quiesce.py script (PostgreSQL)

import psycopg2
import os, time, datetime
dt=datetime.datetime.now().strftime("%I:%M%p on %B %d, %Y")
file1 = open("/scripts/pre-freeze.log","a+" )
conn = None
exit_status = 0
try:
  conn = psycopg2.connect(host='localhost',port='<POSTGRESQL_PORT>',user='<POSTGRESQL_USER>',password='<POSTGRESQL_PASSWORD>',database='<POSTGRESQL_DB_NAME>')
  cur = conn.cursor()
  cur.execute ("select version();")
  data = cur.fetchone()
  file1.write (dt)
  file1.write ("\n-------------------------------------------\n")
  file1.write ("\t PostgreSQL version is %s: "%data)
  file1.write ("\n-------------------------------------------\n")
  file1.write (dt)
  file1.write ("\t executing query to quiesce the database \n")
  cur.execute (" select pg_start_backup('label'); ")
  file1.write (dt)
  file1.write ("\t Database is quiesced now successfully \n")
  cur.close()
except (Exception, psycopg2.DatabaseError) as error:
  file1.write(dt)
  file1.write(str(error))
  file1.write( "\n Error in quiesce DB, please check PostgreSQL logs for more info\n")
  exit_status = 1
finally:
  if conn is not None:
    conn.close()
    file1.write( "\n Database connection closed\n")
file1.close()
exit(exit_status)