dreadatour/tarantool-locksmith

Locksmith: locks implementation for Tarantool

Tarantool locksmith module

An application-level library that provides distributed locks for tarantool 1.6.

Install

1. Clone this git repository to `/usr/local/tarantool-locksmith/.
2. Add init.lua to /etc/tarantool/instances.enabled/.
3. Restart tarantool: sudo service tarantool restart.

FIXME: Add RPM/DEB packages and rewrite installation instructions.

Usage

1. Acquire new lock: locksmith:acquire(lock_name, validity, timeout).

   Arguments:

   • lock_name - name of the lock (string)
   • validity - lock lifetime, seconds (float)
   • timeout - lock wait timeout, seconds (float); 0 - do not wait, nil - wait forever

   Returns:

   • lock tuple if lock acquire is sucessful: [lock_id, lock_name, lock_uid, creation_time, valid_until]
   • nil if lock acquire failed

   Examples:

   > locksmith:acquire('foo', 60, 0)
   ---
   - [0, 'foo', '45961e7f-3b47-49b5-9fc2-985b1e534aec', 1463088131062999, 1463088191062999]
   ...
   

   > locksmith:acquire('foo', 60, 0)
   ---
   - null
   ...
   

2. Update lock validity: locksmith:update(lock_uid, validity).

   Arguments:

   • lock_uid - uid of the lock (string)
   • validity - new lock lifetime, seconds (float)

   Returns:

   • lock tuple if lock update is sucessful: [lock_id, lock_name, lock_uid, creation_time, valid_until]
   • nil if lock is missed or expired

   Examples:

   > locksmith:update('45961e7f-3b47-49b5-9fc2-985b1e534aec', 60)
   ---
   - [0, 'foo', '45961e7f-3b47-49b5-9fc2-985b1e534aec', 1463088131062999, 1463088206428052]
   ...
   

   > locksmith:update('9c5c5354-f975-4811-aa7e-c6e569d359eb', 60)
   ---
   - null
   ...
   

3. Release lock: locksmith:release(lock_uid).

   Arguments:

   • lock_uid - uid of the lock (string)

   Returns:

   • lock tuple if lock release is sucessful: [lock_id, lock_name, lock_uid, creation_time, valid_until]
   • nil if lock is missed or expired

   Examples:

   > locksmith:release('45961e7f-3b47-49b5-9fc2-985b1e534aec')
   ---
   - [0, 'foo', '45961e7f-3b47-49b5-9fc2-985b1e534aec', 1463088131062999, 1463088206428052]
   ...
   

   > locksmith:release('9c5c5354-f975-4811-aa7e-c6e569d359eb')
   ---
   - null
   ...
   

4. Statistics: locksmith:statistics().

   Example:

   > locksmith:statistics()
   ---
   - calls:
       acquire: 1
       acquire_success: 1
       update: 1
       update_success: 1
       release: 1
       release_success: 1
       watchdog_release: 0
       lock_create: 1
       lock_update: 1
       lock_delete: 1
     locks:
       count: 0
     consumers:
       waiting: 0
   ...