Add some useful features to our flags
* No longer dies if there are unknown flags. * Allows you to declare that you will use a flag from another file * Allows you to import new flags at runtime and reparses the original arguments to fill them once they are accessed. This hopefully gets around the issues described by vish in this thread: https://lists.launchpad.net/nova/msg00009.html
This commit is contained in:
andy
141
nova/flags.py
141
nova/flags.py
@@ -21,16 +21,145 @@ Package-level global flags are defined here, the rest are defined
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where they're used.
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"""
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import getopt
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import socket
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import sys
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import gflags
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from gflags import *
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class FlagValues(gflags.FlagValues):
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"""Extension of gflags.FlagValues that allows undefined and runtime flags.
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Unknown flags will be ignored when parsing the command line, but the
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command line will be kept so that it can be replayed if new flags are
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defined after the initial parsing.
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"""
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def __init__(self):
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gflags.FlagValues.__init__(self)
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self.__dict__['__dirty'] = []
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self.__dict__['__was_already_parsed'] = False
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self.__dict__['__stored_argv'] = []
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def __call__(self, argv):
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# We're doing some hacky stuff here so that we don't have to copy
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# out all the code of the original verbatim and then tweak a few lines.
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# We're hijacking the output of getopt so we can still return the
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# leftover args at the end
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sneaky_unparsed_args = {"value": None}
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original_argv = list(argv)
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if self.IsGnuGetOpt():
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orig_getopt = getattr(getopt, 'gnu_getopt')
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orig_name = 'gnu_getopt'
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else:
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orig_getopt = getattr(getopt, 'getopt')
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orig_name = 'getopt'
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def _sneaky(*args, **kw):
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optlist, unparsed_args = orig_getopt(*args, **kw)
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sneaky_unparsed_args['value'] = unparsed_args
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return optlist, unparsed_args
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try:
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setattr(getopt, orig_name, _sneaky)
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args = gflags.FlagValues.__call__(self, argv)
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except gflags.UnrecognizedFlagError:
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# Undefined args were found, for now we don't care so just
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# act like everything went well
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# (these three lines are copied pretty much verbatim from the end
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# of the __call__ function we are wrapping)
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unparsed_args = sneaky_unparsed_args['value']
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if unparsed_args:
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if self.IsGnuGetOpt():
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args = argv[:1] + unparsed
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else:
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args = argv[:1] + original_argv[-len(unparsed_args):]
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else:
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args = argv[:1]
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finally:
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setattr(getopt, orig_name, orig_getopt)
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# Store the arguments for later, we'll need them for new flags
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# added at runtime
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self.__dict__['__stored_argv'] = original_argv
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self.__dict__['__was_already_parsed'] = True
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self.ClearDirty()
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return args
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def SetDirty(self, name):
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"""Mark a flag as dirty so that accessing it will case a reparse."""
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self.__dict__['__dirty'].append(name)
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def IsDirty(self, name):
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return name in self.__dict__['__dirty']
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def ClearDirty(self):
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self.__dict__['__is_dirty'] = []
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def WasAlreadyParsed(self):
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return self.__dict__['__was_already_parsed']
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def ParseNewFlags(self):
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if '__stored_argv' not in self.__dict__:
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return
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new_flags = FlagValues()
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for k in self.__dict__['__dirty']:
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new_flags[k] = gflags.FlagValues.__getitem__(self, k)
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new_flags(self.__dict__['__stored_argv'])
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for k in self.__dict__['__dirty']:
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setattr(self, k, getattr(new_flags, k))
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self.ClearDirty()
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def __setitem__(self, name, flag):
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gflags.FlagValues.__setitem__(self, name, flag)
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if self.WasAlreadyParsed():
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self.SetDirty(name)
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def __getitem__(self, name):
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if self.IsDirty(name):
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self.ParseNewFlags()
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return gflags.FlagValues.__getitem__(self, name)
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def __getattr__(self, name):
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if self.IsDirty(name):
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self.ParseNewFlags()
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return gflags.FlagValues.__getattr__(self, name)
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FLAGS = FlagValues()
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def _wrapper(func):
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def _wrapped(*args, **kw):
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kw.setdefault('flag_values', FLAGS)
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func(*args, **kw)
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_wrapped.func_name = func.func_name
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return _wrapped
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DEFINE_string = _wrapper(gflags.DEFINE_string)
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DEFINE_integer = _wrapper(gflags.DEFINE_integer)
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DEFINE_bool = _wrapper(gflags.DEFINE_bool)
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DEFINE_boolean = _wrapper(gflags.DEFINE_boolean)
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DEFINE_float = _wrapper(gflags.DEFINE_float)
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DEFINE_enum = _wrapper(gflags.DEFINE_enum)
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DEFINE_list = _wrapper(gflags.DEFINE_list)
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DEFINE_spaceseplist = _wrapper(gflags.DEFINE_spaceseplist)
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DEFINE_multistring = _wrapper(gflags.DEFINE_multistring)
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DEFINE_multi_int = _wrapper(gflags.DEFINE_multi_int)
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def DECLARE(name, module_string, flag_values=FLAGS):
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if module_string not in sys.modules:
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__import__(module_string, globals(), locals())
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if name not in flag_values:
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raise gflags.UnrecognizedFlag(
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"%s not defined by %s" % (name, module_string))
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# This keeps pylint from barfing on the imports
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FLAGS = FLAGS
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DEFINE_string = DEFINE_string
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DEFINE_integer = DEFINE_integer
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DEFINE_bool = DEFINE_bool
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# __GLOBAL FLAGS ONLY__
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# Define any app-specific flags in their own files, docs at:
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23
nova/tests/declare_flags.py
Normal file
23
nova/tests/declare_flags.py
Normal file
@@ -0,0 +1,23 @@
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from nova import flags
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FLAGS = flags.FLAGS
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flags.DEFINE_integer('answer', 42, 'test flag')
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87
nova/tests/flags_unittest.py
Normal file
87
nova/tests/flags_unittest.py
Normal file
@@ -0,0 +1,87 @@
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from nova import exception
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from nova import flags
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from nova import test
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class FlagsTestCase(test.TrialTestCase):
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def setUp(self):
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super(FlagsTestCase, self).setUp()
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self.FLAGS = flags.FlagValues()
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self.global_FLAGS = flags.FLAGS
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def test_define(self):
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self.assert_('string' not in self.FLAGS)
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self.assert_('int' not in self.FLAGS)
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self.assert_('false' not in self.FLAGS)
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self.assert_('true' not in self.FLAGS)
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flags.DEFINE_string('string', 'default', 'desc', flag_values=self.FLAGS)
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flags.DEFINE_integer('int', 1, 'desc', flag_values=self.FLAGS)
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flags.DEFINE_bool('false', False, 'desc', flag_values=self.FLAGS)
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flags.DEFINE_bool('true', True, 'desc', flag_values=self.FLAGS)
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self.assert_(self.FLAGS['string'])
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self.assert_(self.FLAGS['int'])
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self.assert_(self.FLAGS['false'])
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self.assert_(self.FLAGS['true'])
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self.assertEqual(self.FLAGS.string, 'default')
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self.assertEqual(self.FLAGS.int, 1)
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self.assertEqual(self.FLAGS.false, False)
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self.assertEqual(self.FLAGS.true, True)
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argv = ['flags_test',
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'--string', 'foo',
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'--int', '2',
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'--false',
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'--notrue']
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self.FLAGS(argv)
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self.assertEqual(self.FLAGS.string, 'foo')
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self.assertEqual(self.FLAGS.int, 2)
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self.assertEqual(self.FLAGS.false, True)
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self.assertEqual(self.FLAGS.true, False)
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def test_declare(self):
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self.assert_('answer' not in self.global_FLAGS)
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flags.DECLARE('answer', 'nova.tests.declare_flags')
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self.assert_('answer' in self.global_FLAGS)
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self.assertEqual(self.global_FLAGS.answer, 42)
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# Make sure we don't overwrite anything
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self.global_FLAGS.answer = 256
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self.assertEqual(self.global_FLAGS.answer, 256)
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flags.DECLARE('answer', 'nova.tests.declare_flags')
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self.assertEqual(self.global_FLAGS.answer, 256)
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def test_runtime_and_unknown_flags(self):
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self.assert_('runtime_answer' not in self.global_FLAGS)
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argv = ['flags_test', '--runtime_answer=60', 'extra_arg']
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args = self.global_FLAGS(argv)
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self.assertEqual(len(args), 2)
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self.assertEqual(args[1], 'extra_arg')
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self.assert_('runtime_answer' not in self.global_FLAGS)
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import nova.tests.runtime_flags
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self.assert_('runtime_answer' in self.global_FLAGS)
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self.assertEqual(self.global_FLAGS.runtime_answer, 60)
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23
nova/tests/runtime_flags.py
Normal file
23
nova/tests/runtime_flags.py
Normal file
@@ -0,0 +1,23 @@
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from nova import flags
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FLAGS = flags.FLAGS
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flags.DEFINE_integer('runtime_answer', 54, 'test flag')
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@@ -54,6 +54,7 @@ from nova.tests.auth_unittest import *
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from nova.tests.api_unittest import *
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from nova.tests.cloud_unittest import *
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from nova.tests.compute_unittest import *
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from nova.tests.flags_unittest import *
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from nova.tests.model_unittest import *
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from nova.tests.network_unittest import *
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from nova.tests.objectstore_unittest import *
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