Add load_plugins to pulp-glue

This allows to auto-detect and load all installed pulp-glue plugins. It
is primarily useful for workflows where knowing all sub-types of an
Entity is only important at runtime.

CHANGES/pulp-glue/+load_plugins.feature

@@ -0,0 +1 @@
+Added `load_plugins` to `pulp_glue.common` so plugins providing a "pulp_glue.plugins" entrypoint can be enumerated and loaded.

pulp-glue/docs/dev/reference/common.md

@@ -0,0 +1,3 @@
+# pulp_glue.common
+
+::: pulp_glue.common

pulp-glue/pulp_glue/common/__init__.py

@@ -1 +1,32 @@
+import sys
+import typing as t
+
+if sys.version_info >= (3, 10):
+    from importlib.metadata import entry_points
+else:
+    from importlib_metadata import entry_points
+
 __version__ = "0.30.0.dev"
+
+# Keep track to prevent loading plugins twice
+loaded_plugins: t.Set[str] = set()
+
+
+def load_plugins(enabled_plugins: t.Optional[t.List[str]] = None) -> None:
+    """
+    Load glue plugins that provide a `pulp_glue.plugins` entrypoint.
+    This may be needed when you rely on the `TYPE_REGISTRY` attributes but cannot load the modules
+    explicitely.
+
+    Parameters:
+        enabled_plugins: Optional list of plugins to consider for loading.
+    """
+    for entry_point in entry_points(group="pulp_glue.plugins"):
+        name = entry_point.name
+        if (
+            enabled_plugins is None or entry_point.name in enabled_plugins
+        ) and entry_point.name not in loaded_plugins:
+            plugin = entry_point.load()
+            if hasattr(plugin, "mount"):
+                plugin.mount()
+            loaded_plugins.add(name)

pulp-glue/pyproject.toml

@@ -33,6 +33,15 @@ documentation = "https://pulpproject.org/pulp-glue/docs/dev/"
 repository = "https://github.com/pulp/pulp-cli"
 changelog = "https://pulpproject.org/pulp-cli/changes/"
 
+[project.entry-points."pulp_glue.plugins"]
+ansible = "pulp_glue.ansible"
+certguard = "pulp_glue.certguard"
+container = "pulp_glue.container"
+core = "pulp_glue.core"
+file = "pulp_glue.file"
+python = "pulp_glue.python"
+rpm = "pulp_glue.rpm"
+
 [tool.setuptools.packages.find]
 where = ["."]
 include = ["pulp_glue.*"]

pulp-glue/tests/test_entity_context.py

@@ -4,6 +4,7 @@
 
 import pytest
 
+from pulp_glue.common import load_plugins, loaded_plugins
 from pulp_glue.common.context import PulpContext, PulpRepositoryContext
 from pulp_glue.file.context import PulpFileRepositoryContext
 
@@ -18,6 +19,15 @@ def file_repository(pulp_ctx: PulpContext) -> t.Dict[str, t.Any]:
     file_repository_ctx.delete()
 
 
+def test_plugin_loading() -> None:
+    load_plugins()
+    assert "core" in loaded_plugins
+
+
+def test_type_registry() -> None:
+    assert "file:file" in PulpRepositoryContext.TYPE_REGISTRY
+
+
 def test_detail_context(pulp_ctx: PulpContext, file_repository: t.Dict[str, t.Any]) -> None:
     master_ctx = PulpRepositoryContext(pulp_ctx)
     detail_ctx = master_ctx.detail_context(pulp_href=file_repository["pulp_href"])