[systemd-devel] [question] networkd: Any support for hooks?

[Dale R. Worley]

> From: Tom Gundersen <teg at jklm.no>

> What we do, however, is to expose the configuration state using the
> sd-network C API, which external programs can watch and react on (see
> how timesyncd and resolved currently works).

In a situation where one wants to do what a "hook" does, having a
separate daemon program that watches for an event and then invokes the
hook when the event happens is not a good solution -- it replaces the
hook with an entire daemon.

I am not experienced, but from what little I know about systemd, the
"natural" way would seem to be to write a new unit file with the
appropriate dependencies.  The event that should call the hook is when
some unit finishes starting, and then the new unit would then be
started.  The new unit's ExecStart command would be the desired
invocation of the hook.

Does that make sense?  If it does, it might be useful to write a
beginner's guide on how to construct and insert such a unit into a
system.

Dale