Class: RestfulResource::Instrumentation

Inherits:
Object
  • Object
show all
Defined in:
lib/restful_resource/instrumentation.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app_name:, api_name:, request_instrument_name:, cache_instrument_name:, server_cache_instrument_name:, metric_class:) ⇒ Instrumentation

Returns a new instance of Instrumentation.



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# File 'lib/restful_resource/instrumentation.rb', line 6

def initialize(app_name:, api_name:, request_instrument_name:, cache_instrument_name:, server_cache_instrument_name:, metric_class:)
  @app_name = app_name
  @api_name = api_name
  @request_instrument_name = request_instrument_name
  @cache_instrument_name = cache_instrument_name
  @server_cache_instrument_name = server_cache_instrument_name
  @metric_class = metric_class
end

Instance Attribute Details

#api_name ⇒ Object (readonly)

Returns the value of attribute api_name.



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# File 'lib/restful_resource/instrumentation.rb', line 15

def api_name
  @api_name
end

#app_name ⇒ Object (readonly)

Returns the value of attribute app_name.



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# File 'lib/restful_resource/instrumentation.rb', line 15

def app_name
  @app_name
end

#cache_instrument_name ⇒ Object (readonly)

Returns the value of attribute cache_instrument_name.



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# File 'lib/restful_resource/instrumentation.rb', line 15

def cache_instrument_name
  @cache_instrument_name
end

#metric_class ⇒ Object (readonly)

Returns the value of attribute metric_class.



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# File 'lib/restful_resource/instrumentation.rb', line 15

def metric_class
  @metric_class
end

#request_instrument_name ⇒ Object (readonly)

Returns the value of attribute request_instrument_name.



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# File 'lib/restful_resource/instrumentation.rb', line 15

def request_instrument_name
  @request_instrument_name
end

#server_cache_instrument_name ⇒ Object (readonly)

Returns the value of attribute server_cache_instrument_name.



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# File 'lib/restful_resource/instrumentation.rb', line 15

def server_cache_instrument_name
  @server_cache_instrument_name
end

Instance Method Details

#base_request_path(event) ⇒ Object

 Converts a path like “/api/v2/cap_derivatives/75423/with_colours” to “api_v2_cap_derivatives_with_colours”



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# File 'lib/restful_resource/instrumentation.rb', line 114

def base_request_path(event)
  path_from_event(event).split('/').drop(1).select {|a| a.match(/\d+/).nil? }.join('_') if event
end

#cache_notifier_namespace(metric:, event: nil) ⇒ Object 



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# File 'lib/restful_resource/instrumentation.rb', line 109

def cache_notifier_namespace(metric:, event: nil)
  [app_name, api_name, base_request_path(event), metric].compact.join('.')
end

#path_from_event(event) ⇒ Object 



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# File 'lib/restful_resource/instrumentation.rb', line 118

def path_from_event(event)
  url_from_event(event)&.path.to_s
end

#status_from_event(event) ⇒ Object 



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# File 'lib/restful_resource/instrumentation.rb', line 126

def status_from_event(event)
  event.payload[:env]&.status || event.payload&.status
end

#subscribe_to_notifications ⇒ Object 



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# File 'lib/restful_resource/instrumentation.rb', line 18

def subscribe_to_notifications
  validate_metric_class!

  # Subscribes to events from Faraday
  ActiveSupport::Notifications.subscribe request_instrument_name do |*args|
    event = ActiveSupport::Notifications::Event.new(*args)

    status = status_from_event(event)

    # Outputs per API log lines like:
    # measure#quotes_site.research_site_api.time=215.161237
    # count#quotes_site.research_site_api.status.200=1
    # count#quotes_site.research_site_api.called=1
    metric_class.measure cache_notifier_namespace(metric: 'time'), event.duration
    metric_class.count cache_notifier_namespace(metric: "status.#{status}"), 1
    metric_class.count cache_notifier_namespace(metric: 'called'), 1

    # Outputs per resource log lines like:
    # measure#quotes_site.research_site_api.api_v2_cap_derivatives.time=215.161237
    # count#quotes_site.research_site_api.api_v2_cap_derivatives.status.200=1
    # count#quotes_site.research_site_api.api_v2_cap_derivatives.called=1
    metric_class.measure cache_notifier_namespace(metric: 'time', event: event), event.duration
    metric_class.count cache_notifier_namespace(metric: "status.#{status}", event: event), 1
    metric_class.count cache_notifier_namespace(metric: 'called', event: event), 1
  end

  # Subscribes to events from Faraday::HttpCache
  ActiveSupport::Notifications.subscribe cache_instrument_name do |*args|
    event = ActiveSupport::Notifications::Event.new(*args)
    cache_status = event.payload.fetch(:cache_status, nil)

    # Outputs log lines like:
    # count#quotes_site.research_site_api.cache_hit=1
    # count#quotes_site.research_site_api.api_v2_cap_derivatives.cache_hit=1
    case cache_status
      when :fresh, :valid
        metric_class.count cache_notifier_namespace(metric: 'cache_hit'), 1
        metric_class.count cache_notifier_namespace(metric: 'cache_hit', event: event), 1
      when :invalid, :miss
        metric_class.count cache_notifier_namespace(metric: 'cache_miss'), 1
        metric_class.count cache_notifier_namespace(metric: 'cache_miss', event: event), 1
      when :unacceptable
        metric_class.count cache_notifier_namespace(metric: 'cache_not_cacheable'), 1
        metric_class.count cache_notifier_namespace(metric: 'cache_not_cacheable', event: event), 1
      when :bypass
        metric_class.count cache_notifier_namespace(metric: 'cache_bypass'), 1
        metric_class.count cache_notifier_namespace(metric: 'cache_bypass', event: event), 1
    end
  end

  # Subscribes to events from Faraday::Cdn::Metrics
  ActiveSupport::Notifications.subscribe server_cache_instrument_name do |*args|
    event = ActiveSupport::Notifications::Event.new(*args)
    client_cache_status = event.payload.fetch(:client_cache_status, nil)
    server_cache_status = event.payload.fetch(:server_cache_status, nil)

    if client_cache_status.nil? || !client_cache_status.in?([:fresh, :valid])
      # Outputs log lines like:
      # count#quotes_site.research_site_api.server_cache_hit=1
      # count#quotes_site.research_site_api.api_v2_cap_derivatives.server_cache_hit=1
      case server_cache_status
      when :fresh
        metric_class.count cache_notifier_namespace(metric: 'server_cache_hit'), 1
        metric_class.count cache_notifier_namespace(metric: 'server_cache_hit', event: event), 1
      when :valid
        metric_class.count cache_notifier_namespace(metric: 'server_cache_hit_while_revalidate'), 1
        metric_class.count cache_notifier_namespace(metric: 'server_cache_hit_while_revalidate', event: event), 1
      when :invalid, :miss
        metric_class.count cache_notifier_namespace(metric: 'server_cache_miss'), 1
        metric_class.count cache_notifier_namespace(metric: 'server_cache_miss', event: event), 1
      when :unacceptable
        metric_class.count cache_notifier_namespace(metric: 'server_cache_not_cacheable'), 1
        metric_class.count cache_notifier_namespace(metric: 'server_cache_not_cacheable', event: event), 1
      when :bypass
        metric_class.count cache_notifier_namespace(metric: 'server_cache_bypass'), 1
        metric_class.count cache_notifier_namespace(metric: 'server_cache_bypass', event: event), 1
      when :unknown
        metric_class.count cache_notifier_namespace(metric: 'server_cache_unknown'), 1
        metric_class.count cache_notifier_namespace(metric: 'server_cache_unknown', event: event), 1
      end
    end
  end
end

#url_from_event(event) ⇒ Object 



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# File 'lib/restful_resource/instrumentation.rb', line 122

def url_from_event(event)
  event.payload[:env]&.url || event.payload&.url
end

#validate_metric_class! ⇒ Object 



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# File 'lib/restful_resource/instrumentation.rb', line 102

def validate_metric_class!
  metric_methods = %i(count sample measure)
  if metric_methods.any? {|m| !metric_class.respond_to?(m) }
    raise ArgumentError.new "Metric class '#{metric_class}' does not respond to #{metric_methods.join ','}"
  end
end