REST API didn't verify json data format

[Yang Ye]

When try to create a server with REST API, I set attribute block_device_mapping with wrong value, not a list<dict> but a string (from "block_device_mapping": [{"volume_id": "1", "delete_on_termination": "0", "device_name": "/dev/vdb"}] to "block_device_mapping": "abc",). And then I got a response with code 500.
In nova CLI, when params are wrong you will get a notice, but in REST you get nothing.
If openstack use json schema to describe every REST API and verify json requested , users can easily know how to use these API and which attribute was wrong.

[Christopher Yeoh (cyeoh-0)]

Confirmed this is an issue. json schema is being introduced as part of v2.1 but we can still patch v2

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/127860
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=d6bf0d06c3bedcdeb211b563cf0923764b411966
Submitter: Jenkins
Branch: master

commit d6bf0d06c3bedcdeb211b563cf0923764b411966
Author: Chris Yeoh <email address hidden>
Date: Mon Oct 13 11:25:39 2014 +1030

    Add more input validation of bdm param in server creation

    Adds a check to ensure that block_device_mapping is a list and
    return 400 Bad Request rather than 500 as currently happens.

    Change-Id: I30551bcbb7d658734da158dbb8dd7d825c526896
    Closes-Bug: 1379973

[Yang Ye (ccyangye)]

Return 500 is not good, but I think it's bearable. It's not necessary to write a piece of code to check only this because there're hundreds of json inputs. I prefer to use json schema. But thank you any way.

[Christopher Yeoh (cyeoh-0)]

So for v2.1 we will eventually have json schema coverage - its just not there for that plugin yet but is for many others. But for v2 we don't support jsonschema and need an explicit check. The V2.1 check was added a stop-gap until the schema for that method is implemented. We don't want 500's occurring because they cause big LOG messages.