lbaas. Adding column level constraints to table definition

[Avishay Balderman]

In https://github.com/openstack/quantum/blob/master/quantum/db/loadbalancer/loadbalancer_db.py the lbaas model is defined.
There are fields the needs extra constraint definition.
Examples:
- All fields in PoolStatistics can not be negative.
- Weight field in Member can not be negative.
- Delay field in HealthMonitor can not be negative.

Those constraints can be added using:
http://docs.sqlalchemy.org/en/rel_0_8/core/schema.html?highlight=checkconstraint#sqlalchemy.schema.CheckConstraint
See here for example:
http://stackoverflow.com/questions/14225998/flask-sqlalchemy-column-constraint-for-positive-integer

[Eugene Nikanorov (enikanorov)]

I think those parameters should be validated in the extension in the first place

[Avishay Balderman (avishayb)]

I agree, and I think they are:
weight - https://github.com/openstack/quantum/blob/master/quantum/extensions/loadbalancer.py#L189
delay - https://github.com/openstack/quantum/blob/master/quantum/extensions/loadbalancer.py#L213
stats field are not input fields, so we are OK here.

So since we do the validation in 2 layers (extension + db) - I think the constraints should be added to the db layer.

[Avishay Balderman (avishayb)]

Note: Not sure that MySQL supports 'CheckConstraint'

[Avishay Balderman (avishayb)]

code below can work for the pool stats fields

@validates('bytes_in','bytes_out','active_connections','total_connections')
def validate_non_negative_int(self, key, value):
    if value < 0:
        raise ValueError
    return value

[Eugene Nikanorov (enikanorov)]

Why do we need to validate stats if they're going from the driver anyway? It's not a user input.

[Avishay Balderman (avishayb)]

because driver can insert negative values by mistake.

[Mark McClain (markmcclain)]

I think it is a good idea to guard against a misconfigured driver in this case since that is only way this value is populated.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/32545

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/32545
Committed: http://github.com/openstack/quantum/commit/135d20218ac8f67153c106d373d3a1c1a00f55d6
Submitter: Jenkins
Branch: master

commit 135d20218ac8f67153c106d373d3a1c1a00f55d6
Author: Avishay Balderman <email address hidden>
Date: Tue Jun 11 01:52:20 2013 -0700

    Protect PoolStats table from negative values.

    Fixes: bug #1188959

    Change-Id: I67038734dae5dc29e5c0666fdc98827dfd50b678