feat: add loader/helper for widget plugins

bec_widgets/utils/bec_plugin_helper.py

@@ -0,0 +1,89 @@
+from __future__ import annotations
+
+import importlib.metadata
+import inspect
+import pkgutil
+from importlib import util as importlib_util
+from importlib.machinery import FileFinder, ModuleSpec, SourceFileLoader
+from types import ModuleType
+from typing import Generator
+
+from bec_widgets.utils.bec_widget import BECWidget
+
+
+def _submodule_specs(module: ModuleType) -> tuple[ModuleSpec | None, ...]:
+    """Return specs for all submodules of the given module."""
+    return tuple(
+        module_info.module_finder.find_spec(module_info.name)
+        for module_info in pkgutil.iter_modules(module.__path__)
+        if isinstance(module_info.module_finder, FileFinder)
+    )
+
+
+def _loaded_submodules_from_specs(
+    submodule_specs: tuple[ModuleSpec | None, ...]
+) -> Generator[ModuleType, None, None]:
+    """Load all submodules from the given specs."""
+    for submodule in (
+        importlib_util.module_from_spec(spec) for spec in submodule_specs if spec is not None
+    ):
+        assert isinstance(
+            submodule.__loader__, SourceFileLoader
+        ), "Module found from FileFinder should have SourceFileLoader!"
+        submodule.__loader__.exec_module(submodule)
+        yield submodule
+
+
+def _submodule_by_name(module: ModuleType, name: str):
+    for submod in _loaded_submodules_from_specs(_submodule_specs(module)):
+        if submod.__name__ == name:
+            return submod
+    return None
+
+
+def _get_widgets_from_module(module: ModuleType) -> dict[str, "type[BECWidget]"]:
+    """Find any BECWidget subclasses in the given module and return them with their names."""
+    from bec_widgets.utils.bec_widget import BECWidget  # avoid circular import
+
+    return dict(
+        inspect.getmembers(
+            module,
+            predicate=lambda item: inspect.isclass(item)
+            and issubclass(item, BECWidget)
+            and item is not BECWidget,
+        )
+    )
+
+
+def _all_widgets_from_all_submods(module):
+    """Recursively load submodules, find any BECWidgets, and return them all as a flat dict."""
+    widgets = _get_widgets_from_module(module)
+    if not hasattr(module, "__path__"):
+        return widgets
+    for submod in _loaded_submodules_from_specs(_submodule_specs(module)):
+        widgets.update(_all_widgets_from_all_submods(submod))
+    return widgets
+
+
+def user_widget_plugin() -> ModuleType | None:
+    plugins = importlib.metadata.entry_points(group="bec.widgets.user_widgets")  # type: ignore
+    return None if len(plugins) == 0 else tuple(plugins)[0].load()
+
+
+def get_plugin_client_module() -> ModuleType | None:
+    """If there is a plugin repository installed, return the client module."""
+    return _submodule_by_name(plugin, "client") if (plugin := user_widget_plugin()) else None
+
+
+def get_all_plugin_widgets() -> dict[str, "type[BECWidget]"]:
+    """If there is a plugin repository installed, load all widgets from it."""
+    if plugin := user_widget_plugin():
+        return _all_widgets_from_all_submods(plugin)
+    else:
+        return {}
+
+
+if __name__ == "__main__":  # pragma: no cover
+    #  print(get_all_plugin_widgets())
+    client = get_plugin_client_module()
+    ...