Circuit Breakers em Ruby

1. Circuit Breakers em Ruby
2. @lucasmazza http://afterhours.io/
5. https://sp.femug.com https://github.com/femug/femug
6. Circuit Breakers em Ruby
11. ❓
14. rescue_from StandardError do render text: 'oops' end
15. rescue_from StandardError do render text: 'oops' end ❓❓❓❓❓❓❓❓❓ ❓❓❓❓❓❓❓❓❓
16. “You wrap a protected function call in a circuit breaker object, which monitors for failures.” http://martinfowler.com/bliki/CircuitBreaker.html
17. https://pragprog.com/book/mnee/release-it
26. Estado + transições
27. ✓ Timeouts
28. ✓ Timeouts ✓ Downtimes
29. ✓ Timeouts ✓ Downtimes ✓ Picos de erros
30. ✓ Timeouts ✓ Downtimes ✓ Picos de erros ✓ Má configuração
31. ★ Limite de falhas
32. ★ Limite de falhas ★ Tempo para reset
33. ★ Limite de falhas ★ Tempo para reset ★ Erros a ignorar
35. ❓API pública ❓Gestão do estado ❓Concorrência
36. jnunemaker/resilient
37. require 'resilient/circuit_breaker' circuit_breaker = Resilient::CircuitBreaker.get('acme-co-api') if circuit_breaker.allow_request? begin # API Call circuit_breaker.success rescue => boom circuit_breaker.failure # do fallback end else # do fallback end
38. circuit_breaker = Resilient::CircuitBreaker.get('example', { # at what percentage of errors should we open the circuit error_threshold_percentage: 50, # do not try request again for 5 seconds sleep_window_seconds: 5, # do not open circuit until at least 5 requests have happened request_volume_threshold: 5, }) # etc etc etc
39. ✅ Boa API pública ⚠ Não é distribuído ⚠ Não é concorrente
40. ✅ Instrumentação & Métricas
41. shopify/semian
42. gem 'semian', require: %w(semian semian/redis) def fetch_user User.find(session[:user_id]) rescue Redis::CannotConnectError nil end
43. Semian.register(:mysql_shard0, timeout: 0.5, error_threshold: 3, error_timeout: 10) Semian[:mysql_shard0].acquire do # Perform a MySQL query here end
44. “Semian is not a trivial library to understand, introduces complexity and thus should be introduced with care.” https://github.com/shopify/semian#do-i-need-semian
45. “It is paramount that you understand Semian before including it in production as you may otherwise be surprised by its behaviour.” https://github.com/shopify/semian#do-i-need-semian
46. ⚠ Monkeypatch ⚠ estado por host ✅ Concorrente
47. ✅ Suporte a instrumentação ✅ Battle tested
48. orgsync/stoplight
49. light = Stoplight('acme-co-api') { do_api_call } .with_fallback { do_fallback } .with_threshold(3) # => Stoplight::Light light.color #=> 'green', 'yellow' ou 'red' light.run
50. require 'redis' redis = Redis.new data_store = Stoplight::DataStore::Redis.new(redis) Stoplight::Light.default_data_store = data_store slack = Slack::Notifier.new('http://www.example.com/webhook-url') notifier = Stoplight::Notifier::Slack.new(slack) Stoplight::Light.default_notifiers += [notifier] notifier = Stoplight::Notifier::Logger.new(Rails.logger) Stoplight::Light.default_notifiers += [notifier]
51. ⚠ API não idiomática ✅ Distribuído ✅ Concorrente
52. ✅ Implementação bem legível
53. netflix/hystrix
55. orgsync/stoplight
56. class CircuitBreaker def initialize(client, name) @client = client @name = name end def method_missing(method, *args, &block) Stoplight(@name) { @client.public_send(method, *args, &block) }.run end end
57. gh_client = GitHub::Client.new('acme-co-oauth2-token') client = CircuitBreaker.new(gh_client, 'client-acme-co') # Requests feito dentro do Circuit Breaker client.repo('plataformatec/devise') client.repo('plataformatec/simple_form') client.repo('plataformatec/faraday-http-cache')
58. Pattern + Gem Você!
59. ❓Monitoramento
60. Métricas
61. StatsD Librato NewRelic AppSignal …
62. Notificações
63. Notificações
64. Reset manual
65. ❓Fallback vs raise
66. Escrita vs leitura sync vs async
67. Executar uma operação em background Retry + backoff
68. Ler dados de uma API Fallback e/ou cache
70. Obrigado! @lucasmazza