A dropped connection used to hang the whole platform permanently, and three
defects composed to do it (BUGS.md B-01):
The read loop's death was invisible. When the socket closed, _read_loop broke out
and finished, but _run_once was blocked on gather() over two notification
consumers waiting on queues nobody would ever fill again — it never returned and
never raised, so the reconnect-with-backoff logic was unreachable.
client.wait_closed() now resolves when the loop ends for any reason, and
_run_once races it against the consumers and a keepalive with
asyncio.wait(FIRST_COMPLETED).
Nothing had a timeout. request() registered a future, wrote to a half-closed
socket (drain() often doesn't raise) and awaited a reply that would never come.
That hung a POST /bets *while holding the per-user lock*, and could stop the
confirmation poller for good. Every request is now bounded at 15s, and a timeout
tears the connection down rather than leaving a server that owes us a reply in
rotation.
There was no keepalive, so on a quiet instance the normal way this connection
dies is an idle-timeout drop by the server (~10 minutes for many). A server.ping
every 60s makes that observable within a minute.
listener.client is also cleared before reconnecting, so callers stop treating a
dead connection as live.
On top of the finding, the listener now rotates over a list of servers:
ELECTRUM_FALLBACK_SERVERS holds comma-separated host:port[:notls] extras, tried
after the primary. Everything the platform does goes through this one connection
— deposit credits, broadcasts, confirmations, the chain tip the draw waits on —
which made a single hardcoded server its biggest point of failure. A failed or
dropped session moves to the next server immediately and only sleeps on the
backoff once every server has had a turn, so one dead server costs one attempt
instead of an outage, while a genuinely offline network still backs off. A
malformed entry fails at startup, not during the outage when the fallback is what
you need.
Also fixes B-19: header handling refuses a height below the current tip and
applies height and hex together, since _wait_for_next_block waits for
tip_height > tip_at_close (a regression silently added a block to the draw's
wait) and that hex is the draw's entropy source, so a mismatched pair would be
worse than a stale one.
Verified in the live deployment: the log shows the endpoint list, then "Electrum
connected to santantonio.sytes.net:50002", and the connection holds.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
davideandClaude Opus 5
7c4e9983ea