Yapsy - Yet Another Plugin System

1.12.2 verified Sat May 09 auth: no python

Yapsy is a simple, reusable plugin system for Python applications. It provides a base class for plugins and a plugin manager that discovers and loads plugins from directories. The latest version is 1.12.2, with sporadic releases.

pip install yapsy

Common errors

error yapsy.IPlugin.IPlugin is not instantiated correctly ↓

cause Trying to instantiate IPlugin base class directly or forgetting to inherit.

fix

Ensure your plugin class inherits from yapsy.IPlugin.IPlugin and implements activate()/deactivate().

error AttributeError: 'NoneType' object has no attribute 'getPluginByName' ↓

cause PluginManagerSingleton.get() returned None because plugins were not collected yet.

fix

Call pm.collectPlugins() before trying to get a plugin by name.

Warnings

gotcha Plugin constructor (__init__) is called before plugin info (name, version, etc.) is set. Do not rely on plugin metadata in __init__; use activate() instead. ↓

fix Override activate() instead of __init__ to access plugin manager or metadata.

deprecated The use of PluginManager without arguments is deprecated in favor of PluginManagerSingleton or custom locations. ↓

fix Use PluginManagerSingleton.get() or pass plugin_places explicitly.

Imports

IPlugin
wrong
```
from yapsy import IPlugin
```
correct
```
from yapsy.IPlugin import IPlugin
```
IPlugin is in the yapsy.IPlugin submodule, not top-level.
PluginManagerSingleton
wrong
```
from yapsy import PluginManagerSingleton
```
correct
```
from yapsy.PluginManager import PluginManagerSingleton
```
Common mistake: PluginManagerSingleton is inside PluginManager module.

Quickstart

Defines a plugin class, uses the singleton plugin manager to discover and activate plugins from a 'plugins' directory.

from yapsy.IPlugin import IPlugin
from yapsy.PluginManager import PluginManagerSingleton

class MyPlugin(IPlugin):
    def activate(self):
        print("Plugin activated")
    def deactivate(self):
        print("Plugin deactivated")

if __name__ == "__main__":
    pm = PluginManagerSingleton.get()
    pm.setPluginPlaces(["plugins"])
    pm.collectPlugins()
    pm.activatePluginByName("MyPlugin")
    pm.deactivatePluginByName("MyPlugin")