RailsConf 2012 - Stack Smashing (Ruby Red)

Transcript

1. stack smashing railsconf 2012 http://speakerdeck.com/u/czarneckid/
2. david czarnecki
3. twitter @czarneckid
4. github/czarneckid
5. work @agoragames
6. github/agoragames
7. infrastructure insanity
8. CEO priority
9. 1 month tour of duty
10. fix (allthethings)
11. document (allthethings)
12. network topology
13. 15 applications intertwined
14. SSO, Profile Service Community Pro Circuit, Live Experience Store Photo Tool, Carousel Tool, League Tool Entitlements, Redemption Starcraft Arena MLG.tv Progamer, Pro Stats
15. app * capacity
16. 15 * 2 = 30 VMs
17. VM profile: 1 GB RAM, 40 GB disk
18. MLG traffic #s: 4MM views 1.2MM uniques 35MM page views
19. quickly need a lot of VMs
20. more servers, more problems
21. we <3 hardware: 4 processors 6 cores/processor 64 GB RAM 146 GB disks
22. chef recipes
23. mostly stock
24. application migration
25. start internal
26. end external
27. iteration breeds abstraction
28. application upgrading
29. embrace the pipeline
30. git checkout -b rails32
31. gem “rails”, “3.2.0”
32. asset pipeline is OPTIONAL
33. Gemfile group :assets do gem 'sass-rails', '~> 3.2.3' gem 'coffee-rails', '~> 3.2.1' gem 'compass', '= 0.12.alpha.4' gem 'uglifier', '~> 1.0.3' end gem ‘jquery-rails’
34. application.rb if defined?(Bundler) # If you precompile assets before deploying to production, use this line Bundler.require(*Rails.groups(:assets => %w(development test))) # If you want your assets lazily compiled in production, use this line # Bundler.require(:default, :assets, Rails.env) end ... # Enable the asset pipeline config.assets.enabled = true
35. production.rb # Compress assets and add digests config.assets.compress = true config.assets.js_compressor = Uglifier.new(:copyright => false) if defined?(Uglifier) config.assets.digest = true # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added) config.assets.precompile += %w( home.css home.js admin.css admin.js custom-application.js ) config.assets.precompile += [/plugins\/jquery\.ui\.selectmenu\.(css|js) $/, /plugins\/jquery\.gwfselect\.(css|js)$/]
36. terminal $ mkdir app/assets $ mv public/images/ app/assets/ $ mv public/javascripts/ app/assets/ $ mv public/stylesheets/ app/assets/
37. the unicorn
38. wicked fast
39. kernel load-balancing
40. can do rolling restarts
41. sv-rails-run.erb #!/bin/bash exec 2>&1 <% unicorn_command = @options[:unicorn_command] || 'unicorn_rails' -%> test -f /var/rails/.rvm/scripts/rvm || exit 1 exec /usr/bin/sudo -u rails -i <<END export HOME=/var/rails source /var/rails/.rvm/scripts/rvm || exit 1 cd <%= @options[:root] %> || exit 1 exec bundle exec <%= unicorn_command %> -c config/unicorn.rb - E <%= @options[:environment] %> END
42. unicorn.rb rails_env = ENV['RAILS_ENV'] || 'production' worker_processes (rails_env == 'production' ? 4 : 1) preload_app true # Restart any workers that haven't responded in 30 seconds timeout 30 # Listen on a Unix data socket case rails_env when 'production' || 'staging' listen "/var/rails/application/tmp/sockets/ #{rails_env}.sock", :backlog => 2048 else listen "#{`pwd`.strip}/tmp/sockets/#{rails_env}.sock" end
43. signal for capacity
44. service configuration
45. if a server fails ...
46. does it make a sound?
47. no, you get a phone call
48. the usual suspect
49. database.yml production: adapter: mysql2 host: machine-name reconnect: true pool: 5 database: appname_production username: secret password: sup3rs3cr3t encoding: utf8
50. spot a problem?
51. database.yml production: adapter: mysql2 host: machine-name reconnect: true pool: 5 database: appname_production username: secret password: sup3rs3cr3t encoding: utf8
52. databases never fail!?
53. how about an alias?
54. /etc/bind/db.int ... mysql.yourcompany IN CNAME machine-name mysql-slave. yourcompany IN CNAME another-machine-name ...
55. database.yml production: adapter: mysql2 host: mysql.yourcompany.int reconnect: true pool: 5 database: appname_production username: secret password: sup3rs3cr3t encoding: utf8
56. no re-deploys for failure!
57. simply update DNS
58. do this for redis
59. and maybe memcached
60. or for any services
61. offline processing
62. who doesn’t use resque?
63. rails recipe resque-aware
64. Individual application ... 'application' => { :root => '/var/rails/application/current', :environment => 'production', :queues => {'application_queue' => 4, 'application_mailer' => 1, 'application_checkin_expiration' => 1}, :queue_intervals => {}, :resque_log => '/var/rails/application/shared/ log/resque.log' }, ...
65. node[:ruby][:sites].each_pair do |site, opts| runit_service site do owner 'rails' group 'rails' template_name 'rails' options opts end if opts[:resque_scheduler] == `hostname`.strip runit_service "resque-scheduler-#{site}" do owner 'rails' group 'rails' template_name 'resque-scheduler' options opts end end if opts[:queues] opts[:queues].each do |queue, workers| options_for_template = opts.dup options_for_template[:queue] = queue 1.upto(workers) do |index| runit_service "resque-#{site}-#{queue}-worker-#{index}" do owner 'rails' group 'rails' template_name 'resque' options options_for_template end end end end end
66. sv-resque-run.erb #!/bin/bash exec 2>&1 test -f /var/rails/.rvm/scripts/rvm || exit 1 exec /usr/bin/sudo -u rails -i <<END export HOME=/var/rails source /var/rails/.rvm/scripts/rvm || exit 1 cd <%= @options[:root] %> || exit 1 RAILS_ENV=<%= @options[:environment] %> QUEUES=<%= @options[:queue] %> INTERVAL=<%= @options[:queue_intervals] [@options[:queue]] || '5' %> exec bundle exec rake environment resque:work >><%= @options[:resque_log] %> 2>&1 END
67. sexy capistrano
68. sexy == DRY
69. deploy.rb
70. deploy.rb set :application, 'some-mlg-app' set :application_server, 'unicorn' require 'capistrano/agora/base' load 'deploy' if respond_to?(:namespace) require 'capistrano/agora/airbrake' require 'capistrano/agora/assets' require 'capistrano/agora/rvm' require 'capistrano/agora/hipchat' set :hipchat_room_name, 'Some MLG Application' require 'capistrano/agora/logging' require 'capistrano/agora/resque' require 'capistrano/agora/symlinks' require 'capistrano/agora/sv' require 'capistrano/agora/unicorn' set :resque_queues, { 'some-mlg-app.retrieve_stuff' => 4, 'some-mlg-app.update_stuff' => 1, 'some-mlg-app.email_stuff' => 1 } set :asset_directory, 'public/players' before 'deploy:restart', 'deploy:assets:precompile_with_skip'
71. gem capistrano-agora
72. common functionality
73. Gemfile ... group :deploy do gem 'capistrano' gem 'capistrano-ext' gem 'capistrano-agora' gem 'hipchat' end ...
74. sensible for > 1 app
75. capistrano-agora/ airbrake assets base helpers hipchat logging resque rvm sv symlinks unicorn version
76. base.rb Capistrano::Configuration.instance.load do default_run_options[:pty] = true ssh_options[:forward_agent] = true set :scm, :git set :deploy_via, :remote_cache set :keep_releases, 7 set :use_sudo, false set :branch, fetch(:branch, "master") unless exists?(:branch) set :gateway, "#{fetch(:user, `whoami`.strip)}@your.dmz.com" unless exists?(:gateway) set :repository, "git@github.com:agoragames/#{application}.git" unless exists?(:repository) set :deploy_to, "/var/rails/#{application}" unless exists?(:deploy_to) set :shared_nfs_dir, "/var/shared/rails/#{application}" end
77. assets.rb Capistrano::Configuration.instance.load do set :asset_directory, 'public/assets' set :assets_dependencies, %w(app/assets vendor/assets Gemfile.lock config/routes.rb) namespace :deploy do namespace :assets do task :precompile_with_skip, :roles => :web, :except => { :no_release => true } do from = source.next_revision(current_revision) if capture("cd #{latest_release} && #{source.local.log(previous_revision, current_revision)} #{assets_dependencies.join(' ')} | wc -l").to_i > 0 run "cd #{fetch(:current_path)} && bundle exec rake assets:precompile RAILS_ENV=#{rails_env}" else logger.info "Skipping asset pre-compilation because there were no asset changes. Copying assets from #{previous_release}." run "cp -R #{previous_release}/#{asset_directory} #{latest_release}/ #{asset_directory}" end end end end end
78. resque.rb Capistrano::Configuration.instance.load do namespace :resque do desc <<-DESC Restart the Resque workers for an application after a deploy or deploy:migrations DESC task :restart_workers, :roles => :app, :except => { :no_release => true } do if exists?(:resque_queues) fetch(:resque_queues).each do |queue_name, worker_count| 1.upto(worker_count) do |worker_index| run "sv restart resque-#{fetch(:application)}-#{queue_name}-worker- #{worker_index}" end end else logger.info('You must define the :resque_queues variable for the resque:restart_workers task to work') end end end after "deploy", "resque:restart_workers" after "deploy:migrations", "resque:restart_workers" end
79. unicorn.rb require 'capistrano/agora/helpers' Capistrano::Configuration.instance.load do namespace :unicorn do desc 'Increase number of unicorn workers' task :increase_workers, :roles => :app do num_workers = fetch(:num_workers, 1) unicorn_hosts = fetch(:unicorn_hosts, ['host1', 'host2']) unicorn_hosts.each do |host| worker_process_id = capture("cat /etc/sv/#{fetch(:application)}/supervise/pid", :hosts => host).chomp 1.upto(num_workers.to_i) do run("kill -TTIN #{worker_process_id}", :hosts => host) end end end desc 'Decrease number of unicorn workers' task :decrease_workers, :roles => :app do num_workers = fetch(:num_workers, 1) unicorn_hosts = fetch(:unicorn_hosts, ['host1', 'host2']) unicorn_hosts.each do |host| worker_process_id = capture("cat /etc/sv/#{fetch(:application)}/supervise/pid", :hosts => host).chomp 1.upto(num_workers.to_i) do run("kill -TTOU #{worker_process_id}", :hosts => host) end end end end end
80. application monitoring
81. it must be visual
82. it must be historical
83. it must be accessible
84. we are using Munin
85. spot problems
86. spot opportunity
88. infrastructure monitoring
89. system engineering project
90. they chose cucumber
91. rackspace-validations
92. runs every 5 minutes
93. step definitions
94. step_definitions/ command_steps.rb dns_steps.rb file_steps.rb ping_steps.rb
95. command_steps.rb def retry_times(times) begin yield rescue case times -= 1 when 0 raise else retry end end end When /^I go to "(https?:\/\/[^"]*)"$/ do |uri| begin @host = uri.host retry_times(3) { http(uri) } rescue Errno::ECONNREFUSED @output = 'connection refused' @status = 127 rescue Timeout::Error @output = 'execution expired' @status = 127 end end
96. command_steps.rb Then /^the (?:output|response) should (?:include|contain) "([^"]*)"$/ do |string| string = eval("\"#{string}\"") assert @output.include?(string), "expected to find \"#{string}\" in the output from #{@host}, but did not" end Then /^the (?:output|response) should not (?:include|contain) "([^"]*)"$/ do |string| string = eval("\"#{string}\"") assert !@output.include?(string), "expected not to find \"#{string}\" in the output from #{@host}, but did" end Then /^the (?:output|response) should (?:include|contain) "([^"]*X[^"]*)", where X is less than (\d+)$/ do |string, value| string = eval("\"#{string}\"") regex = Regexp.new(string.sub('X', '(\d+)')) assert @output =~ regex x = $1.to_i assert x < value, "expected \"#{x}\" to be less than \"#{value}\" in the output from #{@host}" end
97. dns_steps.rb When /^I do a DNS lookup for ([\w\-\.]+)$/ do |name| @host = name begin @alias = Socket.gethostbyname(name).first rescue SocketError @alias = nil end end Then /^it should point (?:at|to) ([\w\-\.]+)$/ do |name| assert_equal name, @alias, "expected #{@host} to CNAME to #{@alias}, but it didn't" end
98. file_steps.rb Before do @stats = [] end When /^I stat (\S+)$/ do |glob| Dir[glob].each do |path| @stats << File.stat(path) end end Then /^there should be at least (\d+) files?$/ do |count| assert @stats.length >= count end Then /^the most recently modified file should be less than (\d+) (\w+)s? old$/ do |count, unit| assert @stats.collect { |stat| stat.mtime }.max > time_ago(count, unit) end
99. ping_steps.rb When /^I ping ([\w\-\.]+)$/ do |host| @host = host body = nil IO.popen(['/bin/ping', '-c', '1', '-n', host]) { |io| body = io.read } if $?.to_i == 0 body =~ /^rtt min\/avg\/max\/mdev = (\d\.\d{3}+)\/(\d\.\d{3}+)\/(\d\.\d{3}+)\/(\d\.\d{3}+) ms$/ @status = true @response = $2.to_f else @status = false @response = 0.0 end end Then /^I receive a response$/ do assert @status, "did not receive a response from #{@host}" end Then /^I receive a response within (\d+)(?: ?ms| milliseconds)$/ do |ms| assert @status, "did not receive a response from #{@host}" assert @response < ms, "response time from #{@host} of #{@response} was slower than #{ms} milliseconds" end
100. <component>.feature
101. features/ applications.feature haproxy.feature memcache.feature mongodb.feature mysql.feature nginx.feature redis.feature varnish.feature
102. applications.feature
103. Feature: Applications @critical Scenario: Ensure the company site is available When I go to "http://www.yourcompany.com/" Then the response should either be a 200 or a 302 to "http://www.yourcompany.com/whateva"
104. mongodb.feature
105. Feature: MongoDB In order to support our environment And avoid lost data resulting from system failure or incompetence As a responsible system administrator I want to ensure that our MongoDB databases are running as expected And that we have good slaves of the masters (well, secondaries to our primaries...) And that our snapshotted backups are up to date @critical Scenario Outline: Ensure MongoD is running When I SSH to <host> and run `pgrep mongod` Then it should exit successfully Examples: | host | | mongo-primary.int | | mongo-secondary.int | | mongo-secondary.int |
106. redis.feature
107. Feature: Redis @critical Scenario Outline: Ensure a Redis host is up and running the expected version When I open a socket to <host>:<port> and send "INFO\r\n" Then the output should include "redis_version:<version>" Examples: | host | port | version | | redis.int | 6379 | 2.4.2 | | redis-staging.int | 6379 | 2.4.2 |
108. continuous integration
109. we use Jenkins
110. builds all internal projects
111. builds all internal gems
112. internal Gem In A Box-secure
113. Gemfile source 'http://rubygems.org' source 'https://username:password@gems.yourcompany.com' ...
114. :git => into your organization
115. shields you from infosuicide
116. build failure?
117. notification via e-mail
118. notification via HipChat
119. notify (allthethings)
120. continuous deployment
121. GitHub flow
122. master is deployable
123. features in branches
124. post-build script trigger
125. PostBuildScript #!/bin/bash if [ "$GIT_BRANCH" == "origin/HEAD" ] || [ "$GIT_BRANCH" == 'master' ]; then curl "http://continuous-integration.com/job/project-deploy/build" else echo "$GIT_BRANCH, not deploying" fi
126. execute only if build succeeds: check
127. Jenkins project-deploy
128. Build #!/bin/bash source "$HOME/.rvm/scripts/rvm" [[ -s ".rvmrc" ]] && source .rvmrc bundle install && bundle exec cap production deploy:migrations -S user=deploy -S branch=$GIT_BRANCH
129. recap (allthethings)
130. simplify
131. upgrade (small to big)
132. alias
133. DRY
134. monitor
135. validate
136. integrate
137. stack smashing http://speakerdeck.com/u/czarneckid/ david czarnecki twitter @czarneckid github/czarneckid github/agoragames