Files
hunjing/backend/app/application/agent/extensions.py
T
2026-08-21 16:00:13 +08:00

230 lines
7.1 KiB
Python

"""Agent 扩展契约与注册表。
扩展只接触本次运行的快照与 ToolResult,不持有数据库会话、密钥或安全治理对象。
"""
from __future__ import annotations
import asyncio
from collections.abc import Awaitable, Callable
from dataclasses import dataclass, field, replace
from typing import Any
from app.ai_provider.types.chat import TokenUsage
from app.ai_provider.types.messages import BaseMessage
from app.modules.tool_runtime.definition import ToolResult
class CancellationToken:
"""协作式取消信号;阻塞 await 仍由活动 asyncio.Task.cancel() 负责中断。"""
def __init__(self) -> None:
self._cancelled = False
@property
def cancelled(self) -> bool:
return self._cancelled
def cancel(self) -> None:
self._cancelled = True
def raise_if_cancelled(self) -> None:
if self._cancelled:
raise asyncio.CancelledError
@dataclass(frozen=True)
class AgentRunContext:
"""扩展可见的最小运行上下文。"""
run_id: str | None = None
session_id: str | None = None
character_id: str | None = None
trace_id: str | None = None
metadata: dict[str, Any] = field(default_factory=dict)
cancellation: CancellationToken = field(default_factory=CancellationToken)
@dataclass(frozen=True)
class AgentContext:
"""每轮发送给模型前可转换的上下文快照。"""
messages: tuple[BaseMessage, ...]
tools: tuple[dict[str, Any], ...]
model_hint: str | None = None
@dataclass(frozen=True)
class AgentEvent:
"""Agent Core 内部生命周期事件。"""
type: str
payload: dict[str, Any] = field(default_factory=dict)
@dataclass(frozen=True)
class ToolCallContext:
"""工具调用 Hook 的稳定输入。"""
tool_call_id: str
name: str
input: dict[str, Any]
messages: tuple[BaseMessage, ...]
@dataclass(frozen=True)
class BeforeToolCallDecision:
"""执行前决策;扩展只能收紧或改参,不能绕过 ToolRuntime。"""
allowed: bool = True
reason: str | None = None
input: dict[str, Any] | None = None
@dataclass(frozen=True)
class AfterToolCallDecision:
"""执行后结果覆盖与提前终止提示。"""
result: ToolResult | None = None
terminate: bool = False
@dataclass(frozen=True)
class TurnSnapshot:
"""一轮模型调用及其工具执行结果摘要。"""
iteration: int
content: str
reasoning: str
tool_calls: tuple[dict[str, Any], ...]
tool_results: tuple[dict[str, Any], ...]
usage: TokenUsage = field(default_factory=TokenUsage)
ContextTransformer = Callable[[AgentContext, AgentRunContext], Awaitable[AgentContext]]
BeforeToolCallHook = Callable[
[ToolCallContext, AgentRunContext], Awaitable[BeforeToolCallDecision | None]
]
AfterToolCallHook = Callable[
[ToolCallContext, ToolResult, AgentRunContext], Awaitable[AfterToolCallDecision | None]
]
TurnPolicy = Callable[[TurnSnapshot, AgentRunContext], Awaitable[bool]]
AgentEventListener = Callable[[AgentEvent, AgentRunContext], Awaitable[None]]
class ExtensionRegistry:
"""受约束的 Agent 扩展注册表;按注册顺序执行 Hook。"""
def __init__(self) -> None:
self._context_transformers: list[ContextTransformer] = []
self._before_tool_hooks: list[BeforeToolCallHook] = []
self._after_tool_hooks: list[AfterToolCallHook] = []
self._turn_policies: list[TurnPolicy] = []
self._event_listeners: list[AgentEventListener] = []
def add_context_transformer(self, transformer: ContextTransformer) -> None:
self._context_transformers.append(transformer)
def add_before_tool_hook(self, hook: BeforeToolCallHook) -> None:
self._before_tool_hooks.append(hook)
def add_after_tool_hook(self, hook: AfterToolCallHook) -> None:
self._after_tool_hooks.append(hook)
def add_turn_policy(self, policy: TurnPolicy) -> None:
self._turn_policies.append(policy)
def add_event_listener(self, listener: AgentEventListener) -> Callable[[], None]:
self._event_listeners.append(listener)
def unsubscribe() -> None:
if listener in self._event_listeners:
self._event_listeners.remove(listener)
return unsubscribe
def extend(self, registry: ExtensionRegistry) -> None:
"""按原注册顺序合并另一组扩展。"""
self._context_transformers.extend(registry._context_transformers)
self._before_tool_hooks.extend(registry._before_tool_hooks)
self._after_tool_hooks.extend(registry._after_tool_hooks)
self._turn_policies.extend(registry._turn_policies)
self._event_listeners.extend(registry._event_listeners)
async def transform_context(
self, context: AgentContext, run: AgentRunContext
) -> AgentContext:
for transformer in self._context_transformers:
run.cancellation.raise_if_cancelled()
context = await transformer(context, run)
return context
async def before_tool_call(
self, call: ToolCallContext, run: AgentRunContext
) -> BeforeToolCallDecision:
current = call
for hook in self._before_tool_hooks:
run.cancellation.raise_if_cancelled()
decision = await hook(current, run)
if decision is None:
continue
if not decision.allowed:
return decision
if decision.input is not None:
current = replace(current, input=decision.input)
return BeforeToolCallDecision(input=current.input)
async def after_tool_call(
self,
call: ToolCallContext,
result: ToolResult,
run: AgentRunContext,
) -> AfterToolCallDecision:
current = result
terminate = False
for hook in self._after_tool_hooks:
run.cancellation.raise_if_cancelled()
decision = await hook(call, current, run)
if decision is None:
continue
if decision.result is not None:
current = decision.result
terminate = terminate or decision.terminate
return AfterToolCallDecision(result=current, terminate=terminate)
async def should_stop(self, turn: TurnSnapshot, run: AgentRunContext) -> bool:
for policy in self._turn_policies:
run.cancellation.raise_if_cancelled()
if await policy(turn, run):
return True
return False
async def publish(self, event: AgentEvent, run: AgentRunContext) -> None:
for listener in tuple(self._event_listeners):
await listener(event, run)
@property
def enabled(self) -> bool:
return any(
(
self._context_transformers,
self._before_tool_hooks,
self._after_tool_hooks,
self._turn_policies,
self._event_listeners,
)
)
__all__ = [
"AfterToolCallDecision",
"AgentContext",
"AgentEvent",
"AgentRunContext",
"BeforeToolCallDecision",
"CancellationToken",
"ExtensionRegistry",
"ToolCallContext",
"TurnSnapshot",
]