You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: replication_monitor.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/pg-0.20.0/sample
    
    the code of the file until where you have to start completion: #!/usr/bin/env ruby
# vim: set noet nosta sw=4 ts=4 :
#
# Get the current WAL segment and offset from a master postgresql
# server, and compare slave servers to see how far behind they
# are in MB.  This script should be easily modified for use with
# Nagios/Mon/Monit/Zabbix/whatever, or wrapping it in a display loop,
# and is suitable for both WAL shipping or streaming forms of replication.
#
# Mahlon E. Smith <mahlon@martini.nu>
#
# First argument is the master server, all other arguments are treated
# as slave machines.
#
#
    
	def get_current_wal
		master_db = PG.connect(
			:dbname   => self.opts.database,
			:host     => self.master,
			:port     => self.opts.port,
			:user     => self.opts.user,
			:password => self.opts.pass,
			:sslmode  => 'prefer'
		)

		self.current_wal[ :segbytes ] = master_db.exec( 'SHOW wal_segment_size' ).
			getvalue( 0, 0 ).sub( /\D+/, '' ).to_i << 20

		current = master_db.exec( 'SELECT pg_current_xlog_location()' ).getvalue( 0, 0 )
		self.current_wal[ :segment ], self.current_wal[ :offset ] = current.split( /\// )

		master_db.close
		return true

	# If we can't get any of the info from the master, then there is no
	# point in a comparison with slaves.
	#
	rescue => err
		self.failures << { :host => self.master,
			:error => 'Unable to retrieve required info from the master (%s)' % [ err.message ] }

		return false
	end