def _select_address(self, *, access_mode, database):
from neo4j.api import READ_ACCESS
""" Selects the address with the fewest in-use connections.
"""
self.create_routing_table(database)
self.ensure_routing_table_is_fresh(access_mode=access_mode,
database=database)
log.debug("[#0000] C: <ROUTING TABLE ENSURE FRESH> %r",
self.routing_tables)
if access_mode == READ_ACCESS:
addresses = self.routing_tables[database].readers
else:
addresses = self.routing_tables[database].writers
addresses_by_usage = {}
for address in addresses:
addresses_by_usage.setdefault(
self.in_use_connection_count(address), []).append(address)
if not addresses_by_usage:
if access_mode == READ_ACCESS:
raise ReadServiceUnavailable(
"No read service currently available")
else:
raise WriteServiceUnavailable(
"No write service currently available")
return choice(addresses_by_usage[min(addresses_by_usage)])
def _select_address(self, access_mode=None):
from neo4j.api import READ_ACCESS
""" Selects the address with the fewest in-use connections.
"""
self.ensure_routing_table_is_fresh(access_mode)
if access_mode == READ_ACCESS:
addresses = self.routing_table.readers
else:
addresses = self.routing_table.writers
addresses_by_usage = {}
for address in addresses:
addresses_by_usage.setdefault(self.in_use_connection_count(address), []).append(address)
if not addresses_by_usage:
if access_mode == READ_ACCESS:
raise ReadServiceUnavailable("No read service currently available")
else:
raise WriteServiceUnavailable("No write service currently available")
return choice(addresses_by_usage[min(addresses_by_usage)])
def on_write_failure(self, *, address):
raise WriteServiceUnavailable("No write service available for pool {}".format(self))