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Thread: Re: [PATCHES] Avahi support for Postgresql

Re: [PATCHES] Avahi support for Postgresql

From
Peter Eisentraut
Date:
Am Dienstag, 27. November 2007 schrieb Mathias Hasselmann:
> Postmaster already has code to announce its services via DNS-SD
> (ZeroConf) by using Apple's Bonjour API. This series of patches
> implements that capability on top of the Avahi library[1] which
> is free software, available for a wider variety of platforms.

Is there a reason we couldn't use the Bonjour compatibility layer offered by 
Avahi to keep the code differences to a minimum?

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/

Re: [PATCHES] Avahi support for Postgresql

From
Mathias Hasselmann
Date:
Am Montag, den 25.02.2008, 15:05 +0100 schrieb Peter Eisentraut:
> Am Dienstag, 27. November 2007 schrieb Mathias Hasselmann:
> > Postmaster already has code to announce its services via DNS-SD
> > (ZeroConf) by using Apple's Bonjour API. This series of patches
> > implements that capability on top of the Avahi library[1] which
> > is free software, available for a wider variety of platforms.
> 
> Is there a reason we couldn't use the Bonjour compatibility layer offered by 
> Avahi to keep the code differences to a minimum?

1) The Avahi's compatibility layer doesn't implement the now deprecated
function DNSServiceRegistrationCreate().

2) Unless DNSServiceRegistrationCreate() installs a lot of black magic,
the Bonjour code in postmaster.c has very poor error handling: There
seem to be no attempts made to handle name collisions (unless Bonjour
does this automatically, of course).

Ciao,
Mathias
-- 
Mathias Hasselmann <mathias@openismus.com>
http://www.openismus.com/ - We can get it done.

Re: [PATCHES] Avahi support for Postgresql

From
Tom Lane
Date:
Mathias Hasselmann <mathias@openismus.com> writes:
> Am Montag, den 25.02.2008, 15:05 +0100 schrieb Peter Eisentraut:
>> Is there a reason we couldn't use the Bonjour compatibility layer offered by
>> Avahi to keep the code differences to a minimum?

> 1) The Avahi's compatibility layer doesn't implement the now deprecated
> function DNSServiceRegistrationCreate().

Note that Apple themselves have been deprecating
DNSServiceRegistrationCreate for some time:

postmaster.c: In function 'PostmasterMain':
postmaster.c:856: warning: 'DNSServiceRegistrationCreate' is deprecated (declared at
/usr/include/DNSServiceDiscovery/DNSServiceDiscovery.h:139)

It's a fairly good bet that the function will disappear entirely from OS
X at some point, so we're going to have to change this code soon anyway.

What I'd like to know is whether the Avahi API that this patch is using
is compatible with whatever Apple is pushing as the not-deprecated API.
It would be annoying to tell Mac users that they have to install Avahi
to get at functionality that their platform provides natively.
        regards, tom lane