Use DBus instead of CLI output?

[Obihoernchen]

This is just an improvement idea to have a more stable and probably faster interface to systemd.

Check this nagios service it already uses DBus to get the data instead of parsing CLI output: https://github.com/pengutronix/monitoring-check-systemd-service

Also read systemd/systemd#83

It might be interesting to look into this :)

[Josef-Friedrich]

Sounds interesting. The disadvantage is that an additional dependency is needed. I have no experience with DBus at all. Do you want to contribute and work on a --dbus switch? That would be great!

[uvu9Ba]

Would busctl be a solution? Included since SystemD v221 (2015-06-19)
http://0pointer.net/blog/the-new-sd-bus-api-of-systemd.html

# Get fancy name of service
$ busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LoadUnit s httpd.service
o "/org/freedesktop/systemd1/unit/httpd_2eservice"


# Get unit properties
busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/httpd_2eservice org.freedesktop.systemd1.Unit 
 ActiveState SubState
s "active"
s "running"


# Get service properties 
$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/httpd_2eservice org.freedesktop.systemd1.Service Type                     
s "notify"


# Get all properties
$ busctl introspect org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/httpd_2eservice
[...]
org.freedesktop.systemd1.Unit       interface -               -                                        -
[...]
.ActiveEnterTimestamp               property  t               1610548622757209                         emits-change
.ActiveEnterTimestampMonotonic      property  t               188708154100                             emits-change
.ActiveExitTimestamp                property  t               0                                        emits-change
.ActiveExitTimestampMonotonic       property  t               0                                        emits-change
.ActiveState                        property  s               "active"                                 emits-change
[...]

[Josef-Friedrich]

Thank you for this hint! Using busctl would again end up in CLI output parsing? Wouldn’t it? In this script I played with the Python D-Bus API., which looks promising IMHO. But nevertheless the script has to be rewritten entirely.