def allocate_partially_specified_segment(self, session, **filters):
"""Allocate model segment from pool partially specified by filters.
Return allocated db object or None.
"""
network_type = self.get_type()
with session.begin(subtransactions=True):
select = (session.query(self.model).filter_by(allocated=False,
**filters))
# Selected segment can be allocated before update by someone else,
# We retry until update success or DB_MAX_ATTEMPTS attempts
for attempt in range(1, DB_MAX_ATTEMPTS + 1):
alloc = select.first()
if not alloc:
# No resource available
return
raw_segment = dict((k, alloc[k]) for k in self.primary_keys)
LOG.debug(
"%(type)s segment allocate from pool, attempt "
"%(attempt)s started with %(segment)s ", {
"type": network_type,
"attempt": attempt,
"segment": raw_segment
})
count = (session.query(self.model).filter_by(
allocated=False, **raw_segment).update({"allocated":
True}))
if count:
LOG.debug(
"%(type)s segment allocate from pool, attempt "
"%(attempt)s success with %(segment)s ", {
"type": network_type,
"attempt": attempt,
"segment": raw_segment
})
return alloc
# Segment allocated since select
LOG.debug(
"Allocate %(type)s segment from pool, "
"attempt %(attempt)s failed with segment "
"%(segment)s", {
"type": network_type,
"attempt": attempt,
"segment": raw_segment
})
LOG.warning(
_LW("Allocate %(type)s segment from pool failed "
"after %(number)s failed attempts"), {
"type": network_type,
"number": DB_MAX_ATTEMPTS
})
raise exc.NoNetworkFoundInMaximumAllowedAttempts()
def allocate_partially_specified_segment(self, context, **filters):
"""Allocate model segment from pool partially specified by filters.
Return allocated db object or None.
"""
network_type = self.get_type()
session, ctx_manager = self._get_session(context)
with ctx_manager:
select = (session.query(self.model).filter_by(allocated=False,
**filters))
# Selected segment can be allocated before update by someone else,
allocs = select.limit(IDPOOL_SELECT_SIZE).all()
if not allocs:
# No resource available
return
alloc = random.choice(allocs)
raw_segment = dict((k, alloc[k]) for k in self.primary_keys)
LOG.debug(
"%(type)s segment allocate from pool "
"started with %(segment)s ", {
"type": network_type,
"segment": raw_segment
})
count = (session.query(self.model).filter_by(
allocated=False, **raw_segment).update({"allocated": True}))
if count:
LOG.debug(
"%(type)s segment allocate from pool "
"success with %(segment)s ", {
"type": network_type,
"segment": raw_segment
})
return alloc
# Segment allocated since select
LOG.debug(
"Allocate %(type)s segment from pool "
"failed with segment %(segment)s", {
"type": network_type,
"segment": raw_segment
})
# saving real exception in case we exceeded amount of attempts
raise db_exc.RetryRequest(
exc.NoNetworkFoundInMaximumAllowedAttempts())
def allocate_partially_specified_segment(self, session, **filters):
"""Allocate model segment from pool partially specified by filters.
Return allocated db object or None.
"""
network_type = self.get_type()
with session.begin(subtransactions=True):
select = (session.query(self.model).filter_by(allocated=False,
**filters))
# Selected segment can be allocated before update by someone else,
alloc = select.first()
if not alloc:
# No resource available
return
raw_segment = dict((k, alloc[k]) for k in self.primary_keys)
LOG.debug(
"%(type)s segment allocate from pool "
"started with %(segment)s ", {
"type": network_type,
"segment": raw_segment
})
count = (session.query(self.model).filter_by(
allocated=False, **raw_segment).update({"allocated": True}))
if count:
LOG.debug(
"%(type)s segment allocate from pool "
"success with %(segment)s ", {
"type": network_type,
"segment": raw_segment
})
return alloc
# Segment allocated since select
LOG.debug(
"Allocate %(type)s segment from pool "
"failed with segment %(segment)s", {
"type": network_type,
"segment": raw_segment
})
# saving real exception in case we exceeded amount of attempts
raise db_exc.RetryRequest(
exc.NoNetworkFoundInMaximumAllowedAttempts())
