[SR-Users] Using lock() correctly

[Sebastian Damm]

Hi again,

since there really isn't much to find about the lock() function, can
somebody tell me if my assumptions about how it should work are wrong?
Daniel?

Best Regards,
Sebastian

On Wed, Jun 28, 2017 at 1:39 PM, Sebastian Damm <damm at sipgate.de> wrote:
> Hi,
>
> for a project I need to make sure, I have a setup where I get
> mirror-traffic into Kamailio which has to do something with it. To
> work correctly, I need to make sure, the initial INVITE is processed
> correctly before any reply to the same call. So I thought I use lock()
> and unlock() for it.
>
> This is what the relevant kamailio.cfg part looks like:
>
> request_route {
>   xlog("L_INFO", "Got new packet $rm: $si => $Ri\n");
>   route(li);
> }
>
> onreply_route {
>   xlog("L_INFO", "Got new packet $rm: $si => $Ri - Reply Code $rs\n");
>   route(li);
> }
>
> route[magic] {
>   lock("$ci");
>   xlog("L_INFO", "Obtained lock, calling lua...\n");
>   if(!lua_run("handle_packet")) {
>     xlog("L_ERR", "SCRIPT: failed to execute lua function!\n");
>   }
>   unlock("$ci");
>   xlog("L_INFO", "Lua finished, released lock...\n");
>
>   drop;
>   exit;
> }
>
>
>
> And this is what the log says:
>
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: <script>: Got
> new packet INVITE: 172.20.21.247 => 172.20.21.4
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: <script>:
> Obtained lock, calling lua...
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: app_lua
> [app_lua_sr.c:98]: lua_sr_log(): some logging
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18837]: INFO: <script>: Got
> new packet INVITE: 172.20.21.4 => 172.20.21.247 - Reply Code 407
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18837]: INFO: <script>:
> Obtained lock, calling lua...
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18837]: INFO: <script>: Lua
> finished, released lock...
> Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: app_lua
> [app_lua_sr.c:98]: lua_sr_log(): some more logging
>
>
>
>
> As far as I understand the documentation, the second packet should
> wait for the lock on the Call-ID before executing the lua function. So
> process 18836 should finish its lua execution before 18837 can do
> anything further. Did I completely misunderstand the lock() function?
>
> I'm using Kamailio 5.0.2.
>
> Thanks for helping me understand what Kamailio is doing here.
>
> Best Regards,
> Sebastian