def test_round_robin_execute(self):
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
for client, arg in [(1, 'foo'), (2, 'bar'), (0, 'baz'), (1, 'bax')]:
result = cluster.execute(arg)
self.clients[client].execute.assert_called_with(arg)
self.assertEqual(self.clients[client].execute.return_value, result)
def test_round_robin_execute(self):
"""
seed_clients are chosen in round robin manner
"""
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
for client, arg in [(1, 'foo'), (2, 'bar'), (0, 'baz'), (1, 'bax')]:
result = cluster.execute(arg)
self.clients[client].execute.assert_called_with(arg)
self.assertEqual(self.clients[client].execute.return_value, result)
def test_other_error_propogated(self):
"""
Any error other than subclass of ``ConnectError`` is propgoated
"""
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
rand_err = ValueError('random err')
self.clients[1].execute.return_value = defer.fail(rand_err)
result = cluster.execute(2, 3)
self.assertEqual(self.failureResultOf(result).value, rand_err)
self.assertEqual(self.clients[2].execute.called, False)
self.assertEqual(self.clients[0].execute.called, False)
def test_one_node_down(self):
"""
If a cass node is down, it tries the next node in cluster
"""
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
self.clients[1].execute.return_value = defer.fail(ConnectionRefusedError())
result = cluster.execute(2, 3)
self.assertEqual(self.successResultOf(result), 'exec_ret3')
self.clients[1].execute.assert_called_once_with(2, 3)
self.clients[2].execute.assert_called_once_with(2, 3)
self.assertFalse(self.clients[0].execute.called)
def test_other_error_propogated_on_node_down(self):
"""
If first node gives ``ConnectError`` then second node is tried if it gives
error other than subclass of ``ConnectError`` it is propogated
"""
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
self.clients[1].execute.return_value = defer.fail(NoRouteError())
rand_err = ValueError('random err')
self.clients[2].execute.return_value = defer.fail(rand_err)
result = cluster.execute(2, 3)
self.assertEqual(self.failureResultOf(result).value, rand_err)
self.assertEqual(self.clients[0].execute.called, False)
def test_all_nodes_down(self):
"""
If all cass nodes are down, it gives up eventually by raising the
connection error exception
"""
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
err = ConnectionRefusedError()
for i in range(3):
self.clients[i].execute.side_effect = lambda *_: defer.fail(err)
result = cluster.execute(2, 3)
self.assertEqual(self.failureResultOf(result).value, err)
for i in range(3):
self.clients[i].execute.assert_called_once_with(2, 3)
def test_multiple_clients(self):
"""
When multiple clients execute simultaneously, it does not skip nodes. It basically ensures
that http://bit.ly/1csEIRR situation does not happen
"""
cluster = RoundRobinCassandraCluster(['one', 'two', 'three'], 'keyspace')
def _execute(*args):
cluster.execute(2, 3)
return defer.fail(NoRouteError())
self.clients[1].execute.side_effect = _execute
result = cluster.execute(2, 3)
self.assertEqual(self.successResultOf(result), 'exec_ret3')
self.assertEqual(self.clients[2].execute.call_args_list, [mock.call(2, 3)] * 2)
self.clients[1].execute.assert_called_once_with(2, 3)
