python-manilaclient/manilaclient/utils.py
cFouts c34e3b7d2c Nova Style API Version Support for Client
The Manila client needs the following changes to support microversions:

*   Maintain backwards compatibility with Kilo. When the client detects
    that the server doesn't support microversions it will fall back to
    using the v1 API.
*   The --os-share-api-version option supports overriding the version.
*   If 1.0 is specified as the version the client will load the v1
    client and use the server's v1 API.
*   The client will send a request for the server's API version and
    determine if the client's supported versions and the server's
    supported versions overlap. If not the client will display an error
    and quit. See diagram 1 below.
*   The client supports the @wraps annotation. The annotation is used
    with the v2/shell.py commands and any class that inherits from
    the Manager class in manilaclient/base.py.
*   If an appropriate command version isn't found for commands using
    @wraps then the client will display an error and quit.

following commit: ab49d645be.

Diagram 1:
  Client:
         2.5           2.8
          |-------------|

  Server1:
     2.0           2.5
      |-------------|
     Client uses version 2.5

  Server2:
               2.7           2.10
                |-------------|
               Client uses version 2.8

  Server3:
                  2.9           2.12
                   |-------------|
                  Client displays error and quits

  Server4:
     1.0 (Kilo Server)
      |-|
     Client detects pre-microversion server and loads v1 client

Example usage of wraps annotation:
*   Support 2.0 - 2.4: @api_versions.wraps("2.0", "2.4")
*   Support 2.5 - latest: @api_versions.wraps("2.5")

Implements: blueprint manila-client-advanced-microversion-support

Change-Id: I3733fe85424e39566addc070d42609e508259f19
2015-11-16 19:03:55 +00:00

54 lines
1.5 KiB
Python

# 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.
import six
class HookableMixin(object):
"""Mixin so classes can register and run hooks."""
_hooks_map = {}
@classmethod
def add_hook(cls, hook_type, hook_func):
if hook_type not in cls._hooks_map:
cls._hooks_map[hook_type] = []
cls._hooks_map[hook_type].append(hook_func)
@classmethod
def run_hooks(cls, hook_type, *args, **kwargs):
hook_funcs = cls._hooks_map.get(hook_type) or []
for hook_func in hook_funcs:
hook_func(*args, **kwargs)
def safe_issubclass(*args):
"""Like issubclass, but will just return False if not a class."""
try:
if issubclass(*args):
return True
except TypeError:
pass
return False
def get_function_name(func):
if six.PY2:
if hasattr(func, "im_class"):
return "%s.%s" % (func.im_class, func.__name__)
else:
return "%s.%s" % (func.__module__, func.__name__)
else:
return "%s.%s" % (func.__module__, func.__qualname__)