47fa4385df
/api/status is the desktop's boot liveness probe (polled ~1/s) but since #60537 every call ran a full topology scan — per-profile yaml.safe_load (pure-Python loader), psutil process probes, realpath walks — in the default executor. On multi-profile installs concurrent polls pile up and hold the GIL 14-16s, starving the event loop: the WS sidecar cannot flush gateway.ready, the desktop times out into the next stall, and boot escalates to the 'Hermes couldn't start' overlay (#60800). Memoize the scan behind a 10s TTL with a collapse lock so concurrent polls share one scan. Topology only changes on gateway start/stop, so a <=10s stale badge is an acceptable trade for not starving the loop. The cache also keys on the collector's identity: tests monkeypatch _collect_profile_gateway_topology per case, and the identity check keeps them hermetic (a swapped collector is a miss) without a reset hook. py-spy captures during a failing boot land in _profile_platform_ports -> yaml.safe_load on executor threads (7 profiles, Windows). After: one cold-start scan, zero recurring stalls, desktop boots.
118 lines
3.7 KiB
Python
118 lines
3.7 KiB
Python
"""Regression tests for the /api/status profile-topology cache.
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The desktop app polls /api/status ~1/s while waiting for the backend to become
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ready. Before the cache, every poll ran a full _collect_profile_gateway_topology
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scan (per-profile yaml.safe_load with the pure-Python loader + psutil
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process-table probes + realpath walks) in the default executor; on multi-profile
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installs the concurrent scans held the GIL for 14-16s and starved the event
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loop, so the desktop WS never received gateway.ready and boot escalated to the
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"Hermes couldn't start" overlay (#60800).
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"""
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import threading
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import time
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from hermes_cli import web_server
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def _reset_cache():
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web_server._TOPOLOGY_CACHE["ts"] = 0.0
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web_server._TOPOLOGY_CACHE["data"] = None
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web_server._TOPOLOGY_CACHE["fn"] = None
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def _fake_topology(calls, delay=0.0):
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def _collect():
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if delay:
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time.sleep(delay)
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calls.append(1)
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return {"profiles": ["default"], "gateway_mode": "single", "gateways": []}
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return _collect
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def test_topology_cache_returns_cached_result_within_ttl(monkeypatch):
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calls = []
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monkeypatch.setattr(
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web_server, "_collect_profile_gateway_topology", _fake_topology(calls)
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)
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_reset_cache()
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try:
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first = web_server._collect_profile_gateway_topology_cached()
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second = web_server._collect_profile_gateway_topology_cached()
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finally:
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_reset_cache()
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assert len(calls) == 1
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assert first is second
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def test_topology_cache_rescans_after_ttl(monkeypatch):
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calls = []
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monkeypatch.setattr(
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web_server, "_collect_profile_gateway_topology", _fake_topology(calls)
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)
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_reset_cache()
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try:
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web_server._collect_profile_gateway_topology_cached()
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# Age the cache entry past the TTL instead of sleeping through it.
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web_server._TOPOLOGY_CACHE["ts"] -= web_server._TOPOLOGY_CACHE_TTL + 1.0
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web_server._collect_profile_gateway_topology_cached()
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finally:
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_reset_cache()
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assert len(calls) == 2
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def test_topology_cache_collapses_concurrent_scans(monkeypatch):
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"""Concurrent status polls must not each run their own scan — that pile-up
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is exactly the GIL storm the cache exists to prevent."""
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calls = []
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monkeypatch.setattr(
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web_server,
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"_collect_profile_gateway_topology",
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_fake_topology(calls, delay=0.05),
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)
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_reset_cache()
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results = []
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try:
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threads = [
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threading.Thread(
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target=lambda: results.append(
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web_server._collect_profile_gateway_topology_cached()
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)
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)
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for _ in range(8)
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]
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for t in threads:
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t.start()
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for t in threads:
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t.join()
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finally:
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_reset_cache()
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assert len(calls) == 1
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assert len(results) == 8
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assert all(r == results[0] for r in results)
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def test_topology_cache_misses_when_collector_is_swapped(monkeypatch):
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"""Tests (and hot-reload scenarios) monkeypatch the collector; a swapped
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function identity must be a cache miss so stale data from the previous
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collector never leaks across the swap."""
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calls_a, calls_b = [], []
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monkeypatch.setattr(
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web_server, "_collect_profile_gateway_topology", _fake_topology(calls_a)
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)
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_reset_cache()
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try:
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first = web_server._collect_profile_gateway_topology_cached()
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monkeypatch.setattr(
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web_server, "_collect_profile_gateway_topology", _fake_topology(calls_b)
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)
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second = web_server._collect_profile_gateway_topology_cached()
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finally:
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_reset_cache()
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assert len(calls_a) == 1
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assert len(calls_b) == 1
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assert first is not second
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