Created
April 18, 2012 11:53
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Nagios plugin to check PostgreSQL 9 streaming replication lag.
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| #!/usr/bin/env python | |
| """ | |
| Nagios plugin to check PostgreSQL 9 streaming replication lag. | |
| Requires psycopg2 and nagiosplugin (both installable with pip/easy_install). | |
| See: http://bucardo.org/check_postgres/check_postgres.pl.html#hot_standby_delay | |
| MIT licensed: | |
| Copyright (c) 2010 Jacob Kaplan-Moss. All rights reserved. | |
| Modified April 4th, 2012 Thomas Kishel. | |
| Permission is hereby granted, free of charge, to any person obtaining a | |
| copy of this software and associated documentation files (the | |
| "Software"), to deal in the Software without restriction, including | |
| without limitation the rights to use, copy, modify, merge, publish, | |
| distribute, sublicense, and/or sell copies of the Software, and to | |
| permit persons to whom the Software is furnished to do so, subject to | |
| the following conditions: | |
| The above copyright notice and this permission notice shall be included | |
| in all copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS | |
| OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | |
| MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. | |
| IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY | |
| CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, | |
| TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE | |
| SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
| """ | |
| import nagiosplugin | |
| import psycopg2 | |
| __version__ = '1.1' | |
| class StreamingReplicationCheck(nagiosplugin.Check): | |
| def __init__(self, optparser, log): | |
| optparser.description = 'Check PostgreSQL streaming replication lag.' | |
| optparser.version = __version__ | |
| optparser.add_option('-M', '--master', | |
| metavar='DSN', | |
| help='DSN for the master connection (e.g. "host=foo user=bar")' | |
| ) | |
| optparser.add_option('-S', '--slave', | |
| metavar='DSN', | |
| help='DSN for the slave connection (e.g. "host=foo user=bar")' | |
| ) | |
| optparser.add_option('-w', '--warning', | |
| default='1024', | |
| metavar='WARN', | |
| help='warn if replication (receive,replay) lags by WARN kbytes ' \ | |
| '(default: 1024,1024).' | |
| ) | |
| optparser.add_option('-c', '--critical', | |
| default='4096', | |
| metavar='CRIT', | |
| help='warn if replication (receive,replay) lags by CRIT kbytes ' \ | |
| '(default: 4096,4096).' | |
| ) | |
| def process_args(self, opts, args): | |
| self.master_conn = psycopg2.connect(opts.master) | |
| self.slave_conn = psycopg2.connect(opts.slave) | |
| self.warning = opts.warning.split(',') | |
| self.critical = opts.critical.split(',') | |
| def obtain_data(self): | |
| mc = self.master_conn.cursor() | |
| mc.execute('SELECT pg_current_xlog_location()') | |
| self.master_xlog_loc = mc.fetchone()[0] | |
| self.master_loc = xlog_to_bytes(self.master_xlog_loc) | |
| self.master_conn.commit() | |
| self.master_conn.close() | |
| sc = self.slave_conn.cursor() | |
| sc.execute('SELECT pg_last_xlog_receive_location()') | |
| self.slave_xlog_receive_loc = sc.fetchone()[0] | |
| self.slave_receive_loc = xlog_to_bytes(self.slave_xlog_receive_loc) | |
| sc.execute('SELECT pg_last_xlog_replay_location()') | |
| self.slave_xlog_replay_loc = sc.fetchone()[0] | |
| self.slave_replay_loc = xlog_to_bytes(self.slave_xlog_replay_loc) | |
| self.slave_conn.commit() | |
| self.slave_conn.close() | |
| """ | |
| The mathematics sometimes rounds to zero. | |
| And sometimes returns negative values. | |
| """ | |
| self.receive_lag = (self.master_loc - self.slave_receive_loc) / 1024 | |
| self.replay_lag = (self.master_loc - self.slave_replay_loc) / 1024 | |
| self.data = nagiosplugin.Measure.array( | |
| names=['receive_lag', 'replay_lag'], | |
| values=[self.receive_lag, self.replay_lag], | |
| uoms=['kB'], | |
| warnings=self.warning, | |
| criticals=self.critical) | |
| def states(self): | |
| try: | |
| return [m.state() for m in self.data] | |
| except AttributeError: | |
| return [] | |
| def performances(self): | |
| try: | |
| loc = "pg_current_xlog_location=%s " \ | |
| "pg_last_xlog_receive_location=%s " \ | |
| "pg_last_xlog_replay_location=%s" % ( | |
| self.master_xlog_loc, | |
| self.slave_xlog_receive_loc, | |
| self.slave_xlog_replay_loc) | |
| lag = "receive_lag=%skB;%s;%s " \ | |
| "replay_lag=%skB;%s;%s" % ( | |
| self.receive_lag, self.warning[0], self.critical[0], | |
| self.replay_lag, self.warning[1], self.critical[1]) | |
| return ["%s %s" % (loc, lag)] | |
| except AttributeError: | |
| return [] | |
| def default_message(self): | |
| return "receive_lag %s kB, replay_lag %s kB" % ( | |
| self.receive_lag, self.replay_lag) | |
| def xlog_to_bytes(xlog): | |
| """ | |
| Convert an xlog number like '0/C6321D98' to an integer representing | |
| the number of bytes into the xlog. | |
| Logic here is taken from: | |
| https://github.com/mhagander/munin-plugins/blob/master/postgres/postgres_streaming_.in | |
| I assume it's correct... | |
| """ | |
| logid, offset = xlog.split('/') | |
| return (int('ffffffff', 16) * int(logid, 16)) + int(offset, 16) | |
| if __name__ == '__main__': | |
| nagiosplugin.Controller(StreamingReplicationCheck)() |
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