40 lines
1.0 KiB
Python
40 lines
1.0 KiB
Python
LOCK_MODES = (
|
|
'ACCESS SHARE',
|
|
'ROW SHARE',
|
|
'ROW EXCLUSIVE',
|
|
'SHARE UPDATE EXCLUSIVE',
|
|
'SHARE',
|
|
'SHARE ROW EXCLUSIVE',
|
|
'EXCLUSIVE',
|
|
'ACCESS EXCLUSIVE',
|
|
)
|
|
|
|
|
|
def require_lock(model, lock):
|
|
"""
|
|
Decorator for PostgreSQL's table-level lock functionality
|
|
|
|
Example:
|
|
@transaction.commit_on_success
|
|
@require_lock(MyModel, 'ACCESS EXCLUSIVE')
|
|
def myview(request)
|
|
...
|
|
|
|
PostgreSQL's LOCK Documentation:
|
|
http://www.postgresql.org/docs/8.3/interactive/sql-lock.html
|
|
"""
|
|
|
|
def require_lock_decorator(view_func):
|
|
def wrapper(*args, **kwargs):
|
|
if lock not in LOCK_MODES:
|
|
raise ValueError('%s is not a PostgreSQL supported lock mode.')
|
|
from django.db import connection
|
|
cursor = connection.cursor()
|
|
cursor.execute(
|
|
'LOCK TABLE %s IN %s MODE' % (model._meta.db_table, lock)
|
|
)
|
|
return view_func(*args, **kwargs)
|
|
|
|
return wrapper
|
|
|
|
return require_lock_decorator |