Skip to main content

interface utilities

Project description

# benterfaces - Interface utilities and plugin system
[![Coveralls github](]()
[![GitHub issues](](
[![GitHub license](](

`benterfaces` contains miscellaneous interface utilities and a plugin system.

# Interface utilities
A simple decorator for verifying interface implementations when a class is created.
For example, the following code would raise a BrokenImplementationError if FooBar would not implement IFoo or IBar correctly.

from zope.interfaces import implementer
from benterfaces import verify_implementation

from imyproject import IFoo, IBar

@implementer(IFoo, IBar)
class FooBar(object):


This is useful if your interfaces may change during the developement process.
Also, its a single line (+import), so its not much work to add.

# Plugin system
The plugin system provides an easy way to make your scripts extendandable.
Here is a list of some features of the plugin system:
- plugin priority support (you can use this feature to allow plugins to overwrite each other)
- plugin requirement support (enable/disable plugins depending on conditions and installed modules)
- load plugins from multiple paths
- load plugins from python source files of any file extension
- load plugins from `.pyc`-files

**PluginDiscoverer(paths, extensions=[".py"])**

This class handles the plugin discovery and loading.
- `paths`: list of strings specifying directories to search for plugins.
- `extensions`: list of file extensions in which plugins will be searched for.

Important methods and attributes:
- `load_plugins(max_depth=9999)`: load plugins from self.paths. Descend at most `max_depth` directories.
- `loaded`: number of loaded plugins
- `enabled`: number of enabled plugins
- `clear_plugin_list()`: clears the internal plugin cache.
- `reload_plugins()`: clears the internal plugin cache and the load the plugins again.
- `get_implementation(self, iface, exclude=[])`: returns the plugin implementing `iface` with the highest priority which is not in `exclude`. This raises a `NotImplementedError` if no plugin if found.
- `get_plugin(...)`: same as `get_implementation()`.
- `get_all_plugins(self, iface, exclude=[], sorted_by_priority=True)`: returns a list of all plugins implementing iface excluding `exclude`.
- `is_implemented(iface, exclude=[])`: returns True if iface is implemented by any plugin excluding `exclude`, otherwise False.

**@requires(condition=True, modules=[])**

This decorator function marks the requirements of a plugin.
- `condition`: a boolean which must be `True` in order for the plugin to be enabled.
- `modules`: a list of module names which are required for the plugin to be enabled.
Plugins without a `@requires(...)` decorator are always enabled.


This decorator function sets the priority of a plugin.
Higher values for `n` mean a higher priority.
Plugins without a `@priority(...)` decorator are considered to have a priority of `0`.

# Using plugins
**Creating a plugin**
Creating a plugin is simple:
1. create a file containing a `zope.interface.Interface`-definition which can be imported from your project and the plugin directory.
2. create one or more plugin directories
3. create a `.py` file inside the plugin directory containing an implementation of the plugin (remember to implement the Interface)
4. Done.

**loading plugins**
To load your plugins, just do the following:
1. import `benterfaces.PluginDiscoverer()`
2. create an instance of `benterfaces.PluginDiscoverer(paths)`, passing the plugin directories as `paths`.
3. call the `.load_plugins()` method of the instance.
4. Depending on your use case, use `get_plugin(iface)` or `get_all_plugins(iface)` to access the plugins.

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
benterfaces-0.1.1-py2-none-any.whl (9.3 kB) Copy SHA256 hash SHA256 Wheel 2.7 Jun 13, 2018
benterfaces-0.1.1.tar.gz (5.9 kB) Copy SHA256 hash SHA256 Source None Jun 13, 2018

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page