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