Dependencies

[Scott James Remnant]

On Mon, 2009-07-06 at 19:48 +0300, Иво Георгиев wrote:

> Thanks. What am I searching for is, a system that supports events and
> dependencies, for example: I have a directory with jobs. Every job is
> configured to start on certain events, like upstart.
> Those jobs are configured to start in runlevel 4:
> udev, mount_filesystems, dbus, hal, networkmanager, pulseaudio, gdm.
> Upstart will start them all in once if there are configured that way,
> but what I need is, a system that will allow dependency configuration,
> so it will first start the jobs that don't have any dependencies -
> like udev. It will check all the time for jobs with met dependencies,
> and will start them. I also need events, for the same reason that
> upstart needs.
> 
A true dependency-based system would not do what you describe; it would
start things like udev in parallel with the lowest dependency of things
like gdm.  It wouldn't wait for udev to start first.

(This is what Upstart would do in the same situation as well.)


It sounds like what you actually want is priorities?  The feature being
that Upstart would prioritise starting certain jobs and _wait_ until
those jobs are running before starting anything else - even if it could?

(Without actually going as far to make udev as a dependency.)

I'm still thinking about that as a feature, because the use cases are
pretty murky and each one has its own specific needs right now.

In the simplest case, the event-based system already does exactly what
you need anyway; since you just artificially move them to after udev is
started with "on udev started"

Scott
-- 
Have you ever, ever felt like this?
Had strange things happen?  Are you going round the twist?
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