Files
ai-ticket-platform/backend/apps/modelhub/services.py
2026-07-27 19:02:37 +08:00

202 lines
7.5 KiB
Python

"""模型调用执行器。
统一处理超时预算、可重试错误、凭据脱敏、调用快照和 Token/耗时记录。
"""
from collections.abc import Callable
from dataclasses import dataclass
from time import monotonic, sleep
from typing import Any
from django.utils import timezone
from openai import (
APIConnectionError,
APIStatusError,
APITimeoutError,
AuthenticationError,
BadRequestError,
OpenAI,
RateLimitError,
)
from apps.modelhub.crypto import CredentialEncryptionError, decrypt_secret
from apps.modelhub.models import ModelDeployment, ModelInvocation
TRANSIENT_ERRORS = (APIConnectionError, APITimeoutError, RateLimitError)
@dataclass(frozen=True)
class CompletionResult:
content: str
input_tokens: int | None
output_tokens: int | None
class ModelGatewayError(RuntimeError):
def __init__(self, code: str, message: str):
super().__init__(message)
self.code = code
def _request_completion(
deployment: ModelDeployment,
messages: list[dict[str, Any]],
*,
temperature: float,
max_output_tokens: int,
timeout_seconds: float | None = None,
) -> CompletionResult:
provider = deployment.provider
request_timeout = min(max(provider.default_timeout_seconds, 1), 300)
if timeout_seconds is not None:
request_timeout = min(request_timeout, max(timeout_seconds, 1))
client = OpenAI(
api_key=decrypt_secret(provider.api_key_encrypted),
base_url=provider.base_url,
timeout=request_timeout,
# Retry here so the platform can expose it instead of waiting on opaque SDK retries.
max_retries=0,
)
response = client.chat.completions.create(
model=deployment.model_name,
messages=messages,
temperature=temperature,
max_tokens=max_output_tokens,
)
content = response.choices[0].message.content or ""
usage = response.usage
return CompletionResult(
content=content,
input_tokens=getattr(usage, "prompt_tokens", None) if usage else None,
output_tokens=getattr(usage, "completion_tokens", None) if usage else None,
)
def _error_details(error: Exception) -> tuple[str, str, bool]:
if isinstance(error, AuthenticationError):
return "authentication_failed", "模型渠道鉴权失败", False
if isinstance(error, BadRequestError):
return "bad_request", "模型请求参数不被渠道接受", False
if isinstance(error, RateLimitError):
return "rate_limited", "模型渠道当前限流", True
if isinstance(error, APITimeoutError):
return "timeout", "模型请求超时", True
if isinstance(error, APIConnectionError):
return "connection_failed", "无法连接模型渠道", True
if isinstance(error, APIStatusError) and error.status_code >= 500:
return "provider_unavailable", "模型渠道暂时不可用", True
if isinstance(error, CredentialEncryptionError):
return "credential_unavailable", str(error), False
return "unexpected_error", "模型调用发生未预期错误", False
def execute_invocation(
invocation: ModelInvocation,
messages: list[dict[str, Any]],
*,
temperature: float | None = None,
max_output_tokens: int | None = None,
on_retry: Callable[[int, str], None] | None = None,
total_timeout_seconds: float | None = None,
) -> ModelInvocation:
"""在总时间预算内调用模型,分类错误、限制重试并记录脱敏终态。"""
deployment = invocation.deployment
if deployment is None or not deployment.enabled or not deployment.provider.enabled:
invocation.status = "failed"
invocation.error_code = "deployment_unavailable"
invocation.error_message = "模型配置或渠道未启用"
invocation.finished_at = timezone.now()
invocation.save(update_fields=["status", "error_code", "error_message", "finished_at"])
return invocation
invocation.status = "running"
invocation.started_at = timezone.now()
invocation.model_snapshot = {
"provider_id": deployment.provider_id,
"provider_name": deployment.provider.name,
"base_url": deployment.provider.base_url,
"deployment_id": deployment.id,
"model_name": deployment.model_name,
"capability": deployment.capability,
"temperature": temperature if temperature is not None else deployment.default_temperature,
"max_output_tokens": max_output_tokens or deployment.max_output_tokens,
}
invocation.save(update_fields=["status", "started_at", "model_snapshot"])
started = monotonic()
result: CompletionResult | None = None
last_error: Exception | None = None
for attempt in range(2):
elapsed = monotonic() - started
remaining = total_timeout_seconds - elapsed if total_timeout_seconds is not None else None
if remaining is not None and remaining <= 0:
invocation.error_code = "timeout"
invocation.error_message = "模型请求超过 Agent 时间预算"
break
try:
result = _request_completion(
deployment,
messages,
temperature=temperature
if temperature is not None
else deployment.default_temperature,
max_output_tokens=max_output_tokens or deployment.max_output_tokens,
timeout_seconds=remaining,
)
invocation.retry_count = attempt
break
except Exception as error: # provider libraries expose several subclasses
code, message, transient = _error_details(error)
last_error = error
invocation.retry_count = attempt
if not transient or attempt == 1:
invocation.error_code = code
invocation.error_message = message
break
if total_timeout_seconds is not None:
remaining_after_error = total_timeout_seconds - (monotonic() - started)
if remaining_after_error <= 1:
invocation.error_code = code
invocation.error_message = message
break
invocation.retry_count = attempt + 1
invocation.error_code = code
invocation.error_message = message
invocation.save(update_fields=["retry_count", "error_code", "error_message"])
if on_retry:
on_retry(attempt + 1, code)
sleep(1)
invocation.duration_ms = max(int((monotonic() - started) * 1000), 0)
invocation.finished_at = timezone.now()
if result is not None:
invocation.status = "succeeded"
invocation.output_text = result.content
invocation.input_tokens = result.input_tokens
invocation.output_tokens = result.output_tokens
invocation.error_code = ""
invocation.error_message = ""
else:
invocation.status = "failed"
if not invocation.error_code:
code, message, _ = _error_details(last_error or RuntimeError())
invocation.error_code = code
invocation.error_message = message
invocation.save()
return invocation
def create_model_test(
deployment: ModelDeployment,
prompt: str,
user=None,
) -> ModelInvocation:
"""创建可审计的异步模型连通测试,不绕过正式模型执行器。"""
return ModelInvocation.objects.create(
deployment=deployment,
invocation_type="model_test",
input_snapshot={"messages": [{"role": "user", "content": prompt}]},
created_by=user,
)