mirror of
https://github.com/outbackdingo/patroni.git
synced 2026-08-25 14:53:37 +00:00
Alexander Kukushkin
adcc7ac256
Also check presence of trigger_file on master after promotion when pg_is_in_recovery() = false and if it is there - remove it. Plus check presence of trigger_file on a new slave (after running pg_basebackup) and if it is there - also remove it.
278 lines
9.9 KiB
Python
278 lines
9.9 KiB
Python
import logging
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import os
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import psycopg2
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import subprocess
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import sys
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from helpers.utils import sleep
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if sys.hexversion >= 0x03000000:
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from urllib.parse import urlparse
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else:
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from urlparse import urlparse
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logger = logging.getLogger(__name__)
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def parseurl(url):
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r = urlparse(url)
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ret = {
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'host': r.hostname,
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'port': r.port or 5432,
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'database': r.path[1:],
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'fallback_application_name': 'Governor',
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'connect_timeout': 3,
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'options': '-c statement_timeout=2000',
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}
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if r.username:
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ret['user'] = r.username
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if r.password:
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ret['password'] = r.password
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return ret
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class Postgresql:
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def __init__(self, config):
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self.config = config
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self.name = config['name']
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self.listen_addresses, self.port = config['listen'].split(':')
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self.data_dir = config['data_dir']
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self.replication = config['replication']
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self.recovery_conf = os.path.join(self.data_dir, 'recovery.conf')
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self.pid_path = os.path.join(self.data_dir, 'postmaster.pid')
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self.trigger_file = config.get('recovery_conf', {}).get('trigger_file', None) or 'promote'
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self.trigger_file = os.path.abspath(os.path.join(self.data_dir, self.trigger_file))
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self.is_promoted = False
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self._pg_ctl = ['pg_ctl', '-w', '-D', self.data_dir]
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self.local_address = self.get_local_address()
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connect_address = config.get('connect_address', None) or self.local_address
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self.connection_string = 'postgres://{username}:{password}@{connect_address}/postgres'.format(
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connect_address=connect_address, **self.replication)
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self._connection = None
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self._cursor_holder = None
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self.members = [] # list of already existing replication slots
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def get_local_address(self):
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# TODO: try to get unix_socket_directory from postmaster.pid
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return self.listen_addresses.split(',')[0].strip() + ':' + self.port
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def connection(self):
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if not self._connection or self._connection.closed != 0:
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r = parseurl('postgres://{}/postgres'.format(self.local_address))
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self._connection = psycopg2.connect(**r)
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self._connection.autocommit = True
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return self._connection
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def _cursor(self):
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if not self._cursor_holder or self._cursor_holder.closed:
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self._cursor_holder = self.connection().cursor()
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return self._cursor_holder
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def disconnect(self):
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self._connection and self._connection.close()
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self._connection = self._cursor_holder = None
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def query(self, sql, *params):
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max_attempts = 0
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while True:
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ex = None
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try:
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cursor = self._cursor()
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cursor.execute(sql, params)
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return cursor
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except psycopg2.InterfaceError as e:
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ex = e
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except psycopg2.OperationalError as e:
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if self._connection and self._connection.closed == 0:
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raise e
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ex = e
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if ex:
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self.disconnect()
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max_attempts += 1
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if max_attempts >= 3:
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raise ex
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sleep(5)
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def data_directory_empty(self):
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return not os.path.exists(self.data_dir) or os.listdir(self.data_dir) == []
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def initialize(self):
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ret = subprocess.call(self._pg_ctl + ['initdb', '-o', '--encoding=UTF8']) == 0
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ret and self.write_pg_hba()
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return ret
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def delete_trigger_file(self):
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os.path.exists(self.trigger_file) and os.unlink(self.trigger_file)
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def sync_from_leader(self, leader):
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r = parseurl(leader.address)
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pgpass = 'pgpass'
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with open(pgpass, 'w') as f:
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os.fchmod(f.fileno(), 0o600)
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f.write('{host}:{port}:*:{user}:{password}\n'.format(**r))
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env = os.environ.copy()
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env['PGPASSFILE'] = pgpass
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ret = subprocess.call(['pg_basebackup', '-R', '-D', self.data_dir, '--host=' + r['host'],
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'--port=' + str(r['port']), '-U', r['user']], env=env) == 0
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self.delete_trigger_file()
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return ret
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def is_leader(self):
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ret = not self.query('SELECT pg_is_in_recovery()').fetchone()[0]
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if ret and self.is_promoted:
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self.delete_trigger_file()
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self.is_promoted = False
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return ret
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def is_running(self):
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return subprocess.call(' '.join(self._pg_ctl) + ' status > /dev/null', shell=True) == 0
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def start(self):
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if self.is_running():
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self.load_replication_slots()
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logger.error('Cannot start PostgreSQL because one is already running.')
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return False
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if os.path.exists(self.pid_path):
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os.remove(self.pid_path)
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logger.info('Removed %s', self.pid_path)
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ret = subprocess.call(self._pg_ctl + ['start', '-o', self.server_options()]) == 0
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ret and self.load_replication_slots()
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return ret
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def stop(self):
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return subprocess.call(self._pg_ctl + ['stop', '-m', 'fast']) != 0
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def reload(self):
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return subprocess.call(self._pg_ctl + ['reload']) == 0
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def restart(self):
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return subprocess.call(self._pg_ctl + ['restart', '-m', 'fast']) == 0
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def server_options(self):
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options = "--listen_addresses='{}' --port={}".format(self.listen_addresses, self.port)
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for setting, value in self.config['parameters'].items():
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options += " --{}='{}'".format(setting, value)
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return options
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def is_healthy(self):
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if not self.is_running():
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logger.warning('Postgresql is not running.')
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return False
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return True
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def is_healthiest_node(self, cluster):
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if self.is_leader():
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return True
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if cluster.last_leader_operation - self.xlog_position() > self.config.get('maximum_lag_on_failover', 0):
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return False
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for member in cluster.members:
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if member.hostname == self.name:
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continue
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try:
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r = parseurl(member.address)
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member_conn = psycopg2.connect(**r)
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member_conn.autocommit = True
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member_cursor = member_conn.cursor()
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member_cursor.execute(
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"SELECT pg_is_in_recovery(), %s - (pg_last_xlog_replay_location() - '0/0000000'::pg_lsn)",
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(self.xlog_position(), ))
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row = member_cursor.fetchone()
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member_cursor.close()
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member_conn.close()
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logger.error([self.name, member.hostname, row])
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if not row[0] or row[1] < 0:
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return False
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except psycopg2.Error:
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continue
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return True
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def write_pg_hba(self):
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with open(os.path.join(self.data_dir, 'pg_hba.conf'), 'a') as f:
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f.write('\nhost replication {username} {network} md5\n'.format(**self.replication))
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@staticmethod
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def primary_conninfo(leader_url):
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r = parseurl(leader_url)
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return 'user={user} password={password} host={host} port={port} sslmode=prefer sslcompression=1'.format(**r)
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def check_recovery_conf(self, leader):
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if not os.path.isfile(self.recovery_conf):
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return False
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pattern = leader and leader.address and self.primary_conninfo(leader.address)
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with open(self.recovery_conf, 'r') as f:
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for line in f:
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if line.startswith('primary_conninfo'):
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if not pattern:
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return False
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return pattern in line
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return not pattern
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def write_recovery_conf(self, leader):
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with open(self.recovery_conf, 'w') as f:
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f.write("""standby_mode = 'on'
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recovery_target_timeline = 'latest'
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""")
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if leader and leader.address:
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f.write("""
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primary_slot_name = '{}'
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primary_conninfo = '{}'
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""".format(self.name, self.primary_conninfo(leader.address)))
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for name, value in self.config.get('recovery_conf', {}).items():
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f.write("{} = '{}'\n".format(name, value))
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def follow_the_leader(self, leader):
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if not self.check_recovery_conf(leader):
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self.write_recovery_conf(leader)
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self.restart()
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def promote(self):
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self.is_promoted = subprocess.call(self._pg_ctl + ['promote']) == 0
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return self.is_promoted
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def demote(self, leader):
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self.follow_the_leader(leader)
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def create_replication_user(self):
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self.query('CREATE USER "{}" WITH REPLICATION ENCRYPTED PASSWORD %s'.format(
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self.replication['username']), self.replication['password'])
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def xlog_position(self):
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return self.query("""SELECT CASE WHEN pg_is_in_recovery()
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THEN pg_last_xlog_replay_location() - '0/0000000'::pg_lsn
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ELSE pg_current_xlog_location() - '0/00000'::pg_lsn END""").fetchone()[0]
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def load_replication_slots(self):
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cursor = self.query("SELECT slot_name FROM pg_replication_slots WHERE slot_type='physical'")
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self.members = [r[0] for r in cursor]
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def create_replication_slots(self, cluster):
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members = [m.hostname for m in cluster.members if m.hostname != self.name]
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# drop unused slots
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for slot in set(self.members) - set(members):
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self.query("""SELECT pg_drop_replication_slot(%s)
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WHERE EXISTS(SELECT 1 FROM pg_replication_slots
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WHERE slot_name = %s)""", slot, slot)
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# create new slots
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for slot in set(members) - set(self.members):
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self.query("""SELECT pg_create_physical_replication_slot(%s)
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WHERE NOT EXISTS (SELECT 1 FROM pg_replication_slots
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WHERE slot_name = %s)""", slot, slot)
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self.members = members
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def last_operation(self):
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return self.xlog_position()
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