[OpenSIPS-Users] RFC: text pre-processing in OpenSIPS cfg file
Saúl Ibarra Corretgé
saul at ag-projects.com
Tue Apr 10 22:36:55 CEST 2012
On Apr 10, 2012, at 6:13 PM, Ali Pey wrote:
> I also think it would be a great addition to have a simple build-in text pre-processing. For more advance features people can continue to use m4 as desired.
The problem is the word "simple" on your sentence :-) How do we tell if a feature request qualifies as "simple" or not?
For me, the config file is fine as it is. It does have limitations, but m4 helps in solving them.
> On Tue, Apr 10, 2012 at 12:05 PM, Nick Altmann <nick.altmann at gmail.com> wrote:
> Against for M4:
> Configuration file may not be generated properly from m4 file(s)
> sometimes (because missed errors in m4), then server cannot start in
> some cases. It's when m4 in init.d script. When cfg-file built from m4
> manually, it's uncomfortable.
> In my opinion, opensips is the most powerful sip server, so it should
> have both options. And users should make decision which to better use
> in each case.
You should not attempt to run OpenSIPS with the new generated file before testing it, you may have made a silly typo and the server would be stopped. You can do it in 2 steps:
- Regenerate the cfg file from the m4 files and call use opensips -c to validate the config file
- Restart the service if the config was valid
> 2012/4/10 Bogdan-Andrei Iancu <bogdan at opensips.org>:
> > Hi,
> > I'm bringing here a discussion started on devel list, as I would like to get
> > more opinions on the matter.
> > The discussion started around the decision if makes sense to have MACRO
> > substitution (as text pre-processing) directly in OpenSIPS, considering that
> > right now M4 is heavenly used for this (as additional tool to opensips).
> > So, the debate was : have built-in text pre-processing versus using M4 as
> > text processor
> > Pros for M4:
> > - no effort to develop extra stuff - just install M4
> > - can do really complex things (more than only macros, ifdef, include,
> > etc)
> > - you can use it or not
> > - easy to integrate with start / stop scripts
> > Against for M4:
> > - need to be installed and integrated
I'm not aware of any system where installing m4 is troublesome.
> > - you may have a mismatch for the line number (if errors reported in
> > cfg) between the .m4 file and .cfg file
While this is true, you can look at the generated cfg file, and leaving comments is also a good idea ;-)
> > Pros for buit-in:
> > - you do no need to install M4 at all (everything comes packet)
> > - you may get accurate reporting on errors (for line in cfg)
> > Against for M4:
> > - more devel work to re-implement macros, ifdef, etc
> > Now, I would like to get your opinions on that (you as opensips users), to
> > see if we stick to using M4 for cfg pre-processing or there is a real need
> > to have this functionality as built-in.
As I said in the other thread I think that using resources for enhancing the current configuration language is not a good idea. Ideally I'd like to program my routing logic in a real programming language like Python, Lua or Ruby not something totally different which newcomers need to learn and is not a fully blown programing language.
M4 is a powerful tool which can be used together with the current configuration language to achieve all the requirements mentioned in the previous mail, without modifying OpenSIPS.
Maybe it would be a good idea to use m4 in the sample configs? Having a opensips.m4 file with the main routing logic and some local.m4 file with custom settings like DB configs, etc could help people get their feet wet with m4. Even adding a "opensipsctl reconfigure" command could make sense, it could just do the following:
m4 opensips.m4 > opensips.cfg
opensips -c /etc/opensips/opensips.cfg
So if there is an error you could see it before actually attempting to run OpenSIPS with the change applied.
Those are my 2 cents :-)
Saúl Ibarra Corretgé
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