47 lines
1.6 KiB
Python
47 lines
1.6 KiB
Python
"""
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Adds support for first class plugins that can be added to the edX platform.
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"""
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from collections import OrderedDict
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from stevedore.extension import ExtensionManager
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from openedx.core.lib.cache_utils import memoized
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class PluginError(Exception):
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"""
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Base Exception for when an error was found regarding plugins.
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"""
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pass
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class PluginManager(object):
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"""
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Base class that manages plugins for the edX platform.
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"""
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@classmethod
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@memoized
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def get_available_plugins(cls, namespace=None):
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"""
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Returns a dict of all the plugins that have been made available through the platform.
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"""
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# Note: we're creating the extension manager lazily to ensure that the Python path
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# has been correctly set up. Trying to create this statically will fail, unfortunately.
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plugins = OrderedDict()
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extension_manager = ExtensionManager(namespace=namespace or cls.NAMESPACE) # pylint: disable=no-member
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for plugin_name in extension_manager.names():
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plugins[plugin_name] = extension_manager[plugin_name].plugin
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return plugins
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@classmethod
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def get_plugin(cls, name, namespace=None):
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"""
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Returns the plugin with the given name.
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"""
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plugins = cls.get_available_plugins(namespace)
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if name not in plugins:
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raise PluginError("No such plugin {name} for entry point {namespace}".format(
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name=name,
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namespace=namespace or cls.NAMESPACE, # pylint: disable=no-member
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))
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return plugins[name]
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