* spike: replace sharp with pure-JS image ops (jimp + jsquash WASM)
Removes the last native dependency from the ingest path, so the server no longer
needs a per-platform/per-ABI prebuilt to thumbnail an image. Motivated by getting
the server onto hardware with no toolchain, but the ABI tax is paid on every
install — it is the same failure class lib/preflight-deps.js exists to explain.
lib/image-ops.js is the whole surface: metadata() and writeThumbnail(), which are
the only two things ingest ever asked sharp for.
Format parity holds. jpeg/png/gif/tiff/bmp are native to Jimp; webp and avif go
through @jsquash WASM, whose bundled .wasm must be compiled by hand because the
packages locate it with fetch(file://) and Node has no file:// fetch — the only
symptom otherwise is a bare "fetch failed". heic is unsupported, as it already
was: sharp advertises heif but its prebuilt libvips refuses HEVC.
#170 is preserved by a different mechanism. Jimp applies EXIF orientation at
decode and rewrites the tag to 1, so metadata() reports display dimensions and
imageDisplayDims() runs as a no-op instead of swapping W/H a second time. The
helper stays in the path so the rule keeps living in one place.
Verified: 1643/1643 tests pass, and ingest was exercised in a child process with
node_modules/sharp moved aside — jpeg, EXIF-rotated jpeg, png, webp, avif, gif
all measured and thumbnailed correctly, corrupt input still yields nulls with no
phantom thumbnail_path.
KNOWN BLOCKER, do not ship as-is: Jimp is pure JS on the main thread, where sharp
handed work to a libvips threadpool. A 12MP photo goes 65ms -> 1079ms, and the
event loop stalls for 1003ms of it (sharp: zero stalls). thumbnail-backfill.js
walks a whole library at boot, so this reproduces #240 exactly — blocked loop,
missed heartbeats, panels marked offline, reconnect churn. Needs a worker_thread
offload before this is viable; image-ops.js is the seam for it.
* Run image decoding on a worker thread
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.
* Measure and thumbnail an image from a single decode
Ingest asked for metadata() then writeThumbnail(), which decoded the file twice.
That pairing was free under sharp, whose .metadata() only parses the header, but
every decode here is a full one — ~1s for a 12MP photo — so the naive translation
doubled the most expensive thing on the ingest path.
image-ops.measureAndThumbnail() returns both from one decode. Full ingest of a
12MP photo: 2 decodes/~1.9s -> 1150ms, still with zero event-loop stalls.
The subtlety is the failure contract. In the two-call version width and height
were assigned BEFORE the thumbnail was attempted, so a failed thumbnail still left
usable dimensions on the row — the player needs them to letterbox. Merging naively
would have turned any thumbnail failure into total metadata loss. So a WRITE
failure is reported ({thumbnailWritten:false, thumbnailError}) with the dimensions
intact, and the caller sets thumbnail_path only when the write succeeded, keeping
the phantom-path discipline. A DECODE failure still throws — there is nothing to
report about an unreadable image.
backfill-rotation-dims.js deliberately keeps the separate calls: it probes every
image row but regenerates a thumbnail only for the few whose dimensions changed,
so pairing them there would decode files it has no reason to thumbnail.
Tests count decodes rather than timing them — an exact property, and a wall-clock
comparison would be flaky under load. The count filters for reads of the file under
test: Node's ESM loader also goes through fs.promises.readFile, so a raw call count
picks up jimp's and the WASM codecs' lazy loading and reads 30 instead of 1.
1649/1649 pass. Ingest re-verified across all 7 formats with sharp moved aside.
* Dockerfile: sharp is no longer a production dependency
--omit=dev now leaves it out entirely; better-sqlite3 is the only native module
the builder stage still needs a toolchain for.
The runtime image never had ffmpeg, so every Docker deployment silently
lost video thumbnails and durations; the README never mentioned it for
bare-metal installs either.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0131RYmVh8ePEhparD3mXBhU
The player loads /player/st-bridge.js and /player/st-sync.js, both served from
../brightsign so the copy the player runs can never drift from the copy sitting
on the player's own storage. That runtime path only exists if the directory is
in the image, and the Dockerfile never copied it — so both routes 404 on alpha
while working perfectly from a dev checkout.
Caught by deploying 1.9.29-rc1 to alpha, which is the whole point of alpha.
Worth noting how this fails when the route is absent entirely, as on prod today:
the SPA fallback answers 200 with text/html, so the browser gets a page where it
expected JavaScript, window.ScreenTinkerBS is never defined, and the player
silently falls back to browser behaviour. A missing asset that returns 200 is
considerably harder to notice than one that 404s.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uaeo9MvzKoyXuN6ZsbhtkL
The /openapi.yaml route does res.sendFile(../docs/openapi.yaml) -> /app/docs/openapi.yaml in
the container, but the Dockerfile copied server/, frontend/, VERSION, scripts/ and never docs/,
so the spec 404'd in every deployed build (Redoc's /docs page loaded but couldn't fetch the
spec). Served fine from a dev checkout only because the repo has docs/ on disk. Verified in a
built image: /app/docs/openapi.yaml present, GET /openapi.yaml -> 200 text/yaml.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- .github/workflows/release.yml: on a v* tag - verify the tag matches VERSION
(fail-fast guard), run tests, build a source tarball + the unsigned Tizen .wgt
and publish a GitHub Release with generated notes, and build+push a multi-arch
(amd64 + arm64) image to ghcr.io/screentinker/screentinker:<version> + :latest.
The Release (artifacts) and the docker push are independent jobs, so an
arm64/QEMU docker failure does not block the GitHub Release and is re-runnable.
Nothing deploys to prod. APK-build-in-CI left as a TODO (keystore secret).
- Dockerfile + .dockerignore: multi-stage node:20-slim image with server +
frontend + VERSION + scripts; DATA_DIR=/data volume for db/uploads/jwt-secret.
Verified to build, boot, serve the dashboard + web player, and persist state.
- docker-compose.example.yml: /data volume, SELF_HOSTED, a node-fetch healthcheck
against /api/status, and an admin-lockout recovery note (reset-admin.js).
- server.js: resolve the OTA APK from DATA_DIR first (a container can mount one
at /data/ScreenTinker.apk), fall back to the legacy in-repo path, 404 gracefully.
- ci.yml: bump checkout/setup-node to v6 (clears the Node-20 action deprecation).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
