The reader loop exited silently on any socket error, leaving conn/sock
set so the session still looked open. Every later get()/post()/ping()
then waited out its full request timeout on a session nobody was
reading, raising SessionTimeoutError on repeat, forever.
This started biting in v0.1.3 (d677c72), which moved to connected UDP
sockets: a connected socket surfaces ICMP errors on recv, so one
ECONNREFUSED from a rebooting appliance now killed the reader.
- Advisory ICMP errnos (ECONNREFUSED/EHOSTUNREACH/...) no longer kill
the reader; the next datagram usually works.
- Real reader exits log at WARNING; close()-driven exits stay quiet.
- A _reader_running Event lets get/post/ping/subscribe/refresh_observes
fail fast via _check_live() with SessionClosedError instead of waiting
out a timeout. Callers that never start a reader are unaffected.
Refs QuiteYellow/SmartThings-Local#37
Jack Nagy
7a74a955f3