Traceback instead of error message when argument's format for get_attr is wrong

[Tatiana Kholkina]

When trying to create stack with the following template

heat_template_version: 2013-05-23

resources:
  random_str:
    type: OS::Heat::RandomString

outputs:
  string:
    value: {get_attr: [[random_str, value]]}

heat shows traceback instead of error message:

ERROR: Arguments to "get_attr" must be of the form [resource_name, attribute, (path), ...]
Traceback (most recent call last):

  File "/usr/local/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 134, in _dispatch_and_reply
    incoming.message))

  File "/usr/local/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 177, in _dispatch
    return self._do_dispatch(endpoint, method, ctxt, args)

  File "/usr/local/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 123, in _do_dispatch
    result = getattr(endpoint, method)(ctxt, **new_args)

  File "/usr/local/lib/python2.7/dist-packages/osprofiler/profiler.py", line 105, in wrapper
    return f(*args, **kwargs)

  File "/opt/stack/heat/heat/engine/service.py", line 72, in wrapped
    return func(self, ctx, *args, **kwargs)

  File "/opt/stack/heat/heat/engine/service.py", line 607, in create_stack
    stack_user_project_id)

  File "/opt/stack/heat/heat/engine/service.py", line 517, in _parse_template_and_validate_stack
    **common_params)

  File "/opt/stack/heat/heat/engine/stack.py", line 142, in __init__
    self.outputs = self.resolve_static_data(self.t[self.t.OUTPUTS])

  File "/opt/stack/heat/heat/engine/stack.py", line 1196, in resolve_static_data
    return self.t.parse(self, snippet)

  File "/opt/stack/heat/heat/engine/template.py", line 179, in parse
    return parse(self.functions, stack, snippet)

  File "/opt/stack/heat/heat/engine/template.py", line 218, in parse
    return dict((k, recurse(v)) for k, v in six.iteritems(snippet))

  File "/opt/stack/heat/heat/engine/template.py", line 218, in <genexpr>
    return dict((k, recurse(v)) for k, v in six.iteritems(snippet))

  File "/opt/stack/heat/heat/engine/template.py", line 218, in parse
    return dict((k, recurse(v)) for k, v in six.iteritems(snippet))

  File "/opt/stack/heat/heat/engine/template.py", line 218, in <genexpr>
    return dict((k, recurse(v)) for k, v in six.iteritems(snippet))

  File "/opt/stack/heat/heat/engine/template.py", line 217, in parse
    return Func(stack, fn_name, recurse(args))

  File "/opt/stack/heat/heat/engine/cfn/functions.py", line 154, in __init__
    self._resource_name, self._attribute = self._parse_args()

  File "/opt/stack/heat/heat/engine/hot/functions.py", line 110, in _parse_args
    self.fn_name)

ValueError: Arguments to "get_attr" must be of the form [resource_name, attribute, (path), ...]

[Joe D'Andrea (jdandrea)]

Hi Tetiana,

Can you please try again without double brackets, like this?

outputs:
  string:
    value: {get_attr: [random_str, value]}

That should work, per the error message. Let me know!

[Tatiana Kholkina (tlashchova)]

Hi Joe,

Thanks for your reply. Yes, it works without double brackets. But I think the user should see short error message instead of traceback if he writes something wrong in the template.

[Steve Baker (steve-stevebaker)]

The ValueError needs to be wrapped in a exception.StackValidationFailed in the appropriate place.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/149014

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/149014
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=15ba5c1eb0ccb1ecc1fb4cbcf73b301412295173
Submitter: Jenkins
Branch: master

commit 15ba5c1eb0ccb1ecc1fb4cbcf73b301412295173
Author: Tetiana Lashchova <email address hidden>
Date: Wed Jan 21 19:55:13 2015 +0200

    Enhanced error handling in outputs block

    Change-Id: I20cab805d7a423efc008049c447bde0747530970
    Closes-bug: #1411721