[Freeswitch-users] Limit application usage in Lua

Sat Mar 14 17:19:49 MSK 2015

I think what you did is not a dirty hack but normal scripting. You cannot
exit or stop in the middle of lua script. Just let it finish its job
13 марта 2015 г. 17:32 пользователь "Florent Krieg" <flokrrr at gmail.com>
написал:

> Hi Michael,
>
> Actually, here is what happens:
>
> Context: XML dialplan with the following extensions:
>         <extension name="limit_exceeded">
>             <condition field="destination_number"
> expression="^limit_exceeded$">
>                 <action application="respond" data="503"/>
>             </condition>
>         </extension>
>         <extension name="outgoing_call">
>             <condition>
>                 <action application="lua"
> data="dialplans/caller_script.lua"/>
>             </condition>
>         </extension>
>
> 1/ a call is started, the second extension entry in the XML dialplan
> matches and the action starts the lua script
> 2/ after having set some (a lot actually) variables, here is the code part
> for checking call-rate limits:
> -- Security (to avoid outage): limit CAPS
> --   hash backend is needed when using interval
> --   2 call attempts per 10 seconds here
> logz("[Calls limit] Checking caps for " .. billedcaller)
> session:execute("limit", "hash " .. billedcaller .. " caps 2/10
> !REQUESTED_CHAN_UNAVAIL")
> rate_var = session:getVariable("limit_rate_" .. billedcaller .. "_caps")
> if not rate_var then
>     logz("[Calls limit] CAPS limit reached for " .. billedcaller .. ",
> aborting the dialplan.")
>     return
> end
> 3/ after this code part, a lot of processing is done (for instance
> checking call restrictions calling external web services and so on), it's
> like 600 lines of lua there
> 4/ in the end, the session:execute bridge app is run
>
> At 2/, when limit is exceeded, I see in the log:
> 2015-03-13 12:22:40.454660 [INFO] switch_cpp.cpp:1328 * (caller/0) #
> 7a16c525263a8bb740517f5a28552016 at trunkinge.voip * [Calls limit] Checking
> caps for asteriskrd at trunkinge.voip
> EXECUTE sofia/internal_auth/asteriskrd at trunkinge.voip limit(hash
> asteriskrd at trunkinge.voip caps 2/10 !REQUESTED_CHAN_UNAVAIL)
> 2015-03-13 12:22:40.454660 [DEBUG] switch_limit.c:126 incr called:
> asteriskrd at trunkinge.voip_caps max:2, interval:10
> 2015-03-13 12:22:40.454660 [INFO] mod_hash.c:176 Usage for
> asteriskrd at trunkinge.voip_caps exceeds maximum rate of 2/10s, now at 3
> 2015-03-13 12:22:40.454660 [INFO] switch_cpp.cpp:1328 * (caller/0) #
> 7a16c525263a8bb740517f5a28552016 at trunkinge.voip * [Calls limit] CAPS
> limit reached for asteriskrd at trunkinge.voip, aborting the dialplan.
>
> and the a-leg is successfully hangup.
>
> But here, 3/ and 4/ are aborting only because of that code part:
> rate_var = session:getVariable("limit_rate_" .. billedcaller .. "_caps")
> if not rate_var then
>     logz("[Calls limit] CAPS limit reached for " .. billedcaller .. ",
> aborting the dialplan.")
>     return
> end
>
> It works, but I'm pretty sure that it is not the proper way to do it.
>
> If I remove that code part, even though the a-leg is hangup because of the
> leg being transferred to 'limit_exceeded', the rest of the dialplan is
> still processed, even though the call is aborted.
>
> I'd like to be able to catch right after doing session:execute limit app,
> the return of the command.
> If the call is transferred to 'limit_exceeded', then I'd like to abort the
> rest of the dialplan execution.
>
> I have to admit I might be missing something here therefore if you can
> help me, that'd be amazing.
> Thanks in advance
> Florent
>
>
> 2015-03-12 21:28 GMT+01:00 Michael S Collins <msc at freeswitch.org>:
>
>> Some context here would be helpful. Can you pastebin your Lua script, or
>> at least the relevant lines that demonstrate what is happening? Also, when
>> you say that the rest of the Lua dialplan is still processed, what does
>> that mean?
>>
>>
>>
>> -MC
>>
>>
>>
>> *From:* freeswitch-users-bounces at lists.freeswitch.org [mailto:
>> freeswitch-users-bounces at lists.freeswitch.org] *On Behalf Of *Florent
>> Krieg
>> *Sent:* Thursday, March 12, 2015 11:43 AM
>> *To:* FreeSWITCH Users Help
>> *Subject:* [Freeswitch-users] Limit application usage in Lua
>>
>>
>>
>> Hi all,
>>
>> I wanted to implement call rate limits using this Lua instruction:
>> session:execute("limit", "hash " .. billedcaller .. " caps 10/1
>> !REQUESTED_CHAN_UNAVAIL")
>>
>> It is actually working, but the rest of the Lua dialplan is still
>> processed, which is a problem in my case.
>>
>> I made a dirty but quick workaround, looking like this:
>> rate_var = session:getVariable("limit_rate_" .. billedcaller .. "_caps")
>> if not rate_var then
>>     logz("[Calls limit] CAPS limit reached for " .. billedcaller .. ",
>> aborting the dialplan.")
>>     return
>> end
>>
>> How can it be done properly?
>>
>> Is there a way to be able to get the result of the 'limit' app call?
>>
>> Or shall I check the status of the a-leg just after to decide to process
>> the rest of the dialplan or not?
>>
>> I know that this issue doesn't occur in a 'pure' XML dialplan, but I'm
>> trying to find a solution for my Lua-only dialplan.
>>
>> Thanks in advance if you have any idea.
>>
>> I'm willing to try any possible solution you would think about!
>>
>> Florent
>>
>>
>>
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>
>
> _________________________________________________________________________
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> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
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> http://confluence.freeswitch.org
> http://www.cluecon.com
>
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