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Viewing changes to daemons/cache-database-replication-lag.py

  • Committer: Stuart Bishop
  • Date: 2010-02-05 12:17:56 UTC
  • mto: (7675.1212.22 pending-db-changes)
  • mto: This revision was merged to the branch mainline in revision 10428.
  • Revision ID: stuart.bishop@canonical.com-20100205121756-olgk91iovhc2hpsy
https://launchpad.net/bugs/514267
Cache database replication lag information as querying the live Slony tables can be slow

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daemons/cache-database-replication-lag.py
 
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#!/usr/bin/python2.5
 
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#
 
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# Copyright 2010 Canonical Ltd.  This software is licensed under the
 
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# GNU Affero General Public License version 3 (see the file LICENSE).
 
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"""Calculate database replication lag and cache it."""
 
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__metaclass__ = type
 
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__all__ = []
 
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import _pythonpath
 
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import sys
 
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import time
 
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import psycopg2
 
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from canonical.database.sqlbase import connect, ISOLATION_LEVEL_AUTOCOMMIT
 
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from canonical.launchpad.scripts import db_options, logger
 
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from lp.scripts.helpers import LPOptionParser
 
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def main(args=None):
 
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    parser = LPOptionParser()
 
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    db_options(parser)
 
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    parser.add_option(
 
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        "-s", "--sleep", dest="sleep", type="int", default=5,
 
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        metavar="SECS", help="Wait SECS seconds between refreshes.")
 
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    (options, args) = parser.parse_args(args)
 
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    if len(args) != 0:
 
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        parser.error("Too many arguments.")
 
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    log = logger(options)
 
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    while True:
 
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        try:
 
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            con = connect(user="lagmon", isolation=ISOLATION_LEVEL_AUTOCOMMIT)
 
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            cur = con.cursor()
 
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            while True:
 
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                cur.execute("SELECT update_replication_lag_cache()")
 
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                if cur.fetchone()[0]:
 
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                    log.info("Updated.")
 
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                else:
 
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                    log.error("update_replication_lag_cache() failed.")
 
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                time.sleep(options.sleep)
 
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        except psycopg2.Error, x:
 
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            log.error("%s. Retrying.", str(x).strip())
 
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            time.sleep(options.sleep)
 
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if __name__ == '__main__':
 
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    sys.exit(main())