WIP: Implement `get_network_instances`

[mirceaulinic]

[dbarrosop]

pylama is not happy with you : )

[mirceaulinic]

@dbarrosop did you have a look at the code - I was thinking to move some static hashmaps/globals in a separate class JunOSGlobals. Does this make sense to you?

[dbarrosop]

Yeah, I saw it, I was thinking about it. I think it makes more sense to have a constants.py file. We could have one on napalm-base for constants that might be good for all the drivers, ie, timeout. And then have a constants file on each driver. Something like:

napalm-junos/constants.py
---------------------------
from napalm_base.constants import *

THIS_IS_A_JUNOS_CONSTANT = 'blah'

And then:

napalm_junos.py
----------------

import constants as c

c.MY_GLOBAL_CONSTANT # (comes from the from napalm_base.constants import *)
c.THIS_IS_A_JUNOS_CONSTANT

It also has the benefit that if we need it, we could override MY_GLOBAL_CONSTANT on a particular driver by just adding it to the driver-specific constant files.

[mirceaulinic]

Yes, that looks good @dbarrosop!

[mirceaulinic]

For the record - submitted this PR according to the discussion above: https://github.com/napalm-automation/napalm-base/pull/149

[mirceaulinic]

I've rescheduled this one for 0.6.0 - can't make it this week when I plan to release 0.5.0.