97 lines
3.2 KiB
ReStructuredText
97 lines
3.2 KiB
ReStructuredText
==============================
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Extending StoryBoard: Overview
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==============================
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StoryBoard provides many extension points that allow you to customize its
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functionality to your own needs. All of these are implemented using
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`stevedore <https://docs.openstack.org/stevedore/latest/>`_, so that installing them is
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simple, straightforward, and independent of the storyboard core libraries.
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StoryBoard itself makes use of these extension points,
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providing several 'in-branch' plugins that you may use as a template for your
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own work.
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Getting Started
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---------------
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Registering your extensions
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```````````````````````````
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Stevedore uses setup entry point hooks to determine which plugins are
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available. To begin, you should register your implementation classes in your
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setup.cfg file. For example::
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[entry_points]
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storyboard.plugin.user_preferences =
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my-plugin-config = my.namespace.plugin:UserPreferences
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storyboard.plugin.worker =
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my-plugin-worker = my.namespace.plugin:EventWorker
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storyboard.plugin.cron =
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my-plugin-cron = my.namespace.plugin:CronWorker
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Configuring and enabling your extensions
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````````````````````````````````````````
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Every plugin type builds on `storyboard.plugin.base:PluginBase`,
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which supports your plugin's configuration. Upon creation,
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storyboard's global configuration is injected into the plugin as the `config`
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property. With this object, it is left to the developer to implement the
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`enabled()` method, which informs storyboard that it has all it needs to
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operate.
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An example basic plugin::
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class BasicPlugin(PluginBase):
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def enabled(self):
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return self.config.my_config_property
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Each extension hook may also add its own requirements, which will be detailed
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below.
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Available Extension Points
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--------------------------
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User Preferences
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````````````````
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The simplest, and perhaps most important, extension point,
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allows you to inject default preferences into storyboard. These will be made
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available via the API for consumption by the webclient,
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however you will need to consume those preferences yourself::
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[entry_points]
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storyboard.plugin.user_preferences =
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my-plugin-config = my.namespace.plugin:UserPreferences
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To learn how to write a user preference plugin, please contribute to this
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documentation.
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Cron Workers
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````````````
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Frequently you will need to perform time-based, repeated actions within
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storyboard, such as maintenance. By creating and installing a cron
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plugin, StoryBoard will manage and maintain your crontab registration for you::
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[entry_points]
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storyboard.plugin.cron =
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my-plugin-cron = my.namespace.plugin:CronWorker
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To learn how to write a cron plugin see :doc:`plugin_cron`.
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Event Workers
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`````````````
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If you would like your plugin to react to a specific API event in storyboard,
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you can write a plugin to do so. This plugin will receive notification
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whenever a POST, PUT, or DELETE action occurs on the API,
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and your plugin can decide how to process each event in an asynchronous
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thread which will not impact the stability of the API::
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[entry_points]
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storyboard.plugin.worker =
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my-plugin-worker = my.namespace.plugin:EventWorker
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To learn how to write an event worker plugin, `read more here
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<./plugin_worker.html>`_.
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