screentinker/server/test/loop-lag-integration.test.js
ScreenTinker fa3ab44c20 feat(#146): /api/status.debug throughput counters (gauges -> gauges + work done)
The debug block exposed only gauges (buckets, quarantined, inFlight) — state, not work.
A real flapping Firestick reads as flap.buckets:36, quarantined:0, indistinguishable
from healthy. Add lightweight in-memory throughput counters (total + last-completed
rolling window) so the server tells the flapper/flood story itself.

- lib/rolling-counter.js: shared bounded scalar counter (total, curWindow, lastWindow,
  windowStart); rolls lazily on bump AND read (no timer), idle decays to 0.
  DEBUG_STATS_WINDOW_MS default 60000.
- flap-limiter: refused{Total,LastWindow} (every allow:false), quarantineStarts{Total,
  LastWindow} (a quarantine event stays visible after the gauge decays).
- ota-breaker: stats() rateBackoff{Total,LastWindow}.
- ota-download-guard: servedTotal/shedTotal alongside the per-window values.
- database: maintenance sweepsTotal (confirm the prune is firing, not stalled).
- routes/status: debug block gains ota_breaker + the new fields (aggregate-only, cheap).

Tests: rolling-counter window-roll + idle decay; each counter increments on the right
event; booted /api/status asserts the new fields present + numeric. Suite 285/285.
Fallout doc: observability section lists the fields + what each tells a soak-watcher.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-30 23:24:32 -05:00

82 lines
4.5 KiB
JavaScript

'use strict';
// #142 step 2 — integration: the lag monitor samples, persists to a BOUNDED table,
// and surfaces current lag on /api/status. Boots the real server with fast sampling
// and a tiny (fractional-day) retention so the prune is observable within the test.
const { test, before, after } = require('node:test');
const assert = require('node:assert/strict');
const { spawn } = require('node:child_process');
const path = require('node:path');
const os = require('node:os');
const fs = require('node:fs');
const crypto = require('node:crypto');
const Database = require('better-sqlite3');
const PORT = 3982;
const BASE = `http://127.0.0.1:${PORT}`;
const DATA_DIR = path.join(os.tmpdir(), 'st-lag-int-' + crypto.randomBytes(4).toString('hex'));
const LOG = path.join(os.tmpdir(), 'st-lag-int-' + crypto.randomBytes(4).toString('hex') + '.log');
let proc;
before(async () => {
const logFd = fs.openSync(LOG, 'w');
proc = spawn('node', ['server.js'], {
cwd: path.join(__dirname, '..'),
env: {
...process.env, DATA_DIR, SELF_HOSTED: 'true', PORT: String(PORT), NODE_ENV: 'test',
LAG_SAMPLE_INTERVAL_MS: '200', // sample fast
LAG_FLUSH_MS: '200', // #146 Item E: batch-insert fast so persistence is observable in-test
LAG_TELEMETRY_RETENTION_DAYS: '0.00001', // ~0.86s retention
LAG_PRUNE_INTERVAL_MS: '400', // prune often
},
stdio: ['ignore', logFd, logFd],
});
let up = false;
for (let i = 0; i < 80; i++) {
try { const r = await fetch(BASE + '/api/status'); if (r.ok) { up = true; break; } } catch { /* not yet */ }
await new Promise(r => setTimeout(r, 250));
}
if (!up) throw new Error('server did not boot:\n' + fs.readFileSync(LOG, 'utf8').slice(-2000));
});
after(() => { try { proc.kill('SIGKILL'); } catch { /* */ } });
test('/api/status exposes a current loop_lag snapshot', async () => {
const r = await fetch(BASE + '/api/status');
const body = await r.json();
assert.ok(body.loop_lag, 'loop_lag present on /api/status');
assert.ok(['normal', 'elevated', 'critical'].includes(body.loop_lag.band), 'band is a valid level');
assert.equal(typeof body.loop_lag.p99_ms, 'number', 'p99_ms is numeric');
assert.equal(typeof body.loop_lag.mean_ms, 'number', 'mean_ms is numeric');
// #146 P3.8: soak observability block — gauges + throughput
assert.ok(body.debug, 'debug block present');
assert.equal(typeof body.debug.flap.buckets, 'number', 'flap bucket count exposed');
assert.equal(typeof body.debug.flap.quarantined, 'number', 'flap quarantine count exposed');
assert.equal(typeof body.debug.flap.refusedTotal, 'number', 'flap refusedTotal exposed');
assert.equal(typeof body.debug.flap.refusedLastWindow, 'number', 'flap refusedLastWindow exposed');
assert.equal(typeof body.debug.flap.quarantineStartsTotal, 'number', 'flap quarantineStartsTotal exposed');
assert.equal(typeof body.debug.flap.quarantineStartsLastWindow, 'number', 'flap quarantineStartsLastWindow exposed');
assert.equal(typeof body.debug.ota_breaker.rateBackoffTotal, 'number', 'ota breaker rateBackoffTotal exposed');
assert.equal(typeof body.debug.ota_breaker.rateBackoffLastWindow, 'number', 'ota breaker rateBackoffLastWindow exposed');
assert.equal(typeof body.debug.ota_download.inFlight, 'number', 'download in-flight exposed');
assert.equal(typeof body.debug.ota_download.servedTotal, 'number', 'download servedTotal exposed');
assert.equal(typeof body.debug.ota_download.shedTotal, 'number', 'download shedTotal exposed');
assert.ok('maintenance' in body.debug && typeof body.debug.maintenance.ms === 'number', 'last-prune stats exposed');
assert.equal(typeof body.debug.maintenance.sweepsTotal, 'number', 'maintenance sweepsTotal exposed');
assert.equal(typeof body.debug.log_coalescer_buffer, 'number', 'coalescer buffer size exposed');
});
test('lag samples are persisted AND bounded by retention prune (not unbounded)', async () => {
// Let it sample for ~3s. At 200ms/sample that is ~15 inserts, but with ~0.86s
// retention pruned every 400ms the table must stay small — proving the table
// can never become a second unbounded-growth table.
await new Promise(r => setTimeout(r, 1800));
const dbPath = path.join(DATA_DIR, 'db', 'remote_display.db');
const db = new Database(dbPath, { readonly: true });
const count = db.prepare('SELECT COUNT(*) c FROM event_loop_lag').get().c;
db.close();
assert.ok(count >= 1, 'lag samples are being persisted');
assert.ok(count < 15, `table is bounded by the prune (held ${count} rows over ~3s of 200ms sampling)`);
});