get_make_and_model job script needs error handling

[Jeff Lane ]

The script for the get_make_and_model test needs some error handling:

Traceback (most recent call last):
  File "/tmp/nest-_pl8cjn6.fbd3f20087f458957ae660d98a5fba5b563896d472aaa533495e1cd9dc308272/get_make_and_model", line 17, in <module>
    raise SystemExit(main())
  File "/tmp/nest-_pl8cjn6.fbd3f20087f458957ae660d98a5fba5b563896d472aaa533495e1cd9dc308272/get_make_and_model", line 12, in main
    print_file_contents('Manufacturer', '/sys/class/dmi/id/sys_vendor')
  File "/tmp/nest-_pl8cjn6.fbd3f20087f458957ae660d98a5fba5b563896d472aaa533495e1cd9dc308272/get_make_and_model", line 6, in print_file_contents
    with open(filename) as f:
FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/dmi/id/sys_vendor'

This is the result when run on an ARM system that has no DMI.

Solution: add error handling so that the test gets data from somewhere else on ARM systems, or just does not run on ARM if this data is not retrievable.

[Jeff Lane  (bladernr)]

slightly more complicated... error handling and some revising of the innards is done... but now I need to look into device-tree to add support for the device-tree analogs to the /sys/class/dmi files we use on x86 systems.

[Jeff Lane  (bladernr)]

Ok, so I ended up gutting and rewriting the script.

I needed code to handle both dmi (x86) and device-tree (armhf/arm64).

The problem is that device-tree is entirely arbitrary, so one system may not have the same device-tree nodes as another, and some don't support device-tree at all.

So, I converted the script to instead get the data from lshw as that comes on both x86 and arm systems rather than a bunch of platform dependent ID code.

lshw is at least "fairly" universal and does support both interfaces for system info. The script will return output like so:

Version: NOT FOUND
Model: Model Name
Manufacturer: Big OEM Company

We are looking for three items specifically, and if lshw doesn't provide that item, we simply return NOT FOUND.

I ran this on an x86 system that provided all three via DMI, an armhf system that provided only 1 of them and an arm64 system that provided 2 of the three. I pinged about whether it would work on Power, but that's still an unknown. We can deal with that separately if it comes to it.