66 lines
1.5 KiB
Python
66 lines
1.5 KiB
Python
from datetime import datetime
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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
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class InvalidResponseError(Exception):
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"""Used for all responses other than HTTP 200"""
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pass
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def get_key(data, keys: list):
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try:
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val = data[keys.pop(0)]
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while keys:
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val = val[keys.pop(0)]
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return val
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except KeyError:
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return ''
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def validate_int(integer):
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return isinstance(integer, int) and 0 <= integer < 2147483647 or None
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def log(text):
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return "{} - {}".format(datetime.now().isoformat(), text)
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