o ۷i @stdZddlZddlZddlmZddlmZddlmZee Z de de efdd Z ed ede efd d ZdS) a& Diffusion attention backend selector. This module provides the interface for selecting diffusion attention backends. The actual backend selection logic is delegated to the platform layer (vllm_omni.platforms), similar to how vLLM handles attention backend selection. Usage: from vllm_omni.diffusion.attention.selector import get_attn_backend # Get the appropriate backend for current platform backend_cls = get_attn_backend(head_size=64) # Or override via environment variable # export DIFFUSION_ATTENTION_BACKEND=FLASH_ATTN N)cache) init_logger)AttentionBackendcls_pathreturnc Cs|dd\}}z t|}t||}|WSty+}z td|d|d}~wty@}z td|d|d}~ww)zLoad a backend class from its fully qualified path. Args: cls_path: Fully qualified class path (e.g., "vllm_omni.diffusion.attention.backends.sdpa.SDPABackend") Returns: The loaded backend class .zFailed to import module z: NzClass z not found in module: )rsplit importlib import_modulegetattr ImportErrorAttributeError)r module_path class_namemodule backend_classer\/home/ubuntu/vllm_env/lib/python3.10/site-packages/vllm_omni/diffusion/attention/selector.py_load_backend_cls!s   r head_sizecCs.ddlm}tjd}|j||d}t|S)a Get attention backend for diffusion models. The backend selection is delegated to the current platform (vllm_omni.platforms.current_omni_platform), which selects the appropriate backend based on: 1. User override via DIFFUSION_ATTENTION_BACKEND environment variable 2. Platform-specific defaults and capabilities This is similar to how vLLM's get_attn_backend_cls works, where the platform layer decides which backend to use based on hardware capabilities. Args: head_size: Head size for attention computation (may affect backend selection) Returns: The selected attention backend class r)current_omni_platformDIFFUSION_ATTENTION_BACKEND)selected_backendr)vllm_omni.platformsrosenvirongetget_diffusion_attn_backend_clsr)rrrbackend_cls_pathrrrget_attn_backend6s  r!)__doc__r r functoolsr vllm.loggerr/vllm_omni.diffusion.attention.backends.abstractr__name__loggerstrtyperintr!rrrrs