fix(realsense): lazy-load pyrealsense2 to avoid import errors in simulation

[spomichter]

Problem

pyrealsense2 is a system-level dependency requiring Intel RealSense SDK libraries. Importing it eagerly at module level in camera.py caused ModuleNotFoundError when loading any blueprint from manipulation_blueprints.py — including simulation blueprints that don't use RealSense cameras.

dimos run keyboard-teleop-xarm7
ModuleNotFoundError: No module named 'pyrealsense2'

Import chain: manipulation_blueprints.py → realsense/__init__.py → camera.py → pyrealsense2 💥

Fix

• realsense/__init__.py: Use __getattr__ for lazy package exports — importing the package no longer triggers camera.py loading
• realsense/camera.py: Defer import pyrealsense2 to runtime methods (start, _build_camera_info, _intrinsics_to_camera_info, _get_extrinsics) via local imports
• Use TYPE_CHECKING guard + from __future__ import annotations so type hints still resolve for static analysis

Python's module import cache makes repeated local imports effectively free after the first call.

Testing

Verified from dimos.manipulation.manipulation_blueprints import xarm6_planner_only and from dimos.hardware.sensors.camera.realsense import realsense_camera both succeed without pyrealsense2 installed.

[greptile-apps]

Greptile Summary

Implements lazy-loading for pyrealsense2 to fix ModuleNotFoundError when importing simulation blueprints that don't use RealSense hardware.

Key Changes:

• __init__.py uses __getattr__ pattern to defer loading of camera.py until module attributes are actually accessed
• camera.py moves pyrealsense2 imports from module level into runtime methods (start, _build_camera_info, _intrinsics_to_camera_info, _get_extrinsics)
• Type annotations preserved using TYPE_CHECKING guard and from __future__ import annotations
• Python's import cache ensures repeated local imports are efficient after first call

Impact:

• Simulation blueprints in manipulation_blueprints.py can now be imported without pyrealsense2 installed
• RealSense hardware functionality remains unchanged when the library is available
• No runtime performance impact due to Python's module caching

Confidence Score: 5/5

• Safe to merge with no risk - implements standard Python lazy-loading pattern correctly
• Clean implementation of well-established lazy-loading pattern using __getattr__ and local imports. Type annotations properly handled with TYPE_CHECKING and from __future__ import annotations. No logical errors introduced, only import timing changed. Testing confirms both simulation and hardware imports work as expected.
• No files require special attention

Important Files Changed

Filename	Overview
dimos/hardware/sensors/camera/realsense/init.py	Implements lazy module exports using __getattr__ to defer loading of camera.py until attributes are accessed
dimos/hardware/sensors/camera/realsense/camera.py	Moves pyrealsense2 imports from module level to runtime methods, uses TYPE_CHECKING guard for type hints

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[manipulation_blueprints.py] -->|imports| B[realsense/__init__.py]
    
    subgraph "Before: Eager Import"
        B -->|imports camera.py| C[camera.py]
        C -->|imports pyrealsense2| D[pyrealsense2 💥]
        D -->|ModuleNotFoundError| E[Import Fails]
    end
    
    subgraph "After: Lazy Import"
        B2[realsense/__init__.py] -->|__getattr__ defined| F[No immediate import]
        F -->|Success| G[Import succeeds]
        G -->|Later: attribute accessed| H[camera.py loads]
        H -->|Runtime method called| I[pyrealsense2 imported]
    end
    
    style D fill:#ff6b6b
    style E fill:#ff6b6b
    style G fill:#51cf66
    style I fill:#51cf66

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