# napari plugin engine

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---

**DEPRECATED**:

This project is deprecated. Please use [npe2](https://github.com/napari/npe2) instead.

`napari-plugin-engine` is the first generation napari plugin engine. We
recommend:
- new plugins use the second generation [npe2](https://github.com/napari/npe2)
- existing plugins migrate to npe2 using the [Migration Guide](https://napari.org/stable/plugins/advanced_topics/npe2_migration_guide.html) in our docs.

---

`napari-plugin-engine` is a fork of [pluggy](https://github.com/pytest-dev/pluggy),
modified by the [napari](https://github.com/napari/napari) team.

There are some API and feature changes, including:

- discovery via [naming
  convention](https://packaging.python.org/guides/creating-and-discovering-plugins/#using-naming-convention)
  as well as
  [entry_points](https://packaging.python.org/guides/creating-and-discovering-plugins/#using-package-metadata)
- support for reordering of hook calls after registration.
- enhanced API for retrieving plugin package metadata.
- modified plugin call and registration exception handling
- modified `HookResult` object and hook call loop, with ability to retrieve the
  `HookImplementation` responsible for the result.
- lazy plugin discovery
- some changes to variable and attribute naming
- removed all deprecated code
- type annotations on everything
- pytest fixtures for testing
- a couple napari-specific convenience imports

For usage overview and a reference for the `napari-plugin-engine` API, see our
[Documentation](https://napari-plugin-engine.readthedocs.io/en/latest/)

(see also: the [pluggy documentation](https://pluggy.readthedocs.io/en/latest/))

## install

```shell
pip install napari-plugin-engine
```

## Usage

see [documentation](https://napari-plugin-engine.readthedocs.io/en/latest/usage.html)
