Class: ActiveRecordStats::RackMiddleware

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record_stats/rack_middleware.rb

Constant Summary collapse

ENV_KEY =

The location in the Rack ‘env` where ActionDispatch stores its `parameters` value. This may change across Rails versions, but I am not aware of any more reliable means of retrieving it.

'action_dispatch.request.parameters'.freeze

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ RackMiddleware

Returns a new instance of RackMiddleware.



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# File 'lib/active_record_stats/rack_middleware.rb', line 13

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/active_record_stats/rack_middleware.rb', line 17

def call(env)
  totals  = {}
  db_time = 0

  gather_sql = ->(_name, _started_at, _finished_at, _unique_id, payload) {
    return if payload[:name] == 'SCHEMA' || payload[:sql].blank?
    return unless type = ActiveRecordStats.statement_type(payload[:sql])
    totals[type] ||= 0
    totals[type] += 1
  }

  gather_runtime = ->(_name, _started_at, _finished_at, _unique_id, payload) {
    db_time = payload.fetch(:db_runtime) { 0 }
  }

  subs = [
    ActiveSupport::Notifications.subscribe('sql.active_record', &gather_sql),
    ActiveSupport::Notifications.subscribe('process_action.action_controller', &gather_runtime)
  ]

  @app.call(env)

ensure
  subs.each do |sub|
    ActiveSupport::Notifications.unsubscribe(sub)
  end

  request_params = env[ENV_KEY]
  if request_params && controller = request_params['controller']
    controller = controller.gsub('/', '__')
    action = request_params['action']
    emit(controller, action, db_time, totals.dup)
  end
end