fix lcm load speed

[leshy]

just made some loading lazy, needs repo wide consideration tho

[greptile-apps]

Greptile Overview

Greptile Summary

This PR optimizes LCM module load time by implementing lazy imports and refactoring module dependencies.

Key Changes

1. Lazy Import Optimization

• Moved rerun import in CameraInfo.py from module-level to inside to_rerun() method
• Moved matplotlib.pyplot and rerun imports in PointCloud2.py to be lazy-loaded within their respective functions
• These changes defer heavy library imports until actually needed, significantly improving module load speed

2. Module Refactoring

• Relocated JpegSharedMemoryEncoderMixin class from lcmpubsub.py to jpeg_shm.py
• This removes turbojpeg, Image, and ImageFormat dependencies from the core LCM module
• The class implementation remains identical - purely a code organization change
• Import chain verified: lcmpubsub.py no longer imports jpeg_shm.py, breaking the dependency

3. Dead Code Removal

• Removed unused logger setup from spec.py

Impact Assessment

✅ No breaking changes: The moved class was not in the __all__ exports and no external code imports it from lcmpubsub
✅ Backward compatible: All public APIs remain unchanged
✅ Performance improvement: Heavy imports (rerun, matplotlib, turbojpeg) now load on-demand
✅ Code organization: Better separation of concerns with JPEG shared memory functionality in its own module

Confidence Score: 5/5

• This PR is safe to merge with no risk
• All changes are refactoring/optimization without logic modifications. The moved class is byte-for-byte identical, imports are correctly lazy-loaded, no breaking changes detected, and the refactoring achieves the stated goal of improving LCM load speed.
• No files require special attention

Important Files Changed

File Analysis

Filename	Score	Overview
dimos/msgs/sensor_msgs/CameraInfo.py	5/5	Moved rerun import to lazy load in to_rerun() method - improves module load time without affecting functionality
dimos/msgs/sensor_msgs/PointCloud2.py	5/5	Moved matplotlib and rerun imports to lazy load - improves module load time, correctly placed in functions that use them
dimos/protocol/pubsub/jpeg_shm.py	5/5	Moved JpegSharedMemoryEncoderMixin class from lcmpubsub.py - implementation identical, all imports present
dimos/protocol/pubsub/lcmpubsub.py	5/5	Removed JpegSharedMemoryEncoderMixin class and heavy imports (turbojpeg, Image) - improves LCM load speed
dimos/protocol/pubsub/spec.py	5/5	Removed unused logger import and setup - clean up of dead code

Sequence Diagram

sequenceDiagram
    participant App as Application Code
    participant LCM as lcmpubsub.py
    participant JPEG as jpeg_shm.py
    participant Camera as CameraInfo.py
    participant PC2 as PointCloud2.py
    
    Note over LCM,JPEG: Before: lcmpubsub imports turbojpeg at module load
    Note over LCM,JPEG: After: jpeg_shm owns turbojpeg, isolated from lcmpubsub
    
    App->>LCM: import LCM
    activate LCM
    Note over LCM: ✅ No longer loads turbojpeg<br/>✅ Faster module load
    LCM-->>App: Ready (fast)
    deactivate LCM
    
    App->>JPEG: import JpegSharedMemory
    activate JPEG
    Note over JPEG: Loads turbojpeg, Image<br/>Only when needed
    JPEG-->>App: Ready
    deactivate JPEG
    
    App->>Camera: import CameraInfo
    activate Camera
    Note over Camera: ✅ Rerun NOT loaded yet
    Camera-->>App: Ready (fast)
    deactivate Camera
    
    App->>Camera: camera.to_rerun()
    activate Camera
    Note over Camera: Lazy load rerun here
    Camera-->>App: Rerun archetype
    deactivate Camera
    
    App->>PC2: import PointCloud2
    activate PC2
    Note over PC2: ✅ Matplotlib & Rerun NOT loaded
    PC2-->>App: Ready (fast)
    deactivate PC2

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[greptile-apps]

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[spomichter]

Curious how much this speeds up loading

[leshy]

Curious how much this speeds up loading

from 6 seconds to 0.1ms :D