Platform Plugins¶

YARF allows platforms to be added as plugins. In this guide, we will walk through how to write a platform plugin and how to make it available in YARF.

Writing a Platform Plugin¶

In YARF, all platforms are delivered as a package and must implement the PlatformBase class in an __init__.py, this extends to the platform plugins. For example:

yarf-platform-A
├── pyproject.toml
└── src
    └── yarf_plugin_platform_A
        ├── tests
        └── __init__.py

Code Snippet: An example of a simplest platform plugin module named Platform A

An example of pyproject.toml is:

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

[project]
name = "yarf-platform-A"
version = "0.0.1"
description = "Platform A plugin library for YARF."
authors = [
    { name = "...", email = "..." }
]
readme = "README.md"
requires-python = ">=3.10,<3.13"
dependencies = [
    "yarf @ git+ssh://[email protected]/canonical/[email protected]",
    "...",
]

[tool.hatch.build]
packages = ["src/yarf_plugin_platform_A"]

...

In the __init__.py:

from yarf.rf_libraries.libraries import PlatformBase


class PlatformA(PlatformBase):
    def __init__(self) -> None:
        pass

    @staticmethod
    def get_pkg_path() -> str:
        return str(Path(__file__).parent)

Code Snippet: __init__.py for Platform A

By implementing the PlatformBase class, Platform A will be auto-registered to YARF’s supported platforms when imported.

Note

All YARF platform plugins’ package directory name has to be prefixed by yarf_plugin_.

We can also make use of the base classes in yarf/rf_libraries/libraries to implement classes like VideoInput and Hid if we found these useful for Platform A. If we choose to do so, we will have a module structured like:

yarf-platform-A
├── pyproject.toml
└── src
    └── yarf_plugin_platform_A
        ├── tests
        ├── __init__.py
        ├── Hid.py
        └── VideoInput.py

Code Snippet: An example of plugin Platform A with Hid and VideoInput

Take example of Hid.py, we can have something like:

from yarf.rf_libraries.libraries.hid_base import HidBase
from yarf_plugin_platform_A import PlatformA


@library
class Hid(HidBase):
    """
    Provides robot interface for HID interactions with a running Platform A
    server.
    """

    def __init__(self) -> None:
        super().__init__()
        self.platform = PlatformA()
        self.curr_x = 0
        self.curr_y = 0

    ...

Code Snippet: An example of Hid implementation in Platform A

Managing Plugin Platforms in YARF¶

There are two ways to manage platform plugins in YARF:

pip: We can install and delete the plugin to YARF using pip, for example:

pip install /path/to/your/plugin/directory/platform_A

pip uninstall yarf_plugin_platform_A

Snap: The YARF snap provides a platform-plugins interface to receive a plugin. In the plugin snap, we can just add a plug so that the snap can share the plugin’s location to YARF. For example:
```
plugs:
    write-yarf-platform-plugins:
    interface: content
    target: $SNAP_COMMON/platform-to-plug
```
Code Snippet: An example plug write-yarf-platform-plugins that shares a plugin

Then we can connect the snap with the plugin with YARF:
```
sudo snap connect snap-with-plugin:write-yarf-platform-plugins yarf:platform-plugins
```