Remove six and python 2.7 full support

Six is in use to help us to keep support for python 2.7.
Since the ussuri cycle we decide to remove the python 2.7
support so we can go ahead and also remove six usage from
the python code.

Review process and help
-----------------------
Removing six introduce a lot of changes and an huge amount of modified files
To simplify reviews we decided to split changes into several patches to avoid
painful reviews and avoid mistakes.

To review this patch you can use the six documentation [1] to obtain help and
understand choices.

Additional informations
-----------------------
Changes related to 'six.b(data)' [2]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

six.b [2] encode the given datas in latin-1 in python3 so I did the same
things in this patch.

Latin-1 is equal to iso-8859-1 [3].

This encoding is the default encoding [4] of certain descriptive HTTP
headers.

I suggest to keep latin-1 for the moment and to move to another encoding
in a follow-up patch if needed to move to most powerful encoding (utf8).

HTML4 support utf8 charset and utf8 is the default charset for HTML5 [5].

Note that this commit message is autogenerated and not necesserly contains
changes related to 'six.b'

[1] https://six.readthedocs.io/
[2] https://six.readthedocs.io/#six.b
[3] https://docs.python.org/3/library/codecs.html#standard-encodings
[4] https://www.w3schools.com/charsets/ref_html_8859.asp
[5] https://www.w3schools.com/html/html_charset.asp

Patch 3 of a serie of 28 patches

Change-Id: If6e66839c128dde5fb80d90155dedb598da8d53b

heat/common/exception.py

@@ -21,8 +21,6 @@ import sys
 from oslo_log import log as logging
 from oslo_utils import excutils
 
-import six
-
 from heat.common.i18n import _
 
 _FATAL_EXCEPTION_FORMAT_ERRORS = False
@@ -38,7 +36,6 @@ ERROR_CODE_MAP = {
 }
 
 
-@six.python_2_unicode_compatible
 class HeatException(Exception):
     """Base Heat Exception.
 
@@ -71,7 +68,7 @@ class HeatException(Exception):
                 # kwargs doesn't match a variable in the message
                 # log the issue and the kwargs
                 LOG.exception('Exception in string format operation')
-                for name, value in six.iteritems(kwargs):
+                for name, value in kwargs.items():
                     LOG.error("%(name)s: %(value)s",
                               {'name': name, 'value': value})  # noqa
 
@@ -222,7 +219,7 @@ class HeatExceptionWithPath(HeatException):
         if path is not None:
             if isinstance(path, list):
                 self.path = path
-            elif isinstance(path, six.string_types):
+            elif isinstance(path, str):
                 self.path = [path]
 
         result_path = ''
@@ -247,7 +244,7 @@ class StackValidationFailed(HeatExceptionWithPath):
                  resource=None):
         if path is None:
             path = []
-        elif isinstance(path, six.string_types):
+        elif isinstance(path, str):
             path = [path]
 
         if resource is not None and not path:
@@ -263,8 +260,8 @@ class StackValidationFailed(HeatExceptionWithPath):
                 # oslo.messaging.
                 self.args = error.args
             else:
-                str_error = six.text_type(type(error).__name__)
+                str_error = str(type(error).__name__)
-                message = six.text_type(error)
+                message = str(error)
         else:
             str_error = error
 
@@ -331,8 +328,8 @@ class ResourceFailure(HeatExceptionWithPath):
                 path = exception_or_error.path
             else:
                 self.exc = exception_or_error
-                error = six.text_type(type(self.exc).__name__)
+                error = str(type(self.exc).__name__)
-                message = six.text_type(self.exc)
+                message = str(self.exc)
                 path = res_path
         else:
             self.exc = None
@@ -418,7 +415,7 @@ class UpdateReplace(Exception):
     """Raised when resource update requires replacement."""
     def __init__(self, resource_name='Unknown'):
         msg = _("The Resource %s requires replacement.") % resource_name
-        super(Exception, self).__init__(six.text_type(msg))
+        super(Exception, self).__init__(str(msg))
 
 
 class ResourceUnknownStatus(HeatException):
@@ -443,7 +440,7 @@ class ResourceInError(HeatException):
 class UpdateInProgress(Exception):
     def __init__(self, resource_name='Unknown'):
         msg = _("The resource %s is already being updated.") % resource_name
-        super(Exception, self).__init__(six.text_type(msg))
+        super(Exception, self).__init__(str(msg))
 
 
 class HTTPExceptionDisguise(Exception):

heat/common/grouputils.py

@@ -11,8 +11,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import six
-
 from heat.common import exception
 from heat.common.i18n import _
 from heat.engine import status
@@ -122,7 +120,7 @@ def get_members(group, include_failed=False):
     """
     resources = []
     if group.nested():
-        resources = [r for r in six.itervalues(group.nested())
+        resources = [r for r in group.nested().values()
                      if include_failed or r.status != r.FAILED]
 
     return sorted(resources,

heat/common/i18n.py

@@ -17,29 +17,10 @@
 # recommendations from
 # https://docs.openstack.org/oslo.i18n/latest/user/usage.html
 
-import six
-
 import oslo_i18n as i18n
-from oslo_utils import encodeutils
 
 
 _translators = i18n.TranslatorFactory(domain='heat')
 
 # The primary translation function using the well-known name "_"
 _ = _translators.primary
-
-
-def repr_wrapper(klass):
-    """A decorator that defines __repr__ method under Python 2.
-
-    Under Python 2 it will encode repr return value to str type.
-    Under Python 3 it does nothing.
-    """
-    if six.PY2:
-        if '__repr__' not in klass.__dict__:
-            raise ValueError("@repr_wrapper cannot be applied "
-                             "to %s because it doesn't define __repr__()." %
-                             klass.__name__)
-        klass._repr = klass.__repr__
-        klass.__repr__ = lambda self: encodeutils.safe_encode(self._repr())
-    return klass

heat/common/identifier.py

@@ -15,7 +15,7 @@ import collections
 import re
 
 from oslo_utils import encodeutils
-from six.moves.urllib import parse as urlparse
+from urllib import parse as urlparse
 
 from heat.common.i18n import _
 

heat/common/password_gen.py

@@ -12,11 +12,10 @@
 #    under the License.
 
 import collections
+import io
 import random as random_module
 import string
 
-import six
-
 
 # NOTE(pas-ha) Heat officially supports only POSIX::Linux platform
 # where os.urandom() and random.SystemRandom() are available
@@ -88,19 +87,19 @@ def generate_password(length, char_classes):
     :param char_classes: Iterable over classes of characters from which to
                          generate a password
     """
-    char_buffer = six.StringIO()
+    char_buffer = io.StringIO()
     all_allowed_chars = set()
 
     # Add the minimum number of chars from each char class
     for char_class in char_classes:
         all_allowed_chars |= char_class.allowed_chars
         allowed_chars = tuple(char_class.allowed_chars)
-        for i in six.moves.xrange(char_class.min_count):
+        for i in range(char_class.min_count):
             char_buffer.write(random.choice(allowed_chars))
 
     # Fill up rest with random chars from provided classes
     combined_chars = tuple(all_allowed_chars)
-    for i in six.moves.xrange(max(0, length - char_buffer.tell())):
+    for i in range(max(0, length - char_buffer.tell())):
         char_buffer.write(random.choice(combined_chars))
 
     # Shuffle string

heat/common/plugin_loader.py

@@ -19,12 +19,12 @@ existing package tree, use create_subpackage() to dynamically create a package
 for them before loading them.
 """
 
+import functools
 import pkgutil
 import sys
 import types
 
 from oslo_log import log as logging
-import six
 
 
 LOG = logging.getLogger(__name__)
@@ -46,7 +46,7 @@ def create_subpackage(path, parent_package_name, subpackage_name="plugins"):
     package_name = _module_name(parent_package_name, subpackage_name)
 
     package = types.ModuleType(package_name)
-    package.__path__ = ([path] if isinstance(path, six.string_types)
+    package.__path__ = ([path] if isinstance(path, str)
                         else list(path))
     sys.modules[package_name] = package
 
@@ -75,7 +75,7 @@ def _import_module(importer, module_name, package):
     # Make this accessible through the parent package for static imports
     local_name = module_name.partition(package.__name__ + '.')[2]
     module_components = local_name.split('.')
-    parent = six.moves.reduce(getattr, module_components[:-1], package)
+    parent = functools.reduce(getattr, module_components[:-1], package)
     setattr(parent, module_components[-1], module)
 
     return module

heat/common/pluginutils.py

@@ -12,7 +12,6 @@
 #    under the License.
 
 from oslo_log import log as logging
-import six
 
 
 LOG = logging.getLogger(__name__)
@@ -23,5 +22,5 @@ def log_fail_msg(manager, entrypoint, exception):
                 '"%(message)s". Not using %(name)s.',
                 {'module_name': entrypoint.module_name,
                  'message': getattr(exception, 'message',
-                                    six.text_type(exception)),
+                                    str(exception)),
                  'name': entrypoint.name})

heat/common/policy.py

@@ -21,7 +21,6 @@ from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_policy import policy
 from oslo_utils import excutils
-import six
 
 from heat.common import exception
 from heat.common.i18n import _
@@ -151,7 +150,7 @@ class ResourceEnforcer(Enforcer):
         except policy.PolicyNotRegistered:
             result = True
         except self.exc as ex:
-            LOG.info(six.text_type(ex))
+            LOG.info(str(ex))
             raise
         if not result:
             if self.exc:

heat/common/serializers.py

@@ -23,7 +23,6 @@ import datetime
 from lxml import etree
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
-import six
 
 LOG = logging.getLogger(__name__)
 
@@ -34,7 +33,7 @@ class JSONResponseSerializer(object):
         def sanitizer(obj):
             if isinstance(obj, datetime.datetime):
                 return obj.isoformat()
-            return six.text_type(obj)
+            return str(obj)
 
         response = jsonutils.dumps(data, default=sanitizer)
 
@@ -46,7 +45,7 @@ class JSONResponseSerializer(object):
 
     def default(self, response, result):
         response.content_type = 'application/json'
-        response.body = six.b(self.to_json(result))
+        response.body = self.to_json(result).encode('latin-1')
 
 
 # Escape XML serialization for these keys, as the AWS API defines them as
@@ -75,11 +74,11 @@ class XMLResponseSerializer(object):
                 else:
                     self.object_to_element(value, subelement)
         else:
-            element.text = six.text_type(obj)
+            element.text = str(obj)
 
     def to_xml(self, data):
         # Assumption : root node is dict with single key
-        root = next(six.iterkeys(data))
+        root = next(iter(data.keys()))
         eltree = etree.Element(root)
         self.object_to_element(data.get(root), eltree)
         response = etree.tostring(eltree)

heat/common/short_id.py

@@ -19,8 +19,6 @@ The IDs each comprise 12 (lower-case) alphanumeric characters.
 import base64
 import uuid
 
-import six
-
 from heat.common.i18n import _
 
 
@@ -30,12 +28,12 @@ def _to_byte_string(value, num_bits):
     Padding is added at the end (i.e. after the least-significant bit) if
     required.
     """
-    shifts = six.moves.xrange(num_bits - 8, -8, -8)
+    shifts = range(num_bits - 8, -8, -8)
 
     def byte_at(off):
         return (value >> off if off >= 0 else value << -off) & 0xff
 
-    return b''.join(six.int2byte(byte_at(offset)) for offset in shifts)
+    return b''.join(bytes((byte_at(offset),)) for offset in shifts)
 
 
 def get_id(source_uuid):
@@ -43,7 +41,7 @@ def get_id(source_uuid):
 
     The supplied UUID must be a version 4 UUID object.
     """
-    if isinstance(source_uuid, six.string_types):
+    if isinstance(source_uuid, str):
         source_uuid = uuid.UUID(source_uuid)
     if source_uuid.version != 4:
         raise ValueError(_('Invalid UUID version (%d)') % source_uuid.version)

heat/engine/attributes.py

@@ -17,7 +17,6 @@ from oslo_utils import strutils
 import six
 
 from heat.common.i18n import _
-from heat.common.i18n import repr_wrapper
 from heat.engine import constraints as constr
 from heat.engine import support
 
@@ -139,7 +138,6 @@ BASE_ATTRIBUTES = (SHOW_ATTR, ) = ('show', )
 ALL_ATTRIBUTES = '*'
 
 
-@repr_wrapper
 class Attributes(collections.Mapping):
     """Models a collection of Resource Attributes."""
 

heat/engine/dependencies.py

@@ -18,14 +18,12 @@ import six
 
 from heat.common import exception
 from heat.common.i18n import _
-from heat.common.i18n import repr_wrapper
 
 
 class CircularDependencyException(exception.HeatException):
     msg_fmt = _("Circular Dependency Found: %(cycle)s")
 
 
-@repr_wrapper
 @six.python_2_unicode_compatible
 class Node(object):
     """A node in a dependency graph."""
@@ -172,7 +170,6 @@ class Graph(collections.defaultdict):
                 raise CircularDependencyException(cycle=six.text_type(graph))
 
 
-@repr_wrapper
 @six.python_2_unicode_compatible
 class Dependencies(object):
     """Helper class for calculating a dependency graph."""

heat/engine/rsrc_defn.py

@@ -18,7 +18,6 @@ import operator
 import six
 
 from heat.common import exception
-from heat.common.i18n import repr_wrapper
 from heat.engine import function
 from heat.engine import properties
 
@@ -37,7 +36,6 @@ FIELDS = (
 )
 
 
-@repr_wrapper
 class ResourceDefinition(object):
     """A definition of a resource, independent of any template format."""
 

heat/engine/scheduler.py

@@ -21,7 +21,6 @@ from oslo_utils import excutils
 import six
 
 from heat.common.i18n import _
-from heat.common.i18n import repr_wrapper
 from heat.common import timeutils
 
 LOG = logging.getLogger(__name__)
@@ -365,7 +364,6 @@ def wrappertask(task):  # noqa: C901
     return wrapper
 
 
-@repr_wrapper
 class DependencyTaskGroup(object):
     """Task which manages group of subtasks that have ordering dependencies."""
 

heat/engine/update.py

@@ -15,7 +15,6 @@ from oslo_log import log as logging
 import six
 
 from heat.common import exception
-from heat.common.i18n import repr_wrapper
 from heat.engine import dependencies
 from heat.engine import resource
 from heat.engine import scheduler
@@ -25,7 +24,6 @@ from heat.objects import resource as resource_objects
 LOG = logging.getLogger(__name__)
 
 
-@repr_wrapper
 class StackUpdate(object):
     """A Task to perform the update of an existing stack to a new template."""
 

heat/tests/engine/test_scheduler.py

@@ -18,7 +18,6 @@ import eventlet
 import mock
 import six
 
-from heat.common.i18n import repr_wrapper
 from heat.common import timeutils
 from heat.engine import dependencies
 from heat.engine import scheduler
@@ -1273,7 +1272,6 @@ class DescriptionTest(common.HeatTestCase):
         self.assertEqual('o', scheduler.task_description(C()))
 
     def test_unicode(self):
-        @repr_wrapper
         @six.python_2_unicode_compatible
         class C(object):
             def __str__(self):