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hunjing/backend/app/ai_provider/routing/selector.py
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2026-08-21 16:00:13 +08:00

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Python

from __future__ import annotations
from typing import Any
from app.ai_provider.config.models import ModelConfig
from app.ai_provider.core.registry import ModelRegistry
from app.ai_provider.routing.multimodal import MultiModalDecision
from app.ai_provider.types.errors import AIProviderError
_SELECTOR_CAPABILITY_MAP: dict[MultiModalDecision, str] = {
MultiModalDecision.VISION: "vision",
MultiModalDecision.THINKING: "thinking",
MultiModalDecision.TOOL_USE: "tool_use",
MultiModalDecision.STRUCTURED_OUTPUT: "structured_output",
MultiModalDecision.PLAIN_TEXT: "chat",
}
class ModelSelector:
"""为给定上下文选择最佳模型。
用法::
selector = ModelSelector(registry)
model = selector.select({"capabilities": {"vision", "thinking"}})
model = selector.select({"preferred": "fast-model"})
model = selector.select_from_decisions({MultiModalDecision.VISION})
"""
def __init__(self, registry: ModelRegistry) -> None:
self._registry = registry
def select(self, context: dict[str, Any]) -> ModelConfig:
"""根据给定的上下文选择模型。
上下文键:
* ``capabilities`` (``set[str]``, 可选) — 必需的能力。
* ``preferred`` (``str``, 可选) — 偏好的模型名或别名。
* ``avoid`` (``set[str]``, 可选) — 要排除的模型名。
如果给了偏好模型但不能满足所有必需的能力,此方法会回退到
能满足要求的模型。
"""
capabilities: set[str] = set(context.get("capabilities", set()))
preferred: str | None = context.get("preferred")
avoid: set[str] = set(context.get("avoid", set()))
# If preferred is given, resolve it and check capabilities
if preferred is not None:
model = self._registry.resolve(preferred)
if (
not capabilities or self._model_satisfies_all(model, capabilities)
) and model.name not in avoid:
return model
# Find models that satisfy all required capabilities
if capabilities:
return self._select_by_capabilities(capabilities, avoid)
# Fall back to default
return self._registry.resolve()
def select_from_decisions(
self,
decisions: set[MultiModalDecision],
) -> ModelConfig:
"""基于 :class:`MultiModalDecision` 值选择模型。
将决策翻译为能力字符串并委托给 :meth:`select`。
"""
capabilities: set[str] = set()
for d in decisions:
cap = _SELECTOR_CAPABILITY_MAP.get(d)
if cap and cap != "chat":
capabilities.add(cap)
return self.select({"capabilities": capabilities})
# ------------------------------------------------------------------
def _select_by_capabilities(
self,
capabilities: set[str],
avoid: set[str],
) -> ModelConfig:
"""找到支持所有必需能力的模型。"""
# Narrow down by each capability (ModelConfig is unhashable, use lists)
candidates: list[ModelConfig] = list(self._registry.list_all())
for cap in capabilities:
cap_models = list(self._registry.list_by_capability(cap))
cap_names = {m.name for m in cap_models}
candidates = [m for m in candidates if m.name in cap_names]
# Remove avoided models
candidates = [m for m in candidates if m.name not in avoid]
if not candidates:
raise AIProviderError(
message=f"No active model supports all capabilities: {capabilities}",
code="CAPABILITY_NOT_FOUND",
status_code=404,
)
# Prefer higher-weight models (higher = better)
return max(candidates, key=lambda m: m.weight)
@staticmethod
def _model_satisfies_all(model: ModelConfig, capabilities: set[str]) -> bool:
caps = model.resolved_capabilities()
return all(caps.get(cap, False) for cap in capabilities)