ceph/src/pybind/mgr/dashboard/plugins/pluggy.py

   1 # -*- coding: utf-8 -*-
   2 """
   3 The MIT License (MIT)
   4
   5 Copyright (c) 2015 holger krekel (rather uses bitbucket/hpk42)
   6
   7 Permission is hereby granted, free of charge, to any person obtaining a copy
   8 of this software and associated documentation files (the "Software"), to deal
   9 in the Software without restriction, including without limitation the rights
  10 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11 copies of the Software, and to permit persons to whom the Software is
  12 furnished to do so, subject to the following conditions:
  13
  14 The above copyright notice and this permission notice shall be included in all
  15 copies or substantial portions of the Software.
  16
  17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23 SOFTWARE.
  24 """\
  25 """
  26 CAVEAT:
  27 This is a minimal implementation of python-pluggy (based on 0.8.0 interface:
  28 https://github.com/pytest-dev/pluggy/releases/tag/0.8.0).
  29
  30
  31 Despite being a widely available Python library, it does not reach all the
  32 distros and releases currently targeted for Ceph Nautilus:
  33 - CentOS/RHEL 7.5 [ ]
  34 - CentOS/RHEL 8 [ ]
  35 - Debian 8.0 [ ]
  36 - Debian 9.0 [ ]
  37 - Ubuntu 14.05 [ ]
  38 - Ubuntu 16.04 [X]
  39
  40 TODO: Once this becomes available in the above distros, this file should be
  41 REMOVED, and the fully featured python-pluggy should be used instead.
  42 """
  43 try:
  44     from typing import DefaultDict
  45 except ImportError:
  46     pass  # For typing only
  47
  48
  49 class HookspecMarker(object):
  50     """ Dummy implementation. No spec validation. """
  51     def __init__(self, project_name):
  52         self.project_name = project_name
  53
  54     def __call__(self, function, *args, **kwargs):
  55         """ No options supported. """
  56         if any(args) or any(kwargs):
  57             raise NotImplementedError(
  58                 "This is a minimal implementation of pluggy")
  59         return function
  60
  61
  62 class HookimplMarker(object):
  63     def __init__(self, project_name):
  64         self.project_name = project_name
  65
  66     def __call__(self, function, *args, **kwargs):
  67         """ No options supported."""
  68         if any(args) or any(kwargs):
  69             raise NotImplementedError(
  70                 "This is a minimal implementation of pluggy")
  71         setattr(function, self.project_name + "_impl", {})
  72         return function
  73
  74
  75 class _HookRelay(object):
  76     """
  77     Provides the PluginManager.hook.<method_name>() syntax and
  78     functionality.
  79     """
  80     def __init__(self):
  81         from collections import defaultdict
  82         self._registry = defaultdict(list)  # type: DefaultDict[str, list]
  83
  84     def __getattr__(self, hook_name):
  85         return lambda *args, **kwargs: [
  86             hook(*args, **kwargs) for hook in self._registry[hook_name]]
  87
  88     def _add_hookimpl(self, hook_name, hook_method):
  89         self._registry[hook_name].append(hook_method)
  90
  91
  92 class PluginManager(object):
  93     def __init__(self, project_name):
  94         self.project_name = project_name
  95         self.__hook = _HookRelay()
  96
  97     @property
  98     def hook(self):
  99         return self.__hook
 100
 101     def parse_hookimpl_opts(self, plugin, name):
 102         return getattr(
 103             getattr(plugin, name),
 104             self.project_name + "_impl",
 105             None)
 106
 107     def add_hookspecs(self, module_or_class):
 108         """ Dummy method"""
 109
 110     def register(self, plugin, name=None):  # pylint: disable=unused-argument
 111         for attr in dir(plugin):
 112             if self.parse_hookimpl_opts(plugin, attr) is not None:
 113                 # pylint: disable=protected-access
 114                 self.hook._add_hookimpl(attr, getattr(plugin, attr))