Writing background and automated programs using Ruby. Presentation for RubyJax Meetup 6/13/2013

1. Scripting with Ruby
Stuart Palmer
RubyJax
13 June 2013

2. 6/13/2013Scripting with Ruby
Why scripting?
 Perform regular tasks automatically
 Create daily reports, publish information, back up files, clear history
 Perform background tasks
 Send emails, share information with other systems
 Easily use operating system programs/utilities
 FTP, scp, mail, file storage

3. 6/13/2013Scripting with Ruby
Traditional Scripting
 Shell scripts
 sh, bash, csh, ksh
 DOS batch files
 .bat
 SQL Jobs
 SQL scripts in database

4. 6/13/2013Scripting with Ruby
Sample shell script
#!/bin/tcsh
#
# Expects one parameter in mm/dd/yyyy format
#
setenv TOP /opt/sp
setenv SBIN ${TOP}/sbin
setenv LOG ${TOP}/log
set logDir=${LOG}/trade­totals
#
# Convert mm/dd/yyyy to yyyymmdd
#
set yyyy=`echo $1 | cut ­c7­10`
set mm=`echo $1 | cut ­c1­2`
set dd=`echo $1 | cut ­c4­5`
set tradeDate=${yyyy}${mm}${dd}
set saveDir=${logDir}/${yyyy}
#
# Run the totals
#
fisql ­Uxxx ­Pxxx ­Ssss ­w140 > /tmp/total.out <<EOF
exec getTotals '$1'
go
quit
EOF
#
# See if there was any output
#
if ( ­z /tmp/total.out ) then
rm ­f /tmp/total.out
exit 0
endif
#
# Nice formatting
#
echo "" > /tmp/total.fax
echo "Totals for $1" >> /tmp/total.fax
echo "" >> /tmp/total.fax
#
# Get rid of isql junk
#
cat /tmp/total.out | grep ­v line1 | grep ­v '­­­' | grep ­v
"return stat" | egrep ­v ­e '^$' > /tmp/total.out1
#
# Get rid of tabs
#
sed ­e "s///" /tmp/total.out1 >> /tmp/total.fax
rm ­f /tmp/total.out /tmp/total.out1
#
# Send the file to the mail server for emailing
#
${SBIN}/email­to­finop.csh "Trade Totals for $1" /tmp/total.fax
#
# Save the file for prosperity
#
if ( ! ­d ${saveDir} ) then
mkdir ${saveDir}
endif
mv ­f /tmp/total.fax ${saveDir}/total.${tradeDate}

5. 6/13/2013Scripting with Ruby
What can Ruby do?
Ruby Standard Library
✔ Numbers and Math
✔ Strings
✔ Regular expressions
✔ Collections
✔ Dates and Times
✔ Files and Directories
✔ Networking
✔ Threads

6. 6/13/2013Scripting with Ruby
My First Exposure to Ruby
require 'rubygems'
require 'roo'
require 'fileutils'
ss = Excel.new( "business_plan_cmbs.xls" )
ss.default_sheet = "Recommended"
puts ss.cell('B', 8)
'C'.upto('BJ') do |column|
date = ss.cell(2, column)
monthnum = ss.cell(3, column)
yearnum = ss.cell(4, column)
interest = ss.cell(8, column)
amort = ss.cell(9, column)
other = ss.cell(10, column)
sum = interest + amort + other
puts "#{date} (#{monthnum}/#{yearnum})t#{sum}"
end

7. 6/13/2013Scripting with Ruby
Sending email
require 'net/smtp'
# Send email
Net::SMTP.start('mail.silveradosw.com', 25, 'www.silveradosw.com') do |smtp|
smtp.open_message_stream('stuart@silveradosw.com', 'rubyjax@meetup.com') do |f|
f.puts 'From: Stuart Palmer <stuart@silveradosw.com>'
f.puts 'To: Ruby Jax <rubyjax@meetup.com>'
f.puts "Date: #{DateTime.now.rfc2822}"
f.puts 'Subject: Your Report for today'
f.puts 'Message­ID: <ruby­1234@silveradosw.com>'
lines.each do |line|
f.puts line
end
end
end

8. 6/13/2013Scripting with Ruby
File functions and FTP
require 'file'
require 'fileutils'
# Write to a file
report_file = File.new('/tmp/report­new', 'w')
lines.each do |line|
report_file.puts line
end
report_file.close
FileUtils.mv('/tmp/report­new', '/opt/xxx/todays­report')
# FTP the file
ftp = Net::FTP.new('ftp.silveradosw.com')
ftp.login('stuart@silveradosw.com', 'xxx')
ftp.passive = true
ftp.chdir('Reports')
ftp.puttextfile('/tmp/report­new', 'todays_report')
ftp.close

9. 6/13/2013Scripting with Ruby
File functions and FTP
require 'file'
require 'fileutils'
require 'net/ftp'
# Write to a file
report_file = File.new('/tmp/report­new', 'w')
lines.each do |line|
report_file.puts line
end
report_file.close
FileUtils.mv('/tmp/report­new', '/opt/xxx/todays­report')
# FTP the file
ftp = Net::FTP.new('ftp.silveradosw.com')
ftp.login('stuart@silveradosw.com', 'xxx')
ftp.passive = true
ftp.chdir('Reports')
ftp.puttextfile('/tmp/report­new', 'todays_report')
ftp.close

10. 6/13/2013Scripting with Ruby
Client / Server
require 'socket'
socket = TCPSocket.open('localhost', 3333)
socket.puts('hello')
socket.puts('what?')
socket.puts('done')
socket = TCPSocket.open('localhost', 3333)
socket.puts('quit')
require 'socket'
socket = TCPSocket.new('localhost', 3333)
done_listening = false
while !done_listening
done_reading = false
while !done_reading
message = socket.read
if message =~ /^quit$|^stop$/i
puts "Received shutdown message."
done_listening = true
done_reading = true
elsif message =~ /^done$/i
puts "Received client end message."
done_reading = true
else
puts "Read message: [#{message}]"
socket.puts "OKn"
end
end
socket.close
end

11. 6/13/2013Scripting with Ruby
Threading
require 'thread'
done = false
socket = TCPServer.open(3333)
connections = Queue.new
processor = Thread.new { process(connections, cfg) }
while !done
# Block, waiting for a request
client, client_sock_adr = socket.accept
port, host, ipno = client.peeraddr[1..3]
# Process the request
begin
message = client.readline
rescue => ex
client.close
next
end
# Pass off the message and go wait for another one
connections << OpenStruct.new(client: client, msg: message)
end
processor.join
socket.close
def process(connections, cfg)
while !connections.empty?
connection = connections.pop
client = connection.get_client
port, host, ipno = client.peeraddr[1..3]
# Do stuff
end
end

12. 6/13/2013Scripting with Ruby
Database Access
require 'date'
require 'rubygems'
require 'dbi'
# Call database for data
dbhandle = DBI.connect("dbi:#{sss}", 'xxx', 'xxx')
rows = dbhandle.select_all("EXEC getTotals ?",
ARGV[0])
if rows.nil? or rows.empty?
puts "Nothing to report"
exit
end
lines = ['']
lines << "Your report for #{Date.today.to_s}"
lines << ''
rows.each do |row|
lines << row['column_name']
end

13. 6/13/2013Scripting with Ruby
Other Useful Modules
● Log files
require 'logger'
log = Logger.new(STDOUT)
log.level = Logger::WARN
log.debug( 'Created logger' )
log.info( 'Program started' )
log.warn( 'Nothing to do!' )
● Configuration files
config = File.open( 'report.yaml' ) { |yf| YAML::load( yf ) }
config = JSON.parse( IO.read( 'report.json' ) )

14. 6/13/2013Scripting with Ruby
Gems
● XML Generation
✔ nokogiri
● PDF Generation
✔ prawn
● Events / Timers
✔ eventmachine

15. 6/13/2013Scripting with Ruby
Test First
● The usual test frameworks can be used
➢ rspec, test::unit, minitest
C:UsersStuartClientswhbbiwhbbireports> rspec ­c ­fs trade­totals­email­spec.rb
TradeTotalsEmail
initialize
should call BaseEmail::new
should call BaseEmail#from with name and email when set in config
set_sender
should call BaseEmail#from with name and email
set_recipients
should call add_recipients with passed­in name/email array
should call add_recipients with config name/email
set_default_recipients
should call add_to with config name and email
add_recipients
should call add_to with each passed­in name and email
add_to
should call BaseEmail:to when non­null name and email passed in
Finished in 0.018 seconds
8 examples, 0 failures

16. 6/13/2013Scripting with Ruby
exit(0)
Stuart Palmer
Silverado Consulting, Inc.
stuart@silveradosw.com
(408)529-6891