zaqar/zaqar/storage/swift/claims.py

248 lines
9.7 KiB
Python

# 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 hashlib
import math
from oslo_serialization import jsonutils
from oslo_utils import timeutils
from oslo_utils import uuidutils
import swiftclient
from zaqar.common import decorators
from zaqar import storage
from zaqar.storage import errors
from zaqar.storage.swift import utils
class ClaimController(storage.Claim):
"""Implements claims resource operations with swift backend
Claims are scoped by project + queue.
"""
def __init__(self, *args, **kwargs):
super(ClaimController, self).__init__(*args, **kwargs)
self._client = self.driver.connection
@decorators.lazy_property(write=False)
def _queue_ctrl(self):
return self.driver.queue_controller
def _exists(self, queue, claim_id, project=None):
try:
return self._client.head_object(
utils._claim_container(queue, project),
claim_id)
except swiftclient.ClientException as exc:
if exc.http_status == 404:
raise errors.ClaimDoesNotExist(claim_id, queue, project)
raise
def _get(self, queue, claim_id, project=None):
try:
container = utils._claim_container(queue, project)
headers, claim = self._client.get_object(container, claim_id)
except swiftclient.ClientException as exc:
if exc.http_status != 404:
raise
return
now = timeutils.utcnow_ts(True)
return {
'id': claim_id,
'age': now - float(headers['x-timestamp']),
'ttl': int(headers['x-delete-at']) - math.floor(now),
}
def get(self, queue, claim_id, project=None):
message_ctrl = self.driver.message_controller
now = timeutils.utcnow_ts(True)
self._exists(queue, claim_id, project)
container = utils._claim_container(queue, project)
headers, claim_obj = self._client.get_object(container, claim_id)
def g():
for msg_id in jsonutils.loads(claim_obj):
try:
headers, msg = message_ctrl._find_message(queue, msg_id,
project)
except errors.MessageDoesNotExist:
continue
else:
yield utils._message_to_json(msg_id, msg, headers, now)
claim_meta = {
'id': claim_id,
'age': now - float(headers['x-timestamp']),
'ttl': int(headers['x-delete-at']) - math.floor(now),
}
return claim_meta, g()
def create(self, queue, metadata, project=None,
limit=storage.DEFAULT_MESSAGES_PER_CLAIM):
message_ctrl = self.driver.message_controller
queue_ctrl = self.driver.queue_controller
try:
queue_meta = queue_ctrl.get_metadata(queue, project=project)
except errors.QueueDoesNotExist:
return None, iter([])
ttl = metadata['ttl']
grace = metadata['grace']
msg_ts = ttl + grace
claim_id = uuidutils.generate_uuid()
dlq = True if ('_max_claim_count' in queue_meta and
'_dead_letter_queue' in queue_meta) else False
include_delayed = False if queue_meta.get('_default_message_delay',
0) else True
messages, marker = message_ctrl._list(queue, project, limit=limit,
include_claimed=False,
include_delayed=include_delayed)
claimed = []
for msg in messages:
claim_count = msg.get('claim_count', 0)
md5 = hashlib.md5()
md5.update(
jsonutils.dump_as_bytes(
{'body': msg['body'], 'claim_id': None,
'ttl': msg['ttl'],
'claim_count': claim_count}))
md5 = md5.hexdigest()
msg_ttl = max(msg['ttl'], msg_ts)
move_to_dlq = False
if dlq:
if claim_count < queue_meta['_max_claim_count']:
# Check if the message's claim count has exceeded the
# max claim count defined in the queue, if not ,
# Save the new max claim count for message
claim_count = claim_count + 1
else:
# if the message's claim count has exceeded the
# max claim count defined in the queue, move the
# message to the dead letter queue.
# NOTE: We're moving message by changing the
# project info directly. That means, the queue and dead
# letter queue must be created on the same pool.
dlq_ttl = queue_meta.get("_dead_letter_queue_messages_ttl")
move_to_dlq = True
if dlq_ttl:
msg_ttl = dlq_ttl
content = jsonutils.dumps(
{'body': msg['body'], 'claim_id': claim_id,
'ttl': msg_ttl,
'claim_count': claim_count})
if move_to_dlq:
dead_letter_queue = queue_meta.get("_dead_letter_queue")
utils._put_or_create_container(
self._client,
utils._message_container(dead_letter_queue, project),
msg['id'],
content,
content_type='application/json',
headers={'x-object-meta-clientid': msg['client_uuid'],
'if-match': md5,
'x-object-meta-claimid': claim_id,
'x-delete-after': msg_ttl})
message_ctrl._delete(queue, msg['id'], project)
else:
try:
self._client.put_object(
utils._message_container(queue, project),
msg['id'],
content,
content_type='application/json',
headers={'x-object-meta-clientid': msg['client_uuid'],
'if-match': md5,
'x-object-meta-claimid': claim_id,
'x-delete-after': msg_ttl})
except swiftclient.ClientException as exc:
if exc.http_status == 412:
continue
raise
else:
msg['claim_id'] = claim_id
msg['ttl'] = msg_ttl
msg['claim_count'] = claim_count
claimed.append(msg)
utils._put_or_create_container(
self._client,
utils._claim_container(queue, project),
claim_id,
jsonutils.dumps([msg['id'] for msg in claimed]),
content_type='application/json',
headers={'x-delete-after': ttl}
)
return claim_id, claimed
def update(self, queue, claim_id, metadata, project=None):
if not self._queue_ctrl.exists(queue, project):
raise errors.QueueDoesNotExist(queue, project)
container = utils._claim_container(queue, project)
try:
headers, obj = self._client.get_object(container, claim_id)
except swiftclient.ClientException as exc:
if exc.http_status == 404:
raise errors.ClaimDoesNotExist(claim_id, queue, project)
raise
self._client.put_object(container, claim_id, obj,
content_type='application/json',
headers={'x-delete-after': metadata['ttl']})
def delete(self, queue, claim_id, project=None):
message_ctrl = self.driver.message_controller
try:
header, obj = self._client.get_object(
utils._claim_container(queue, project),
claim_id)
for msg_id in jsonutils.loads(obj):
try:
headers, msg = message_ctrl._find_message(queue, msg_id,
project)
except errors.MessageDoesNotExist:
continue
md5 = hashlib.md5()
md5.update(msg)
md5 = md5.hexdigest()
msg = jsonutils.loads(msg)
content = jsonutils.dumps(
{'body': msg['body'], 'claim_id': None, 'ttl': msg['ttl']})
client_id = headers['x-object-meta-clientid']
self._client.put_object(
utils._message_container(queue, project),
msg_id,
content,
content_type='application/json',
headers={'x-object-meta-clientid': client_id,
'if-match': md5,
'x-delete-at': headers['x-delete-at']})
self._client.delete_object(
utils._claim_container(queue, project),
claim_id)
except swiftclient.ClientException as exc:
if exc.http_status != 404:
raise