[systemd-devel] how to get sd_notify state/variables from dbus?

[Lennart Poettering]

On Fri, 08.01.16 18:09, Rick Richardson (rick.richardson at gmail.com) wrote:

> I have a fleet of applications that need to pass some critical variables
> back to systemd so that our services monitor can collect them.  My hope is
> that this can be done via sd_notify as it is very much a config-management
> and process monitoring related task.
> 
> Currently my monitor subscribes to PropertiesChanged in dbus, and gets the
> active/running notification upon an sd_notify from the service, I can see
> the StatusText variable set via the STATUS=... but I can't seem to figure
> out where the rest of the notify state is stored.

It currently is not. 

We could expose this data I figure, but I am not entirely sure how
that could even look like, as for unknown sd_notify() fields it's not
clear whether they are supposed to extend or replace any unrelated
previously set settings... i.e. if you first send X_FOO=1 and then
X_BAR=1 and then query the data, would you get "X_FOO=1 X_BAR=1" back,
or just "X_BAR=1"? The former would mean we'd might get into trouble
if people keep inventing new fields. The latter would mean it's
useless if people assume additive operation of the the data...

Hence, let's take a step back: which field are you particularly
interested in?

Lennart

-- 
Lennart Poettering, Red Hat