translate failed in scaling policy while param involved in tosca

[GUO Larry]

Based on this tosca template: https://github.com/openstack/heat-translator/blob/master/translator/tests/data/nfv/test_tosca_nfv_autoscaling.yaml

replace image name to parameter, such like:
tosca_definitions_version: tosca_simple_profile_for_nfv_1_0_0

description: >
  Template for deploying servers based on policies.

imports:
  - tacker_defs.yaml
  - tacker_nfv_defs.yaml

topology_template:
  inputs:
    image_name:
      type: string
      description: Image Name

  node_templates:
    VDU1:
      type: tosca.nodes.nfv.VDU.Tacker
      properties:
        image: { get_input: image_name }
        mgmt_driver: noop
        availability_zone: nova
        flavor: m1.tiny

    CP1:
      type: tosca.nodes.nfv.CP.Tacker
      properties:
        management: true
        order: 0
        anti_spoofing_protection: false
      requirements:
        - virtualLink:
            node: VL1
        - virtualBinding:
            node: VDU1

    VDU2:
      type: tosca.nodes.nfv.VDU.Tacker
      properties:
        image: { get_input: image_name }
        mgmt_driver: noop
        availability_zone: nova
        flavor: m1.tiny

    CP2:
      type: tosca.nodes.nfv.CP.Tacker
      properties:
        management: true
        order: 0
        anti_spoofing_protection: false
      requirements:
        - virtualLink:
            node: VL1
        - virtualBinding:
            node: VDU2

    VL1:
      type: tosca.nodes.nfv.VL
      properties:
        network_name: net_mgmt
        vendor: Tacker

  policies:
    - SP1:
        type: tosca.policies.tacker.Scaling
        targets: [VDU1, VDU2]
        properties:
          increment: 1
          cooldown: 120
          min_instances: 1
          max_instances: 3
          default_instances: 2

Run generate template command and it will fail:
# python heat_translator.py --template-file=translator/tests/data/nfv/test_tosca_nfv_autoscaling_param.yaml --template-type=tosca --parameters="image_name=cirros"
Traceback (most recent call last):
  File "heat_translator.py", line 20, in <module>
    translator_shell.main()
  File "/root/heat-translator/translator/shell.py", line 303, in main
    TranslatorShell().main(args)
  File "/root/heat-translator/translator/shell.py", line 199, in main
    self._write_output(translator, output_file)
  File "/root/heat-translator/translator/shell.py", line 297, in _write_output
    print(translator.translate())
  File "/root/heat-translator/translator/hot/tosca_translator.py", line 58, in translate
    self._translate_to_hot_yaml()
  File "/root/heat-translator/translator/hot/tosca_translator.py", line 46, in _translate_to_hot_yaml
    self.node_translator.translate()
  File "/root/heat-translator/translator/hot/translate_node_templates.py", line 168, in translate
    return self._translate_nodetemplates()
  File "/root/heat-translator/translator/hot/translate_node_templates.py", line 362, in _translate_nodetemplates
    self._recursive_handle_properties(resource)
  File "/root/heat-translator/translator/hot/translate_node_templates.py", line 191, in _recursive_handle_properties
    extra_res = copy.deepcopy(res)
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 230, in _deepcopy_list
    y.append(deepcopy(a, memo))
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 230, in _deepcopy_list
    y.append(deepcopy(a, memo))
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 230, in _deepcopy_list
    y.append(deepcopy(a, memo))
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 230, in _deepcopy_list
    y.append(deepcopy(a, memo))
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 334, in _reconstruct
    state = deepcopy(state, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 257, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "/usr/lib64/python2.7/copy.py", line 163, in deepcopy
    y = copier(x, memo)
  File "/usr/lib64/python2.7/copy.py", line 230, in _deepcopy_list
    y.append(deepcopy(a, memo))
  File "/usr/lib64/python2.7/copy.py", line 190, in deepcopy
    y = _reconstruct(x, rv, 1, memo)
  File "/usr/lib64/python2.7/copy.py", line 329, in _reconstruct
    y = callable(*args)
  File "/usr/lib64/python2.7/copy_reg.py", line 93, in __newobj__
    return cls.__new__(cls, *args)
TypeError: __new__() takes exactly 4 arguments (1 given)

It is the same error if this template used on Tacker.

[GUO Larry (larrygu)]

It caused by toscaparser/elements/constraints.py
class Constraint(object):
........

    def __new__(cls, property_name, property_type, constraint):

__new__ must be called during deepcopy to create a new object.
one problem is that deepcopy and copy have no way of knowing which arguments to pass to __new__, therefore they only work with classes that don't require constructor arguments.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/530176

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/530176
Committed: https://git.openstack.org/cgit/openstack/tosca-parser/commit/?id=784227cce42569a07380076dd12c2ff5d63a0930
Submitter: Zuul
Branch: master

commit 784227cce42569a07380076dd12c2ff5d63a0930
Author: Larry GUO <[e-mail]>
Date: Wed Dec 27 06:08:06 2017 +0000

    Closes-Bug: #1740063
    Add default value None to __new__ method, this avoid exception when
    __deepcopy__ method used

    Change-Id: I744d293818e7019a188f9b093d2cf12c47f1f2b4

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tosca-parser 0.9.0 release.