C4: a device's `viewers` (superusers by default, or members) covers the
image and video messages its ports publish. Anyone else gets none of their
values on the socket, in the catalogue or a flow's state, 403 for their
history, for the frames they hold (the last 8 included) and for TURN
credentials, no bytes when asking for them, and `bye: forbidden` for a live
view. A device credential stays bounded by its dashboards. The device page
sets it in its Camera section, and a tile the viewer may not see says
"No access to this camera" and asks the camera for nothing.
C3:
- A volatile upload is held to MAX_FRAME_BYTES (4 MiB, 413 above it, read
without extra copies), and so is a frame on a device's socket.
- A frame the engine holds in memory is written to the ring directory
before a local worker is handed it, so load_artifact finds it.
- A socket the bus dropped events for catches up with a snapshot, demand
included, and a device's credential is checked again per frame, cached by
the flow store revision and its nonce, so a lost event never keeps an
unpaired device's frames coming.
- A report is at most 64 KB once its named config_schemas are put in place.
- A device away for 60 s has its true bool messages set to false.
- Refused frames are logged by fixed keys, a frame is named after its
message, `fluksio serve` waits 5 s for open connections, a tile with a
stream URL creates no demand, the 8-name cap keeps the newest names.
- Every container's log rotates (json-file, 3 x 10 MB).
A three-node cascade publishes 13-16 events and each one crossed to the
event loop on its own. They are one `call_soon_threadsafe` now — whatever
was published between two turns of the loop goes over together — and every
subscriber still receives every event, oldest still dropped first when one
falls behind.
The socket end of the same path:
- **any frame from the client ended its stream.** `receive_text` was
awaited once, outside the loop, so a keepalive — or anything else a
client decided to say — satisfied it and was read as the client going
away. It is recreated per iteration; only a disconnect ends the stream.
- events go out in one frame per wave (`{"type": "batch", "events": [...]}`,
capped at 64), serialised once with orjson rather than per client with
the stdlib's `json.dumps` through `send_json`. The client unpacks a batch
and still understands single frames, so an older engine behind a newer
bundle keeps working.
- authenticating and building the snapshot happen on a thread. Both were on
the event loop: one is a database round trip, the other reads the whole
of state, per connect and again per `dashboard_changed` per panel.
`Pipeline.values()` — what that snapshot is — no longer SCANs the whole
Redis namespace. It scanned five bookkeeping keys for every message to find
the messages; `RedisState` keeps a set of the names beside them and answers
from it. Maintained wherever a message is written, so a seeded value or a
deleted flow keeps it exact.
On the client, while in the same file:
- a `node_health` event invalidates the flow's detail. The canvas draws
health from the server-derived `issues`, so a node going down or
recovering only showed on mount, navigation or a rebuild. The store had
a health map of its own that nothing ever read; it and `useNodeHealth`
are gone rather than wired up, since the server's view is the one the
canvas already uses.
- a reconnect invalidates the five key families this socket feeds instead
of the entire cache, and the backoff is jittered. The usual reason a
socket dropped is the engine restarting, so every tab and every wall
panel refetched everything, together, at the moment it was least able to
answer.
- a frame that will not parse costs the frame, not the connection. It was
the one unguarded `JSON.parse` in the app; an exception there escaped to
`window.onerror` and left whatever it had already applied behind.
stroblme
Melvin Strobl