NFV VIM fails on StopIterator exceptions in newer python

[Al Bailey]

When running the VIM (nfv) on debian bullseye (which uses python 3.9.2) the VIM fails to start.

The exception is a little misleading

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/nfv_vim/vim.py", line 167, in process_main
    selobj.selobj_dispatch(PROCESS_TICK_INTERVAL_IN_MS)
  File "/usr/lib/python3/dist-packages/nfv_common/selobj/_selobj_module.py", line 105, in selobj_dispatch
    callback.send(selobj)
  File "/usr/lib/python3/dist-packages/nfv_common/tasks/_task_scheduler.py", line 332, in task_work_complete
    task.task_work_complete(task_work)
  File "/usr/lib/python3/dist-packages/nfv_common/tasks/_task.py", line 193, in task_work_complete
    self._target.send(task_result)
RuntimeError: generator raised StopIteration

_task.py", line 193 target.send is expected to raise a StopIteration
and _task_scheduler.py" line 332 expects to catch it.

However in python 3.7 (and later) a change was introduced (mentioned here)
https://docs.python.org/3/whatsnew/3.7.html#changes-in-python-behavior
and described here:
https://www.python.org/dev/peps/pep-0479/

which means we need to change the vim code everywhere that does this:
except StopIteration:

to instead be this:
except (StopIteration, RuntimeError):

These are the places in the code that need to be updated:
nfv_common/tasks/_task_scheduler.py (5 places)
nfv_common/timers/_timer.py (1 place)
nfv_common/selobj/_selobj_module.py (3 places)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/nfv/+/831841

[Al Bailey (albailey1974)]

Even though I uploaded a review, I am leaving this unassigned because I hate that I get so many emails for launchpads

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/nfv/+/831841
Committed: https://opendev.org/starlingx/nfv/commit/94ce75c0d45589b197b5481d21f85035e16291ce
Submitter: "Zuul (22348)"
Branch: master

commit 94ce75c0d45589b197b5481d21f85035e16291ce
Author: albailey <email address hidden>
Date: Thu Mar 3 12:59:28 2022 -0600

    Update nfv code to work properly on python3.7+

    The coroutines in nfv internally raise StopIteration,
    however in python 3.7, that exception is converted to
    a RuntimeError: https://www.python.org/dev/peps/pep-0479/

    The vim code that catches a StopIteration exception has
    been updated to catch both types.

    The OCF scripts on a Debian system runs python3, and need
    explicit /usr/bin/python3 added to them

    Test-Plan:
     - Verified a Debian environment running python 3.9 is able
    to start nfv-vim without the process immediately crashing.
     - Verified a Centos environment running the older python2.7
    still able to run nfv-vim.
     - Verified Centos installation

    Closes-Bug: 1963277
    Closes-Bug: 1962787
    Signed-off-by: albailey <email address hidden>
    Change-Id: Ib54926738aeafbee0c90e7a2b5a4ad9556a3d7f1