How can I modify Slicer's PYTHONPATH variable?

Support
1

Hi all,

afaik, Slicer does not inherit the system’s environment variables at startup, does it? If so, where does the python kernel in Slicer read its PYTHONPATH environment variable from? I have a few convenience functions which I currently have to import manually in the python console after every startup via:
import sys
sys.path.append("/path/to/my/utility/code")
For my native python kernel (anaconda env) in my OS (Mac), I put that info into ~/.bash_profile:
export PYTHONPATH=/path/to/my/utility/code:$PYTHONPATH
in order to access my custom code in all projects.
So, two questions:

  1. Is there an equivalent I can do for Slicer, such that my utility paths are loaded at startup?
  2. I regularly replace my Slicer nightly build with the latest version. Apart from “losing” all my extensions, I would then lose this path as well. Is there a way to make ideally both (extensions and PYTHONPATH) persistent?

Many thanks in advance!!
Cheers,
Ahmad

2

You can put such initialization code in .slicerrc.py file in your HOME folder. See details here: https://www.slicer.org/wiki/Documentation/Nightly/Developers/Python_scripting#How_to_systematically_execute_custom_python_code_at_startup_.3F

3

That’s great, many thanks for the quick response! :slight_smile:
About question 2: Is there any way to restore my extensions and my additional module paths after installing a new version of Slicer (e.g. a new nightly build), i.e. making them persistent? If not, I will keep re-loading/re-entering them manually.
Again, many thanks for your help!

4

In recent nightly builds, in the extension manager you can reinstall all previously installed extension by a few clicks.

If you want to add local modules (not installed through the extension manager) then you can do it manually in the slicerrc file. For example:

moduleFactory = slicer.app.moduleManager().factoryManager()
moduleFactory.registerModule(qt.QFileInfo(‘c:/D/SlicerDebuggingToolsExtension/PyDevRemoteDebug/PyDevRemoteDebug.py’))
moduleFactory.loadModules([‘PyDevRemoteDebug’])

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5

OK, that’s excellent… many thanks for these tips!

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