mirror of
https://github.com/outbackdingo/patroni.git
synced 2026-08-25 14:53:37 +00:00
Alexander KukushkinandGitHub
c7173aadd7
Effectively, this PR consists of a few changes: 1. The easy part: In case of permanent logical slots are defined in the global configuration, Patroni on the primary will not only create them, but also periodically update DCS with the current values of `confirmed_flush_lsn` for all these slots. In order to reduce the number of interactions with DCS the new `/status` key was introduced. It will contain the json object with `optime` and `slots` keys. For backward compatibility the `/optime/leader` will be updated if there are members with old Patroni in the cluster. 2. The tricky part: On replicas that are eligible for a failover, Patroni creates the logical replication slot by copying the slot file from the primary and restarting the replica. In order to copy the slot file Patroni opens a connection to the primary with `rewind` or `superuser` credentials and calls `pg_read_binary_file()` function. When the logical slot already exists on the replica Patroni periodically calls `pg_replication_slot_advance()` function, which allows moving the slot forward. 3. Additional requirements: In order to ensure that primary doesn't cleanup tuples from pg_catalog that are required for logical decoding, Patroni enables `hot_standby_feedback` on replicas with logical slots and on cascading replicas if they are used for streaming by replicas with logical slots. 4. When logical slots are copied from to the replica there is a timeframe when it could be not safe to use them after promotion. Right now there is no protection from promoting such a replica. But, Patroni will show the warning with names of the slots that might be not safe to use. Compatibility. The `pg_replication_slot_advance()` function is only available starting from PostgreSQL 11. For older Postgres versions Patroni will refuse to create the logical slot on the primary. The old "permanent slots" feature, which creates logical slots right after promotion and before allowing connections, was removed. Close: https://github.com/zalando/patroni/issues/1749
248 lines
9.6 KiB
Python
248 lines
9.6 KiB
Python
import select
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import six
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import unittest
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from kazoo.client import KazooState
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from kazoo.exceptions import NoNodeError, NodeExistsError
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from kazoo.handlers.threading import SequentialThreadingHandler
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from kazoo.protocol.states import ZnodeStat
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from mock import Mock, patch
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from patroni.dcs.zookeeper import Leader, PatroniSequentialThreadingHandler, ZooKeeper, ZooKeeperError
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class MockKazooClient(Mock):
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leader = False
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exists = True
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def __init__(self, *args, **kwargs):
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super(MockKazooClient, self).__init__()
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self._session_timeout = 30000
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@property
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def client_id(self):
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return (-1, '')
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@staticmethod
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def retry(func, *args, **kwargs):
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return func(*args, **kwargs)
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def get(self, path, watch=None):
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if not isinstance(path, six.string_types):
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raise TypeError("Invalid type for 'path' (string expected)")
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if path == '/broken/status':
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return (b'{', ZnodeStat(0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0))
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elif path in ('/no_node', '/legacy/status'):
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raise NoNodeError
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elif '/members/' in path:
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return (
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b'postgres://repuser:rep-pass@localhost:5434/postgres?application_name=http://127.0.0.1:8009/patroni',
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ZnodeStat(0, 0, 0, 0, 0, 0, 0, 0 if self.exists else -1, 0, 0, 0)
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)
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elif path.endswith('/optime/leader'):
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return (b'500', ZnodeStat(0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0))
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elif path.endswith('/leader'):
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if self.leader:
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return (b'foo', ZnodeStat(0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0))
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return (b'foo', ZnodeStat(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
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elif path.endswith('/initialize'):
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return (b'foo', ZnodeStat(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
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elif path.endswith('/status'):
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return (b'{"optime":500,"slots":{"ls":1234567}}', ZnodeStat(0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0))
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return (b'', ZnodeStat(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
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@staticmethod
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def get_children(path, watch=None, include_data=False):
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if not isinstance(path, six.string_types):
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raise TypeError("Invalid type for 'path' (string expected)")
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if path.startswith('/no_node'):
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raise NoNodeError
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elif path in ['/service/bla/', '/service/test/']:
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return ['initialize', 'leader', 'members', 'optime', 'failover', 'sync']
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return ['foo', 'bar', 'buzz']
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def create(self, path, value=b"", acl=None, ephemeral=False, sequence=False, makepath=False):
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if not isinstance(path, six.string_types):
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raise TypeError("Invalid type for 'path' (string expected)")
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if not isinstance(value, (six.binary_type,)):
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raise TypeError("Invalid type for 'value' (must be a byte string)")
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if b'Exception' in value:
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raise Exception
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if path.endswith('/initialize') or path == '/service/test/optime/leader':
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raise Exception
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elif b'retry' in value or (b'exists' in value and self.exists):
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raise NodeExistsError
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def create_async(self, path, value=b"", acl=None, ephemeral=False, sequence=False, makepath=False):
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return self.create(path, value, acl, ephemeral, sequence, makepath) or Mock()
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@staticmethod
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def set(path, value, version=-1):
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if not isinstance(path, six.string_types):
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raise TypeError("Invalid type for 'path' (string expected)")
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if not isinstance(value, (six.binary_type,)):
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raise TypeError("Invalid type for 'value' (must be a byte string)")
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if path == '/service/bla/optime/leader':
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raise Exception
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if path == '/service/test/members/bar' and b'retry' in value:
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return
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if path in ('/service/test/failover', '/service/test/config', '/service/test/sync'):
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if b'Exception' in value:
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raise Exception
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elif value == b'ok':
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return
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raise NoNodeError
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def set_async(self, path, value, version=-1):
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return self.set(path, value, version) or Mock()
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def delete(self, path, version=-1, recursive=False):
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if not isinstance(path, six.string_types):
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raise TypeError("Invalid type for 'path' (string expected)")
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self.exists = False
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if path == '/service/test/leader':
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self.leader = True
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raise Exception
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elif path == '/service/test/members/buzz':
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raise Exception
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elif path.endswith('/') or path.endswith('/initialize') or path == '/service/test/members/bar':
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raise NoNodeError
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def delete_async(self, path, version=-1, recursive=False):
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return self.delete(path, version, recursive) or Mock()
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class TestPatroniSequentialThreadingHandler(unittest.TestCase):
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def setUp(self):
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self.handler = PatroniSequentialThreadingHandler(10)
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@patch.object(SequentialThreadingHandler, 'create_connection', Mock())
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def test_create_connection(self):
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self.assertIsNotNone(self.handler.create_connection(()))
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self.assertIsNotNone(self.handler.create_connection((), 40))
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self.assertIsNotNone(self.handler.create_connection(timeout=40))
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@patch.object(SequentialThreadingHandler, 'select', Mock(side_effect=ValueError))
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def test_select(self):
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self.assertRaises(select.error, self.handler.select)
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class TestZooKeeper(unittest.TestCase):
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@patch('patroni.dcs.zookeeper.KazooClient', MockKazooClient)
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def setUp(self):
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self.zk = ZooKeeper({'hosts': ['localhost:2181'], 'scope': 'test',
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'name': 'foo', 'ttl': 30, 'retry_timeout': 10, 'loop_wait': 10})
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def test_session_listener(self):
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self.zk.session_listener(KazooState.SUSPENDED)
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def test_reload_config(self):
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self.zk.reload_config({'ttl': 20, 'retry_timeout': 10, 'loop_wait': 10})
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self.zk.reload_config({'ttl': 20, 'retry_timeout': 10, 'loop_wait': 5})
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def test_get_node(self):
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self.assertIsNone(self.zk.get_node('/no_node'))
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def test_get_children(self):
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self.assertListEqual(self.zk.get_children('/no_node'), [])
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def test__inner_load_cluster(self):
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self.zk._base_path = self.zk._base_path.replace('test', 'bla')
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self.zk._inner_load_cluster()
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self.zk._base_path = self.zk._base_path = '/broken'
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self.zk._inner_load_cluster()
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self.zk._base_path = self.zk._base_path = '/legacy'
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self.zk._inner_load_cluster()
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self.zk._base_path = self.zk._base_path = '/no_node'
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self.zk._inner_load_cluster()
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def test_get_cluster(self):
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self.assertRaises(ZooKeeperError, self.zk.get_cluster)
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cluster = self.zk.get_cluster(True)
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self.assertIsInstance(cluster.leader, Leader)
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self.zk.touch_member({'foo': 'foo'})
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self.zk._name = 'bar'
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self.zk.status_watcher(None)
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with patch.object(ZooKeeper, 'get_node', Mock(side_effect=Exception)):
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self.zk.get_cluster()
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cluster = self.zk.get_cluster()
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self.assertEqual(cluster.last_lsn, 500)
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def test_delete_leader(self):
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self.assertTrue(self.zk.delete_leader())
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def test_set_failover_value(self):
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self.zk.set_failover_value('')
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self.zk.set_failover_value('ok')
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self.zk.set_failover_value('Exception')
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def test_set_config_value(self):
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self.zk.set_config_value('', 1)
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self.zk.set_config_value('ok')
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self.zk.set_config_value('Exception')
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def test_initialize(self):
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self.assertFalse(self.zk.initialize())
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def test_cancel_initialization(self):
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self.zk.cancel_initialization()
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def test_touch_member(self):
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self.zk._name = 'buzz'
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self.zk.get_cluster()
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self.zk.touch_member({'new': 'new'})
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self.zk._name = 'bar'
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self.zk.touch_member({'new': 'new'})
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self.zk._name = 'na'
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self.zk._client.exists = 1
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self.zk.touch_member({'Exception': 'Exception'})
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self.zk._name = 'bar'
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self.zk.touch_member({'retry': 'retry'})
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self.zk._fetch_cluster = True
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self.zk.get_cluster()
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self.zk.touch_member({'conn_url': 'postgres://repuser:rep-pass@localhost:5434/postgres',
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'api_url': 'http://127.0.0.1:8009/patroni'})
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def test_take_leader(self):
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self.zk.take_leader()
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with patch.object(MockKazooClient, 'create', Mock(side_effect=Exception)):
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self.zk.take_leader()
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def test_update_leader(self):
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self.assertTrue(self.zk.update_leader(12345))
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def test_write_leader_optime(self):
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self.zk.last_lsn = '0'
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self.zk.write_leader_optime('1')
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with patch.object(MockKazooClient, 'create_async', Mock()):
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self.zk.write_leader_optime('1')
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with patch.object(MockKazooClient, 'set_async', Mock()):
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self.zk.write_leader_optime('2')
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self.zk._base_path = self.zk._base_path.replace('test', 'bla')
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self.zk.write_leader_optime('3')
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def test_delete_cluster(self):
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self.assertTrue(self.zk.delete_cluster())
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def test_watch(self):
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self.zk.watch(None, 0)
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self.zk.event.isSet = Mock(return_value=True)
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self.zk._fetch_status = False
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self.zk.watch(None, 0)
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def test__kazoo_connect(self):
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self.zk._client._retry.deadline = 1
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self.zk._orig_kazoo_connect = Mock(return_value=(0, 0))
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self.zk._kazoo_connect(None, None)
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def test_sync_state(self):
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self.zk.set_sync_state_value('')
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self.zk.set_sync_state_value('ok')
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self.zk.set_sync_state_value('Exception')
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self.zk.delete_sync_state()
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def test_set_history_value(self):
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self.zk.set_history_value('{}')
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