Feature #2388 Fix Python environment issue

[georgemccabe]

These changes fix the issue that occurs when the X.Y version of Python in the user's environment matches the X.Y version used to complile MET, but the user's version doesn't have the required packages needed to run Python Embedding.

Expected Differences

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
  

Pull Request Testing

• Describe testing already performed for these changes:
  

Set up an environment to recreate the issue, confirmed it occurs before the changes and is resolved after the changes.

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  

On seneca, load a conda environment that has only the minimum METplus wrappers requirements, then run a Python Embedding example using the latest release and the branch to verify that the failure occurs and is resolved with the branch changes.

Set up env and verify the correct version of Python is in the path:

conda deactivate; conda activate /home/met_test/.conda/envs/metplus_base.v5
which python3

This should show /home/met_test/.conda/envs/metplus_base.v5/bin/python3

Run using /usr/local (currently MET 11.0.0):
/usr/local/met/bin/plot_data_plane PYTHON_NUMPY /d1/personal/mccabe/out/met_tool_wrapper/plot_data_plane/py_embed_fcst.ps 'name="/usr/local/met/share/met/python/read_ascii_numpy.py /d1/projects/METplus/METplus_Data/met_test/data/python/fcst.txt FCST";' -title "Python Embedding FCST" -v 1

Run using the branch:
/d1/projects/METplus/pull_requests/METplus-5.1.0/feature_2388/MET/bin/plot_data_plane PYTHON_NUMPY /d1/personal/mccabe/out/met_tool_wrapper/plot_data_plane/py_embed_fcst.ps 'name="/usr/local/met/share/met/python/read_ascii_numpy.py /d1/projects/METplus/METplus_Data/met_test/data/python/fcst.txt FCST";' -title "Python Embedding FCST" -v 1

Also test that a Python Embedding script can import met_point_obs without having to set PYTHONPATH.

Unset PYTHONPATH and update the path so the same version of Python used to compile is in the path:

export PYTHONPATH=
export PATH=/usr/local/met-python3/bin:$PATH

This should fail:
/usr/local/met/bin/ascii2nc "/d1/projects/METplus/pull_requests/METplus-5.1.0/feature_2388/read_ascii_point_mod.py /d1/projects/METplus/METplus_Data/met_test/data/sample_obs/ascii/sample_ascii_obs.txt" /d1/personal/mccabe/out/met_tool_wrapper/ASCII2NC/ascii2nc_python.nc -format python -v 2

This should succeed:
/d1/projects/METplus/pull_requests/METplus-5.1.0/feature_2388/MET/bin/ascii2nc "/d1/projects/METplus/pull_requests/METplus-5.1.0/feature_2388/read_ascii_point_mod.py /d1/projects/METplus/METplus_Data/met_test/data/sample_obs/ascii/sample_ascii_obs.txt" /d1/personal/mccabe/out/met_tool_wrapper/ASCII2NC/ascii2nc_python.nc -format python -v 2

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes]

• Do these changes include sufficient testing updates? [Yes]

After this is merged, another test would be to update the version of Python used to compile MET in Docker to match the conda envs used in the METplus use case tests, then see if the use cases run successfully. This previously failed.

• Will this PR result in changes to the test suite? [No]
  

• Please complete this pull request review by 1/16/2023.
  

Pull Request Checklist

See the METplus Workflow for details.

• Review the source issue metadata (required labels, projects, and milestone).
• Complete the PR definition above.
• Ensure the PR title matches the feature or bugfix branch name.
• Define the PR metadata, as permissions allow.
  Select: Reviewer(s)
  Select: Organization level software support Project or Repository level development cycle Project
  Select: Milestone as the version that will include these changes
• After submitting the PR, select Development issue with the original issue number.
• After the PR is approved, merge your changes. If permissions do not allow this, request that the reviewer do the merge.
• Close the linked issue and delete your feature or bugfix branch from GitHub.

[hsoh-u]

I approve the changes. It gives the proper messages when MET_PYTHON_BIN_EXE was not set on building. No instance of "python-config" except ./INSTALL (python-config was replaced with python3-config)

Running configure to create the Makefiles
configure: error: MET_PYTHON_CC or MET_PYTHON_LD environment variable set, but MET_PYTHON_BIN_EXE not set.  If one of these variables is set, then all must be set.

I did not check the differences between 1) by using environment variable "MET_PYTHON_EXE" and 2) by using MET_PYTHON_BIN_EXE (./src/libcode/vx_python3_utils/global_python.h)