pluginlib 0.9.2

Description:

pluginlib 0.9.2

Overview
Pluginlib makes creating plugins for your project simple.

Features

Plugins are validated when they are imported
Plugins can be loaded through different mechanisms (modules, filesystem paths, entry points)
Multiple versions of the same plugin are supported (The newest one is used by default)
Plugins can be blacklisted by type, name, or version
Multiple plugin groups are supported so one program can use multiple sets of plugins that won’t conflict
Plugins support conditional loading (examples: os, version, installed software, etc)
Once loaded, plugins can be accessed through dictionary or dot notation




Installation
PIP
$ pip install pluginlib

Fedora and EL (RHEL/CentOS/Rocky/Alma)
(EPEL repositories must be configured for EL8)
$ dnf install python3-pluginlib


EL7 (RHEL/CentOS)
(EPEL repositories must be configured)
$ yum install python2-pluginlib
$ yum install python36-pluginlib



Usage

Step 1: Define plugin parent classes
All plugins are subclasses of parent classes. To create a parent class, use the
@Parent decorator.
The @Parent decorator can take a plugin type for accessing child plugins
of the parent. If a plugin type isn’t given, the class name will be used.
The @Parent decorator can also take a group keyword which
restricts plugins to a specific plugin group. group should be specified if plugins for
different projects could be accessed in an single program, such as with libraries and frameworks.
For more information, see the Plugin Groups section.
Methods required in child plugins should be labeled as abstract methods.
Plugins without these methods or with parameters
that don’t match, will not be loaded.
For more information, see the Abstract Methods section.
"""
sample.py
"""
import pluginlib

@pluginlib.Parent('parser')
class Parser(object):

@pluginlib.abstractmethod
def parse(self, string):
pass


Step 2: Define plugin classes
To create a plugin, subclass a parent class and include any required methods.
Plugins can be customized through optional class attributes:


_alias_
Changes the name of the plugin which defaults to the class name.

_version_
Sets the version of the plugin. Defaults to the module __version__ or None
If multiple plugins with the same type and name are loaded, the plugin with
the highest version is used. For more information, see the Versions section.

_skipload_
Specifies the plugin should not be loaded. This is useful when a plugin is a parent class
for additional plugins or when a plugin should only be loaded under certain conditions.
For more information see the Conditional Loading section.



"""
sample_plugins.py
"""
import json
import sample

class JSON(sample.Parser):

_alias_ = 'json'

def parse(self, string):
return json.loads(string)


Step 3: Load plugins
Plugins are loaded when the module they are in is imported. PluginLoader
will load modules from specified locations and provides access to them.

PluginLoader can load plugins from several locations.

A program’s standard library
Entry points
A list of modules
A list of filesystem paths



Plugins can also be filtered through blacklists and type filters.
See the Blacklists and Type Filters sections for more information.
Plugins are accessible through the PluginLoader.plugins property,
a nested dictionary accessible through dot notation. For other ways to access plugins,
see the Accessing Plugins section.
import pluginlib
import sample

loader = pluginlib.PluginLoader(modules=['sample_plugins'])
plugins = loader.plugins
parser = plugins.parser.json()
print(parser.parse('{"json": "test"}'))