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.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M6hPWS6YEbT1P8LxhhFb2T
Measured with `make bench-engine` against a real Redis: 103.6 -> 164.4
messages a second on a five-node chain (p50 latency 2125 -> 1171 ms) and
34.8 -> 63.2 on a fan-out of twenty. Against the memory backend, which is
what a pip install runs on, 262 -> 626.
The two that bought most of it:
- `StateBackend.record` puts a published value, its timestamp, its series
and its version counter in one round trip. They were four calls building
four pipelines, and a value crossing an edge pays them twice. A released
rate-limit hold rides along instead of a DEL per port.
- the readiness check reads a node's inputs and hands them to the node,
rather than reading the triggering ones to count them and having the node
read the same keys again a moment later.
`apply_outputs` was a second copy of `_record_outputs` and is now the same
code plus the event that distinguishes it.
The rest, each small:
- `_derive` builds a node-by-id map and a `consumes` index, so dispatching
an item and publishing a value stop scanning every node in the
installation.
- `read_all` is memoised against the store revision — it sits on the
publish path, so a dashboard slider was reading and validating every
flow file per value. Same mechanism `_wiring` already uses.
- the `message_value` source block is built once per node instead of per
emission.
- both timer threads ask the queue to promote only when something is
actually due, which takes an idle engine from ~4 Redis round trips a
second to one.
- the shared httpx client is bounded (32 connections, one retry); its
default pool is 100 with no per-host cap, so one slow endpoint could
take it and every other sender node with it.
- the MQTT and delay nodes no longer log a line per message at INFO.
Robustness, in the same pass:
- `MemoryWorkQueue._done` was a set nothing ever removed from — one entry
per non-idempotent node per item, for the life of the process, in the
default configuration. Capped, the way the Redis side expires its
markers.
- a saturated engine can claim from the due lane past the cascade limit.
The capacity gate sits in front of the claim, so the due lane's priority
— decided inside it — did not apply while every slot was held: a motor's
stop was not behind the long nodes, it was unread. Only after a slot has
genuinely failed to free for half a second, and briefly, so the backlog
is not starved in turn.
- `reclaim_stale` dispatches through that same gate. It could return sixty
entries and push in-flight far past the limit the gate exists to hold.
- a flow's nodes are stopped together rather than one after another. Each
gets `NODE_STOP_TIMEOUT`, so a flow whose broker was unreachable took
five seconds per node — long enough to outlast `REBUILD_WAIT` and 503
the deploy.
- the worker pool and the HTTP client are closed on a thread, not on the
event loop, and a run closes the state backend it built (on Redis, a
client and a connection pool per run).
- the five background tasks say something when they die. Each catches
exceptions inside its loop, so one raised anywhere else left the engine
serving with no metrics, no alerts or no artifact sweep, silently.
`tests/flow/test_round_trips.py` counts the state operations one message
costs — four, where it was about eleven — because none of the above would
fail a behavioural test if it were undone.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M6hPWS6YEbT1P8LxhhFb2T
A bool was excluded from the history as "not a measurement", so a true/false
port had no curve in the node panel and none on an edge — only the word. It is
recorded as 0/1 now and drawn as steps, since a bezier through two states
slopes through readings that never happened. The axis is pinned to 0..1, so a
flag that was never on sits at the floor rather than mid-box.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The engine was I/O-bound on its own state backend. `RedisState.lock()` is one
key — `pipeline:_lock` — for the whole process, taken five times a message at
two round trips each, and every cascade and every node read queued behind it.
Inside it, reading a node's inputs was three round trips per input (an EXISTS
for `in`, then EXISTS and GET for the value), writing was two updates that a
single transaction already gives, and the version counters went one INCR at a
time.
Replaced with the atomic command that was always available: `get_present` is
one MGET and tells a missing key from one holding null, so the lock it used to
be read under bought nothing; value and timestamp land in one `update`, which
is a MULTI/EXEC; `increment_multi` pipelines the counters. `values()` — what
every websocket snapshot calls — is two reads whatever the message count
instead of two per message.
Beside that: every webhook did its blocking XADD on the asyncio event loop
(MQTT already used `to_thread`); the per-execution `NodeOutcome` was built and
validated even with no run watching; `_minute` built a tz-aware datetime per
event on the loop thread to key a dict, and now keys on an int; `move_due`
promoted delayed items one round trip each, every second; `FLOW_MAX_CASCADES`
makes the in-flight ceiling a setting rather than a constant.
`orjson` replaces stdlib json where a message pays for it — state, the
journal, the engine side of the worker pipe. `fluksio-worker` stays
dependency-free, and the run-cache digest stays on stdlib so no stored key is
invalidated. A non-finite number now stores as `null` rather than the bare
`NaN` that was never JSON.
Measured with `scripts/bench_engine.py` against a real Redis, 200 messages:
a five-node chain went from 43.9 to 103.1 msg/s with p50 latency 2110ms →
782ms and p95 3913ms → 1439ms; one source into twenty consumers went from 5.4
to 33.7 msg/s. In memory, twenty consumers went from 187 to 448 msg/s.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BpfSinyCBfjuieikyfMPbf
A wheel whose top-level module is `app` collides with anything else in a
user's venv, so the package that is about to be published takes the name
it is published under. Only the Python package moves; the repo, the
Docker WORKDIR and the compose project keep theirs.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
stroblmeandClaude Opus 5