115 lines
3.5 KiB
Python
115 lines
3.5 KiB
Python
"""
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异步 Redis 缓存封装 —— 100% 异步化基建
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========================================
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Django 的 cache 框架（django-redis）没有异步 API，本模块基于 redis.asyncio 直连，
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复用 settings 中的 REDIS 配置，提供与 django cache 对等的异步接口。
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用法：
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from utils.async_cache import aget_cache, aset_cache, adelete_cache
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value = await aget_cache('key')
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await aset_cache('key', obj, timeout=3600)
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await adelete_cache('key')
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序列化：msgpack（快速紧凑）+ JSON 兜底；与 django-redis 缓存池互不干扰（独立 key 前缀）。
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"""
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import asyncio
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import json
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import logging
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from django.conf import settings
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from django.core.cache import caches
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from asgiref.sync import sync_to_async
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import msgpack
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logger = logging.getLogger(__name__)
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_cache_pool = None
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_lock = asyncio.Lock()
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async def _get_pool():
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"""懒初始化 redis.asyncio 连接池（复用 settings.REDIS 配置）"""
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global _cache_pool
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async with _lock:
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if _cache_pool is None:
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import redis.asyncio as aioredis
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_cache_pool = aioredis.Redis(
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host=settings.REDIS_HOST,
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port=int(settings.REDIS_PORT),
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db=int(getattr(settings, 'REDIS_DB', 0)),
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password=getattr(settings, 'REDIS_PASSWORD', '') or None,
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decode_responses=False,
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socket_connect_timeout=5,
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socket_timeout=5,
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max_connections=50,
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)
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return _cache_pool
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def _pack(value):
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try:
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return b'async-cache:' + msgpack.packb(value, use_bin_type=True, default=str)
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except (TypeError, ValueError):
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return b'async-cache-json:' + json.dumps(value, ensure_ascii=False, default=str).encode()
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def _unpack(raw):
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if raw is None:
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return None
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if raw.startswith(b'async-cache-json:'):
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return json.loads(raw[17:].decode())
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return msgpack.unpackb(raw[12:], raw=False)
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async def aget_cache(key, default=None):
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try:
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pool = await _get_pool()
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raw = await pool.get(f'async:{key}')
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if raw is None:
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return default
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return _unpack(raw)
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except Exception:
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logger.warning('aget_cache failed for %s, falling back to sync cache', key)
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try:
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return await sync_to_async(caches['default'].get)(key, default)
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except Exception:
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return default
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async def aset_cache(key, value, timeout=300):
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try:
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pool = await _get_pool()
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await pool.set(f'async:{key}', _pack(value), ex=timeout)
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return True
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except Exception:
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logger.warning('aset_cache failed for %s, falling back to sync cache', key)
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try:
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await sync_to_async(caches['default'].set)(key, value, timeout)
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return True
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except Exception:
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return False
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async def adelete_cache(key):
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try:
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pool = await _get_pool()
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await pool.delete(f'async:{key}')
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return True
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except Exception:
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logger.warning('adelete_cache failed for %s', key)
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try:
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await sync_to_async(caches['default'].delete)(key)
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return True
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except Exception:
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return False
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async def aget_or_set(key, factory, timeout=300):
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"""原子性不保证（与 django cache 用法一致），value 为 await factory() 结果"""
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v = await aget_cache(key)
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if v is not None:
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return v
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v = await factory() if asyncio.iscoroutinefunction(factory) else factory()
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await aset_cache(key, v, timeout)
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return v
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