639562593e
之前 service.translate 写 cache 无条件,导致:
- 第一次翻译失败时,'[翻译失败: ...]' 占位符被写进 cache
- 30 天内相同文本的请求(新文章 title 与老文章 title 相同时)全部返回占位符
- 触发 200+ 文章 title_zh 字段被永久污染
修法:仅在 engine ∈ {tencent, nllb, cache} 且文本不含错误标记时,才写 cache。
152 lines
5.5 KiB
Python
152 lines
5.5 KiB
Python
"""翻译服务门面:配额检查 + 缓存 + 引擎选择 + 月度计数。"""
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from __future__ import annotations
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import asyncio
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import hashlib
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import logging
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from datetime import datetime, timezone
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from typing import Protocol
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from app.config import settings
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from app.redis_client import get_redis
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from app.services.translation.base import BaseTranslator, TranslationResult
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from app.services.translation.local import LocalTranslator
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from app.services.translation.tencent import TencentTranslator
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logger = logging.getLogger("news.translate.service")
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# 缓存 key
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def _cache_key(text: str, src: str, tgt: str) -> str:
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h = hashlib.sha1(f"{src}|{tgt}|{text}".encode()).hexdigest()
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return f"translation:cache:{h}"
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def _month_key() -> str:
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now = datetime.now(timezone.utc)
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return f"translation:month:{now:%Y%m}"
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class TranslationService:
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def __init__(self):
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self._tencent: BaseTranslator | None = None
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self._local: BaseTranslator | None = None
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# 串行:1 个并发;避免触发腾讯 TMT 限速
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self._sem = asyncio.Semaphore(1)
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def _primary(self) -> BaseTranslator:
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if self._tencent is None:
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self._tencent = TencentTranslator()
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return self._tencent
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def _fallback(self) -> BaseTranslator | None:
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if self._local is None and settings.local_translate_enabled:
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try:
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self._local = LocalTranslator()
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except Exception as e:
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logger.warning("local translator init failed: %s", e)
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self._local = None
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return self._local
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async def can_use_tencent(self, chars: int) -> bool:
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if not settings.tencentcloud_secret_id:
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return False
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r = get_redis()
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used = int(await r.get(_month_key()) or 0)
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buffered = int(
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settings.tencent_tmt_quota_month * (1 - settings.tencent_tmt_quota_buffer)
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)
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return (used + chars) <= buffered
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async def add_usage(self, chars: int) -> None:
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r = get_redis()
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key = _month_key()
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now = datetime.now(timezone.utc)
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# 下个月第一天
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if now.month == 12:
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next_month = now.replace(year=now.year + 1, month=1, day=1)
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else:
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next_month = now.replace(month=now.month + 1, day=1, hour=0, minute=0, second=0, microsecond=0)
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ttl = max(60, int((next_month - now).total_seconds()) + 86400) # +1 天 buffer
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async with r.pipeline(transaction=False) as pipe:
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pipe.incrby(key, chars)
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pipe.expire(key, ttl)
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await pipe.execute()
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async def translate(
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self, text: str, source: str = "auto", target: str = "zh"
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) -> TranslationResult:
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if not text.strip():
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return TranslationResult(text=text, engine="skip", chars=0)
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chars = len(text)
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# 1) 缓存
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r = get_redis()
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ck = _cache_key(text, source, target)
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cached = await r.get(ck)
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if cached is not None:
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return TranslationResult(text=cached, engine="cache", chars=chars, cached=True)
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# 2) 选引擎
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use_tencent = await self.can_use_tencent(chars)
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engine: BaseTranslator
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if use_tencent:
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engine = self._primary()
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else:
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fb = self._fallback()
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if fb is None:
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# 没本地:返回原文 + 标记
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return TranslationResult(
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text=text + "\n\n[本条未翻译:配额耗尽且未启用本地翻译]",
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engine="skip",
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chars=chars,
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)
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engine = fb
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logger.info("fallback to local translator for %d chars", chars)
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# 3) 调用
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async with self._sem:
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res = None
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try:
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res = await engine.translate(text, source=source, target=target)
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except Exception as e:
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# 失败:降级
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logger.exception("translate failed with %s: %s", engine.name, e)
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fb = self._fallback()
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if fb is not None and engine is not fb:
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try:
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res = await fb.translate(text, source=source, target=target)
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except Exception as e2:
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logger.exception("fallback %s also failed: %s", fb.name, e2)
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res = None
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if res is None:
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# 主 + fallback 都失败:抛异常,让上层标记 status=failed
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raise RuntimeError(f"translation failed for {chars} chars (engine={engine.name})")
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# 4) 写缓存 — 只缓存真实翻译结果;失败/降级文本不缓存(避免污染 30 天)
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if res.engine in ("tencent", "nllb", "cache") and not res.cached:
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# 二次保险:如果文本里仍含错误标记,也不缓存
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if "[翻译失败" not in res.text and "[本条未翻译" not in res.text:
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try:
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await r.set(ck, res.text, ex=60 * 60 * 24 * 30) # 30 天
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except Exception:
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pass
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# 5) 计数(只在 tencent 上计)
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if res.engine == "tencent":
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try:
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await self.add_usage(res.chars or chars)
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except Exception as e:
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logger.warning("add_usage failed: %s", e)
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return res
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# 全局单例
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service = TranslationService()
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# 让后端 worker 直接调
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class _Protocol(Protocol):
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async def translate(self, text: str, source: str = "auto", target: str = "zh") -> TranslationResult: ...
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