TIANHE
129 lines
3.6 KiB
Python
129 lines
3.6 KiB
Python
"""
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Cache utilities.
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Local-first behavior: use in-memory cache by default.
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Redis is only used when explicitly enabled via environment variables.
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"""
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import time
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import threading
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from typing import Optional, Any
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import json
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from app.utils.logger import get_logger
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from app.config import CacheConfig
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logger = get_logger(__name__)
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class MemoryCache:
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"""内存缓存（Redis 不可用时的备选方案）"""
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def __init__(self):
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self._cache = {}
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self._lock = threading.Lock()
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def get(self, key: str) -> Optional[str]:
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with self._lock:
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if key in self._cache:
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data, expiry = self._cache[key]
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if expiry > time.time():
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return data
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else:
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del self._cache[key]
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return None
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def setex(self, key: str, ttl: int, value: str):
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with self._lock:
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expiry = time.time() + ttl
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self._cache[key] = (value, expiry)
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def delete(self, key: str):
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with self._lock:
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if key in self._cache:
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del self._cache[key]
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def clear(self):
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with self._lock:
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self._cache.clear()
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class CacheManager:
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"""缓存管理器"""
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_instance = None
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_lock = threading.Lock()
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def __new__(cls):
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if cls._instance is None:
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with cls._lock:
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if cls._instance is None:
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cls._instance = super().__new__(cls)
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cls._instance._initialized = False
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return cls._instance
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def __init__(self):
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if self._initialized:
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return
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self._initialized = True
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self._client = None
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self._use_redis = False
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# Local-first: do NOT touch Redis unless explicitly enabled.
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if not CacheConfig.ENABLED:
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self._client = MemoryCache()
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self._use_redis = False
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return
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# Try Redis only when enabled.
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try:
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import redis
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from app.config import RedisConfig
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self._client = redis.Redis(
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host=RedisConfig.HOST,
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port=RedisConfig.PORT,
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db=RedisConfig.DB,
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password=RedisConfig.PASSWORD,
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decode_responses=True,
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socket_connect_timeout=RedisConfig.CONNECT_TIMEOUT,
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socket_timeout=RedisConfig.SOCKET_TIMEOUT
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)
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self._client.ping()
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self._use_redis = True
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logger.info("Redis cache connected")
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except Exception as e:
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# Fall back silently (keep startup logs clean in local mode).
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logger.info(f"Redis is enabled but unavailable; using in-memory cache instead: {e}")
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self._client = MemoryCache()
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self._use_redis = False
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def get(self, key: str) -> Optional[Any]:
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"""获取缓存"""
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try:
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data = self._client.get(key)
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if data:
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return json.loads(data)
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return None
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except Exception as e:
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logger.error(f"Cache read failed: {e}")
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return None
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def set(self, key: str, value: Any, ttl: int = 300):
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"""设置缓存"""
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try:
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self._client.setex(key, ttl, json.dumps(value))
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except Exception as e:
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logger.error(f"Cache write failed: {e}")
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def delete(self, key: str):
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"""删除缓存"""
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try:
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self._client.delete(key)
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except Exception as e:
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logger.error(f"Cache delete failed: {e}")
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@property
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def is_redis(self) -> bool:
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return self._use_redis
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