Patterns of Pluggable Gems (ConFoo 2014)

One strength of the Ruby community is the simplicity of sharing code via gems. Popular gems even develop their own ecosystem of plugins around them.

But extending a gem that wasn't built with flexibility in mind isn't easy. This talk covers the highs and lows of interacting with other gems. We'll cover how to make your gem easy to plug into, from patterns and events, to configuration and documentation.

Transcript

1. Patterns of Pluggable Gems Jason Clark @jasonrclark Ruby Agent Engineer Wednesday, February 26, 14
2. Storytime! Wednesday, February 26, 14
3. newrelic_rpm module NewRelic::Agent::BrowserMonitoring def browser_monitoring_queue_time queue_time = current_transaction.queue_time millis = queue_time.to_f * 1000.0 clamp_to_positive(millis.round) end def footer_js_string(config) "<script>...#{browser_monitoring_queue_time}" end end Wednesday, February 26, 14
4. module NewRelic::Agent::BrowserMonitoring def current_timings TransactionTimings.new end def footer_js_string(config) "<script>...#{current_timings.queue_time_in_millis}" end end newrelic_rpm Wednesday, February 26, 14
5. Meanwhile... Elsewhere At New Relic http://flic.kr/p/9xEUug Wednesday, February 26, 14
6. module NewRelic::Agent::BrowserMonitoring # MONKEY PATCH! def footer_js_string(config) "<script>...#{browser_monitoring_queue_time}" end end rpm_site Wednesday, February 26, 14
7. http://pixabay.com/en/elephant-foot-ten-foot-elephant-52536/ Wednesday, February 26, 14
8. Wednesday, February 26, 14
9. Reskiq It forks then it threads! Wednesday, February 26, 14
10. gem install my_awesome_code Wednesday, February 26, 14
11. Where We're Going • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
12. Pass It On Wednesday, February 26, 14
13. Loggers Wednesday, February 26, 14
14. activerecord ActiveRecord::Base.logger = ::Logger.new("my_special.log") Wednesday, February 26, 14
15. http://flic.kr/p/7GDRue Dependency Injection Wednesday, February 26, 14
16. http://flic.kr/p/gzxjKu Duck Typing Wednesday, February 26, 14
17. Instrumentors Wednesday, February 26, 14
18. excon connection = Excon.new( 'http://nerd.jasonrclark.com', :instrumentor => SimpleInstrumentor ) Wednesday, February 26, 14
19. excon class SimpleInstrumentor class << self def instrument(name, params = {}, &blk) puts "#{name} just happened." yield if block_given? end end end Wednesday, February 26, 14
20. http://pixabay.com/en/elephant-foot-ten-foot-elephant-52536/ Wednesday, February 26, 14
21. Backends Wednesday, February 26, 14
22. Delayed::Job # without delayed_job @user.activate!(@device) # with delayed_job @user.delay.activate!(@device) Wednesday, February 26, 14
23. Delayed::Job Wednesday, February 26, 14
24. Delayed::Job ::Delayed.const_set(:Job, backend) Wednesday, February 26, 14
25. newrelic_rpm def failed_jobs Delayed::Job.count( :conditions => 'failed_at is not NULL') end Wednesday, February 26, 14
26. Gem-Specific Wednesday, February 26, 14
27. Resque class SendMessageJob def self.perform(id, text) user = User.find(id) user.send_message(text) end end Resque.enqueue(SendMessageJob, 42, "Yo") Wednesday, February 26, 14
28. Resque https://github.com/resque/resque/blob/master/docs/HOOKS.md class SendMessageJob def self.before_perform_log_it(*args) logger.debug("Messaging #{args}") end ... end Wednesday, February 26, 14
29. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
30. Events Wednesday, February 26, 14
31. See my talk tomorrow at 3! Wednesday, February 26, 14
32. Resque Resque.after_fork do |job| ActiveRecord::Base.establish_connection end Wednesday, February 26, 14
33. http://pixabay.com/en/elephant-foot-ten-foot-elephant-52536/ Wednesday, February 26, 14
34. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
35. Middleware Wednesday, February 26, 14
36. Rack::Cache ActionDispatch::Cookies YourApplication Web Request Wednesday, February 26, 14
37. # [status, headers, response] def call(env) # ... before result = @app.call(env) # ... after result end Wednesday, February 26, 14
38. # [status, headers, response] def call(env) # ... before result = @app.call(env) # ... after result end Wednesday, February 26, 14
39. http://flic.kr/p/SSGmF ActionDispatch::Static Rack::Lock <ActiveSupport::Cache::Strategy> Rack::Runtime Rack::MethodOverride ActionDispatch::RequestId Rails::Rack::Logger ActionDispatch::ShowExceptions ActionDispatch::DebugExceptions ActionDispatch::RemoteIp ActionDispatch::Reloader ActionDispatch::Callbacks ActiveRecord::ConnectionAdapters ActiveRecord::QueryCache ActionDispatch::Cookies ActionDispatch::Session::CookieStore ActionDispatch::Flash ActionDispatch::ParamsParser Rack::Head Rack::ConditionalGet Rack::ETag AgentSnoop::Middleware RpmTestApp::Application.routes Wednesday, February 26, 14
40. Who's There? Wednesday, February 26, 14
41. # [status, headers, response] def call(env) # ... before result = @app.call(env) # ... after result end Wednesday, February 26, 14
42. class MyMiddleware def initialize(options={}) # options == { :foo => 1 } end def call(worker, msg, queue) yield end end Wednesday, February 26, 14
43. Sidekiq.configure_server do |config| config.server_middleware do |chain| chain.add MyMiddleware, :foo => 1 end end Wednesday, February 26, 14
44. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
45. Lifecycle Wednesday, February 26, 14
46. Forks and Daemons http://flic.kr/p/79tE5Q Wednesday, February 26, 14
47. Forking fork() state Wednesday, February 26, 14
48. fork() state fork() Forking state Wednesday, February 26, 14
49. before_fork after_fork Wednesday, February 26, 14
50. Add Threads fork() Wednesday, February 26, 14
51. fork() Add Threads Wednesday, February 26, 14
52. Enter the Lock fork() @lock Wednesday, February 26, 14
53. @loick fork() Enter the Lock @lock Wednesday, February 26, 14
54. https://github.com/resque/resque/issues/1101 Forks + Threads + == Locks Resque Wednesday, February 26, 14
55. Load Up! Wednesday, February 26, 14
56. unicorn ♥ὑὑ~/myapp:unicorn_rails -c ./unicorn.rb unicorn_rails master unicorn_rails worker[0] unicorn_rails worker[1] unicorn_rails worker[2] unicorn_rails worker[3] Wednesday, February 26, 14
57. loads gems forks after_fork starts loop forks after_fork starts loop loads gems preload_app true preload_app false unicorn Wednesday, February 26, 14
58. loads gems forks after_fork starts loop forks after_fork starts loop loads gems preload_app true preload_app false unicorn Wednesday, February 26, 14
59. loads gems forks after_fork starts loop forks after_fork starts loop loads gems preload_app true preload_app false unicorn Wednesday, February 26, 14
60. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
61. Names and Paths Wednesday, February 26, 14
62. Forced Wednesday, February 26, 14
63. Sequel.plugin :newrelic_instrumentation Wednesday, February 26, 14
64. Sequel.plugin :newrelic_instrumentation => require 'sequel/plugins/newrelic_instrumentation' Wednesday, February 26, 14
65. ~/source/newrelic/ruby_agent/lib: ls -la drwxr-xr-x Sep 19 14:46 . drwxr-xr-x Oct 10 11:19 .. drwxr-xr-x Oct 10 11:20 new_relic -rw-r--r-- Sep 19 14:46 newrelic_rpm.rb drwxr-xr-x Sep 19 14:46 sequel drwxr-xr-x Oct 7 08:53 tasks Wednesday, February 26, 14
66. ~/source/newrelic/ruby_agent/lib: ls -la drwxr-xr-x Sep 19 14:46 . drwxr-xr-x Oct 10 11:19 .. drwxr-xr-x Oct 10 11:20 new_relic -rw-r--r-- Sep 19 14:46 newrelic_rpm.rb drwxr-xr-x Sep 19 14:46 sequel drwxr-xr-x Oct 7 08:53 tasks Wednesday, February 26, 14
67. Sequel.plugin NewRelic::Sequel::Instrumentation Wednesday, February 26, 14
68. Generic Wednesday, February 26, 14
69. Wednesday, February 26, 14
70. ActiveRecord Wednesday, February 26, 14
71. ActiveRecord DataMapper Wednesday, February 26, 14
72. ActiveRecord DataMapper HTTPClient Wednesday, February 26, 14
73. Qualify Yourself Wednesday, February 26, 14
74. newrelic_rpm module NewRelic module Agent class Thread < ::Thread ... end end end Wednesday, February 26, 14
75. elsewhere... class Thread # Re-opens NewRelic::Agent::Thread # D'oh! end Wednesday, February 26, 14
76. newrelic_plugin module NewRelic class Logger ... end end Wednesday, February 26, 14
77. newrelic_rpm module NewRelic module Agent class AgentLogger LOG_LEVELS = { "debug" => Logger::DEBUG, ... } end end end Wednesday, February 26, 14
78. newrelic_rpm module NewRelic module Agent class AgentLogger LOG_LEVELS = { "debug" => Logger::DEBUG, ... } end end end Wednesday, February 26, 14
79. newrelic_rpm module NewRelic module Agent class AgentLogger LOG_LEVELS = { "debug" => ::Logger::DEBUG, ... } end end end Wednesday, February 26, 14
80. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
81. Config Wednesday, February 26, 14
82. yml Wednesday, February 26, 14
83. yml + ERB Wednesday, February 26, 14
84. yml + ERB file = File.read("./config/awesome_gem.yml") # Locals available in ERB default_awesome_key = "YEAH!" erb = ERB.new(file).result(binding) config = YAML.load(erb) Wednesday, February 26, 14
85. yml + ERB ~/config/awesome_gem.yml development: name: <%= default_awesome_key %> license_key: <%= ENV["LICENSE_KEY"] %> Wednesday, February 26, 14
86. Ruby Wednesday, February 26, 14
87. unicorn worker_processes 5 preload_app true timeout 30 after_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection end Wednesday, February 26, 14
88. on_worker_boot do ActiveSupport.on_load(:active_record) do ActiveRecord::Base.establish_connection end end Wednesday, February 26, 14
89. Great for Apps? What about Gems? Wednesday, February 26, 14
90. newrelic_rpm if defined?(::Puma) && ::Puma.respond_to?(:cli_config) config = ::Puma.cli_config config.options[:worker_boot] << Proc.new do NewRelic::Agent.after_fork(...) end end Wednesday, February 26, 14
91. newrelic_rpm if defined?(::Puma) && ::Puma.respond_to?(:cli_config) config = ::Puma.cli_config config.options[:worker_boot] << Proc.new do NewRelic::Agent.after_fork(...) end end Wednesday, February 26, 14
92. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
93. Docs Wednesday, February 26, 14
94. README Wednesday, February 26, 14
95. sinatra Wednesday, February 26, 14
96. Wednesday, February 26, 14
97. Wednesday, February 26, 14
98. Wednesday, February 26, 14
99. Expected Extensions? Wednesday, February 26, 14
100. Wednesday, February 26, 14
101. Don't Bury It Wednesday, February 26, 14
102. Wednesday, February 26, 14
103. Wednesday, February 26, 14
104. Versioning Wednesday, February 26, 14
105. Wednesday, February 26, 14
106. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
107. Where We've Been Wednesday, February 26, 14
108. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Wednesday, February 26, 14
109. Where We've Been • Pass It On • Events • Middleware • Lifecycle • Names and Paths • Config • Docs Jason Clark @jasonrclark Ruby Agent Engineer Wednesday, February 26, 14