How to run nrfutil in a container to maintain the python2 installation.

[sylvanco]

I have python 2 and 3 on my Macbook.  I can't run nrfutil which I believe is due to the python installation.  I need to keep python 3 for other utilities. I would like to run nrfutil in a container with the correct python configuration.

Running nrfutil is producing errors as shown.

nrfutil keys generate private.pem
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/bin/nrfutil", line 11, in <module>
    load_entry_point('nrfutil==3.5.1', 'console_scripts', 'nrfutil')()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/nordicsemi/__main__.py", line 321, in generate
    signer.gen_key(key_file)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/nordicsemi/dfu/signing.py", line 79, in gen_key
    sk_file.write(self.sk.to_pem())
TypeError: write() argument must be str, not bytes

[Jørgen Holmefjord]

Hi,

You should be able to install pip for both Python 2 and Python 3. Have you tried googling some solutions for this? This thread sounds like it could solve your request.

Best regards,
Jørgen

[sylvanco]

That's a great reference, thanks.

The problem I have is how to control which Python is used when executing nrfutil.  The article is general to Python and I'm looking for something specific to NRF development.  I think that setting up a docker container would be great and have no impact on the OS which I hate to meddle with as it can break other tools and applications.

[Jørgen Holmefjord]

nrfutil currently only works with Python 2. I would expect it to execute with the correct Python version that it was installed with though pip. Unfortunately, I'm not familiar with setting up docker containers on MacOS (or any OS for that matter).

[sylvanco]

There's some work in this area and it looks really interesting.  Jumper is setting up continuous integration (CI/CD) for embedded software which is based on a docker container with the embedded tools installed. 

https://blog.jumper.io/nrf52-build-server/#comment-4028101209