trove/reddwarf/common/utils.py
Russell Bryant 1aaed59b4b s/OpenStack LLC/OpenStack Foundation/ in Copyright.
Update Copyright statements that previously said 'OpenStack LLC' to now
say 'OpenStack Foundation'.  Note that the files under openstack/common/
were not updated, as those changes should be brought in by syncing with
oslo-incubator.

Change-Id: I22db9858e899cff72053a4b48100fcc039f5d9dd
2013-04-29 18:33:42 -04:00

275 lines
7.9 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2011 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.
"""I totally stole most of this from melange, thx guys!!!"""
import datetime
import inspect
import re
import signal
import sys
import time
import urlparse
import uuid
from eventlet import event
from eventlet import greenthread
from eventlet import semaphore
from eventlet.green import subprocess
from eventlet.timeout import Timeout
from reddwarf.common import exception
from reddwarf.openstack.common import importutils
from reddwarf.openstack.common import log as logging
from reddwarf.openstack.common import processutils
from reddwarf.openstack.common import timeutils
from reddwarf.openstack.common import utils as openstack_utils
from reddwarf.openstack.common.gettextutils import _
LOG = logging.getLogger(__name__)
import_class = importutils.import_class
import_object = importutils.import_object
import_module = importutils.import_module
bool_from_string = openstack_utils.bool_from_string
execute = processutils.execute
isotime = timeutils.isotime
def create_method_args_string(*args, **kwargs):
"""Returns a string representation of args and keyword args.
I.e. for args=1,2,3 and kwargs={'a':4, 'b':5} you'd get: "1,2,3,a=4,b=5"
"""
# While %s turns a var into a string but in some rare cases explicit
# repr() is less likely to raise an exception.
arg_strs = [repr(arg) for arg in args]
arg_strs += ['%s=%s' % (repr(key), repr(value))
for (key, value) in kwargs.items()]
return ', '.join(arg_strs)
def stringify_keys(dictionary):
if dictionary is None:
return None
return dict((str(key), value) for key, value in dictionary.iteritems())
def exclude(key_values, *exclude_keys):
if key_values is None:
return None
return dict((key, value) for key, value in key_values.iteritems()
if key not in exclude_keys)
def generate_uuid():
return str(uuid.uuid4())
def utcnow():
return datetime.datetime.utcnow()
class cached_property(object):
"""A decorator that converts a function into a lazy property.
Taken from : https://github.com/nshah/python-memoize
The function wrapped is called the first time to retrieve the result
and than that calculated result is used the next time you access
the value:
class Foo(object):
@cached_property
def bar(self):
# calculate something important here
return 42
"""
def __init__(self, func, name=None, doc=None):
self.func = func
self.__name__ = name or func.__name__
self.__doc__ = doc or func.__doc__
def __get__(self, obj, type=None):
if obj is None:
return self
value = self.func(obj)
setattr(obj, self.__name__, value)
return value
class MethodInspector(object):
def __init__(self, func):
self._func = func
@cached_property
def required_args(self):
return self.args[0:self.required_args_count]
@cached_property
def optional_args(self):
keys = self.args[self.required_args_count: len(self.args)]
return zip(keys, self.defaults)
@cached_property
def defaults(self):
return self.argspec.defaults or ()
@cached_property
def required_args_count(self):
return len(self.args) - len(self.defaults)
@cached_property
def args(self):
args = self.argspec.args
if inspect.ismethod(self._func):
args.pop(0)
return args
@cached_property
def argspec(self):
return inspect.getargspec(self._func)
def __str__(self):
optionals = ["[{0}=<{0}>]".format(k) for k, v in self.optional_args]
required = ["{0}=<{0}>".format(arg) for arg in self.required_args]
args_str = ' '.join(required + optionals)
return "%s %s" % (self._func.__name__, args_str)
class LoopingCallDone(Exception):
"""Exception to break out and stop a LoopingCall.
The poll-function passed to LoopingCall can raise this exception to
break out of the loop normally. This is somewhat analogous to
StopIteration.
An optional return-value can be included as the argument to the exception;
this return-value will be returned by LoopingCall.wait()
"""
def __init__(self, retvalue=True):
""":param retvalue: Value that LoopingCall.wait() should return."""
super(LoopingCallDone, self).__init__()
self.retvalue = retvalue
class LoopingCall(object):
"""Nabbed from nova."""
def __init__(self, f=None, *args, **kw):
self.args = args
self.kw = kw
self.f = f
self._running = False
def start(self, interval, now=True):
self._running = True
done = event.Event()
def _inner():
if not now:
greenthread.sleep(interval)
try:
while self._running:
self.f(*self.args, **self.kw)
if not self._running:
break
greenthread.sleep(interval)
except LoopingCallDone, e:
self.stop()
done.send(e.retvalue)
except Exception:
LOG.exception(_('in looping call'))
done.send_exception(*sys.exc_info())
return
else:
done.send(True)
self.done = done
greenthread.spawn(_inner)
return self.done
def stop(self):
self._running = False
def wait(self):
return self.done.wait()
def poll_until(retriever, condition=lambda value: value,
sleep_time=1, time_out=None):
"""Retrieves object until it passes condition, then returns it.
If time_out_limit is passed in, PollTimeOut will be raised once that
amount of time is eclipsed.
"""
start_time = time.time()
def poll_and_check():
obj = retriever()
if condition(obj):
raise LoopingCallDone(retvalue=obj)
if time_out is not None and time.time() > start_time + time_out:
raise exception.PollTimeOut
lc = LoopingCall(f=poll_and_check).start(sleep_time, True)
return lc.wait()
# Copied from nova.api.openstack.common in the old code.
def get_id_from_href(href):
"""Return the id or uuid portion of a url.
Given: 'http://www.foo.com/bar/123?q=4'
Returns: '123'
Given: 'http://www.foo.com/bar/abc123?q=4'
Returns: 'abc123'
"""
return urlparse.urlsplit("%s" % href).path.split('/')[-1]
def execute_with_timeout(*args, **kwargs):
time = kwargs.get('timeout', 30)
def cb_timeout():
msg = _("Time out after waiting"
" %(time)s seconds when running proc: %(args)s"
" %(kwargs)s") % locals()
LOG.error(msg)
raise exception.ProcessExecutionError(msg)
timeout = Timeout(time)
try:
return execute(*args, **kwargs)
except Timeout as t:
if t is not timeout:
LOG.error("Timeout reached but not from our timeout. This is bad!")
raise
else:
msg = _("Time out after waiting "
"%(time)s seconds when running proc: %(args)s"
" %(kwargs)s") % locals()
LOG.error(msg)
raise exception.ProcessExecutionError(msg)
finally:
timeout.cancel()