Add SETNX cache stampede protection#378
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| def test_cache_miss_uses_setnx_refresh_claim(): | ||
| assert "claim_key = f\"{key}:refresh-lock\"" in CACHE_SOURCE |
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| def test_cache_miss_uses_setnx_refresh_claim(): | ||
| assert "claim_key = f\"{key}:refresh-lock\"" in CACHE_SOURCE | ||
| assert "nx=True" in CACHE_SOURCE |
| def test_cache_miss_uses_setnx_refresh_claim(): | ||
| assert "claim_key = f\"{key}:refresh-lock\"" in CACHE_SOURCE | ||
| assert "nx=True" in CACHE_SOURCE | ||
| assert "ex=_REFRESH_CLAIM_SECONDS" in CACHE_SOURCE |
| assert "claim_key = f\"{key}:refresh-lock\"" in CACHE_SOURCE | ||
| assert "nx=True" in CACHE_SOURCE | ||
| assert "ex=_REFRESH_CLAIM_SECONDS" in CACHE_SOURCE | ||
| assert "_REFRESH_CLAIM_SECONDS = 5" in CACHE_SOURCE |
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| def test_concurrent_miss_waits_for_claimer_before_fetching(): | ||
| assert "if not claimed:" in CACHE_SOURCE |
| assert "if not claimed:" in CACHE_SOURCE | ||
| assert "refreshed = await _wait_for_refresh(client, key)" in CACHE_SOURCE | ||
| assert "if refreshed is not None:" in CACHE_SOURCE | ||
| assert "return refreshed" in CACHE_SOURCE |
| assert "refreshed = await _wait_for_refresh(client, key)" in CACHE_SOURCE | ||
| assert "if refreshed is not None:" in CACHE_SOURCE | ||
| assert "return refreshed" in CACHE_SOURCE | ||
| assert "value = await fetch_fn()" in CACHE_SOURCE |
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| def test_wait_loop_polls_cached_value_with_deadline(): | ||
| assert "deadline = asyncio.get_running_loop().time() + _REFRESH_CLAIM_SECONDS" in CACHE_SOURCE |
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| def test_wait_loop_polls_cached_value_with_deadline(): | ||
| assert "deadline = asyncio.get_running_loop().time() + _REFRESH_CLAIM_SECONDS" in CACHE_SOURCE | ||
| assert "await asyncio.sleep(_REFRESH_POLL_SECONDS)" in CACHE_SOURCE |
| def test_wait_loop_polls_cached_value_with_deadline(): | ||
| assert "deadline = asyncio.get_running_loop().time() + _REFRESH_CLAIM_SECONDS" in CACHE_SOURCE | ||
| assert "await asyncio.sleep(_REFRESH_POLL_SECONDS)" in CACHE_SOURCE | ||
| assert "cached = await _read_cached_value(client, key)" in CACHE_SOURCE No newline at end of file |
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Fixes #236.
This adds TTL-bound cache stampede protection to get_cached_or_fetch:
I did not run local pytest in this workspace because we are intentionally avoiding dependency installation and project toolchain execution.