Pinry/docs/src/plugin-system.md

# New plugin system for Pinry

New plugin system is under development and a naive version has been released.

A `PinryPlugin` is a python class or object which is callable.
The plugin loader will call the plugin argument only once and use the plugin
instance after specified events triggered just like the way django-middleware works.

You could create a plugin as python-package with content:

```
from core.models import Image
from django_images.models import Thumbnail


class Plugin:
    
    def __init__(self):
        # do something you want, just be called only
        pass

    def process_image_pre_creation(self, django_settings, image_instance: Image):
        pass

    def process_thumbnail_pre_creation(self, django_settings, thumbnail_instance: Thumbnail):
        pass

```


You could make some changes on Image object and Thumbnail object 
before they actually be saved (for example, add water-mark to them).

You could access example plugin via `pinry_plugins/batteries/plugin_example.py`.

After all, enable the plugin in local_settings.py:

```
ENABLED_PLUGINS = [
    'pinry_plugins.batteries.plugin_example.Plugin',
]
```

Now the plugin will work like a charm!

# List of Available Plugins

left blank to fill, coming soon...


# Install Plugin in Docker
If you have a plugin named `hello.py` and it have a `Plugin` class inside.

You could just copy it to directory `pinry_plugins/batteries`.

Now add config to local_settings.py

```
ENABLED_PLUGINS = [
    'pinry_plugins.batteries.hello.Plugin',
]
```

Then, rebuild your docker image, the plugin will work 
if no further python dependencies required.