Open Stack

Hi
I think we violate the DRY principal  quite heavily when we define the data constraints  in 3 different locations.
Here is an example: (focusing on the 'type' field of 'HealthMonitor')

1- DB layer:

class HealthMonitor(model_base.BASEV2, models_v2.HasId, models_v2.HasTenant):

    """Represents a v2 quantum loadbalancer healthmonitor."""

    type = sa.Column(sa.Enum("PING", "TCP", "HTTP", "HTTPS",

                             name="healthmontiors_type"),

                     nullable=False)

    delay = sa.Column(sa.Integer, nullable=False)

    timeout = sa.Column(sa.Integer, nullable=False)

    max_retries = sa.Column(sa.Integer, nullable=False)

    http_method = sa.Column(sa.String(16))

    url_path = sa.Column(sa.String(255))

    expected_codes = sa.Column(sa.String(64))

    status = sa.Column(sa.String(16), nullable=False)

    admin_state_up = sa.Column(sa.Boolean(), nullable=False)

2- API layer:

 'health_monitors': {

        'id': {'allow_post': False, 'allow_put': False,

               'validate': {'type:uuid': None},

               'is_visible': True},

        'tenant_id': {'allow_post': True, 'allow_put': False,

                      'validate': {'type:string': None},

                      'required_by_policy': True,

                      'is_visible': True},

        'type': {'allow_post': True, 'allow_put': False,

                 'validate': {'type:values': ['PING', 'TCP', 'HTTP', 'HTTPS']},

                 'is_visible': True},


3- The UI layer:
In the UI the developer will probably will define this 'type'  field as a combo box and will hard code the possible values (there is no other way since there is no {API | Config file} to get the constraints of an entity)



What can we do?
The idea is to be able to define the constraints once and consume those constraints in the layers mentioned above.

#option 1:  define a "config" file that will contain the constraints  in Quantum. The API layer and the DB layer will consume this configuration. The UI will have to get a copy of this file (since it a different project)
#option 2:  define a "config" file that will contain the constraints  in Quantum. The API layer and the DB layer will consume this configuration. The UI will consume it remotely through REST API.
#option 3: do nothing ... and keep duplication the constraints :(

It is obvious that option 2 is much "cleaner" but it requires extending the REST API.

Please let me know what do you think.


Thanks

Avishay


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20130123/f7300d24/attachment.html>