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5171f09f96
Fixes the blocker the previous commit shipped with. Pure-JS decoding costs ~1s of solid CPU for a 12MP photo, and in-process that is not a slow upload but a stalled event loop — no heartbeats, no socket traffic. thumbnail-backfill.js walks a whole library at boot, so it reproduced #240 (blocked loop -> missed heartbeats -> panels offline -> reconnect churn) from our own maintenance. sharp never did this because libvips works on a threadpool. image-ops.js is now a dispatcher over image-ops-worker.js; the work moved unchanged to image-ops-core.js, so callers and their failure contract are untouched. Measured on a 12MP photo: 1079ms wall with the loop stalled 1003ms, to 1881ms wall for two ops with ZERO stalls and 185 timer ticks serviced. Wall time is worse and that is fine — it is off the main thread now. Design notes, all load-bearing: - ONE JOB AT A TIME. A decoded 12MP bitmap is ~48MB of RGBA; overlapping jobs multiply peak memory by queue depth, which is the wrong failure on the small targets this change exists to reach. Costs no throughput — the work is CPU-bound and one busy worker already saturates its core. - unref'd while idle, ref'd only in flight. Otherwise scripts/backfill-rotation- dims.js never exits and `node --test` hangs forever. Verified: a CLI-style run exits in 104ms, code 0. - decode failures reply as messages, so one bad upload cannot tear down the worker and take unrelated queued jobs with it. - in-process fallback if a thread cannot be had, warned rather than silent. test/image-ops.test.js pins the loop-liveness property, which no functional test would catch. Its thresholds were mutation-tested against the inline path: the first version passed there too (4MP stalls only ~355ms, under a non-flaky threshold), so the fixture is 12MP and the thresholds sit in the gap between the two behaviours — worker ~90 ticks/~0ms, inline ~3 ticks/~897ms. It now fails inline, as a guard must. 1647/1647 pass. Ingest re-verified with node_modules/sharp moved aside.
30 lines
1.1 KiB
JavaScript
30 lines
1.1 KiB
JavaScript
'use strict';
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/*
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* Worker-thread host for image-ops-core. One job per message, one reply per job, keyed by id.
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*
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* Deliberately thin: every decision (queueing, lifecycle, fallback) lives in ../lib/image-ops so
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* there is one place to reason about them. This end only does the work and reports what happened.
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*
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* Errors come back as a message rather than a thrown exception, so one undecodable upload does
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* not tear down the worker and take the queued jobs of unrelated callers with it.
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*/
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const { parentPort } = require('worker_threads');
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const core = require('./image-ops-core');
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const OPS = {
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metadata: (job) => core.metadata(job.src),
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writeThumbnail: (job) => core.writeThumbnail(job.src, job.dest, job.width, job.quality),
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};
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parentPort.on('message', async (job) => {
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try {
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const op = OPS[job.op];
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if (!op) throw new Error(`unknown image op: ${job.op}`);
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parentPort.postMessage({ id: job.id, ok: true, result: await op(job) });
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} catch (err) {
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parentPort.postMessage({ id: job.id, ok: false, error: err && err.message ? err.message : String(err) });
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}
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});
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