[systemd-devel] [HEADS-UP] Packaging systemd

[Lennart Poettering]

On Wed, 07.07.10 07:37, David Zeuthen (zeuthen at gmail.com) wrote:

> > Interesting. So one one hand, you're saying "we're using the a
> > Desktop-file format because there's so many parsers / API for it", yet
> > with this move you break compatibility with a lot of them (in
> > particular GKeyFile [1]). Embrace and extend? Anyway, it's a bit too
> > clever... and, without getting all emotional... a bit inconsiderate
> > for my taste. Not that I'm super-invested in this (I'm not planning to
> > parse any of these files myself, anyway), but, any chance you can
> > figure out a better way to do this? Thanks!
> 
> In fact, turns out that valid desktop-files must not have multiple
> keys with the same name; from
> http://standards.freedesktop.org/desktop-entry-spec/desktop-entry-spec-1.0.html
> 
>   Multiple keys in the same group may not have the same name.
>   Keys in different groups may have the same name.
> 
> OK, so you actually said "closely follows"

I already downgraded that in the man pages a while back, after going
through the .deskop spec and comparing it with my own parser. It now
says "The syntax is inspired by XDG Desktop Entry Specification[1]
.desktop files, which are in turn inspired by Microsoft Windows .ini
files."

There are a few more places where we deviate from the .desktop
logic. For example: .desktop files tend to use ";" to seperate multiple
data values in the same fields. We use spaces.

BTW: GKeyFile says the following about multiple entries of the same name:

"Note that in contrast to the Desktop Entry Specification, groups in key
files may contain the same key multiple times; the last entry wins. Key
files may also contain multiple groups with the same name; they are
merged together. Another difference is that keys and group names in key
files are not restricted to ASCII characters. "

> Still, I think it might be nice to actually make it easy for GKeyFile
> and other software to use your configuration files. Anyway, I'm not
> terribly invested in this.

Yes, that would be nice. But unfortunately I am not convinced this would
really help the readability of the .service files. So I gave up on
providing full compatibility (though I must admit I never thought about
the GKeyFile parser, and now that I did I am a bit disappointed about
the fact that GKeyFile is more DOM-like than SAX-like, if you understand
what I mean). However, what I am thinking now would be a worthy goal is
to provide one-way compatibility at least: i.e. make GKeyFile useful to
write systemd unit files, although not all systemd unit files may
correctly be read by GKeyFile.

But yepp, it's a bit disappointing, and I am open for suggestions to fix
this differently...

Lennart

-- 
Lennart Poettering - Red Hat, Inc.