Introducing Invenio for Developers

This page summarizes adoption of frameworks used in Invenio. It describes the anatomy of extensions and modules and the concept of pluggable components across modules.

Invenio development adopts the following principles:

  • Convention over Configuration means that common building blocks are provided for you, so use them! If you are not sure or documentation of certain feature is missing, contact the developers at the mailing list or IRC.

  • Don’t Repeat Yourself (DRY) to help us keep our software maintainable. Duplication of code fragments makes application codebase larger and more importantly it can become a source of many errors during future development (refactoring).

  • Agile Development where each iteration should lead to working code in relatively short time while incremental steps are small and easy to understand by other developers. When you start with development take advantage of built-in tools provided by Python and underlying libraries:

    # Install package in editable mode
$ pip install -e git+http://invenio-software.org/repo/invenio.git
# Follow the instructions in src/invenio/INSTALL file.
# Edit a file
$ `$EDITOR` src/invenio/invenio/<module>/<file>.py
# See that your server has been reloaded automatically.

    When you are done with editing do not forget to run our tests to make sure that all other modules are working fine (python setup.py test).

Extensions

There are many Flask extensions which extend the functionality of your application in various ways. For instance they can add support for databases, user authentication & authorization, menu & breadcrumbs and other common tasks.

Many Flask extensions can be found in the Flask Extension Registry. All extensions are automatically loaded from the EXTENSIONS configuration option list. If they should a function setup_app(app) or function accepting app needs to be specified (e.g. foo.bar:init, mymodule:setup).

Continue with Extensions.

Modules

Modules are application components that can be used within an application or across applications. They can contain SQLAlchemy models, Flask views, Jinja2 templates and other ref:pluggable-objects.

Discovery of modules is done based on a configuration parameter called PACKAGES, where the expansion character * is supported at the end of package path after the last dot (e.g. foo.bar.something.*).

Continue with Modules.