106 lines
2.9 KiB
Python
106 lines
2.9 KiB
Python
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"""Redis 缓存工具模块。
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提供 Redis 连接管理和缓存读写操作，所有操作在 Redis 不可用时静默降级。
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被 OrderService、CustomerService、pricing 路由等调用。
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"""
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import hashlib
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import json
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import logging
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import redis
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from backend.app.core.config import get_settings
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logger = logging.getLogger(__name__)
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_redis_client: redis.Redis | None = None
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def get_redis() -> redis.Redis | None:
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"""获取 Redis 连接单例，连接失败时返回 None。"""
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global _redis_client
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if _redis_client is not None:
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return _redis_client
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try:
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settings = get_settings()
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_redis_client = redis.Redis(
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host=settings.redis_host,
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port=settings.redis_port,
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db=settings.redis_db,
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password=settings.redis_password or None,
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decode_responses=True,
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socket_connect_timeout=2,
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socket_timeout=2,
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)
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_redis_client.ping()
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logger.info("Redis 连接成功: %s:%s/%s", settings.redis_host, settings.redis_port, settings.redis_db)
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return _redis_client
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except Exception as exc:
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logger.warning("Redis 连接失败，降级为无缓存模式: %s", exc)
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_redis_client = None
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return None
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def cache_get(key: str):
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"""读取缓存，返回反序列化后的 dict/list，未命中或异常返回 None。"""
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try:
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r = get_redis()
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if r is None:
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return None
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raw = r.get(key)
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if raw is None:
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return None
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return json.loads(raw)
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except Exception:
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return None
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def cache_set(key: str, data, ttl: int = 60) -> None:
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"""写入缓存，JSON 序列化后存储并设置 TTL（秒）。异常时静默跳过。"""
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try:
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r = get_redis()
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if r is None:
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return
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r.set(key, json.dumps(data, ensure_ascii=False, default=str), ex=ttl)
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except Exception:
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pass
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def cache_delete(key: str) -> None:
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"""精确删除单个缓存 key。"""
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try:
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r = get_redis()
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if r is not None:
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r.delete(key)
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except Exception:
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pass
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def cache_delete_pattern(pattern: str) -> None:
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"""按模式批量删除缓存（SCAN + DELETE），如 "order:list:*"。"""
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try:
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r = get_redis()
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if r is None:
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return
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cursor = 0
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while True:
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cursor, keys = r.scan(cursor=cursor, match=pattern, count=100)
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if keys:
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r.delete(*keys)
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if cursor == 0:
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break
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except Exception:
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pass
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def make_cache_key(prefix: str, **params) -> str:
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"""生成带参数哈希的缓存 key。
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例: make_cache_key("order:list", user_id=1, status="draft")
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→ "order:list:a1b2c3d4"
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"""
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raw = json.dumps(params, sort_keys=True, ensure_ascii=False, default=str)
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suffix = hashlib.md5(raw.encode()).hexdigest()[:8]
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return f"{prefix}:{suffix}"
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