Install daemon in stopped state

[Evan]

If you use an interface in your snap that is not auto-connected, for example system-files, and you have a daemon that relies on that interface being connected (in this case because it reads /sys/class/dmi/id/product_serial), the snap will fail to install and remove itself.

You could get most of the way there by using interface hooks and `snap set some-service command=start`, but you wouldn't have any way to install the snap with the daemon in a stopped state.

[Zygmunt Krynicki (zyga)]

This area is under development / cleanup / design extensions by Ian from the snapd team. I will relay this bug to my colleague.

[Ian Johnson (anonymouse67)]

This is not a bug exactly because what happens is that the service fails to start, and thus the install is aborted.

The solution here is to use the install hook to disable the service as the install hook runs before the services are started, and we no longer start services which have been disabled from the install hook. Then in the post-connect hook you can restart the service.

We may eventually enable a way for a service to be declared as initially disabled in the snapcraft.yaml, but this is not on our current roadmap.