/usr/lib/python3/dist-packages/etcd3gw/lock.py is in python3-etcd3gw 0.2.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 | # 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 uuid
from etcd3gw.utils import _encode
from etcd3gw.utils import DEFAULT_TIMEOUT
from etcd3gw.utils import LOCK_PREFIX
class Lock(object):
def __init__(self, name, ttl=DEFAULT_TIMEOUT, client=None):
"""Create a lock using the given name with specified timeout
:param name:
:param ttl:
:param client:
"""
self.name = name
self.ttl = ttl
self.client = client
self.key = LOCK_PREFIX + self.name
self.lease = None
self._uuid = None
@property
def uuid(self):
"""The unique id of the lock"""
return self._uuid
def acquire(self):
"""Acquire the lock."""
self.lease = self.client.lease(self.ttl)
self._uuid = str(uuid.uuid1())
base64_key = _encode(self.key)
base64_value = _encode(self._uuid)
txn = {
'compare': [{
'key': base64_key,
'result': 'EQUAL',
'target': 'CREATE',
'create_revision': 0
}],
'success': [{
'request_put': {
'key': base64_key,
'value': base64_value,
'lease': self.lease.id
}
}],
'failure': [{
'request_range': {
'key': base64_key
}
}]
}
result = self.client.transaction(txn)
if 'succeeded' in result:
return result['succeeded']
return False
def release(self):
"""Release the lock"""
base64_key = _encode(self.key)
base64_value = _encode(self._uuid)
txn = {
'compare': [{
'key': base64_key,
'result': 'EQUAL',
'target': 'VALUE',
'value': base64_value
}],
'success': [{
'request_delete_range': {
'key': base64_key
}
}]
}
result = self.client.transaction(txn)
if 'succeeded' in result:
return result['succeeded']
return False
def refresh(self):
"""Refresh the lease on the lock
:return:
"""
return self.lease.refresh()
def is_acquired(self):
"""Check if the lock is acquired"""
values = self.client.get(self.key)
return self._uuid in values
def __enter__(self):
"""Use the lock as a contextmanager"""
self.acquire()
return self
def __exit__(self, exception_type, exception_value, traceback):
self.release()
|