deb-sahara/sahara/context.py

212 lines
6.1 KiB
Python

# Copyright (c) 2013 Mirantis Inc.
#
# 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 eventlet
from eventlet.green import threading
from eventlet.green import time
from eventlet import greenpool
from eventlet import semaphore
from oslo.config import cfg
from sahara.api import acl
from sahara import exceptions as ex
from sahara.i18n import _
from sahara.i18n import _LE
from sahara.i18n import _LW
from sahara.openstack.common import log as logging
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
# TODO(slukjanov): it'll be better to use common_context.RequestContext as base
class Context(object):
def __init__(self,
user_id=None,
tenant_id=None,
token=None,
service_catalog=None,
username=None,
tenant_name=None,
roles=None,
is_admin=None,
remote_semaphore=None,
auth_uri=None,
**kwargs):
if kwargs:
LOG.warn(_LW('Arguments dropped when creating context: %s'),
kwargs)
self.user_id = user_id
self.tenant_id = tenant_id
self.token = token
self.service_catalog = service_catalog
self.username = username
self.tenant_name = tenant_name
self.is_admin = is_admin
self.remote_semaphore = remote_semaphore or semaphore.Semaphore(
CONF.cluster_remote_threshold)
self.roles = roles
self.auth_uri = auth_uri or acl.AUTH_URI
def clone(self):
return Context(
self.user_id,
self.tenant_id,
self.token,
self.service_catalog,
self.username,
self.tenant_name,
self.roles,
self.is_admin,
self.remote_semaphore,
self.auth_uri)
def to_dict(self):
return {
'user_id': self.user_id,
'tenant_id': self.tenant_id,
'token': self.token,
'service_catalog': self.service_catalog,
'username': self.username,
'tenant_name': self.tenant_name,
'is_admin': self.is_admin,
'roles': self.roles,
'auth_uri': self.auth_uri,
}
def is_auth_capable(self):
return (self.service_catalog and self.token and self.tenant_id and
self.user_id)
def get_admin_context():
return Context(is_admin=True)
_CTX_STORE = threading.local()
_CTX_KEY = 'current_ctx'
def has_ctx():
return hasattr(_CTX_STORE, _CTX_KEY)
def ctx():
if not has_ctx():
raise ex.IncorrectStateError(_("Context isn't available here"))
return getattr(_CTX_STORE, _CTX_KEY)
def current():
return ctx()
def set_ctx(new_ctx):
if not new_ctx and has_ctx():
delattr(_CTX_STORE, _CTX_KEY)
if new_ctx:
setattr(_CTX_STORE, _CTX_KEY, new_ctx)
def _wrapper(ctx, thread_description, thread_group, func, *args, **kwargs):
try:
set_ctx(ctx)
func(*args, **kwargs)
except BaseException as e:
LOG.exception(
_LE("Thread '%(thread)s' fails with exception: '%(exception)s'"),
{'thread': thread_description, 'exception': e})
if thread_group and not thread_group.exc:
thread_group.exc = e
thread_group.failed_thread = thread_description
finally:
if thread_group:
thread_group._on_thread_exit()
set_ctx(None)
def spawn(thread_description, func, *args, **kwargs):
eventlet.spawn(_wrapper, current().clone(), thread_description,
None, func, *args, **kwargs)
class ThreadGroup(object):
"""ThreadGroup object.
It is advised to use TreadGroup as a context manager instead
of instantiating and calling _wait() manually. The __exit__()
guaranties to exit only after all child threads are done, even if
spawning code have thrown an exception
"""
def __init__(self, thread_pool_size=1000):
self.tg = greenpool.GreenPool(size=thread_pool_size)
self.exc = None
self.failed_thread = None
self.threads = 0
self.cv = threading.Condition()
def spawn(self, thread_description, func, *args, **kwargs):
self.tg.spawn(_wrapper, current().clone(), thread_description,
self, func, *args, **kwargs)
with self.cv:
self.threads += 1
def _on_thread_exit(self):
with self.cv:
self.threads -= 1
if self.threads == 0:
self.cv.notifyAll()
# NOTE(dmitryme): A little rationale on why we reimplemented wait():
# * Eventlet's GreenPool.wait() can hung
# * Oslo's ThreadGroup.wait() can exit before all threads are done
#
def _wait(self):
"""Using of _wait() method.
It is preferred to use the class as a context manager and do not
use _wait() directly, see class docstring for an explanation.
"""
with self.cv:
while self.threads > 0:
self.cv.wait()
if self.exc:
raise ex.ThreadException(self.failed_thread, self.exc)
def __enter__(self):
return self
def __exit__(self, *ex):
if not any(ex):
self._wait()
else:
# If spawning code thrown an exception, it had higher priority
# for us than the one thrown inside child thread (if any)
try:
self._wait()
except Exception:
# that will make __exit__ throw original exception
pass
def sleep(seconds=0):
time.sleep(seconds)