Ports subcontroller doesn't properly handle incorrect node names

[Vladyslav Drok]

Here is what happens if an invalid node identifier is passed, in this case 1234~1234~1234:

2016-08-31 17:10:57.806 27972 INFO eventlet.wsgi.server [-] Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/eventlet/wsgi.py", line 481, in handle_one_response
    result = self.application(self.environ, start_response)
  File "/opt/stack/new/ironic/ironic/api/app.py", line 101, in __call__
    return self.v1(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 "/usr/local/lib/python2.7/dist-packages/oslo_middleware/base.py", line 126, in __call__
    response = req.get_response(self.application)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1299, in send
    application, catch_exc_info=False)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1263, in call_application
    app_iter = application(self.environ, start_response)
  File "/opt/stack/new/ironic/ironic/api/middleware/auth_token.py", line 64, in __call__
    return super(AuthTokenMiddleware, self).__call__(env, 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 "/usr/local/lib/python2.7/dist-packages/keystonemiddleware/auth_token/__init__.py", line 323, in __call__
    response = req.get_response(self._app)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1299, in send
    application, catch_exc_info=False)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1263, in call_application
    app_iter = application(self.environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/pecan/middleware/recursive.py", line 56, in __call__
    return self.application(environ, start_response)
  File "/opt/stack/new/ironic/ironic/api/middleware/parsable_error.py", line 67, in __call__
    app_iter = self.app(environ, replacement_start_response)
  File "/usr/local/lib/python2.7/dist-packages/pecan/core.py", line 835, in __call__
    return super(Pecan, self).__call__(environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/pecan/core.py", line 677, in __call__
    controller, args, kwargs = self.find_controller(state)
  File "/usr/local/lib/python2.7/dist-packages/pecan/core.py", line 853, in find_controller
    controller, args, kw = super(Pecan, self).find_controller(_state)
  File "/usr/local/lib/python2.7/dist-packages/pecan/core.py", line 455, in find_controller
    controller, remainder = self.route(req, self.root, path)
  File "/usr/local/lib/python2.7/dist-packages/pecan/core.py", line 293, in route
    node, remainder = lookup_controller(node, path, req)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 139, in lookup_controller
    request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 244, in find_object
    next_obj, next_remainder = route(remainder)
  File "/opt/stack/new/ironic/ironic/api/controllers/root.py", line 121, in _route
    return super(RootController, self)._route(args)
  File "/usr/local/lib/python2.7/dist-packages/pecan/rest.py", line 120, in _route
    result = self._find_sub_controllers(args, request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/rest.py", line 233, in _find_sub_controllers
    request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 139, in lookup_controller
    request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 244, in find_object
    next_obj, next_remainder = route(remainder)
  File "/opt/stack/new/ironic/ironic/api/controllers/v1/__init__.py", line 205, in _route
    return super(Controller, self)._route(args)
  File "/usr/local/lib/python2.7/dist-packages/pecan/rest.py", line 120, in _route
    result = self._find_sub_controllers(args, request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/rest.py", line 233, in _find_sub_controllers
    request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 139, in lookup_controller
    request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 246, in find_object
    next_obj, next_remainder = route(remainder, request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/rest.py", line 145, in _route
    _lookup_result = self._handle_lookup(args, request)
  File "/usr/local/lib/python2.7/dist-packages/pecan/rest.py", line 190, in _handle_lookup
    result = handle_lookup_traversal(lookup, args)
  File "/usr/local/lib/python2.7/dist-packages/pecan/routing.py", line 172, in handle_lookup_traversal
    result = obj(*args)
  File "/opt/stack/new/ironic/ironic/api/controllers/v1/node.py", line 1067, in _lookup
    ident = types.uuid_or_name.validate(ident)
  File "/opt/stack/new/ironic/ironic/api/controllers/v1/types.py", line 60, in validate
    raise exception.InvalidUuidOrName(name=value)
InvalidUuidOrName: Expected a logical name or UUID but received 1234~1234~1234.

2016-08-31 17:10:57.807 27972 INFO eventlet.wsgi.server [-] 127.0.0.1 "GET /v1/nodes/1234~1234~1234/validate HTTP/1.1" status: 500 len: 139 time: 0.0404370

The reason is, the _lookup method is exposed via pecan.expose, not wsme, and does not do exception handling the way wsme does.