On 03.09.2014 13:02, Saúl Ibarra Corretgé wrote:
On 03 Sep 2014, at 11:59, Bogdan-Andrei Iancu <bog...@opensips.org> wrote:
On 03.09.2014 12:06, Saúl Ibarra Corretgé wrote:
On 02 Sep 2014, at 18:26, Răzvan Crainea <raz...@opensips.org> wrote:
Hi all,
Among the last discussion of the last IRC meeting[1] was related to
Asynchronous processing in OpenSIPS script - we want to add a new mechanism
that allows you to perform asynchronous operations (such as DB , REST or exec
operations) directly from the script. Using this feature will increase the
throughput of OpenSIPS, since the SIP processes will no longer be stuck waiting
for I/O responses.
When reaching an asynchronous operation, the SIP message processing will be
stopped, and resumed in a different script route. In the script, this should be
reflected something like this:
route {
...
# other non I/O operations
async(my_resume_route) {
avp_db_query("SELECT setid from subscribers where username = '$fU'",
"$avp(setid)");
}
# we never get here.
exit;
}
route[my_resume_route] {
xlog("The set used by the callee is $avp(setid)\n");
# continue message processing
}
Only the functions that are used in an "async" block will be ran asynchronously. If the
function does not support async processing, it will block waiting for the response and resume in
the route indicated by the "async" block - so the scripting experience will be the same
even if the async OP could not be done.
I find this quite problematic. How does John Doe know a function supports async
or not? Maybe the configuration checker can know this and not let OpenSIPS
start if you are doing it wrong? Alternatively, blocking functions could be ran
in a thread pool thus giving the illusion of them being async.
First of all, the function will be documented as supporting Async and the script parser
may check it (we will export some extra flags for the function to say "it can do
async").
Secondly, the script will allow you to use any combination of functions and
script macro - I mean the script will allow you to use an async function in a
non-async way (and the function will act as sync) or to use a non-async
function in an async way (the function will act as async and with a jump to
resume route).
My concern is with that last part: if a function which doesn’t support async is
called within an async block it will block but then make the jump thus
deceiving the user into believing it was async when it isn’t. We need to fail
loudly and tell users they are doing it wrong, iMHO.
Of course, we can detect that at script parsing and decide how to handle it:
- ignore and do it blocking
- warning and do it blocking
- error and do not start.
Regards,
Bogdan
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