CDN. Files are versioned according to the egg they come from.

• During extraction, CSS and JS files can be optionally minified.

• In production, the system administrator configures the application to use static files from the CDN.

This workflow has these advantages:

• Minimal impact on development. Changes to files are immediately visible, also developers work with un-compressed files.

• CDN served files can have very long cache-control times while still allowing the it to be updated almost immediately on application upgrade.

Testing an extraction

You can try out the extract tool by running the cdn.py file directly. The following commands will extract the static resource from the deform package to the test_extract directory:

$ mkdir test_extract $ python cdn.py –target “file://$(pwd)/test_extract” –resource deform:static

NOTE: the deform package must be on the python path.

If you use a url like this s3://mybucket/path/to/files/ the extracted resources will be placed directly in Amazon S3. You need to manually install boto to be able to use this functionality.

Implementing in your application

One way would be to have code like this:

>>> from van.static import cdn

>>> GLOBAL_LIST_OF_STATIC_RESOURCES = (
...     ('my_app_static_view_name': 'myapp:static'),
...     ('deform_static_view_name': 'deform:static'))

>>> def my_extract_filesystem_command():
...     """Customized extract command for my application"""
...     cdn.extract_cmd([r[1] for r in GLOBAL_LIST_OF_STATIC_RESOURCES], yui_compressor=True)

>>> def make_pyramid_app(static_cdn=None):
...     config = Configurator()
...     cdn.config_static(config, GLOBAL_LIST_OF_STATIC_RESOURCES, static_cdn=static_cdn)
...     return config.make_wsgi_app()

You would make my_extract_filesystem_command a command line script for the system administrator to run on deployment. Likewise static_cdn is set by the system administrator to the url where the files were exported to.

TODO:

• Write tests, this was a spike that turned out to work.

• Try get enough bits of this into Pyramid so the config_static function is unnecessary.

JSLint testing support

NOTE: To use this functionality you must have a jslint command on your PATH.

This allows you to run jslint on all the files in a directory from a unittest. For example:

>>> import unittest

>>> class TestJSLint(unittest.TestCase):
...
...     def test_static(self):
...         from van.static.testing import assert_jslint_dir
...         from pkg_resources import resource_filename, cleanup_resources
...         assert_jslint_dir(resource_filename('vanguardistas.publicview', 'static/js'))
...         cleanup_resources()

YUI3 loader configuration helper

van.static.yui holds utilities to simplify setting up a YUI3 loader configuration from a directory of JS modules.