dynamodb-persistent-lock 0.0.4

DynamoDB Persistent Lock

Getting Started

1. Install the library

% python3 -m pip install dynamodb-persistent-lock

2. Usage

Non-async DynamoDB local download:

from dynamodb_persistent_lock import (
    DynamoDBPersistentLockFactory,
    DynamoDBPersistentLockClient,
)
from datetime import timedelta
...
# Create a lock factory
lock_factory = DynamoDBPersistentLockFactory(
    table_name="locks",
    region_name="eu-central-1",
    partition_key_name="lock_key",
    sort_key_name="sort_key",
    record_version_number_name="rvn",
    heartbeat_period=timedelta(seconds=10),
    ttl_attribute_name="expire_at",
    ttl_heartbeat_multiplier=3,
)
lock_factory.ensure_table()
...
# Open a lock client
lock_client = lock_factory.open_lock_client()
try:
    lock_token = lock_client.try_acquire_lock("my_lock_key")
    ...
    while lock_client.lock_acquired(lock_token):
        # Lock-guarded code here.
finally:
    lock_client.close()

Features

• Creates a new lock, if there is none, in DynamoDB table.

• Reacquires stale existing lock based on the ttl column value.

• Keeps extending the ttl of an acquired lock with a given heartbeat rate.

Credits

• Building Distributed Locks with the DynamoDB Lock Client.