Add versionutils from oslo-incubator

versionutils is necessary to implement versioned objects copied
from Nova/Ironic.

Change-Id: I81a228a186ce583e9cd2cf8cd98bcb6167a6a5f0

magnum/openstack/common/versionutils.py

@@ -0,0 +1,183 @@
+# Copyright (c) 2013 OpenStack Foundation
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""
+Helpers for comparing version strings.
+"""
+
+import functools
+
+import pkg_resources
+
+from magnum.openstack.common._i18n import _
+from magnum.openstack.common import log as logging
+
+
+LOG = logging.getLogger(__name__)
+
+
+class deprecated(object):
+    """A decorator to mark callables as deprecated.
+
+    This decorator logs a deprecation message when the callable it decorates is
+    used. The message will include the release where the callable was
+    deprecated, the release where it may be removed and possibly an optional
+    replacement.
+
+    Examples:
+
+    1. Specifying the required deprecated release
+
+    >>> @deprecated(as_of=deprecated.ICEHOUSE)
+    ... def a(): pass
+
+    2. Specifying a replacement:
+
+    >>> @deprecated(as_of=deprecated.ICEHOUSE, in_favor_of='f()')
+    ... def b(): pass
+
+    3. Specifying the release where the functionality may be removed:
+
+    >>> @deprecated(as_of=deprecated.ICEHOUSE, remove_in=+1)
+    ... def c(): pass
+
+    4. Specifying the deprecated functionality will not be removed:
+    >>> @deprecated(as_of=deprecated.ICEHOUSE, remove_in=0)
+    ... def d(): pass
+
+    5. Specifying a replacement, deprecated functionality will not be removed:
+    >>> @deprecated(as_of=deprecated.ICEHOUSE, in_favor_of='f()', remove_in=0)
+    ... def e(): pass
+
+    """
+
+    # NOTE(morganfainberg): Bexar is used for unit test purposes, it is
+    # expected we maintain a gap between Bexar and Folsom in this list.
+    BEXAR = 'B'
+    FOLSOM = 'F'
+    GRIZZLY = 'G'
+    HAVANA = 'H'
+    ICEHOUSE = 'I'
+    JUNO = 'J'
+    KILO = 'K'
+
+    _RELEASES = {
+        # NOTE(morganfainberg): Bexar is used for unit test purposes, it is
+        # expected we maintain a gap between Bexar and Folsom in this list.
+        'B': 'Bexar',
+        'F': 'Folsom',
+        'G': 'Grizzly',
+        'H': 'Havana',
+        'I': 'Icehouse',
+        'J': 'Juno',
+        'K': 'Kilo',
+    }
+
+    _deprecated_msg_with_alternative = _(
+        '%(what)s is deprecated as of %(as_of)s in favor of '
+        '%(in_favor_of)s and may be removed in %(remove_in)s.')
+
+    _deprecated_msg_no_alternative = _(
+        '%(what)s is deprecated as of %(as_of)s and may be '
+        'removed in %(remove_in)s. It will not be superseded.')
+
+    _deprecated_msg_with_alternative_no_removal = _(
+        '%(what)s is deprecated as of %(as_of)s in favor of %(in_favor_of)s.')
+
+    _deprecated_msg_with_no_alternative_no_removal = _(
+        '%(what)s is deprecated as of %(as_of)s. It will not be superseded.')
+
+    def __init__(self, as_of, in_favor_of=None, remove_in=2, what=None):
+        """Initialize decorator
+
+        :param as_of: the release deprecating the callable. Constants
+            are define in this class for convenience.
+        :param in_favor_of: the replacement for the callable (optional)
+        :param remove_in: an integer specifying how many releases to wait
+            before removing (default: 2)
+        :param what: name of the thing being deprecated (default: the
+            callable's name)
+
+        """
+        self.as_of = as_of
+        self.in_favor_of = in_favor_of
+        self.remove_in = remove_in
+        self.what = what
+
+    def __call__(self, func):
+        if not self.what:
+            self.what = func.__name__ + '()'
+
+        @functools.wraps(func)
+        def wrapped(*args, **kwargs):
+            msg, details = self._build_message()
+            LOG.deprecated(msg, details)
+            return func(*args, **kwargs)
+        return wrapped
+
+    def _get_safe_to_remove_release(self, release):
+        # TODO(dstanek): this method will have to be reimplemented once
+        #    when we get to the X release because once we get to the Y
+        #    release, what is Y+2?
+        new_release = chr(ord(release) + self.remove_in)
+        if new_release in self._RELEASES:
+            return self._RELEASES[new_release]
+        else:
+            return new_release
+
+    def _build_message(self):
+        details = dict(what=self.what,
+                       as_of=self._RELEASES[self.as_of],
+                       remove_in=self._get_safe_to_remove_release(self.as_of))
+
+        if self.in_favor_of:
+            details['in_favor_of'] = self.in_favor_of
+            if self.remove_in > 0:
+                msg = self._deprecated_msg_with_alternative
+            else:
+                # There are no plans to remove this function, but it is
+                # now deprecated.
+                msg = self._deprecated_msg_with_alternative_no_removal
+        else:
+            if self.remove_in > 0:
+                msg = self._deprecated_msg_no_alternative
+            else:
+                # There are no plans to remove this function, but it is
+                # now deprecated.
+                msg = self._deprecated_msg_with_no_alternative_no_removal
+        return msg, details
+
+
+def is_compatible(requested_version, current_version, same_major=True):
+    """Determine whether `requested_version` is satisfied by
+    `current_version`; in other words, `current_version` is >=
+    `requested_version`.
+
+    :param requested_version: version to check for compatibility
+    :param current_version: version to check against
+    :param same_major: if True, the major version must be identical between
+        `requested_version` and `current_version`. This is used when a
+        major-version difference indicates incompatibility between the two
+        versions. Since this is the common-case in practice, the default is
+        True.
+    :returns: True if compatible, False if not
+    """
+    requested_parts = pkg_resources.parse_version(requested_version)
+    current_parts = pkg_resources.parse_version(current_version)
+
+    if same_major and (requested_parts[0] != current_parts[0]):
+        return False
+
+    return current_parts >= requested_parts

openstack-common.conf

@@ -3,6 +3,7 @@
 # The list of modules to copy from oslo-incubator.git
 module=context
 module=log
+module=versionutils
 
 # The base module to hold the copy of openstack.common
 base=magnum