Like the Pulp Core itself, all Pulp Plugins are Django Applications, and could be created like any
other Django app with
django-admin startapp <your_plugin>. However, instead of writing all of
the boilerplate yourself, it is recommmended that you start your plugin by utilizing the Plugin
Template. This guide will assume that you have used
the plugin_template, but if you are interested in the details of what it provides you, please see
Plugin Django Application for more information for how plugins are “discovered” and connected to
pulpcore Django app. Additional information is given as inline comments in the template.
Plugin API Usage¶
Plugin Applications interact with pulpcore with two high level interfaces, subclassing and adding tasks. Additionally, plugins that need to implement dynamic web APIs can optionally provide their own Django views. See our Live APIs page for more information.
Pulp Core and each plugin utilize Django and the Django Rest
Framework. Each plugin provides
Models, Serializers, and Viewsets. For
each object that a plugin writer needs to make, the
pulpcore.plugin API provides base classes.
These base classes handle most of the boilerplate code, resulting in CRUD for each object out of
Any action that can run for a long time should be an asynchronous task. Plugin writers do not need to understand the internals of the pulpcore tasking system, workers automatically execute tasks from RQ, including tasks deployed by plugins.
The tasking system adds a concept called reservations which ensures that actions that act on the same resources are not run at the same time. To ensure data correctness, any action that alters the content of a repository (thus creating a new version) must be run asynchronously, locking on the repository and any other models which cannot change during the action. For example, sync tasks must be asynchronous and lock on the repository and the remote. Publish should lock on the repository version being published as well as the publisher.
Tasks are deployed from Views or Viewsets, please see Kick off Tasks.
Users can configure a
ContentGuard to protect a
Distribution on their own, but some plugins
want to offer built-in content protection features. For example pulp_container may only want a user
to download container images they have rights to based on some permissions system pulp_container could
For more information see the ContentGuard Usage by Plugin Writers documentation.
Plugins can define settings by creating a
<your plugin>.app.settings module containing settings
as you would define in the Django Settings File itself.
pulpcore ships the actual settings.py
file so settings cannot be added directly as with most Django deployments. Instead as each plugin is
loaded, pulpcore looks for the
<your plugin>.app.settings module and uses
overlay the settings on top of
pulpcore’s settings and user provided settings.
Settings are parsed in the following order with later settings overwriting earlier ones:
pulpcore.app.settings(the pulpcore provided settings defaults).
Plugin settings from
In some cases a setting should not overwrite an existing setting, but instead add to it. For
example, consider adding a custom log handler or logger to the LOGGING
settings. You don’t want to fully overwrite it, but instead add or overwrite only a sub-portion.
dynaconf provides the dynaconf_merge feature which is for merging settings instead of overwriting them. For
example, pulp_ansible makes use of this here.