peter
05121fbc99
The module admitted its two opt-outs under a stated rule — "both enforce their own limit on the bytes they actually read, which is what makes opting them out safe" — and that rule is false for one of them. `POST /api/downloads/upload` declares `file: UploadFile = File(...)`, so FastAPI parses and spools the whole multipart part to a temp file BEFORE the first dependency runs, `require_human` included: its in-handler cap measures bytes that have already landed. Measured on the installed fastapi 0.141.1 / starlette 1.6.0 — starlette's max_part_size guards non-file parts only, so an anonymous chunked upload was bounded by nothing. In the shipped self-host compose that lands in a RAM-backed tmpfs. The exposure predates SEC-20 (no route was capped before it); what this branch added was the claim. So the list becomes a mapping of per-route CEILINGS instead of a set of exemptions: every request now gets a finite number, the upload route's being the same one the route itself enforces. `sysconfig`'s knob is bounded by it so an admin cannot raise the handler's cap past the edge and start collecting 413s from a layer the admin page never mentions — held by a test, not by prose. Two more things the review caught in the same module: The 413 was not byte-identical to `capped_body`'s after all. `json.dumps` puts spaces where JSONResponse does not, and the test that promised to hold them together compared PARSED JSON, so it could never have seen it. Built through the same JSONResponse now, and compared as raw bytes. And the middleware sat outside CORS and the security headers, so its 413 carried neither — on the split-origin dev setup the browser drops it and the user gets a generic network failure instead of the translated too_large, while the identical refusal from capped_body one layer down renders fine. It moves to just inside CORS: still ahead of the session, the setup gate and every auth dependency. Also corrected: the docblock's "largest non-exempt body is 64 KiB, ~16x headroom" (it is 512 KiB and 2x — the diagnostics sink, named eleven lines further down), and CLAUDE.md's Request SIZE row, which forbade the one correct use of capped_body that is actually in the tree.
Backend conventions
The rules below are already followed across backend/app — they lived only in a few module
docstrings (demo.py, userscope.py, routes/_common.py) until this file collected them (E3 S3,
B-core-20). When you add code, match these so the next reader doesn't have to guess "which pattern do
I copy".
Module layering
Three layers, by who runs the code — not by feature:
-
routes/…— request-only. A route module holds HTTP concerns: auth dependencies, request/ response models, status-code mapping, serialization. It owns logic that runs only on a request. Business logic that a request happens to trigger does not live here if anything else runs it too. -
plex/,downloads/,sync/,issues/— domain logic shared by more than one caller. Anything the scheduler or the worker runs (not just a request) lives in one of these domain packages, so the route, the worker, and the scheduler share one definition. Examples from this codebase:downloads/service.pyowns enqueue + the job state transitions (routes call it);plex/sync.pyis run by both the admin route and the scheduler;downloads/pipeline.pyis the worker's child pipeline;issues/bundle.pyis the one definition of a bug report's files, for the zip export and the tracker. -
Flat
app/*.pycore modules — cross-cutting primitives.auth,sysconfig,quota,audit,notifications,userscope,realtime,ratelimit,progress,logs(the one logging configuration),logsink(itslog_eventstable),diagnostics(a user's consented log level) anddebugsession(a recording that tags its user's lines, E16), … are single-file primitives many layers import. They depend on nothing above them (a core module must never import aroutes/…module).
Extraction trigger: the SECOND consumer. Keep new logic inline in its first caller. The moment a second caller needs it (a worker as well as a route; a scheduler as well as a route), extract it down a layer — into the relevant domain package, or a flat core module if it's cross-cutting. Don't pre-abstract for a single caller; don't leave shared logic duplicated once there are two.
Transaction ownership
This follows CLAUDE.md's canonical rule verbatim — "the handler/job-wrapper commits; helpers flush
(only quota owns its session)" — so read it that way, not as an exception to it. The commit belongs
to the operation owner; anything called inside another transaction only stages its change
(db.add / flush) and lets the owner commit, so the whole operation is one transaction.
audit.record() is the reference: it adds the audit row and the caller commits it together with the
mutation it records, so an audit entry can never exist without its change (or vice-versa).
- The operation owner is usually the route handler. A
service.*operation the handler delegates a whole transition to (e.g.service.cancel) is that owner and commits its one transition — it isn't a mid-operation helper. A helper that owns its OWN short-lived session (the worker'sjobdbwrites, the same carve-out CLAUDE.md grantsquota) commits that session. Everything else flushes. SessionLocalisexpire_on_commit=False: after a rawUPDATE+ commit, an ORM object you already loaded is stale. Read the fresh value from the row (RETURNING, or a re-SELECT), not the ORM attribute — seeservice.decr_ref_count.
Shared counters and status: do it atomically at the DB
- Never read-modify-write a shared counter in Python (
x.count = x.count + 1). Concurrent sessions lose an update. Use a DB-atomic statement —col = col + 1, orgreatest(col - 1, 0)withRETURNINGso the caller branches on the post-value under the row lock (service.incr_ref_count/decr_ref_count). - Download job status is a
JobStatusStrEnum (downloads/status.py), not bare strings. TheHOLDINGset defines which states hold aMediaAsset(so release accounting stays correct);STOPPED_BY_ROUTEis the route-initiated stop set. A worker child's terminal write goes throughservice.finalize_if_running(an atomicUPDATE … WHERE status='running') so a finishing child can't resurrect a job a route just stopped.
Config: one home per kind
app.config.settings— boot/env config (DB URL, download root, worker concurrency): read once at startup, not user-tunable at runtime.sysconfig.SPECS— the runtime admin knobs (DB-override-or-default). A new admin-tunable value goes inSPECS; don't invent a fourth store. (state.py'smaintenance_batchpredates this and is slated to fold intosysconfig— do not add more like it.)
The gate
Everything below must be green before a change is done (run via siftlode check):
ruff (backend) · tsc ×3 + eslint + prettier + knip (frontend) · vitest · pytest. The
pytest lane runs in backend/docker-compose.test.yml — an ephemeral Postgres + the backend tree
bind-mounted — so the DB-backed integration tests (the db fixture) actually run; SIFTLODE_TEST_ REQUIRE_DB=1 there turns a would-be silent skip into a hard failure. See docs/development.md.