list_tables throws 500 error when passing in start_table_name

[Charles Wang]

Steps to reproduce:

1. create a few tables
2. invoke list_tables, you should see a list of tables
3. use one of the table name as "start_table_name" and invoke list_tables again
4. you will see 500 error

  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
    return self.func(req, *args, **kwargs)
  File "/opt/stack/magnetodb/magnetodb/common/wsgi.py", line 61, in __call__
    response = req.get_response(self.application)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1320, in send
    application, catch_exc_info=False)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1284, in call_application
    app_iter = application(self.environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
    return resp(environ, start_response)
  File "/usr/lib/python2.7/dist-packages/routes/middleware.py", line 131, in __call__
    response = self.app(environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
    return resp(environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 130, in __call__
    resp = self.call_func(req, *args, **self.kwargs)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
    return self.func(req, *args, **kwargs)
  File "/opt/stack/magnetodb/magnetodb/common/wsgi.py", line 244, in __call__
    action_result = self.execute_action(action, request, **action_args)
  File "/opt/stack/magnetodb/magnetodb/common/wsgi.py", line 258, in execute_action
    return self.dispatch(self.controller, action, request, **action_args)
  File "/opt/stack/magnetodb/magnetodb/common/wsgi.py", line 267, in dispatch
    return method(*args, **kwargs)
  File "/opt/stack/magnetodb/magnetodb/common/probe.py", line 94, in wrapper
    return f(*args, **kwargs)
  File "/opt/stack/magnetodb/magnetodb/api/openstack/v1/request/list_tables.py", line 51, in list_tables
    validation.validate_unexpected_props(params, "params")
  File "/opt/stack/magnetodb/magnetodb/api/validation.py", line 130, in validate_unexpected_props
    unexpected_props=json.dumps(value)
  File "/usr/lib/python2.7/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python2.7/json/encoder.py", line 201, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python2.7/json/encoder.py", line 264, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python2.7/json/encoder.py", line 178, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: MultiDict([(u'start_table_name', u'AThread')]) is not JSON serializable

2014-10-16 14:53:05.460 3345 INFO magnetodb.common.probe [-] PROBE: <class 'magnetodb.common.middleware.fault.FaultWrapper'>, <_MainThread(MainThread, started 140279752873728)>, finished, 3.87501716614 ms
192.168.33.1 - - [16/Oct/2014 14:53:05] "GET /v1/6542e7a7502e4e498ff87f5610e7e493/data/tables?start_table_name=AThread HTTP/1.1" 500 461 0.004425

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/129387
Committed: https://git.openstack.org/cgit/stackforge/magnetodb/commit/?id=5724b25ead6771d16b99eca7ea0dcc6b4f6ffdc8
Submitter: Jenkins
Branch: master

commit 5724b25ead6771d16b99eca7ea0dcc6b4f6ffdc8
Author: Charles Wang <email address hidden>
Date: Fri Oct 17 17:22:42 2014 -0400

    Fix validation error handling and doc on list_tables

    DocImpact
    Closes-Bug: #1382088
    Change-Id: I3e55d6cd606a100e4cea5209c342a5f7a5c87056