~daisy-pluckers/oops-repository/trunk

Schema creation is possible.

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# Canonical Ltd ("Canonical") distributes the oops-repository source code under

# the GNU Affero General Public License, version 3 ("AGPLv3"). See the file

# LICENSE in the source tree for more information.

"""Things to ease working with cassandra."""

from pycassa.cassandra.Cassandra import InvalidRequestException

def workaround_1779(callable, *args, **kwargs):

"""Workaround cassandra not being able to do concurrent schema edits.

The callable is tried until it does not raised InvalidRequestException

with why = "Previous version mismatch. cannot apply."

:param callable: The callable to call.

:param args: The args for it.

:param kwargs: The kwargs for it.

:return: The result of calling the callable.

"""

while True:

# Workaround https://issues.apache.org/jira/browse/CASSANDRA-1779:

# Cassandra cannot do concurrent schema changes.

try:

return callable(*args, **kwargs)

break

except InvalidRequestException as e:

if e.why != 'Previous version mismatch. cannot apply.':

raise