Enable method config registration from env variable (#1869)

docs/developer_guides/new_methods.md

@@ -70,6 +70,12 @@ finally run the following to register the method,
 pip install -e .
 ```
 
+When developing a new method you don't always want to install your code as a package.
+Instead, you may use the `NERFSTUDIO_METHOD_CONFIGS` environment variable to temporarily register your custom method.
+```
+export NERFSTUDIO_METHOD_CONFIGS="my-method=my_method.my_config:MyMethod"
+```
+
 ## Running custom method
 
 After registering your method you should be able to run the method with,

nerfstudio/plugins/registry.py

@@ -16,6 +16,8 @@
 Module that keeps all registered plugins and allows for plugin discovery.
 """
 
+import importlib
+import os
 import sys
 import typing as t
 
@@ -34,6 +36,7 @@ CONSOLE = Console(width=120)
 def discover_methods() -> t.Tuple[t.Dict[str, TrainerConfig], t.Dict[str, str]]:
     """
     Discovers all methods registered using the `nerfstudio.method_configs` entrypoint.
+    And also methods in the NERFSTUDIO_METHOD_CONFIGS environment variable.
     """
     methods = {}
     descriptions = {}
@@ -48,4 +51,22 @@ def discover_methods() -> t.Tuple[t.Dict[str, TrainerConfig], t.Dict[str, str]]:
         specification = t.cast(MethodSpecification, specification)
         methods[specification.config.method_name] = specification.config
         descriptions[specification.config.method_name] = specification.description
+
+    if "NERFSTUDIO_METHOD_CONFIGS" in os.environ:
+        try:
+            strings = os.environ["NERFSTUDIO_METHOD_CONFIGS"].split(",")
+            for definition in strings:
+                if not definition:
+                    continue
+                name, path = definition.split("=")
+                CONSOLE.print(f"[bold green]Info: Loading method {name} from environment variable")
+                module, config_name = path.split(":")
+                method_config = getattr(importlib.import_module(module), config_name)
+                assert isinstance(method_config, MethodSpecification)
+                methods[name] = method_config.config
+                descriptions[name] = method_config.description
+        except Exception:  # pylint: disable=broad-except
+            CONSOLE.print_exception()
+            CONSOLE.print("[bold red]Error: Could not load methods from environment variable NERFSTUDIO_METHOD_CONFIGS")
+
     return methods, descriptions

tests/plugins/test_registry.py

@@ -1,6 +1,7 @@
 """
 Tests for the nerfstudio.plugins.registry module.
 """
+import os
 import sys
 
 from nerfstudio.engine.trainer import TrainerConfig
@@ -49,3 +50,23 @@ def test_discover_methods():
     finally:
         # Revert mock
         registry.entry_points = entry_points_backup
+
+
+def test_discover_methods_from_environment_variable():
+    """Tests if a custom method from env variable gets properly registered using the discover_methods method"""
+    old_env = None
+    try:
+        old_env = os.environ.get("NERFSTUDIO_METHOD_CONFIGS", None)
+        os.environ["NERFSTUDIO_METHOD_CONFIGS"] = "test-method-env=test_registry:TestConfig"
+
+        # Discover plugins
+        methods, _ = registry.discover_methods()
+        assert "test-method-env" in methods
+        config = methods["test-method-env"]
+        assert isinstance(config, TrainerConfig)
+    finally:
+        # Revert mock
+        if old_env is not None:
+            os.environ["NERFSTUDIO_METHOD_CONFIGS"] = old_env
+        else:
+            del os.environ["NERFSTUDIO_METHOD_CONFIGS"]