Call dbus methods provided by non-Snap daemon from Snap

Is it possible to call non-Snap application dbus methods from Snaps?

For example, I want to access com.redhat.tuned provided by the tuned native Ubuntu package.

I added the following to my snapcraft.yaml file:

      - tuned-dbus

    interface: dbus
    bus: system
    name: com.redhat.tuned

But AppArmor blocks access:

= AppArmor =
Time: Jul 24 17:51:18
Log: apparmor="DENIED" operation="dbus_method_call"  bus="system" path="/Tuned" interface="com.redhat.tuned.control" member="profiles" mask="send" name="com.redhat.tuned" pid=13010 label="snap.tuned-switcher.tuned-switcher" peer_pid=7524 peer_label="unconfined"
DBus access

Trying to connect slots manually, but got an error:

ubuntu@ubuntu:~$ sudo snap connect tuned-switcher:systemd-dbus
error: snap "snapd" has no "dbus" interface slots
ubuntu@ubuntu:~$ sudo snap connect tuned-switcher:tuned-dbus
error: snap "snapd" has no "dbus" interface slots

snapcraft.yaml source

Hi! I’m afraid that you need to create a snap for the tuned service, because the dbus interface always requires a matching slot. See also this thread.