December 2011 - Plain Ol' Ruby, Part 3, Logging, Rake, and Command Line Arguments

Barrett Clark continues a mini series on using Ruby without external frameworks. This session builds on the previous while adding logging, rake tasks, and command line arguments.

Source available at: https://github.com/barrettclark/DallasRubyPOR

Barrett can be found on Twitter at http://twitter.com/barrettclark

Transcript

1. Ruby Core Etcetera, Part 3 Tuesday, December 6, 2011
2. Do useful stuff with Plain Ol’ Ruby Tuesday, December 6, 2011
3. What’s So Great About Me? • I work at Geoforce • I have a Yellow lab • I have this cool sticker on my laptop @barrettclark Tuesday, December 6, 2011
4. Recap • We create records in a database • Without ActiveRecord • We also have tests Tuesday, December 6, 2011
5. Tonight • Logger • Rake • Inputs Tuesday, December 6, 2011
6. Logger Tuesday, December 6, 2011
7. Logs Have Levels • debug • info • warn • error • fatal Tuesday, December 6, 2011
8. Yuck $ grep "puts " * */* Rakefile: puts "Hello from rake!" lib/db_connection.rb: puts "Unable to connect to the #{ENV['SCRIPT_ENV']} database" lib/db_connection.rb: puts "Attempting to connect to the #{ENV['SCRIPT_ENV']} database" lib/file_reader.rb: puts "#{zipcode.zip} is #{zipcode.city}, #{zipcode.state}" lib/zipcode.rb: puts "#{sql}\n Tuples: #{result.cmd_tuples}" if ENV['SCRIPT_ENV'] == 'test' lib/zipcode.rb: puts "#{e}: Unable to insert the zipcode: #{@zipcode}" test/zipcode_test.rb: puts 'This does nothing' Tuesday, December 6, 2011
9. require 'logger' module Logging # This is the magical bit that gets mixed into your classes def logger Logging.logger end # Global, memoized, lazy initialized instance of a logger def self.logger @logger ||= Logging.brand_new_logger end protected def self.brand_new_logger if ENV['SCRIPT_ENV'] filename = File.join(File.expand_path(File.dirname(__FILE__)), '..', 'log', ENV['SCRIPT_ENV'] + '.log') Logger.new(filename) else Logger.new(STDOUT) end end end Logger Mixin If we have an environment we will log to that environmental file (like Rails does), otherwise we will log to STDOUT. Tuesday, December 6, 2011
10. class DBConnection require 'yaml' require 'logging' include Logging attr_reader :conn def initialize config = database_config @conn = PGconn.open( :dbname => config['dbname'], :user => config['user'], :port => config['port'] ) rescue logger.error "Unable to connect to the #{ENV['SCRIPT_ENV']} database" end def exec(sql) logger.debug(sql) @conn.exec(sql) end private def database_config logger.debug "Attempting to connect to the #{ENV['SCRIPT_ENV']} database" filename = File.join(File.expand_path(File.dirname(__FILE__)), '..', 'config', 'database.yml') config = YAML.load(File.read(filename)) config[ENV['SCRIPT_ENV'] || 'development'] end end Magic Profit And now we can log queries like you are used to seeing with ActiveRecord! Tuesday, December 6, 2011
11. Rake Tuesday, December 6, 2011
12. Rake tasks $ rake -T (in /Users/barrettclark/Projects/Training/DallasRubyPOR) rake db:truncate # Truncate the zipcode table rake default # rake test is the default action. rake log:clear # Clear log files rake test # Run tests rake testing_rake # this is a test Tuesday, December 6, 2011
13. Quick Bundler pro-tip Tuesday, December 6, 2011
14. require 'bundler/setup' Bundler.require -- OR -- $ bundle exec rake Rake is just Ruby. Nothing magic about it. * Show the Rakefile * Tuesday, December 6, 2011
15. Command Line Inputs Tuesday, December 6, 2011
16. def self.help puts <<-TXT \n#{__FILE__} [-t|--truncate] [-h|--help]\n...where... -h or --help = show this help message and exit -t or --truncate = truncate the zip_code table first \nIf you wish to just load the file don't enter any command line arguments.\n TXT exit end def self.option_parser ARGV.each do |arg| case arg when '-h', '--help' help when '-t', '--truncate' ZipCode.delete_all else help end end end Sometimes puts is ok Tuesday, December 6, 2011
17. $ ruby lib/file_reader.rb -h lib/file_reader.rb [-t|--truncate] [-h|--help] ...where... -h or --help = show this help message and exit -t or --truncate = truncate the zip_code table first If you wish to just load the file don't enter any command line arguments. Tuesday, December 6, 2011
18. Better yet... def self.option_parser opts = OptionParser.new opts.on("-t", "--truncate") { ZipCode.delete_all } opts.on("-l LEVEL", "--level LEVEL", String) { |level| logger.set_log_level(level) } opts.on("-h", "--help") { puts opts.to_s; exit } opts.parse(ARGV) end $ ruby lib/file_reader.rb -h Usage: file_reader [options] -t, --truncate -l, --level LEVEL -h, --help Tuesday, December 6, 2011
19. So let’s see it run Tuesday, December 6, 2011
20. Questions? Anything you’d do different? Anything you’d like to see discussed? Tuesday, December 6, 2011