screentinker/server/test/loop-lag-integration.test.js
ScreenTinker 4bda49cf60 fix(#146) E: log/write self-protection — coalesced logs, batched telemetry, bounded maps
Don't let telemetry/logging cook the loop under a storm.

- lib/log-coalescer.js: dedup+count high-frequency lines, flush ONE summarized line per
  key per window ("[loop-lag] band=critical (x47 in 30s)"). Bounded buffer (auto-flush
  at MAX_KEYS). Applied to the loop-lag "still loaded" line (band CHANGES stay immediate),
  the per-request OTA check line, and "Device reconnected".
- loop-lag: event_loop_lag rows are BUFFERED and batch-inserted on a flush interval
  (was a synchronous INSERT per sample); the buffer is bounded (drop-oldest). Its
  retention prune now rides the Item-A chunkedDelete so this table can never repeat the
  status_log bloat-then-freeze. /api/status still reads in-memory current (real-time
  band unaffected).
- Bounded the previously un-evicted per-device Maps: content-ack limiter gets an idle
  sweep (started in server.js); status-log-writer.lastWritten is capped (drop-oldest;
  it only suppresses a redundant consecutive row, so eviction is safe).

Tests: N identical lines -> one counted line; single line verbatim; coalescer buffer
bounded under a distinct-key flood; content-ack Map swept of idle buckets.
loop-lag-integration updated for the batched-insert cadence. Suite 266/266.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-30 21:34:01 -05:00

66 lines
3 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');
});
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)`);
});