feat(platform): discover out-of-tree backends via entry points

lightx2v_platform/README.md

@@ -18,3 +18,40 @@ Currently supported backends include:
 For the corresponding Docker environments, see: https://github.com/ModelTC/LightX2V/tree/main/dockerfiles/platforms
 
 For the corresponding usage scripts, see: https://github.com/ModelTC/LightX2V/tree/main/scripts/platforms
+
+## Out-of-tree platform plugins
+
+Besides in-tree backends, a chip backend can be shipped as a separate
+pip-installable package and discovered at runtime via entry points — no edits to
+this repository required.
+
+A plugin package declares an entry point in the `lightx2v.platform_plugins`
+group:
+
+```toml
+# plugin package's pyproject.toml
+[project.entry-points."lightx2v.platform_plugins"]
+my_backend = "my_backend_pkg:register"
+```
+
+The referenced callable registers a `Device` class into
+`PLATFORM_DEVICE_REGISTER` and its operators into the `PLATFORM_*` op registries:
+
+```python
+# my_backend_pkg/__init__.py
+def register():
+    from . import device   # @PLATFORM_DEVICE_REGISTER("my_backend")
+    from .ops import register_ops
+    register_ops()
+```
+
+`set_ai_device()` scans this group before initialising the device and before the
+op registries are imported, so plugin registrations reach the framework. Then:
+
+```bash
+pip install my-backend-package
+PLATFORM=my_backend python lightx2v/infer.py ...
+```
+
+When no plugins are installed this scan is a no-op, and a plugin that fails to
+load is logged and skipped rather than aborting device setup.

lightx2v_platform/set_ai_device.py

@@ -1,10 +1,49 @@
 import os
 
+from loguru import logger
+
 from lightx2v_platform import *
 
 
+def _load_platform_plugins():
+    """Discover out-of-tree platform backends via entry points.
+
+    Third-party packages register under the ``lightx2v.platform_plugins`` entry
+    point group. Each entry point is a zero-arg callable that registers its
+    Device class into ``PLATFORM_DEVICE_REGISTER`` and its ops into the
+    ``PLATFORM_*`` op registries.
+
+    This runs before ``init_ai_device`` (so a plugin-provided device is visible
+    to the lookup) and before ``lightx2v_platform.ops`` is imported, i.e. before
+    ``lightx2v.utils.registry_factory`` snapshots the platform registries via
+    ``merge()``. That ordering is what makes plugin registrations reach the
+    framework-facing registries.
+
+    No effect when no plugins are installed; a failing plugin is logged and
+    skipped rather than aborting device setup.
+    """
+    try:
+        from importlib.metadata import entry_points
+    except Exception:  # pragma: no cover - importlib.metadata is stdlib on 3.8+
+        return
+
+    try:
+        eps = entry_points(group="lightx2v.platform_plugins")
+    except TypeError:
+        # importlib.metadata < 3.10 returns a dict-like mapping.
+        eps = entry_points().get("lightx2v.platform_plugins", [])
+
+    for ep in eps:
+        try:
+            ep.load()()
+            logger.info(f"Loaded LightX2V platform plugin: {ep.name}")
+        except Exception as e:
+            logger.warning(f"Failed to load platform plugin '{ep.name}': {e}")
+
+
 def set_ai_device():
     platform = os.getenv("PLATFORM", "cuda")
+    _load_platform_plugins()
     init_ai_device(platform)
     check_ai_device(platform)