RFC: ENH: allow direct execution of CLI python scripts using Slicer's python
This is a quick hack demonstrating a potential solution to this issue and related problems (e.g. running multiprocessing).
tl;dr, this detects a .pycli file in a CLI directory (cli-modules), and then configures the CLI node to run the script via Slicer's python interpreter. As an example, for SlicerRadiomicsCLI, this gives the following command line:
RadiomicsCLI command line:
/opt/bld/s5nj/python-install/bin/python inner-build/lib/Slicer-4.9/cli-modules/SlicerRadiomicsCLI.py --label 1 --out /var/folders/7l/2qsp6sqx4_b5x9kf_yzzm4lc0000gn/T/Slicer/EBACJ_vtkMRMLTableNodeB.csv /var/folders/7l/2qsp6sqx4_b5x9kf_yzzm4lc0000gn/T/Slicer/EBACJ_vtkMRMLScalarVolumeNodeB.nrrd /var/folders/7l/2qsp6sqx4_b5x9kf_yzzm4lc0000gn/T/Slicer/EBACJ_vtkMRMLLabelMapVolumeNodeB.nrrdThe command is exec'd via the existing CLI mechanism, runs out-of-process and async as any other CLI would be, but it inherits the full Slicer environment without requiring any launcher/cmake/etc. steps. Running directly also avoids OS security policy issues caused by shelling-out to protected interpreters.
Note that this is different from the current scripted CLI module path which runs in-process and blocks on the interpreter for the duration of the call (but should have no effect on that code path).
This PR does not handlepython-real in a factory-packaged Slicer, and other issues, but I wanted to put it up for feedback before spending time on it.