[Freeswitch-users] Which Lua script am I?

[Mike van Lammeren]

I can only talk about the project in vague terms, due to client
confidentiality, but here goes:

Many thousands of devices will be reporting events, via HTTP Post, to a
central server farm. There will be at least 5 or 6 web servers recording
these events, and a similar number of VoIP servers running FreeSWITCH.
Communication between the web servers and VoIP servers is via a shared MySQL
Cluster. Certain events will result in FreeSWITCH originating a phone call,
playing a voice message to a human, then recording a number typed in by that
human.

It is important that each event result in just one phone call. We don't want
people bothered with multiple, simultaneous calls, and we don't want things
to be missed, either.

What do you think?


On Fri, Mar 5, 2010 at 2:16 PM, Michael Collins <msc at freeswitch.org> wrote:

> May I ask what the end goal is? It could be that there are better tools in
> the toolbox to help you...
>
> -MC
>
> On Fri, Mar 5, 2010 at 11:04 AM, Mike van Lammeren <mike at van.lammeren.net>wrote:
>
>> Hello!
>>
>> I am working on a high-availability system and need a Lua script that can
>> run in the background and loop forever, periodically waking up to accomplish
>> some tasks. I would like to be able to handle at least 10 concurrent tasks.
>>
>> My first idea was to have a simple background script that would call
>> another script, let's call it the 'task' script, every 5 seconds or so. This
>> would spread the work around, and if any task script quit with an error, the
>> background script would remain running, and would continue to launch new
>> task scripts.
>>
>> However, I can see no way for the background script to launch other Lua
>> scripts. Am I missing something? I need something like session:execute(),
>> but unfortunately this background script has no session, and I'm not sure if
>> session:execute() can even make a call like the "luarun" console command.
>>
>> So, my next ideas was to have 10 copies of the background script. Each
>> script would loop forever. Upon launch, each script would perform a single
>> task, then sleep for 60 seconds. This allows handling of 10 concurrent
>> tasks.
>>
>> However, there are some problems with running 10 copies of the same
>> script, which I believe can be solved if each script could be given a unique
>> identifier. One problem is that I would like the scripts to actually sleep
>> for a variable amount of time, say between 55 and 65 seconds, so that the
>> workload would spread around. Another, similar problem, is that each script
>> needs to 'claim' a number of database records from a table that is queuing
>> up work for the scripts. Once again, if each script had a unique identifier,
>> then I could use an update query to effectively 'set and test' a record that
>> would be tied to that script instance.
>>
>> I could use a random number to identify each script, but since math.random
>> is seeded with a timestamp that only resolves to seconds, then all 10
>> scripts will be given the same sequence of random numbers, and all 10 will
>> run in lock-step with each other. So, random numbers are out. (If I had a
>> unique ID to seed the random number generator, then I could just use that
>> unique ID and wouldn't need random numbers.)
>>
>> Is there a way of uniquely identifying 10 Lua scripts that FreeSWITCH
>> launches at startup?
>>
>> Or is there a better way of handling this situation altogether? I'm open
>> to any suggestions that people would care to make!
>>
>> (I would entertain the idea of a single script that would start with
>> FreeSWITCH, then launch 10 other scripts, giving each a unique identifier,
>> but that brings me back to the original problem of not knowing how to launch
>> other Lua scripts under FreeSWITCH.)
>>
>> Mike van Lammeren
>>
>>
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