[LEDE-DEV] Stock config files as templates

[Magnus Kroken]

Hi Philip

On 25.07.2017 18:29, Philip Prindeville wrote:
> I’m guessing I’d need a sed script with a loop to gather all of the ‘server’ lines and replace them with one.
> 
> Or am I missing something obvious?

I think you are. Look at Dnsmasq and OpenVPN for two examples of UCI 
config integration. They do things slightly differently in terms of 
handling config files in upstream format (Dnsmasq/OpenVPN native config 
files), but they both use them.

Dnsmasq ships /etc/dnsmasq.conf, completely commented out. Users who 
need to or prefer to configure Dnsmasq in its native format can add 
their options to this file. The Dnsmasq init script parses the UCI 
configuration, and writes out a native Dnsmasq config file based on the 
UCI config to /tmp/etc/dnsmasq.conf.${cfg}. This temporary file includes 
/etc/dnsmasq.conf. Dnsmasq is finally started with the temporary config 
file specified on the command line, and will then include everything 
specified in /etc/dnsmasq.conf.

The OpenVPN init script parses each UCI openvpn section, and writes out 
an OpenVPN native config file to /tmp/etc for each section. OpenVPN is 
then started with the temporary config file specified on the command 
line. The OpenVPN init script also checks for any *.conf files in 
/etc/openvpn, and if any exist it will start an OpenVPN instance for 
each of them, specifying each *.conf file in /etc/openvpn on the command 
line.

Unlike Dnsmasq, OpenVPN UCI instances and native config instances 
(/etc/openvpn/*.conf) do not overlap (one exception: a native config 
instance can be disabled in UCI). Each single OpenVPN instance must be 
configured *either* entirely in UCI, *or* entirely in /etc/openvpn/*.conf.

If it makes sense to run onlye one instance, or more instances with some 
options common to all instances, the Dnsmasq approach makes sense. If 
running several instances with no common options between all, the 
OpenVPN approach makes more sense.

There may be more ways to do it, but both of these seem better than 
sed-ing a file. If you can avoid writing to flash outside of package 
install/image upgrade, it is best to do so (by only writing to /tmp).

> Thanks,
> 
> -Philip

Regards
/Magnus