penpot/exporter
Andrey Antukh b1cd524f9b ♻️ Drop the ! suffix from the exporter namespaces
Mechanical rename, no behavior change: every function the exporter
defines loses the `!`, at the definition and at every call site, in
`src` and in the tests. Two names could not just drop it: the
mutating `merge!` shares the namespace with a persistent `merge` of
another contract, so it becomes `merge-into`; the test restore thunks
take the role as their name (`fetch-restore`, `render-restore`). Two
dead pieces go away with their bangs: the never-called `rmdir!` and
an unused `mark!` binding in the cancel test. Untouched on purpose:
the stdlib (`swap!`, `run!`, `try!`, …), the `set!` special form,
`common` (`serialize-shape!`, `write-shape-*`), and the shared-key
config the deploy still reads.

AI-assisted-by: glm-5.3-flash
2026-10-07 14:37:08 +00:00
..
2026-09-29 09:07:34 +02:00
2026-10-06 15:12:15 +02:00
2026-10-06 15:12:15 +02:00
2020-08-05 11:19:34 +02:00

Exporter

Node process that renders shapes, frames and files to bitmap, SVG and PDF. It is a consumer: it polls the backend's :exporter job queue on Redis and drives each export through the backend's management API — claim, report the milestones, and settle (complete-job multipart with the artifact, or fail-job on error). There is no HTTP surface of its own and nothing is persisted on this side: the row of the job, its cancel button and its result all live in the backend.

How a job runs

  1. The backend dispatcher pushes [job-id, scheduled-at] (JSON) into penpot.worker.queue:<tenant>:exporter.
  2. One of the K pollers pops it and owns that connection for the whole run: the blocking pop is both the semaphore of the slot and the backpressure, so the process never runs more exports than pollers. K is PENPOT_EXPORTER_WORKER_CONCURRENCY (default 2, and the browser and wasm pools size themselves to the same figure).
  3. The poller claims the job over the management API and, on :run, mints a render session (create-job-session) through which every asset fetch happens as the owner of the job.
  4. The milestones are reported as beats (:preparing, :rendering, :packaging, with the objects and pages counters). A watchdog re-sends the last one every second, whatever the run is doing.
  5. It settles with complete-job (the artifact rides multipart, the session is closed in the same step) or fail-job. The settle never rejects: a worker that cannot talk leaves the row to the backend's lease GC.

Cancellation

A cancellation reaches the worker through the beats: a skip answer means the backend no longer listens (the row is terminal), so the runner stops between units of work; mid-Skia the watchdog terminates the leased render worker. The row was already cancelled by the backend's cancel-job.

Configuration

Variable Default Description
PENPOT_PUBLIC_URI — The frontend the assets render through
PENPOT_INTERNAL_URI public-uri Same network's frontend; the management API too
PENPOT_REDIS_URI redis://redis/0 The queue and the rest of redis
PENPOT_TENANT default Queue prefix (workspace name in devenv)
PENPOT_EXPORTER_SHARED_KEY — The shared key; derived from the secret otherwise
PENPOT_EXPORTER_JOB_TTL 3600 Lifetime of the temp files a job owns, in seconds
PENPOT_EXPORTER_WORKER_CONCURRENCY 2 K: pollers, running exports, pool sizes
PENPOT_WASM_WORKER_POOL_MIN 1 Render workers kept warm; clamped to the max
PENPOT_WASM_WORKER_IDLE_TIMEOUT 300 Silence before a worker is terminated, in seconds
PENPOT_WASM_WORKER_IMAGE_CACHE_SIZE 134217728 Per-worker image cache budget, in bytes

Inspecting the backend

Nothing about a job is stored here: get-job in the backend answers the full row, and its app.debug/admin surfaces render the same records.