Can't select interface in scripts

[mamert]

trafficstars

When I create and receive on a bus, it works fine: bus = can.interface.Bus(bustype='vector', app_name='CANoe', channel=0, bitrate=500000) or bus = can.interface.Bus(bustype='vector', serial=HW_SN, channel=2, bitrate=500000) # HW_SN defined elsewhere

However, the scripts don't work for me: python -m can.viewer -i vector -c 1 -b 500000 gives:

Traceback (most recent call last):
  File "C:\Python36-32\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\Python36-32\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Python36-32\lib\site-packages\can\logger.py", line 120, in 
    main()
  File "C:\Python36-32\lib\site-packages\can\logger.py", line 97, in main
    bus = Bus(results.channel, **config)
  File "C:\Python36-32\lib\site-packages\can\interface.py", line 127, in __new__
    return cls(channel, *args, **kwargs)
  File "C:\Python36-32\lib\site-packages\can\interfaces\vector\canlib.py", line 136, in __init__
    "xlGetChannelIndex")
can.interfaces.vector.exceptions.VectorError: xlGetChannelIndex failed (XL_ERR_HW_NOT_PRESENT)

Same for -c 0. Other values give:

...
File "C:\Python36-32\lib\site-packages\can\interface.py", line 127, in __new__
    return cls(channel, *args, **kwargs)
  File "C:\Python36-32\lib\site-packages\can\interfaces\vector\canlib.py", line 125, in __init__
    hw_channel, vxlapi.XL_BUS_TYPE_CAN)
  File "C:\Python36-32\lib\site-packages\can\interfaces\vector\vxlapi.py", line 206, in check_status
    raise VectorError(result, xlGetErrorString(result).decode(), function.__name__)
can.interfaces.vector.exceptions.VectorError: xlGetApplConfig failed (XL_ERROR)

I am confused that the scripts take neither app name, nor serial.

[mamert]

It seems the scripts take the FIRST available app config for the specified backend. In my case, it defaulted to CANalyzer (while I was using CANoe), and CANalyzer's logical interfaces were not configured in Vector Hardware Config.

Setting them helped, but it is a workaround, not a solution.

[karlding]

Right, this is because app_name and serial are Vector-specific arguments in the initializer, and the script currently doesn't actually provide a way to account for those options. We might want to consider adding a way to do so? I'm not exactly sure what the original intended scope of these scripts were, but perhaps @Lauszus can maybe provide some insight.

And as you mentioned, it takes the default channel configuration for CANalyzer, which is documented in the docs for the Vector interface, but perhaps that can be made more clear in the script documentation.

[Lauszus]

@karlding it should be fairly simply to add those Vector specific argument just like when CAN-FD was added to the script: https://github.com/hardbyte/python-can/commit/b1c7c131e63df182cf63c375c1cff713187cdd8a#diff-dad5644a0e09eac1a7acbf60b62d4eeb

[felixdivo]

This should be covered by #1170

[felixdivo]

I suppose it is.