[bug#54986] [PATCH] gnu: mpd: Add support for socket activation.

["Ludovic Courtès" <ludo@gnu.org>]

Hi,

Liliana Marie Prikler <liliana.prikler@gmail.com> skribis:

> Am Mittwoch, dem 10.05.2023 um 17:14 +0200 schrieb Ludovic Courtès:
>> Hi,
>> 
>> Liliana Marie Prikler <liliana.prikler@gmail.com> skribis:
>> 
>> > Am Mittwoch, dem 03.05.2023 um 15:27 +0200 schrieb Ludovic Courtès:
>> > > It’s not just possible: several services in (gnu services …) and
>> > > (gnu home services …) use endpoints for systemd or inetd-style
>> > > startup.
>> > True, but to my knowledge they don't yet allow the user to specify
>> > those endpoints directly.  At the very least, they didn't when I
>> > started this thread, which was shortly after shepherd itself gained
>> > endpoints.  I'm happy to be proven wrong on this point.
>> 
>> They don’t let users specify the endpoints as such, but closely
>> enough.  For instance, the ‘interface’ field of <bitlbee-
>> configuration> is used to build it endpoint, and similarly for
>> ‘openssh’ and ‘dicod’.
>> 
>> Overall, it seems to me we don’t need a first-class <endpoint> type
>> in Guix System itself.
> It's funny you would argue that, because imho openssh would actually be
> a good candidate for supporting first-class endpoints:  Doing so would
> allow the user to specify whether IPv4, IPv6 or both (default) should
> be allowed for connections.  For other service that support sockets as
> well as TCP/IP ports, the benefit would be even greater.

For the services I mentioned, I don’t feel that lack of first-class
endpoints is a hindrance in terms of flexibility.  We’re trading
expressivity for ease of use.

> I understand that copypasting all the fields into Guix records is a bit
> of a non-starter, but I don't think it's a good idea to simply give up.
> I just need some pointers in which direction to continue.

Like I wrote, I’m kinda skeptical about the idea.  :-)

Now, if you find good motivating examples and find a way to express
endpoints that remain concise in common cases, that may be more
appealing to me!

Ludo’.