Circuit Breakers em Ruby

Transcript

1. Circuit Breakers em Ruby

2. @lucasmazza http://afterhours.io/

3. None
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5. https://sp.femug.com https://github.com/femug/femug

6. Circuit Breakers em Ruby

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11. ❓

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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

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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
34. None

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

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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

69. None

70. Obrigado! @lucasmazza