Hosted assets

Français · Type: how-to + reference · Audience: author · Context: hosted Studio · Status: ready · Applies from: 4.2.3

The Studio Server (hosted team Studio) · contract: experimental · verified by CI (support matrix of 4.4.0, 2026-10-23): Postgres, S3 and Keycloak in CI; Chromium and Firefox (job studio-hosted); WebKit on macOS, by hand only · automated checks: jobs studio-hosted, studio-install-smoke; CI plan studioHosted; 3 test files · people's passes: studio-hosted not run (#149), studio-collab not run (#150), studio-preview not run (#166), studio-assets-hosted not run (#167), studio-mcp-remote not run (#196), studio-oidc-generic not run (#197) · known limits: upload-bounds, cut-on-worker, prepare-bounds

On a team Studio the Assets tab works on the server: a reviewer reads the listing, the prompts and the files; a dev uploads sounds and decors, cuts sprite sheets, and prepares the game's images and sounds, as jobs on the worker. This page gives each action, its bounds, and the routes.

What you get

New art and sounds in the hosted game, each written as one operation; the prepared images and sounds every preview and build plays; and long work (cuts, Prepare) you can follow and cancel.

Context and versions

A hosted Studio with its worker: Prepare from 4.2.2, the Assets tab's uploads and cuts and the jobs from 4.2.3. The code is studio-server/src/server/hosted-assets.ts, prepared.ts and jobs.ts. On a local Studio, see Assets and cutting.

Prerequisites

• reviewer to read, dev to upload, cut and prepare (see Roles and actions).
• The worker deployed with its Python packages (its build hook installs ops/studio/worker-requirements.lock; see Configuration).

Where to run the commands

In the Studio, the Assets tab, and the Play tab for Prepare assets. Or through the API with a member's token.

Steps

1. Upload a sound or a decor (a dev). A sound is music or an effect (kind), an .ogg, .mp3 or .wav file whose bytes say the same; a decor is a PNG or a JPEG image. It is written as one operation, never run.

2. Cut a sprite sheet (a dev). Upload the sheet (a PNG, JPEG or WebP image) with its id and grid (6x4 by default). Cells that already exist are never recut by accident: name the cells to recut (r1c1,r2c3), or upload into a new sheet id. The cut runs on the worker as a job.

3. Replace or key one cell (a dev): one image for one cell of a sheet, keyed (its background made transparent) auto, always or never. Also a job.

4. Prepare the assets (a dev). Click Prepare assets (Play or Assets tab). The worker runs prepare on the head's art and sounds; the prepared set is kept by the Studio and served before publicDir, and the game's assets.gen.json is written as one operation. Each run prepares everything again.

5. Follow the job. A cut, a keying or Prepare answers at once (202) with a job; a small panel says where it is ("Cutting the sheet", "Keying the cell", "Preparing the assets") with a Cancel button.

Jobs

• The request answers 202 with the job. Its states go to the live stream (job events, in order: queued, running with its steps packing, on the worker, writing, then done, failed or cancelled), and GET /api/jobs/<id> reads it again (the page does when the stream is down).
• One runs at a time; four more may wait (429 past them).
• Cancel (POST /api/jobs/<id>/cancel, who started it, or an owner): a waiting job never runs; a running one has its request to the worker closed, and the worker kills its child with its process group; nothing is written (no operation, no prepared set kept) and the exclusive lease is given back. Once a job is writing, it is past cancelling (409).
• A job lives in the instance's memory: after a restart its state is gone (its write, if it was made, is in the journal).
• Cuts and Prepare run under the exclusive lease of the member who started them: nobody writes meanwhile, and someone else's span refuses them, with their name (the job fails with that 423).

Routes

data is the file in base64 (a data URL is accepted).

Bounds

Limit · upload-bounds An upload is 10 MiB at most once decoded (413 past it). Its type is read from its bytes: a PNG, JPEG or WebP image (a decor: PNG or JPEG), an Ogg, MP3 or WAV sound whose extension says the same (415 otherwise). A local Studio also takes M4A, FLAC, AAC, Opus and WebM sounds.

Limit · cut-on-worker A sheet's cutting and a cell's keying run on the worker (cut jobs, Python with the hook's packages, no game code). The worker gets the image, that sheet's cells and site.json, and gives back only cells of that sheet; the cells, with the backups of those recut, are written as one operation. A hosted Studio does not keep the uploaded sheet itself (a local one keeps it under private/sheets/, which no span names).

Limit · prepare-bounds Prepare runs within 2 minutes. It is refused, and the game is prepared on a local Studio, when its art and sounds pass about 31 MiB (in base64) or the prepared files about 22 MiB; when it names its sources in sources.json (they live outside the art and sounds a hosted Studio holds); or when the new manifest would lose an image or a sound the game had. Published builds serve the prepared set as it is now, not the one they were built against. The game's code runs on the worker as the asset tools' user (ADR 0028: one machine, one user).

Expected result, and how to check it

An upload or a cut adds a revision (the header moves); the listing shows the new files. After Prepare, the previews built from then on play the new images and sounds, and GET /api/assets/prepared lists the run.

Common errors

Files or data changed

art/, audio/ (span assets), the backups of recut cells, assets.gen.json; the prepared set in the bucket and a row of studio_prepared.

Recovery or going back

Uploads, cuts and Prepare are written without an undo. A file an upload or a cut replaced is kept as a backup (the answer names it, backup or backups): to go back, upload that earlier file again, or prepare again. A whole-game return is a restore (see Backups).

References

• ADR 0028.
• tests/studio-assets-hosted.test.ts, tests/studio-prepared.test.ts.

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