CentOS - Jun 2015 - Old and new package version numbers during RPM update

On 28/06/15 17:50, John R Pierce wrote:
> On 6/27/2015 5:38 PM, Anand Buddhdev wrote:
>> Thanks Joseph. I am aware of this option, but it would be only a last
>> resort, because checking the format of the config file is error-prone.
> 
> why doesn't the config file have the version in it ?   not having that
> makes your whole system error prone.
Perhaps I wasn't clear. Version 1 of the package uses a config file that
looks like this:

system {
  setting1 value1;
  setting2 value2;
}

interfaces {
  iface1;
  iface2;
}


Version 2 of the package has switched to a YAML-based syntax, so the
config file needs to look like this:

system:
  setting1: value1
  setting2: value2


So, I need to be able to program the RPM so that when upgrading from 1.x
to 2.x, it triggers the conversion utility that converts from v1 to v2
format.

Anand

On 6/28/2015 2:26 PM, Anand Buddhdev wrote:
> On 28/06/15 17:50, John R Pierce wrote:
>
>> why doesn't the config file have the version in it ? not having
that
>> makes your whole system error prone. 
> Perhaps I wasn't clear. Version 1 of the package uses a config file
that
> looks like this:
>
> system {
>    setting1 value1;
>    setting2 value2;
> }
>
> interfaces {
>    iface1;
>    iface2;
> }
>
>
> Version 2 of the package has switched to a YAML-based syntax, so the
> config file needs to look like this:
>
> system:
>    setting1: value1
>    setting2: value2
>
>
> So, I need to be able to program the RPM so that when upgrading from 1.x
> to 2.x, it triggers the conversion utility that converts from v1 to v2
> format.
so a regex looking for "system:" vs "system {"   should
nicely delineate
these.   I dunno, I might even put that into the conversion utility and 
have it just quit if the file is already in the new format, and always 
run it.



-- 
john r pierce, recycling bits in santa cruz

On 29 June 2015 at 07:37, John R Pierce <pierce at hogranch.com> wrote:
> so a regex looking for "system:" vs "system {"   should
nicely delineate
> these.   I dunno, I might even put that into the conversion utility and
> have it just quit if the file is already in the new format, and always run
> it.
>
?+1 for the idempotent approach. IMHO much more robust. Also consider what
will happen if someone does a 'yum downgrade' on the package or a
dependency -- you might want to allow the conversion to go both ways or at
least complain appropriately.

?K?