Server 20.04 verses 16.04: python-gnuplot

[Bryce Harrington]

On Sun, Jan 19, 2020 at 04:24:13PM -0800, Doug Smythies wrote:
> I have been unable to get it working on a new 20.04 installation.
> If I attempt to install "python-gnuplot" I get:

Yes, efforts in focal development are striving to remove python2, so for
20.04 forward the python3-* packages are the ones to prefer.

> If I try to install "python3-gnuplot", it wants to convert
> my server installation into a full blown desktop.

  # apt-get install python3-gnuplot
  ...
  ...
  ...
  4 upgraded, 375 newly installed, 0 to remove and 122 not upgraded.
  Need to get 129 MB of archives.

Yikes, yes you're right, that's kind of crazy.

python3-gnuplot only has a couple dependencies; the problem appears to
be gnuplot itself, which is pulling the whole X11 stack in.  Looking at
the gnuplot package, it actually provides three variants:  gnuplot-x11,
gnuplot-qt, and gnuplot-nox.

If you do this:

  # apt-get install gnuplot-nox python3-gnuplot
  ...
  0 upgraded, 45 newly installed, 0 to remove and 126 not upgraded.
  Need to get 32.7 MB of archives.

it cuts down quite a bit.  Most of this appears to be fonts and file
formats, which seems reasonable although it's probably still more than
you actually need.

  triage-focal+20.04:~/ubuntu/Gnuplot/gnuplot-5.2.8+dfsg1/debian$ python3
  Python 3.7.5 (default, Oct 27 2019, 15:43:29) 
  [GCC 9.2.1 20191027] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import Gnuplot
  >>> print(Gnuplot.__version__)
  1.8
  >>> 


> I do not
> want that. Even if I do allow it (i.e. I did already, by mistake),
> the script still doesn't work:
> 
> doug at s18:~/freq-scalers/trace$ sudo ./intel_pstate_tracer.py --interval 300 --name t01 --memory 800000
> Traceback (most recent call last):
>   File "./intel_pstate_tracer.py", line 35, in <module>
>     import Gnuplot
> ImportError: No module named Gnuplot
> doug at s18:~/freq-scalers/trace$
> 
> Any suggestions how I can get this stuff to work on a
> 20.04 server?

Make sure your script is using python3 in its shbang:

  #!/usr/bin/env python3

HTH,
Bryce