[Asterisk-Users] Re: Proposed solution for exit code priority jumps

[John Todd]

At 8:53 PM -0600 1/14/04, Steven Critchfield wrote:
>On Wed, 2004-01-14 at 14:12, Jeremy McNamara wrote:
>>  John Todd wrote:
>>
>>  > I realize this is a major code shift, since it would require work in
>>  > pretty much every single application.  It's easy for me to talk about
>>  > this since I can't accomplish such a task.  However, without attention
>>  > now, this may never be solved, which would be a pity because it's a
>>  > real crimp in the style of anyone doing more than trivial dialplan
>>  > manipulation - anyone doing cascading dial failovers will attest to that.
>>
>>
>>  We were talking in the conf the other day about possibly creating a 'F'
>>  extension for 'failure'.  I'm not sure if this is even remotely close to
>  > what your talking about or not.
>
>Hmm, F would be good, possibly B also. I could see a good case for the
>lead digit for a pattern doing a goto to a context that could define
>those for outbound calls.
>
>[normal_extensions]
>exten => 9,1,Goto(Extended_out,s,1)
>
>[Extended_out]
>exten => s,1,Playtones(dialtone)
>
>exten => F,1,background(Failed)
>exten => F,2,hangup
>
>exten => B,1,congestion
>
>exten => _NXXXXXX,1,Dial(Zap/g2/${EXTEN})
>
>
>This example tightly controls the B and F special extensions to a
>specific dial in the context.
>--
>Steven Critchfield <critch at basesys.com>

That's a step in the right direction, I suppose, but we've already 
got applications that break this model (ENUM lookups, as an example, 
have a third return state of +51 on successful tel: lookups.)  As we 
get more sophisticated applications, we start crippling ourselves 
just to stick with "the way it's always been."

I see sanity only in one of two paths:

   - eliminate exceptions; reduce possible returns from an application 
to either Success, Fail or Busy, and hand back any other possible 
values by setting some arbitrary string

   - have some method that allows controlled Goto's based on the 
numeric failure code, and then have every application list it's 
possible failure codes in the "show application <blah>" summary

JT