Lockpick is an utility for distributed locking using zookeeper. Its intended to be used in distributed environments where scripts need synchronization between runs.
Lockpick uses the kazoo library but provides following benefits over kazoo recipes :
- Use non ephemeral zknode to allow explicit lock release
- Exits with correct return codes
- Correct signal Handling and cleanup
- Retires and timeout
$ lockpick --help
usage: lockpick [-h] [-s SERVERS] [-c CHROOT] [-i IDENTIFIER] [-v]
[-r RETRY_COUNT] [-p RETRY_SLEEP]
{lock,rlock,wlock,unlock,list} lock_path
Distributed locking using Zookeeper primarily for scripting. After acquiring
the lock, the zk node is printed to STDOUT. This zk node should be passed to
unlock. Note: all logs are printed to STDERR
positional arguments:
{lock,rlock,wlock,unlock,list}
lock: acquire a mutex lock. rlock: acquire a read lock
wlock: acquire a write lock. unlock: release lock
identified by zk node. list: list all lock contenders
lock_path ZK path to lock OR ZK node to unlock. For the
unlockaction this must be the chrooted zk path to the
node e.g.lockpick lock -c /devops /mylocklockpick
unlock -c /devops /mylock/9d2badeec7684f35b10f4860db42
e45c__rlock__0000000022
optional arguments:
-h, --help show this help message and exit
-s SERVERS, --servers SERVERS
-c CHROOT, --chroot CHROOT
ZK chroot for the lock path
-i IDENTIFIER, --identifier IDENTIFIER
Optional string identifier to add to the lock node OR
verify when unlocking
-v, --verbose
-r RETRY_COUNT, --retry-count RETRY_COUNT
-p RETRY_SLEEP, --retry-sleep RETRY_SLEEP
We recommend using pip to install in a virtualenv :
$ virtualenv lockpick
$ pip install lockpick
$ lockpick -s localhost:2181 -c /test -i "test lock1" rlock /mylock
/mylock/503e61fadc8f492497db823b87e64afe__rlock__0000000038
$ lockpick -s localhost:2181 -c /test -i "test lock1" rlock /mylock
/mylock/e21b0ecd480346aaaba23e77946e16e9__rlock__0000000039
$ lockpick -s localhost:2181 -c /test -i "test lock1" list /mylock
'test lock1' /mylock/e21b0ecd480346aaaba23e77946e16e9__rlock__0000000039
'test lock1' /mylock/503e61fadc8f492497db823b87e64afe__rlock__0000000038
$ lockpick -s localhost:2181 -c /test -i "test lock1" wlock /mylock
[2018-07-25 19:09:53,095] WARNING lockpick: Waiting to acquire lock, contenders are :
[2018-07-25 19:09:53,103] WARNING lockpick: 'test lock1' /mylock/e21b0ecd480346aaaba23e77946e16e9__rlock__0000000039
[2018-07-25 19:09:53,103] WARNING lockpick: 'test lock1' /mylock/503e61fadc8f492497db823b87e64afe__rlock__0000000038
[2018-07-25 19:09:53,104] WARNING lockpick: 'test lock1' /mylock/492b4a6c1727417daf511b343d0d11b7__lock__0000000042
[2018-07-25 19:09:56,104] WARNING lockpick: Waiting to acquire lock, contenders are :
[2018-07-25 19:09:56,114] WARNING lockpick: 'test lock1' /mylock/e21b0ecd480346aaaba23e77946e16e9__rlock__0000000039
[2018-07-25 19:09:56,114] WARNING lockpick: 'test lock1' /mylock/503e61fadc8f492497db823b87e64afe__rlock__0000000038
[2018-07-25 19:09:56,114] WARNING lockpick: 'test lock1' /mylock/492b4a6c1727417daf511b343d0d11b7__lock__0000000042
[2018-07-25 19:09:59,116] WARNING lockpick: LockTimeout exception rasied by locker thread
[2018-07-25 19:09:59,117] ERROR lockpick: Failed to acquire lock within timeout!
$ lockpick -s localhost:2181 -c /test -i "test lock1" unlock /mylock/503e61fadc8f492497db823b87e64afe__rlock__0000000038
$ lockpick -s localhost:2181 -c /test -i "test lock1" unlock /mylock/e21b0ecd480346aaaba23e77946e16e9__rlock__0000000039
$ lockpick -s localhost:2181 -c /test -i "test lock1" wlock /mylock
/mylock/d6602d4a54124826b27c50a43ab67a5e__lock__0000000043
Spawns the given command only if it can acquire the given lock.
./syncd_spawn -n /test -C 'test' -l rlock sleep 5
Got lock on /test
Running your command sleep 5
Unlocked '/test/141bcfad04c6459591164ea12d1604af__rlock__0000000011'