[systemd-devel] systemd DBus services exit when they have clients

[Simon McVittie]

On 14/11/14 16:46, Stef Walter wrote:
> On 14.11.2014 16:39, Lennart Poettering wrote:
>> The services like hostnamed explicitly provide stable object
>> paths and suchlike so that clients can completely ignore when
>> the services go away and come back...
> 
> Most DBus services are not like that, and usually callers do need
> to be aware of a service that goes away.
> 
> But I guess we could provide an option that instructs the proxy to 
> ignore a service's absence for use with systemd and any other 
> stateless services like this.

Er, don't D-Bus frameworks have that option already?

dbus-python has get_object() for stateful services and
get_object(follow_name_owner_changes=True) for stateless.

dbus-glib (which is otherwise awful, don't use it) has
dbus_g_proxy_new_for_name_owner() for stateful and
dbus_g_proxy_new_for_name() for stateless.

In both cases, the proxy will watch the name owner and keep a record
of it, so that it can trigger a signal subscription on signals that
come from from the current owner of the desired name.

(Having said that, I can't find whether GDBus has a way to get a proxy
for a stateless service. Perhaps it doesn't yet?)

Regards,
    S