Short human readable instrument snapshot.

[AdriaanRol]

@giulioungaretti
If we use instrument.snapshot() we get an overview of all parameters of an instrument, this is very useful for data storage. However, there is too much information to quickly scan over it.

Below I give an example, desired output first, current output after. I think the snippet below should (with some enhancements) be part of the base instrument class. Callable in the form of instrument.snapshot(concise=True).

Please let me know what you think.

Output of

for parname, par in FM_LaDucati.parameters.items():
    print('{}: \t{} ({})'.format(parname, par.get_latest(), par.units))

T_MClo: 	49.0 (mK)
IDN: 	{'vendor': 'QuTech', 'model': 'FridgeMon', 'firmware': '0.2', 'serial': None} ()
T_Still: 	None (mK)
T_Sorb: 	3836.0 (mK)
T_MChi: 	0.0 (mK)
fridge_name: 	LaDucati ()
update_interval: 	60 (s)

Output of fridge_monitor.snapshot():

{'__class__': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
 'functions': {},
 'name': 'FM_LaFerrari',
 'parameters': {'IDN': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'IDN',
   'name': 'IDN',
   'ts': '2016-11-19 13:23:17',
   'units': '',
   'value': {'firmware': '0.2',
    'model': 'FridgeMon',
    'serial': None,
    'vendor': 'QuTech'}},
  'T_MCStage': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'T_MCStage',
   'name': 'T_MCStage',
   'ts': '2016-11-19 13:23:17',
   'units': 'mK',
   'value': 0.0},
  'T_MChi': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'T_MChi',
   'name': 'T_MChi',
   'ts': '2016-11-19 13:23:17',
   'units': 'mK',
   'value': 0.0},
  'T_MClo': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'T_MClo',
   'name': 'T_MClo',
   'ts': '2016-11-19 13:23:17',
   'units': 'mK',
   'value': 32.3},
  'T_MCmid': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'T_MCmid',
   'name': 'T_MCmid',
   'ts': '2016-11-19 13:23:17',
   'units': 'mK',
   'value': 141.0},
  'T_Sorb': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'T_Sorb',
   'name': 'T_Sorb',
   'ts': '2016-11-19 13:23:17',
   'units': 'mK',
   'value': 4039.0},
  'T_Still': {'__class__': 'qcodes.instrument.parameter.StandardParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'T_Still',
   'name': 'T_Still',
   'ts': '2016-11-19 13:23:17',
   'units': 'mK',
   'value': None},
  'fridge_name': {'__class__': 'qcodes.instrument.parameter.ManualParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'fridge_name',
   'name': 'fridge_name',
   'ts': '2016-11-19 13:22:50',
   'units': '',
   'value': 'LaFerrari'},
  'update_interval': {'__class__': 'qcodes.instrument.parameter.ManualParameter',
   'instrument': 'pycqed.instrument_drivers.physical_instruments.Fridge_monitor.Fridge_Monitor',
   'instrument_name': 'FM_LaFerrari',
   'label': 'update_interval',
   'name': 'update_interval',
   'ts': '2016-11-19 13:22:50',
   'units': 's',
   'value': 60}}}

[nulinspiratie]

I like the idea a lot, it's currently a bit cumbersome to get the useful information out of a snapshot.
Would it make more sense to call this a separate function, such as instrument.print_snapshot(), where you can specify the level of output detail you want. I'm thinking this because otherwise the snapshot() would return either a dict or nothing, which feel like quite different behaviours.