trying to separate pyDevSup as a module from IOC

[iljabek]

Hello,

I'm testing following design:

/opt/epics
          /modules
                  /[...]
                  /pyDevSup
                           /devsupApp
                           /mysupApp
                                     /fitting_sup.py
                                     /fitting_sup.db
                           /python3.5/linux-x86_64/fitting_sup.py
          /iocs
                  /iocmy
                           /myApp
                                  /fitting.py
                                  /fitting.db
                           /python3.5/linux-x86_64/fitting.py

• once with the mysupApp inside the pyDevSup (which works fine)
• and once with the myApp separate from pyDevSup, linking to its binary
• the last one is giving me the following error

MY:PV: Exception in add_record
Traceback (most recent call last):
  File "/opt/epics/modules/pyDevSup/python3.5/linux-x86_64/devsup/db.py", line 338, in processLink
    mod = importmod(modname)
  File "/opt/epics/modules/pyDevSup/python3.5/linux-x86_64/devsup/util.py", line 18, in importmod
    return __import__(modname, fromlist=['__should_not_exist'])
ImportError: No module named 'fitting'

I guess it tries to look for modules in /opt/epics/modules/pyDevSup/python3.5/linux-x86_64/and does not know about /opt/epics/iocs/iocmy/python3.5/linux-x86_64/

does this error interpretation make sense? is this desired behaviour?

[mdavidsaver]

External modules need to set $TOP (and optionally $ARCH) in their environment prior to iocInit() to include $TOP/python$PY_VER/$ARCH in $PYTHONPATH. A simple way to do this is by sourcing 'envPaths'.

http://mdavidsaver.github.io/pyDevSup/environment.html#pythonpath

https://github.com/mdavidsaver/pyDevSup/blob/44e5bd98b9bf2516585da6fcd844a68d36a3311c/devsupApp/src/setup.c#L339-L360

[iljabek]

I think I have given the correct values for $TOP and $ARCH in 'iocmy'. the error does not change.

at the time of execution of /opt/epics/iocs/iocBoot/iocmy/st.cmd the binary (in my case) /opt/epics/modules/pyDevSup/bin/linux-x86_64/softIocPy3.5 is already compiled and is being called.
it will not contain the specific python path.

sofar what works for me is to call the st.cmd with export PYTHONPATH=${PYTONPATH}:$$PWD/python$(PY_VER)/$(EPICS_HOST_ARCH); cd ./iocBoot/iocmy/; ./st.cmd

I'm sorry, I don't understand how to tell python in run-time where to look for includes. could you expand?

[mdavidsaver]

sofar what works for me is ...

This looks very nearly the same as what the code I quoted above is doing if your st.cmd script contains:

epicsEnvSet("TOP", "$PWD")

This is only a convince though. You may find it more convenient/clear to explicitly setting $PYTHONPATH before lanching softIocPy, or extending sys.path within. All the usual ways of defining the python module search path should work as normal.

After starting softIocPy you can inspect the search path with:

py "import sys"
py "print(sys.path)"

This often helps me to get an idea of what settings have actually been applied.

[mdavidsaver]

Were you able to resolve this issue and set the python path?