So then Alan Conway says:
On Mon, Jun 17, 2019 at 3:33 AM Schaik, Jacco van <jacco.van.sch...@nlr.nl>
wrote:
Hi,
I'm building an application using the Qpid Proton C API, version 0.28.0.
I'm using a Connection Driver because my application has its own event
loop.?
Everything seems to be working, but the application on the other side of
the connection has an idle timeout, so if nothing comes over the line for
(in my case) 30 seconds it times out and drops the connection. I know AMQP
has heartbeat messages that can be used to keep the connection open, but
obviously Proton doesn't get a chance to send them when I'm waiting in my
own event loop.
Now I can have my event loop wake up every now and then, and call a Proton
function to send a heartbeat. But I haven't been able to find a function
that does that?. I've tried calling pn_transport_tick() but that doesn't
seem to work. Is there some other function that will send a heartbeat for
me?
pn_transport_tick() takes a timestamp and checks if a heartbeat is needed.
If it is, it adds that to the "to-do" list for the next outgoing write and
marks the transport as writable. The heartbeat actually will be sent on the
next write. Note that heart beats are *only* sent if the connection is idle
for longer than the idle-timeout, as if there is normal traffic then no
heart beats are needed.
It is safe and recommended to call pn_transport_tick() every time you wake
for IO. It will queue up a heartbeat frame for writing if needed, and
return the next time at which it should be called. You should set a timer
on your event loop in case there is no IO before then. You can reset the
timer on each call to pn_transport_tick to avoid un-necessary wakeups, but
it's always safe to make extra calls to tick(). The timestamp you use
doesn't have to represent any particular time, it should be a monotonically
increasing count of milliseconds, for exmaple libuv's uv_time() or the
POSIX CLOCK_MONOTONIC.
Right, that was the missing link. I was using a counter that went up by
one on every call (that also rises monotonically, after all). I've
changed it to go up by 1000 on every call, and now Proton is giving me
heartbeats to send out.
Thank you!
Groeten, - Jacco
--
+--------------------------+ It's 15:32 CEST on Monday June 17 2019.
| Jacco van Schaik | Outside it's 24°C with a light breeze from
| ja...@jaccovanschaik.net | the southwest.
| www.jaccovanschaik.net |
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