mirror of
https://github.com/Ark0N/Codeman.git
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Tenggan ZhangandTeigen
06f9ff6d9c
The stats collector (~2s) and mouse-mode sync (5s) ran execSync (pgrep/ps/ list-panes, 5s timeout each) per session on the server's single thread, blocking the event loop. With several sessions or a momentarily slow tmux this froze port 3000 for seconds-to-tens-of-seconds while the process stayed alive and other ports were unaffected — self-healing, so it never restarted and the 60s loopback healthcheck missed it. Convert these hot-path calls to execAsync. Also add an always-on event-loop lag monitor (utils/event-loop-monitor.ts) that logs stalls >=1s to the web log, so this otherwise-invisible class of incident leaves a quantified, timestamped trace. Co-authored-by: Teigen <teigen@TeigendeMac-mini.local>
55 lines
1.8 KiB
TypeScript
55 lines
1.8 KiB
TypeScript
/**
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* @fileoverview Event-loop lag monitor.
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*
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* Node is single-threaded: any synchronous work (e.g. a blocking `execSync`)
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* freezes the whole event loop, so the HTTP server stops answering on its port
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* while the process stays alive and other ports are unaffected. Such stalls
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* self-heal and never restart the process, so a periodic loopback healthcheck
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* misses them entirely — they leave no trace.
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*
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* This monitor samples how late a fixed-interval timer actually fires versus when
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* it was scheduled; the excess is time the loop was blocked. When that exceeds a
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* threshold it logs the measured stall, turning otherwise-invisible "port briefly
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* unreachable" incidents into a timestamped, quantified log line.
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*
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* @module utils/event-loop-monitor
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*/
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export interface EventLoopMonitorHandle {
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stop(): void;
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}
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/**
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* Start sampling event-loop lag.
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*
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* @param sampleMs How often to sample (and the baseline interval lag is measured against).
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* @param thresholdMs Only stalls at or above this many ms are logged (noise floor).
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* @param log Sink for stall reports; defaults to console.warn (lands in the web log).
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*/
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export function startEventLoopMonitor(
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sampleMs = 1000,
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thresholdMs = 1000,
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log: (msg: string) => void = (m) => console.warn(m)
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): EventLoopMonitorHandle {
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let last = performance.now();
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const timer = setInterval(() => {
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const now = performance.now();
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// Lag = elapsed beyond the scheduled interval = time the loop was blocked.
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const lag = Math.round(now - last - sampleMs);
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if (lag >= thresholdMs) {
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log(`[EventLoopLag] event loop blocked ~${lag}ms (at ${new Date().toISOString()})`);
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}
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last = now;
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}, sampleMs);
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// Never keep the process alive solely for this monitor.
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timer.unref?.();
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return {
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stop() {
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clearInterval(timer);
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},
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};
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}
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