Class: TimeBasedHistogram

Inherits:
TimeBasedChart show all
Includes:
GroupableIssueChart, PercentileValidation
Defined in:
lib/jirametrics/time_based_histogram.rb

Constant Summary

Constants inherited from TimeBasedChart

TimeBasedChart::VALUE_AXIS_LABELS

Constants inherited from ChartBase

ChartBase::LABEL_POSITIONS, ChartBase::OKABE_ITO_PALETTE

Instance Attribute Summary collapse

Attributes included from GroupableIssueChart

#group_by_block, #issue_hints, #issue_periods

Attributes inherited from ChartBase

#aggregated_project, #all_boards, #atlassian_document_format, #board_id, #canvas_height, #canvas_width, #color_palette, #data_quality, #date_range, #file_system, #fix_versions, #holiday_dates, #issues, #settings, #time_range, #timezone_offset, #x_axis_title, #y_axis_title

Instance Method Summary collapse

Methods included from PercentileValidation

validate_percentile, validate_percentiles

Methods included from GroupableIssueChart

#accumulate_issue_for_group, #group_issues, #grouping_rules, #init_configuration_block, #reconcile_percentiles

Methods inherited from TimeBasedChart

#cycletime_unit, #duration_in_unit, #label_cycletime

Methods inherited from ChartBase

#aggregated_project?, #before_run, #call_before_run, #canvas, #canvas_responsive?, #chart_format, #collapsible_issues_panel, #color_block, #color_for, #comma_and, #completed_issues_in_range, #current_board, #cycletime, #cycletime_for_issue, #daily_chart_dataset, #date_annotation, #describe_non_working_days, #description_text, #format_integer, #format_status, #header_text, #holidays, #html_directory, #icon_span, #link_to_issue, #next_id, #next_palette_color, #non_working_day?, #normalize_annotation_datetime, #not_visible_icon, #not_visible_text, #ordinal, #percentile_of, #render, #render_axis_title, #render_top_text, #resolve_status, #stagger_label_positions, #status_category_color, #to_human_readable, #working_days_annotation, #wrap_and_render

Constructor Details

#initialize ⇒ TimeBasedHistogram

Returns a new instance of TimeBasedHistogram.



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# File 'lib/jirametrics/time_based_histogram.rb', line 13

def initialize
  super

  percentiles [50, 85, 98]
  @show_stats = true
end

Instance Attribute Details

#show_stats ⇒ Object (readonly)

Returns the value of attribute show_stats.



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# File 'lib/jirametrics/time_based_histogram.rb', line 11

def show_stats
  @show_stats
end

Instance Method Details

#any_empty_stats?(the_stats) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jirametrics/time_based_histogram.rb', line 107

def any_empty_stats? the_stats
  the_stats.any? { |_label, stats| stats.empty? }
end

#average_for(histogram_data, total_values) ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 125

def average_for histogram_data, total_values
  return 0 if total_values.zero?

  weighted_sum = histogram_data.reduce(0) { |sum, (value, frequency)| sum + (value * frequency) }
  weighted_sum.to_f / total_values
end

#data_set_for(histogram_data:, label:, color:) ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 156

def data_set_for histogram_data:, label:, color:
  {
    type: 'bar',
    label: label,
    data: histogram_data.keys.sort.filter_map do |days|
      items = histogram_data[days]
      next if items.empty?

      {
        x: days,
        y: items.size,
        title: [title_for_item(count: items.size, value: days)] +
          sort_items(items).collect do |item|
            hint = @issue_hints&.fetch(item, nil)
            label_for_item(item, hint: hint)
          end
      }
    end,
    backgroundColor: color,
    borderRadius: 0
  }
end

#disable_stats ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 33

def disable_stats
  @show_stats = false
end

#histogram_data_for(items:) ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 88

def histogram_data_for items:
  items_hash = {}
  items.each do |item|
    days = value_for_item item
    (items_hash[days] ||= []) << item if days.positive?
  end
  items_hash
end

#label_for_item(item, hint:) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/jirametrics/time_based_histogram.rb', line 152

def label_for_item item, hint:
  raise NotImplementedError, "#{self.class} must implement label_for_item"
end

#modes_for(histogram_data) ⇒ Object

Every value that ties for the highest frequency, so a flat or multi-modal distribution returns them all.



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# File 'lib/jirametrics/time_based_histogram.rb', line 133

def modes_for histogram_data
  sorted_by_frequency = histogram_data.sort_by { |_value, frequency| frequency }
  max_frequency = sorted_by_frequency[-1][1]
  sorted_by_frequency.select { |_value, frequency| frequency == max_frequency }.collect(&:first).sort
end

#percentile_explanation(percentile) ⇒ Object

What a given percentile is actually good for. These used to be a hardcoded list describing the 50th, 85th and 98th, sitting underneath a table whose columns follow the configuration, so the two drifted apart the moment anyone changed the setting. Bands rather than exact values, because 90 deserves an answer just as much as 85 does.



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# File 'lib/jirametrics/time_based_histogram.rb', line 41

def percentile_explanation percentile
  case percentile
  when 0..49
    'below the median, so half or more of your work takes longer than this. Useful for ' \
      'understanding your faster cases, but not a number to plan around.'
  when 50
    'also known as the <b>Median</b>. Useful to establish short feedback loops, to monitor ' \
      "that it's not drifting to the right."
  when 51..94
    'useful to establish service level expectations, accounting for rare events.'
  else
    'useful to gauge worst case expectations.'
  end
end

#percentiles(list = nil) ⇒ Object

Which percentiles to show as columns in the statistics table. An empty list drops the columns entirely. Values are validated here rather than at use, because they feed the percentile arithmetic and the table headers, where a bad one produces a wrong chart instead of an error.



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# File 'lib/jirametrics/time_based_histogram.rb', line 28

def percentiles list = nil
  @percentiles = validate_percentiles(list) unless list.nil?
  @percentiles
end

#percentiles_for(histogram_data, percentiles, _total_values) ⇒ Object

The data arrives as value => count. Expanded back to a flat list so that the one shared percentile implementation is used here too: this chart and the scatterplot must not report different answers for the same percentile of the same data. Chart sized data makes the expansion cheap.



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# File 'lib/jirametrics/time_based_histogram.rb', line 143

def percentiles_for histogram_data, percentiles, _total_values
  values = histogram_data.flat_map { |value, count| Array.new(count, value) }
  percentiles.to_h { |percentile| [percentile, percentile_of(values, percentile)] }
end

#run ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 56

def run
  histogram_items = all_items
  rules_to_items = group_issues histogram_items

  the_stats = {}

  overall_histogram = histogram_data_for(items: histogram_items).transform_values(&:size)
  the_stats[:all] = stats_for histogram_data: overall_histogram, percentiles: @percentiles
  data_sets = rules_to_items.keys.collect do |rules|
    the_label = rules.label
    the_histogram = histogram_data_for(items: rules_to_items[rules])
    if @show_stats
      the_stats[the_label] = stats_for(
        histogram_data: the_histogram.transform_values(&:size), percentiles: @percentiles
      )
    end

    data_set_for(
      histogram_data: the_histogram,
      label: the_label,
      color: rules.color
    )
  end

  if data_sets.empty?
    return "<h1 class='foldable'>#{@header_text}</h1>" \
           '<div>No data matched the selected criteria. Nothing to show.</div>'
  end

  wrap_and_render(binding, __FILE__)
end

#sort_items(items) ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 148

def sort_items items
  items
end

#stats_cell(value) ⇒ Object

One cell of the statistics table. A group can survive grouping and still have nothing to plot, when every item in it was excluded for having no measurable cycle time, and then there are no statistics to show for it at all. Dashing the cells keeps the group visible: dropping the row would make it look like the group had never existed.



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# File 'lib/jirametrics/time_based_histogram.rb', line 101

def stats_cell value
  return '&ndash;' if value.nil?

  block_given? ? yield(value) : value
end

#stats_for(histogram_data:, percentiles:) ⇒ Object 



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# File 'lib/jirametrics/time_based_histogram.rb', line 111

def stats_for histogram_data:, percentiles:
  return {} if histogram_data.empty?

  total_values = histogram_data.values.sum
  min, max = histogram_data.keys.minmax
  {
    average: average_for(histogram_data, total_values),
    mode: modes_for(histogram_data),
    min: min,
    max: max,
    percentiles: percentiles_for(histogram_data, percentiles, total_values)
  }
end

#value_axis_title=(title) ⇒ Object

On a histogram the cycle time is plotted along the x-axis (count is on the y-axis).



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# File 'lib/jirametrics/time_based_histogram.rb', line 21

def value_axis_title= title
  @x_axis_title = title
end