[systemd-devel] Starting units when a port is available for connections

[Adam Zegelin]

> On 27 May 2015, at 8:40 pm, Andrei Borzenkov <arvidjaar at gmail.com> wrote:
> 
> Hmm ... this sounds suspiciously like what D-Bus does. Did you consider
> using D-Bus in your application? 
> 
> But for now there is no way to express such dependency in systemd;
> D-Bus being exception, you can make services dependent on D-Bus end
> points.

I’ve considered it now :) I communicate with systemd via D-Bus for starting & stopping services.

How does one write a service unit that depends on a D-Bus endpoint? Is this supported by systemd, or is this an application level thing? I’m unable to find anything in the systemd docs about creating dependencies on D-Bus endpoints. 


> I wonder - can your master service trigger startup of clients when it is
> ready? Note that it can be done in completely generic way - it can
> simply run something like cassandra.target and you can plug in any
> client into this target.

This is another option that I’ll play with. 

Thanks,
Adam