95 lines
2.9 KiB
Python
95 lines
2.9 KiB
Python
"""cache.py 本地层（不碰 Redis）：TTL 过期、容量淘汰、熔断冷却恢复。"""
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from __future__ import annotations
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import pytest
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import app.cache as cache_mod
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from app import cache
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class _FakeClock:
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"""替换 cache 命名空间里的 time（不影响全局 time 模块）。"""
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def __init__(self):
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self.now = 1000.0
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def monotonic(self) -> float:
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return self.now
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def time(self) -> float:
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return self.now
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@pytest.fixture(autouse=True)
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def _reset_state():
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"""每个用例干净的本地缓存状态。"""
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cache._local_store.clear()
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cache._local_bytes = 0
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cache._disabled_until = 0.0
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yield
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cache._local_store.clear()
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cache._local_bytes = 0
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cache._disabled_until = 0.0
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def test_local_set_get_roundtrip():
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cache.local_set("k", '{"a":1}', ttl=60)
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assert cache.local_get("k") == '{"a":1}'
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def test_local_get_miss():
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assert cache.local_get("nope") is None
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def test_local_expiry(monkeypatch):
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clock = _FakeClock()
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monkeypatch.setattr(cache_mod, "time", clock)
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cache.local_set("k", "v", ttl=10)
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clock.now = 1005.0
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assert cache.local_get("k") == "v"
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clock.now = 1101.0 # 过期
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assert cache.local_get("k") is None
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assert "k" not in cache._local_store # 过期读取顺手清理
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def test_local_ttl_capped_at_120s():
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"""本地层恒 ≤120s（多进程部署时最多比 Redis 多陈旧 120s 的约定）。"""
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base = cache.time.monotonic()
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cache.local_set("k", "v", ttl=99999)
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ent = cache._local_store["k"]
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assert ent[0] - base <= 120.0 + 5 # 相对当前 monotonic 的上限（留误差余量）
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def test_local_entries_cap_evicts_oldest():
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for i in range(cache._LOCAL_MAX_ENTRIES + 5):
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cache.local_set(f"k{i}", "v", ttl=60)
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assert len(cache._local_store) <= cache._LOCAL_MAX_ENTRIES
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# 先插入的（最旧）被近似 LRU 淘汰
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assert cache.local_get("k0") is None
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assert cache.local_get(f"k{cache._LOCAL_MAX_ENTRIES + 4}") == "v"
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def test_local_overwrite_releases_bytes():
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cache.local_set("k", "x" * 1000, ttl=60)
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before = cache._local_bytes
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cache.local_set("k", "y", ttl=60)
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assert cache._local_bytes < before
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assert cache.local_get("k") == "y"
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def test_bail_cooldown_recovers(monkeypatch):
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"""熔断 60s：期间 _client 为 None，到期自动放行（Redis 未配置时也返回 None，但不熔断）。"""
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clock = _FakeClock()
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monkeypatch.setattr(cache_mod, "time", clock)
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cache._bail()
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assert cache._disabled_until > clock.now
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clock.now += 59.0
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assert clock.monotonic() < cache._disabled_until # 仍在熔断期
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clock.now += 2.0 # 越过 60s 冷却
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assert clock.monotonic() >= cache._disabled_until # 恢复探测资格
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def test_digest_stable_and_distinct():
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assert cache.digest("a", 1, None) == cache.digest("a", 1, None)
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assert cache.digest("a", 1) != cache.digest("a", 2)
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