HTTP 500 when `nova list --name` contains invalid regexp

[Rene Soto]

Detailed bug description:
When a Nova CLI command contains a regexp, it fails with HTTP 500 error
Steps to reproduce:
root@node-6:~# nova list --name \*
ERROR (ClientException): Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<class 'sqlalchemy.exc.OperationalError'> (HTTP 500) (Request-ID: req-9c59f50c-21cc-4d1b-87d3-6e0d3d5afb3b)

Expected results:
Catch the syntax error in the command before the request is made

Actual result:
Request goes through, and returned with a HTTP 500 error. Nova API log is attached with more details.

Reproducibility:
100%

Workaround:
None

Impact:
Nothing major, but in this case, the HTTP 500 error triggered alerts in the monitoring system.

Description of the environment:
- Operation system: Ubuntu 14.04
- Versions of components: MOS 9.1
- Reference architecture: N/A
- Network model: N/A
- Related projects installed: N/A
Additional information:
N/A

[Denis Meltsaykin (dmeltsaykin)]

Roman, could you please take a look? It looks like a general issue of all the versions of novaclient. Though, I'm not sure if it is even possible to "validate" a regular expression, but may be some sort of sanitizing of inputs...

[Roman Podoliaka (rpodolyaka)]

While we could "validate" (basically re.compile()) a regular expression both on the client side before making a request and on the server side before executing a DB query, that would only give us so much - the problem is that we pass this regular expression to MySQL as is and we can't guarantee that something valid in Python RE is going to be valid in MySQL as well.

I guess, I'd rather let it fail in the DB layer, but catch the exception up the stack, so that we return a proper 400 Bad Request to a user.

Anyway, this sounds like an enhancement request to me. I suggest we give it Wishlist priority and see if we can implement this in upstream (at this point - Pike or Queens).