Re: [PATCH 6/6] dts: add statefulness to TestPmdShell

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

On Thu, Mar 28, 2024 at 5:49 PM Jeremy Spewock <jspewock@iol.unh.edu> wrote:
>
> On Tue, Mar 26, 2024 at 3:04 PM Luca Vizzarro <luca.vizzarro@arm.com> wrote:
> >
> > This commit provides a state container for TestPmdShell. It currently
> > only indicates whether the packet forwarding has started
> > or not, and the number of ports which were given to the shell.
> >
> > This also fixes the behaviour of `wait_link_status_up` to use the
> > command timeout as inherited from InteractiveShell.
> >
> > Signed-off-by: Luca Vizzarro <luca.vizzarro@arm.com>
> > Reviewed-by: Jack Bond-Preston <jack.bond-preston@arm.com>
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > ---
> <snip>
> > @@ -723,7 +731,13 @@ def _start_application(self, get_privileged_command: Callable[[str], str] | None
> >          if self._app_args.app_params is None:
> >              self._app_args.app_params = TestPmdParameters()
> >
> > -        self.number_of_ports = len(self._app_args.ports) if self._app_args.ports is not None else 0
> > +        assert isinstance(self._app_args.app_params, TestPmdParameters)
> > +
>
> This is tricky because ideally we wouldn't have the assertion here,
> but I understand why it is needed because Eal parameters have app args
> which can be any instance of params. I'm not sure of the best way to
> solve this, because making testpmd parameters extend from eal would
> break the general scheme that you have in place, and having an
> extension of EalParameters that enforces this app_args is
> TestPmdParameters would solve the issues, but might be a little
> clunky. Is there a way we can use a generic to get python to just
> understand that, in this case, this will always be TestPmdParameters?
> If not I might prefer making a private class where this is
> TestPmdParameters, just because there aren't really any other
> assertions that we use elsewhere and an unexpected exception from this
> (even though I don't think that can happen) could cause people some
> issues.
>
> It might be the case that an assertion is the easiest way to deal with
> it though, what do you think?
>

We could change the signature (just the type of app_args) of the init
method - I think we should be able to create a type that's
EalParameters with .app_params being TestPmdParameters or None. The
init method would just call super().

Something like the above is basically necessary with inheritance where
subclasses are all extensions (not just implementations) of the
superclass (having differences in API).

> > +        if self._app_args.app_params.auto_start:
> > +            self.state.packet_forwarding_started = True
> > +
> > +        if self._app_args.ports is not None:
> > +            self.state.number_of_ports = len(self._app_args.ports)
> >
> >          super()._start_application(get_privileged_command)
> >
> <snip>
> > 2.34.1
> >