sqlalchemy-dlock 0.1.1.post1

A distributed lock implementation based on SQLAlchemy

SQLAlchemy-DLock

Distributed lock based on Database and SQLAlchemy.

It currently supports locks of:

• MySQL: https://dev.mysql.com/doc/refman/8.0/en/locking-functions.html
• PostgreSQL: https://www.postgresql.org/docs/current/explicit-locking.html#ADVISORY-LOCKS

It's not stable and DO NOT use it in production.

Usages

Basic:

from sqlalchemy import create_engine
from sqlalchemy_dlock import make_session_level_lock as sd_lock

# ...

lock_key = 'user/001'

# ...

engine = create_engine()

# ...

with engine.connect() as conn:
    with sd_lock(conn, lock_key):
        # do sth...
        pass
# ...

Made from SQLAlchemy's Session:

# ...

lock_key = 'user/001'

# ...

with Session.bind.connect() as conn:
    with sd_lock(conn, lock_key):
        # ...
        user = Session.query(User).filter(id='001').one()
        user.password = new_pass
        Session.commit()
        # ...
# ...

Or, if the session has no commit, rollback, close:

# ...

lock_key = 'user/001'

# ...

with sd_lock(Session.connection(), lock_key):
    # ...
    user = Session.query(User).filter(id='001').one()
    password = user.password
    # ...
# ...

CHANGELOG

v0.1.1

• An early version, maybe not stable enough.
• Replace black2b with crc64-iso in PostgreSQL key convert function
• Only named arguments as extra parameters allowed in Lock's implementation class

AUTHORS

• Liu Xue Yan ([e-mail])