[Rdo-list] Migrating from MySQL-python to PyMySQL

[Javier Pena]

Hi all,

During the review of a packaging change to the Neutron package [1], we realized that our installation tools are still using MySQL-python for the db connections, and several of our packages still depend on the MySQL-python package, even though they rely on oslo.db, which has now moved to PyMySQL as default driver [2]. 

I'd like to propose the following plan for this migration:

  a) To avoid any short-term breakage, make python-oslo-db require MySQL-python and python-PyMySQL.
  b) Remove all MySQL-python dependencies from those packages that should no longer require it ([3], if I did not miss anyone). All these packages already require python-oslo-db, so there would be no missing deps.
  c) Update installers to support PyMySQL in their db connection strings. 
  d) Once MySQL-python is no longer necessary, remove it from the dependencies for python-oslo-db

What do you think? Steps a) and b) should be relatively easy to do in the short term, but I'm concerned about the testing implications of c) at this time of the Liberty cycle.

Regards,
Javier

[1]- https://review.gerrithub.io/247972
[2]- http://docs.openstack.org/developer/oslo.db/installation.html#using-with-mysql-python
[3] python-cinder
    python-glance
    openstack-heat-common
    python-keystone
    python-manila
    python-neutron
    python-nova
    python-octavia
    openstack-designate-central
    openstack-designate-mdns