build(core): demote numba/scipy/imageio to optional extras

motrix_env_core/pyproject.toml

@@ -10,19 +10,37 @@ authors = [{ name = "Motphys", email = "developers@motphys.com" }]
 requires-python = "==3.10.*"
 readme = "README.md"
 license = "Apache-2.0"
+# Heavy runtime deps (numba/scipy for manager kernel compilation, imageio for
+# video recording) are optional extras so deployment-side installs
+# (motrix-deploy and its backend plugins) only pull the lightweight config,
+# registry and input layers of this package. gymnasium stays in the base
+# dependencies because ``motrix_env_core.base`` (on the bare package import
+# path) types observation/action spaces with it, and it is a small
+# pure-Python distribution. array-api-compat is only used by the frontend
+# helper module and is likewise small.
 dependencies = [
     "array-api-compat==1.15.0",
     "gymnasium==1.1.1",
-    "imageio>=2.30",
-    "imageio-ffmpeg>=0.5",
-    "numba==0.61.2",
     "numpy>=1.26",
-    "scipy==1.15.3", # numba requires scipy at compile time for np.linalg in kernels
     "omegaconf>=2.3,<2.4",
     "typing-extensions>=4.1",
 ]
 
 [project.optional-dependencies]
+# Manager kernel compilation and numba-accelerated mdp terms.
+numba = [
+    "numba==0.61.2",
+    "scipy==1.15.3", # numba requires scipy at compile time for np.linalg in kernels
+]
+# Headless video recording via VideoRecorder.
+video = [
+    "imageio>=2.30",
+    "imageio-ffmpeg>=0.5",
+]
+# Everything the training-side workspace needs from this package.
+all = [
+    "motrix-env-core[numba,video]",
+]
 # TBB threading layer for numba parallel kernels: on many-core machines the
 # default OpenMP layer pays a per-region thread-wakeup storm that dominates
 # short kernels. The wheel drops libtbb.so.12 into <venv>/lib, so the runtime

motrix_env_core/src/motrix_env_core/renderer.py

@@ -11,7 +11,6 @@
 from pathlib import Path
 from typing import Protocol
 
-import imageio.v2 as imageio
 import numpy as np
 
 from motrix_env_core.base import EnvCfg
@@ -104,6 +103,17 @@ def close(self) -> None:
 
     def _write_frame(self, frame: np.ndarray) -> None:
         if self._writer is None:
+            # imageio is an optional dependency (``motrix-env-core[video]``):
+            # importing it lazily keeps this module importable in installs
+            # that only run headless training without video recording.
+            try:
+                import imageio.v2 as imageio
+            except ImportError as e:
+                raise ImportError(
+                    "VideoRecorder requires the optional video dependencies; "
+                    "install them with `pip install motrix-env-core[video]`"
+                ) from e
+
             self._path.parent.mkdir(parents=True, exist_ok=True)
             # macro_block_size=None keeps the configured frame size untouched;
             # the yuv420p pixel format still requires even dimensions, which

motrix_env_core/tests/test_rendering.py

@@ -13,7 +13,6 @@
 import numpy as np
 import pytest
 
-from motrix_env_core import renderer as core_renderer
 from motrix_env_core.renderer import VideoRecorder, create_renderer
 from motrix_env_core.sim.backend import RenderConfig, SimRenderer
 
@@ -58,7 +57,12 @@ def test_video_recorder_paces_frames_and_closes_frame_source(tmp_path, monkeypat
     frames.capture.return_value = np.zeros((4, 4, 3), dtype=np.uint8)
     writer = MagicMock()
     get_writer = MagicMock(return_value=writer)
-    monkeypatch.setattr(core_renderer, "imageio", MagicMock(get_writer=get_writer))
+    # renderer imports imageio lazily inside _write_frame, so patch the real
+    # module attribute the function resolves on import. imageio is optional
+    # (motrix-env-core[video]); skip cleanly on minimal core installs.
+    imageio = pytest.importorskip("imageio.v2", reason="video recording requires motrix-env-core[video]")
+
+    monkeypatch.setattr(imageio, "get_writer", get_writer)
 
     recorder = VideoRecorder(
         frames,

motrix_envs/pyproject.toml

@@ -12,7 +12,7 @@ readme = "README.md"
 license = "Apache-2.0"
 dependencies = [
     "gymnasium==1.1.1",
-    "motrix-env-core",
+    "motrix-env-core[numba,video]",
     "motrix-env-motrixsim",
     "numpy>=1.26",
     "omegaconf>=2.3,<2.4",

motrix_rl/pyproject.toml

@@ -13,7 +13,7 @@ license = "Apache-2.0"
 dependencies = [
     "gymnasium==1.1.1",
     "python-abc>=0.2.0",
-    "motrix-env-core",
+    "motrix-env-core[numba,video]",
     "motrix-env-motrixsim",
     "rich>=13",
     "hydra-core>=1.3,<1.4",