recorder.rb

# frozen_string_literal: true


require "opencensus/stats/view"
require "opencensus/stats/view_data"

module OpenCensus
  module Stats
    # Stats recorder.
    #
    # Recorder record measurement against measure for registered views.
    class Recorder
      # @private
      # @return [Hash<String,View>] Hash of view name and View object.
      attr_reader :views

      # @private
      # @return [Hash<String,Measure>] Hash of measure name and Measure object.
      attr_reader :measures

      # @private
      # @return [Hash<String,Array<<ViewData>>]
      # Hash of view name and View data objects array.
      attr_reader :measure_views_data

      # @private
      # Create instance of the recorder.
      def initialize
        @views = {}
        @measures = {}
        @measure_views_data = {}
        @time = Time.now.utc
      end

      # Register view
      #
      # @param [View] view
      # @return [View]
      def register_view view
        return if @views.key? view.name

        @views[view.name] = view
        @measures[view.measure.name] = view.measure

        unless @measure_views_data.key? view.measure.name
          @measure_views_data[view.measure.name] = []
        end

        @measure_views_data[view.measure.name] << ViewData.new(
          view,
          start_time: @time,
          end_time: @time
        )
        view
      end

      # Record measurements.
      #
      # @param [Array<Measurement>, Measurement] measurements
      #   A list of measurements to or single measurement.
      #   All passed measurements will be rejected If any one of the measurement
      #  has negative value.
      # @param [Hash<String,String>] attachments The contextual information
      #   associated with an example value. The contextual information is
      #   represented as key, value string pairs.
      def record *measurements, attachments: nil
        return if measurements.any? { |m| m.value < 0 }

        measurements.each do |measurement|
          views_data = @measure_views_data[measurement.measure.name]
          next unless views_data

          views_data.each do |view_data|
            view_data.record measurement, attachments: attachments
          end
        end
      end

      # Get recorded data for given view name
      #
      # @param [String] view_name View name
      # @return [ViewData]
      def view_data view_name
        view = @views[view_name]
        return unless view

        views_data = @measure_views_data[view.measure.name]
        views_data.find { |view_data| view_data.view.name == view.name }
      end

      # Get all views data list
      # @return [Array<ViewData>]
      def views_data
        @measure_views_data.values.flatten
      end

      # Clear recorded stats.
      def clear_stats
        @measure_views_data.each_value do |views_data|
          views_data.each(&:clear)
        end
      end
    end
  end
end