Import time

[Dreamsorcerer]

Problem

This improves import time for some dimos.core modules, which are needed for #1543. Separating the import improvements for easier review.

Solution

To avoid having too many repetitive inline imports harming readability, JpegEncoderMixin is moved to a separate module to avoid the heavy import of Image when importing the other classes in that module,

[bri-tong]

Code Review

Summary

Clean refactoring that defers heavy imports (scipy, langchain_core, Image/cv2/rerun via JPEG codecs) to improve module load time. The approach is sound — splitting JpegEncoderMixin/JpegLCM into jpeg_lcm.py and converting top-level imports to deferred inline imports is a well-targeted strategy. However, there is one regression that will cause a runtime crash.

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🔴 Blocking Issue

NameError at runtime in dimos/core/transport.py

The from dimos.utils import colors import was removed (line 26), but colors.green() and colors.blue() are still used in PubSubTransport.__str__():

def __str__(self) -> str:
    return (
        colors.green(f"{self.__class__.__name__}(")  # ❌ NameError
        + colors.blue(self.topic)
        + colors.green(")")
    )

Any call to str() on a transport instance (e.g. during logging in Blueprint._connect_streams) will crash.

Fix: Either restore the import, or defer it into __str__() if it has undesirable transitive deps:

def __str__(self) -> str:
    from dimos.utils import colors
    return (
        colors.green(f"{self.__class__.__name__}(")
        + colors.blue(self.topic)
        + colors.green(")")
    )

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Non-blocking Suggestions

1. Quaternion.py — duplicate deferred import: from scipy.spatial.transform import Rotation appears identically in both from_rotation_matrix() and to_euler(). Python caches module imports so there's no performance penalty, but a shared private helper like _scipy_rotation() would keep the deferral in one place and reduce visual noise. Minor readability preference.

2. Backwards-compat re-export: JpegEncoderMixin was removed from encoders.py and JpegLCM from lcmpubsub.py. I verified all consumers on dev import via dimos.core.transport.JpegLcmTransport, so nothing is broken today. But if external users or downstream forks import from the old module paths, they'll get ImportError. Consider adding a deprecation re-export in lcmpubsub.py if backwards compat matters for these internal symbols.

3. New module jpeg_lcm.py: Well-structured — good docstring explaining why it exists, correct MRO composition. No issues.

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Questions / Clarifications

None — the intent is clear from the PR description and code.