Plugin system¶

Note

This page explains how to contribute to the plugin system in aiida-core. For instrucions on how to develop plugins, see How to package plugins.

Design Principles¶

Only restrict plugin developers when really necessary;
Avoid database schema changes whenever reasonably possible;
Finding and loading plugins must be as fast as the plugin allows, especially for command line interface (CLI) commands. In other words, directly importing a plugin class should not be noticeably faster than using the plugin loader/factory;
Implement as a drop-in replacement, provide backwards compatibility to pre-0.9 plugin system;
Plugin management should be as user friendly from the verdi shell as from the CLI.

Mini-Spec¶

Nomenclature¶

plugin_name

A unique name identifying the plugin. Suggested naming scheme is

aiida-<plugin-name> for pypi distribution / source code repository
aiida_<plugin_name> for python package (import aiida_<plugin_name>; dashes replaced by underscores)
<plugin_name>.ep_name for entry points

category

A name given to each aspect of AiiDA that can be extended via plugins, such as calculations, schedulers, … (see output of verdi plugin list for a complete list).

Each category maps to an entry point group aiida.<category>.

Interfaces¶

Pluginloader¶

The plugin loading functionality is defined in aiida.plugins.entry_point and relies on the reentry package to find and load entry points. reentry is about 10x faster than the equivalent functionality in pkg_resources from setuptools, leading to significant speedup of tab-autocompletion in the verdi cli. If, for some reason, reentry is not found, the plugin system falls back on pkg_resources.

Registry Tools¶

See the API documentation in aiida.plugins.