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# Copyright 2021 BMW Group
#
# 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 logging
from contextlib import contextmanager
from urllib.parse import quote_plus
from kazoo.protocol.states import KazooState
from zuul.zk.exceptions import LockException
from zuul.zk.vendor.lock import Lock, ReadLock, WriteLock
LOCK_ROOT = "/zuul/locks"
TENANT_LOCK_ROOT = f"{LOCK_ROOT}/tenant"
CONNECTION_LOCK_ROOT = f"{LOCK_ROOT}/connection"
class SessionAwareMixin:
def __init__(self, client, path, identifier=None, extra_lock_patterns=()):
self._zuul_ephemeral = None
self._zuul_session_expired = False
self._zuul_watching_session = False
super().__init__(client, path, identifier, extra_lock_patterns)
def acquire(self, blocking=True, timeout=None, ephemeral=True):
ret = super().acquire(blocking, timeout, ephemeral)
self._zuul_session_expired = False
if ret and ephemeral:
self._zuul_ephemeral = ephemeral
self.client.add_listener(self._zuul_session_watcher)
self._zuul_watching_session = True
return ret
def release(self):
if self._zuul_watching_session:
self.client.remove_listener(self._zuul_session_watcher)
self._zuul_watching_session = False
return super().release()
def _zuul_session_watcher(self, state):
if state == KazooState.LOST:
self._zuul_session_expired = True
# Return true to de-register
return True
def is_still_valid(self):
if not self._zuul_ephemeral:
return True
return not self._zuul_session_expired
class SessionAwareLock(SessionAwareMixin, Lock):
pass
class SessionAwareWriteLock(SessionAwareMixin, WriteLock):
pass
class SessionAwareReadLock(SessionAwareMixin, ReadLock):
pass
@contextmanager
def locked(lock, blocking=True, timeout=None):
if not lock.acquire(blocking=blocking, timeout=timeout):
raise LockException(f"Failed to acquire lock {lock}")
try:
yield lock
finally:
try:
lock.release()
except Exception:
log = logging.getLogger("zuul.zk.locks")
log.exception("Failed to release lock %s", lock)
@contextmanager
def tenant_read_lock(client, tenant_name, blocking=True):
safe_tenant = quote_plus(tenant_name)
with locked(
SessionAwareReadLock(
client.client,
f"{TENANT_LOCK_ROOT}/{safe_tenant}"),
blocking=blocking
) as lock:
yield lock
@contextmanager
def tenant_write_lock(client, tenant_name, blocking=True, identifier=None):
safe_tenant = quote_plus(tenant_name)
with locked(
SessionAwareWriteLock(
client.client,
f"{TENANT_LOCK_ROOT}/{safe_tenant}",
identifier=identifier),
blocking=blocking,
) as lock:
yield lock
@contextmanager
def pipeline_lock(client, tenant_name, pipeline_name, blocking=True):
safe_tenant = quote_plus(tenant_name)
safe_pipeline = quote_plus(pipeline_name)
with locked(
SessionAwareLock(
client.client,
f"/zuul/locks/pipeline/{safe_tenant}/{safe_pipeline}"),
blocking=blocking
) as lock:
yield lock
@contextmanager
def management_queue_lock(client, tenant_name, blocking=True):
safe_tenant = quote_plus(tenant_name)
with locked(
SessionAwareLock(
client.client,
f"/zuul/locks/events/management/{safe_tenant}"),
blocking=blocking
) as lock:
yield lock
@contextmanager
def trigger_queue_lock(client, tenant_name, blocking=True):
safe_tenant = quote_plus(tenant_name)
with locked(
SessionAwareLock(
client.client,
f"/zuul/locks/events/trigger/{safe_tenant}"),
blocking=blocking
) as lock:
yield lock
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