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# vi: ts=4 expandtab
#
# Copyright (C) 2012 Canonical Ltd.
# Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
# Copyright (C) 2012 Yahoo! Inc.
#
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
# Author: Joshua Harlow <harlowja@yahoo-inc.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3, as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from time import time
import contextlib
import os
from cloudinit.settings import (PER_INSTANCE, PER_ALWAYS, PER_ONCE)
from cloudinit import log as logging
from cloudinit import util
from cloudinit.user_data import boot_hook as bh_part
from cloudinit.user_data import cloud_config as cc_part
from cloudinit.user_data import shell_script as ss_part
from cloudinit.user_data import upstart_job as up_part
LOG = logging.getLogger(__name__)
class DummySemaphores(object):
def __init__(self):
pass
@contextlib.contextmanager
def lock(self, _name, _freq, _clear_on_fail):
yield True
def has_run(self, _name, _freq):
return False
class Semaphores(object):
def __init__(self, sem_path):
self.sem_path = sem_path
@contextlib.contextmanager
def lock(self, name, freq, clear_on_fail):
try:
yield self._acquire(name, freq)
except:
if clear_on_fail:
self.clear(name, freq)
raise
def clear(self, name, freq):
sem_file = self._get_path(name, freq)
try:
util.del_file(sem_file)
except (IOError, OSError):
return False
return True
def _acquire(self, name, freq):
if self.has_run(name, freq):
return None
# This is a race condition since nothing atomic is happening
# here, but this should be ok due to the nature of when
# and where cloud-init runs... (file writing is not a lock..)
sem_file = self._get_path(name, freq)
contents = "%s: %s\n" % (os.getpid(), time())
try:
util.write_file(sem_file, contents)
except (IOError, OSError):
return None
return sem_file
def has_run(self, name, freq):
if freq == PER_ALWAYS:
return False
sem_file = self._get_path(name, freq)
if os.path.exists(sem_file):
return True
return False
def _get_path(self, name, freq):
sem_path = self.sem_path
if not freq or freq == PER_INSTANCE:
return os.path.join(sem_path, name)
else:
return os.path.join(sem_path, "%s.%s" % (name, freq))
class Runners(object):
def __init__(self, paths):
self.paths = paths
self.sems = {}
def _get_sem(self, freq):
if freq == PER_ALWAYS or not freq:
return None
sem_path = None
if freq == PER_INSTANCE:
sem_path = self.paths.get_ipath("sem")
elif freq == PER_ONCE:
sem_path = self.paths.get_cpath("sem")
if not sem_path:
return None
if sem_path not in self.sems:
self.sems[sem_path] = Semaphores(sem_path)
return self.sems[sem_path]
def run(self, name, functor, args, freq=None, clear_on_fail=False):
sem = self._get_sem(freq)
if not sem:
sem = DummySemaphores()
if not args:
args = []
if sem.has_run(name, freq):
LOG.info("%s already ran (freq=%s)", name, freq)
return None
with sem.lock(name, freq, clear_on_fail) as lk:
if not lk:
raise RuntimeError("Failed to acquire lock on %s" % name)
else:
LOG.debug("Running %s with args %s using lock %s",
functor, args, lk)
return functor(*args)
class ContentHandlers(object):
def __init__(self, paths):
self.paths = paths
self.registered = {}
def __contains__(self, item):
return self.is_registered(item)
def __getitem__(self, key):
return self._get_handler(key)
def is_registered(self, content_type):
return content_type in self.registered
def register(self, mod):
types = set()
for t in mod.list_types():
self.registered[t] = mod
types.add(t)
return types
def _get_handler(self, content_type):
return self.registered[content_type]
def items(self):
return self.registered.items()
def iteritems(self):
return self.registered.iteritems()
def _get_default_handlers(self):
def_handlers = []
cc_path = self.paths.get_ipath("cloud_config")
if cc_path:
cc_h = cc_part.CloudConfigPartHandler(cc_path)
def_handlers.append(cc_h)
sc_path = self.paths.get_ipath_cur('scripts')
if sc_path:
ss_h = ss_part.ShellScriptPartHandler(sc_path)
def_handlers.append(ss_h)
bh_path = self.paths.get_ipath("boothooks")
if bh_path:
bh_h = bh_part.BootHookPartHandler(bh_path)
def_handlers.append(bh_h)
upstart_pth = self.paths.upstart_conf_d
if upstart_pth:
up_h = up_part.UpstartJobPartHandler(upstart_pth)
def_handlers.append(up_h)
return def_handlers
def register_defaults(self):
registered = set()
for mod in self._get_default_handlers():
for t in mod.list_types():
if not self.is_registered(t):
self.registered[t] = mod
registered.add(t)
return registered
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