virEventRunDefaultImpl waits for an event that an idle domain need not
produce, so the thread could outlive a deactivation that reported success, and
every later activation was refused while it did. Registering a timeout is what
makes it return: measured, a thread with nothing registered was still running
four seconds after being asked to stop, and with a half second timer it came
out at once.
Deactivation dropped its reference once the wait expired, whether or not the
thread had stopped, so the next activation started a second one and revived
the first by setting run_console again. The reference is cleared only when the
thread is really gone, and activation refuses with 0x80 while one is alive.
That makes the wait a courtesy rather than a correctness measure, so it drops
to a second.
Activation started an event thread whichever way the base handler had just
answered, so a refusal started one anyway and an already active console got a
second. activated alone cannot tell the two refusals apart, being true
already on the already active path, so the value from before the call decides.
Deactivation joined that thread on the event loop, where it could stall every
other session and its own response. The wait moves off the loop and is
bounded, and the thread is a daemon.
The console awaits its output handler, but both sample BMCs supplied a plain
function, and both dropped the send_data coroutine. virshbmc additionally
receives its stream callback on a libvirt thread, so the send goes through
run_coroutine_threadsafe against the loop captured at activation, called
asyncloop because the class already has a loop method it uses as a thread
target.
ServerConsole asked the session layer to retry, which a ServerSession cannot
do: it never runs Session.__init__, so it has no timeout, and its _timedout
does nothing. IpmiServer.logout was synchronous and an argument short while
_cleanup awaits logout(False). The boot options handler answered, then read an
unbound name and answered again with 0xff.
bmc.py, serversession.py, fakebmc.py and virshbmc.py were byte identical to
upstream pyghmi: the async port went through the session layer beneath them
and left the server side alone. So every response created a coroutine and
dropped it, and the overrides the now async parent awaits returned None.
Running fakebmc bound no socket, spun a core, and answered nothing.
Everything that sends a response is a coroutine now, and so is the dispatch
that reaches it; the hooks a subclass implements stay ordinary functions, so
an out of tree Bmc is unaffected unless it overrides the payload handlers.
Two things had to leave their constructors, both being coroutines: assigning
the server socket, into bind(), which is why listen() is no longer a
classmethod, and answering the open session request, into
send_open_session_response.
Verified against upstream with ipmitool over nine commands, with identical
output. SOL is not covered: fakebmc reports the payload disabled on both.
A task per read swallowed failures, could deliver keystrokes out of order, and
at end of input returned with the reader still registered, so a level
triggered selector called it again for the same EOF. The reader queues now,
one consumer sends in order, and it is gathered with the main loop so a
failure reaches the caller.
The Console was never connected, so main_loop ran against a session that had
never been established. Input arrived on a thread that called send_data and
dropped the coroutine; the thread is gone and the loop watches stdin with
add_reader instead. The output handler was a plain function that
Console._print_data awaits.
Command lost its constructor for an async create classmethod, so the utility
raised TypeError before connecting. The onlogon callback it was built around
is gone as well: create establishes the session itself, so both the callback
and the eventloop that waited for it are unnecessary.
docommand awaited nothing, so every operation produced a coroutine that was
printed and dropped, and three of its calls are async generators. Each BMC is
handled in turn now rather than only the last.
Console.main_loop drives Session.wait_for_rsp, which is a coroutine, so it
spun without ever waiting for a packet. It is a coroutine now, and pyghmicons
runs its main under asyncio.run. pyghmiutil had the same shape around
Command.eventloop.
Markus Hilger
Jarrod Johnson