This module contains plugin interface for plainbox. Plugins are based on pkg_resources entry points feature. Any python package can advertise the existence of entry points associated with a given namespace. Any other package can query a given namespace and enumerate a sequence of entry points.
Each entry point has a name and importable identifier. The identifier can be imported using the load() method. A loaded entry point is exposed as an instance of PlugIn. A high-level collection of plugins (that may eventually also query alternate backends) is offered by PlugInCollection.
Using PlugInCollection.load() one can load all plugins from a particular namespace and work with them using provided utility methods such as PlugInCollection.get_by_name() or PlugInCollection.get_all_names()
The set of loaded plugins can be overridden by mock/patching PlugInCollection._get_entry_points(). This is especially useful for testing in isolation from whatever entry points may exist in the system.
Collection of plug-ins based on filesystem entries
Instantiate with dir_list and ext, call load() and then access any of the loaded plug-ins using the API offered. All loaded plugin information files are wrapped by a plug-in container. By default that is PlugIn but it may be adjusted if required.
The name of each plugin is the base name of the plugin file, the object of each plugin is the text read from the plugin file.
Piece of code loaded at runtime, one of many for a given extension point
A collection of IPlugIn objects.
Context manager for using fake list of plugins
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The provided list of plugins and exceptions overrides any previously loaded plugins and prevent loading any other, real, plugins. After the context manager exits the previous state is restored.
Get an list of plug-in objects
This is a shortcut that gives fastest access to a list of IPlugIn.plugin_object of each loaded plugin.
Collection of plug-ins based on pkg_resources
Instantiate with namespace, call load() and then access any of the loaded plug-ins using the API offered. All loaded objects are wrapped by a plug-in container. By default that is PlugIn but it may be adjusted if required.
Simple plug-in that does not offer any guarantees beyond knowing it’s name and some arbitrary external object.
Base class that shares some of the implementation with the other PlugInCollection implemenetations.
Context manager for using fake list of plugins
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The provided list of plugins overrides any previously loaded plugins and prevent loading any other, real, plugins. After the context manager exits the previous state is restored.
Get a list of all the pairs of plugin name and plugin
Returns: | a list of tuples (plugin.plugin_name, plugin) |
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Get the specified plug-in (by name)
Parameters: | name – name of the plugin to locate |
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Returns: | PlugIn like object associated with the name |
Raises KeyError: | |
if the specified name cannot be found |
Internal method of PlugInCollectionBase.
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This method prepares a wrapper (PlugIn subclass instance) for the specified plugin name/object by attempting to instantiate the wrapper class. If a PlugInError exception is raised then it is added to the problem_list and the corresponding plugin is not added to the collection of plugins.