def test_consistent_hash_3_machines_3_replicas(self):
ch = ConsistentHash(3, 3)
self.assertEqual(ch.get_machine('key'), 1)
self.assertEqual(ch.get_machine('key2'), 0)
self.assertEqual(ch.get_machine('key3'), 0)
self.assertEqual(ch.get_machine('key4'), 1)
self.assertEqual(ch.get_machine('key5'), 1)
self.assertEqual(ch.get_machine('key6'), 2)
def test_consistent_hash_200_machines_20_replicas(self):
ch = ConsistentHash(200, 20)
self.assertEqual(ch.get_machine('key'), 93)
self.assertEqual(ch.get_machine('key2'), 79)
self.assertEqual(ch.get_machine('key3'), 164)
self.assertEqual(ch.get_machine('key4'), 141)
self.assertEqual(ch.get_machine('key5'), 22)
self.assertEqual(ch.get_machine('key6'), 121)
def test_consistent_hash_one_replica(self):
ch = ConsistentHash(1, 1)
self.assertEqual(ch.get_machine('key'), 0)
self.assertEqual(ch.get_machine('key2'), 0)
self.assertEqual(ch.get_machine('key3'), 0)
self.assertEqual(ch.get_machine('key4'), 0)
self.assertEqual(ch.get_machine('key5'), 0)
self.assertEqual(ch.get_machine('key6'), 0)
def get_node_by_key(self, key):
"""Gets the right machine based on the ky.
:param key: The key to be set. It will be used to define which
node that key should go.
:returns: A `brainer.node.client.NodeClient` object.
"""
if not self._nodes:
raise ZeroNodeError
hashing = ConsistentHash(len(self._nodes))
node_number = hashing.get_machine(key)
node_id = self._nodes[node_number]
if self._debug:
log.msg('Machine {} ({}) picked for key {}'.format(
node_id, node_number, key))
return self._nodes_connections[node_id]
