Please add Documentation= field in systemd .service files

[bigon]

Hi,

systemd .service files can add a reference to a man page with documentation about the daemon it starts (ie Documentation=man:upsd(8))

Would be nice if this was added

[jimklimov]

Per https://www.freedesktop.org/software/systemd/man/latest/systemd.unit.html

Documentation=

A space-separated list of URIs referencing documentation for this unit or its configuration. Accepted are only URIs of the types "http://", "https://", "file:", "info:", "man:". For more information about the syntax of these URIs, see uri(7). The URIs should be listed in order of relevance, starting with the most relevant. It is a good idea to first reference documentation that explains what the unit's purpose is, followed by how it is configured, followed by any other related documentation. This option may be specified more than once, in which case the specified list of URIs is merged. If the empty string is assigned to this option, the list is reset and all prior assignments will have no effect.

Added in version 201.

• [ ] I think this would be best implemented as a mix of manually added links to man pages (perhaps right in the .in templates) and an URL generated to rolling NUT website (for branch builds) or specific "historic" release snapshot website (when building from a release tag).

• Should configure check for systemd version (and/or support of the property?) given that v201 is Apr 2013? The oldest systemd-equipped Linux currently in NUT CI farm, CentOS 7, had systemd v234 already.

• Wondering if usage()/help() methods of programs would benefit from a similar reference...

• [ ] The nut-driver-enumerator should create similar entries when it creates service unit instances for each nut-driver@DEVICENAME.

• [ ] Similar links make sense for SMF units (static and NDE-generated if possible).