feat(devices): add lazy loading for 3rd party robots cameras and teleoperators (#2123)

* feat(devices): add lazy loading for 3rd party robots cameras and teleoperators

Co-authored-by: Darko Lukić <lukicdarkoo@gmail.com>

* feat(devices): load device class based on assumptions in naming

* docs(devices): instructions for using 3rd party devices

* docs: address review feedback

* chore(docs): add example for 3rd party devices

---------

Co-authored-by: Darko Lukić <lukicdarkoo@gmail.com>

src/lerobot/utils/import_utils.py

@@ -15,6 +15,10 @@
 # limitations under the License.
 import importlib
 import logging
+import pkgutil
+from typing import Any
+
+from draccus.choice_types import ChoiceRegistry
 
 
 def is_package_available(pkg_name: str, return_version: bool = False) -> tuple[bool, str] | bool:
@@ -58,3 +62,93 @@ def is_package_available(pkg_name: str, return_version: bool = False) -> tuple[b
 
 
 _transformers_available = is_package_available("transformers")
+
+
+def make_device_from_device_class(config: ChoiceRegistry) -> Any:
+    """
+    Dynamically instantiates an object from its `ChoiceRegistry` configuration.
+
+    This factory uses the module path and class name from the `config` object's
+    type to locate and instantiate the corresponding device class (not the config).
+    It derives the device class name by removing a trailing 'Config' from the config
+    class name and tries a few candidate modules where the device implementation is
+    commonly located.
+    """
+    if not isinstance(config, ChoiceRegistry):
+        raise ValueError(f"Config should be an instance of `ChoiceRegistry`, got {type(config)}")
+
+    config_cls = config.__class__
+    module_path = config_cls.__module__  # typical: lerobot_teleop_mydevice.config_mydevice
+    config_name = config_cls.__name__  # typical: MyDeviceConfig
+
+    # Derive device class name (strip "Config")
+    if not config_name.endswith("Config"):
+        raise ValueError(f"Config class name '{config_name}' does not end with 'Config'")
+
+    device_class_name = config_name[:-6]  # typical: MyDeviceConfig -> MyDevice
+
+    # Build candidate modules to search for the device class
+    parts = module_path.split(".")
+    parent_module = ".".join(parts[:-1]) if len(parts) > 1 else module_path
+    candidates = [
+        parent_module,  # typical: lerobot_teleop_mydevice
+        parent_module + "." + device_class_name.lower(),  # typical: lerobot_teleop_mydevice.mydevice
+    ]
+
+    # handle modules named like "config_xxx" -> try replacing that piece with "xxx"
+    last = parts[-1] if parts else ""
+    if last.startswith("config_"):
+        candidates.append(".".join(parts[:-1] + [last.replace("config_", "")]))
+
+    # de-duplicate while preserving order
+    seen: set[str] = set()
+    candidates = [c for c in candidates if not (c in seen or seen.add(c))]
+
+    tried: list[str] = []
+    for candidate in candidates:
+        tried.append(candidate)
+        try:
+            module = importlib.import_module(candidate)
+        except ImportError:
+            continue
+
+        if hasattr(module, device_class_name):
+            cls = getattr(module, device_class_name)
+            if callable(cls):
+                try:
+                    return cls(config)
+                except TypeError as e:
+                    raise TypeError(
+                        f"Failed to instantiate '{device_class_name}' from module '{candidate}': {e}"
+                    ) from e
+
+    raise ImportError(
+        f"Could not locate device class '{device_class_name}' for config '{config_name}'. "
+        f"Tried modules: {tried}. Ensure your device class name is the config class name without "
+        f"'Config' and that it's importable from one of those modules."
+    )
+
+
+def register_third_party_devices() -> None:
+    """
+    Discover and import third-party lerobot_* plugins so they can register themselves.
+
+    Scans top-level modules on sys.path for packages starting with
+    'lerobot_robot_', 'lerobot_camera_' or 'lerobot_teleoperator_' and imports them.
+    """
+    prefixes = ("lerobot_robot_", "lerobot_camera_", "lerobot_teleoperator_")
+    imported: list[str] = []
+    failed: list[str] = []
+
+    for module_info in pkgutil.iter_modules():
+        name = module_info.name
+        if name.startswith(prefixes):
+            try:
+                importlib.import_module(name)
+                imported.append(name)
+                logging.info("Imported third-party plugin: %s", name)
+            except Exception:
+                logging.exception("Could not import third-party plugin: %s", name)
+                failed.append(name)
+
+    logging.debug("Third-party plugin import summary: imported=%s failed=%s", imported, failed)