[ome-devel] Reconsidering the minimum Python version for 5.2

[Roger Leigh]

In
http://www.openmicroscopy.org/site/support/omero5.1/sysadmins/version-requirements.html#python
we had planned to drop Python 2.6 in OMERO 5.2 after deprecation in 5.1.
  However, we might want to reconsider that and leave it deprecated for
5.2 as well.

The main reason, as pointed out in today's meeting, is that currently
CentOS6 is much more widely used than CentOS6, and this is likely to
remain true during the 5.2 release timeframe.  After discussion with
Kenny and Simon, we came to the conclusion that there would be
significant benefit to retaining Python 2.6 support.  The main
consideration for retaining Python 2.6 is that while moving to Python
2.7 is technically possible using the SCL python 2.7 package, in
practice this complicates the life of the admin for little benefit and
has an additional issue with regard to Ice.

ZeroC provides Ice 3.5 builds for CentOS6 using Python 2.6 and CentOS7
using Python 2.7.  There is no build for CentOS6 using Python 2.7,
unless you were to to a custom rebuild.

The new Ice 3.6 release will work with either Python 2.6 or 2.7, and
again builds are provided for both CentOS 6 and 7.  This version, once
supported by OMERO, will give the flexibility to use either Python
version.  However, using Python 2.7 on CentOS 6 will require fixing up
the OMERO start-up scripts or user shell to enable the use of Python 2.7.

If we were to require Python 2.7, using Ice 3.5 therefore becomes
difficult on CentOS 6.  We would likely need to recommend the use of Ice
3.6, with SCL Python 2.7.


On the other hand, there may well be compelling reasons to require
Python 2.7 which are more important than the above points.  I think Ola
wanted to raise the limit regarding django support; what are the precise
constraints here?  Are there any additional requirements for 2.7?


Regards,
Roger

--
Dr Roger Leigh -- Open Microscopy Environment
Wellcome Trust Centre for Gene Regulation and Expression,
School of Life Sciences, University of Dundee, Dow Street,
Dundee DD1 5EH Scotland UK   Tel: (01382) 386364

The University of Dundee is a registered Scottish Charity, No: SC015096