On 16/08/13 11:42 -0400, Monty Taylor wrote:
On 08/16/2013 09:31 AM, Victor Sergeyev wrote:
Hello All.
Glance cores (Mark Washenberger, Flavio Percoco, Iccha Sethi) have some
questions about Oslo DB code, and why is it so important to use it
instead of custom implementation and so on. As there were a lot of
questions it was really hard to answer on all this questions in IRC. So
we decided that mailing list is better place for such things.
There is another main point - which is at the last summit, we talked
about various legit database things that need to be done to support CD
and rolling deploys. The list is not small, and it's a task that's
important. Needing to implement it in all of the projects separately is
kind of an issue, whereas if the projects are all using the database the
same way, then the database team can engineer the same mechanisms for
doing rolling schema changes, and then operators can have a consistent
expectation when they're running a cloud.
Just to be clear, AFAIK, the concerns were around how / when to migrate
Glance and not about why we should share database code.
List of main questions:
1. What includes oslo DB code?
2. Why is it safe to replace custom implementation by Oslo DB code?
3. Why oslo DB code is better than custom implementation?
4. Why oslo DB code won’t slow up project development progress?
5. What we are going actually to do in Glance?
6. What is the current status?
Answers:
1. What includes oslo DB code?
Currently Oslo code improves different aspects around DB:
-- Work with SQLAlchemy models, engine and session
-- Lot of tools for work with SQLAlchemy
-- Work with unique keys
-- Base test case for work with database
-- Test migrations against different backends
-- Sync DB Models with actual schemas in DB (add test that they are
equivalent)
2. Why is it safe to replace custom implementation by Oslo DB code?
Oslo module, as base openstack module, takes care about code quality.
Usually, common code more readable (most of flake8 checks enabled in
Oslo) and have better test coverage. Also it was tested in different
use-cases (in production also) in an other projects so bugs in Oslo code
were already fixed. So we can be sure, that we use high-quality code.
This is the point I was most worried about - and I'm still are. The
migration to Oslo's db code started a bit late in Glance and no code
has been merged yet. As for Glance, there still seems to be a lot of
work ahead on this matter.
That being said, thanks a lot for the email and for explaining all
those details.
FF
--
@flaper87
Flavio Percoco
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