lint

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_bucket_histogram.rb

@@ -10,14 +10,13 @@
 require_relative 'exponential_histogram/logarithm_mapping'
 require_relative 'exponential_histogram/exponent_mapping'
 
-
 module OpenTelemetry
  module SDK
  module Metrics
  module Aggregation
  # Contains the implementation of the ExponentialBucketHistogram aggregation
  # https://opentelemetry.io/docs/specs/otel/metrics/data-model/#exponentialhistogram
- class ExponentialBucketHistogram
+ class ExponentialBucketHistogram # rubocop:disable Metrics/ClassLength
  attr_reader :aggregation_temporality
 
  # relate to min max scale: https://opentelemetry.io/docs/specs/otel/metrics/sdk/#support-a-minimum-and-maximum-scale
@@ -71,11 +70,10 @@ def collect(start_time, end_time)
  end
  end
 
- # ruby seems only record local min and max
+ # rubocop:disable Metrics/MethodLength, Metrics/CyclomaticComplexity
  def update(amount, attributes)
  # fetch or initialize the ExponentialHistogramDataPoint
  hdp = @data_points.fetch(attributes) do
-
  if @record_min_max
  min = Float::INFINITY
  max = -Float::INFINITY
@@ -95,7 +93,7 @@ def update(amount, attributes)
  nil, # :exemplars
  min, # :min
  max, # :max
- @zero_threshold,  # :zero_threshold)
+ @zero_threshold # :zero_threshold)
  )
  end
 
@@ -123,7 +121,7 @@ def update(amount, attributes)
  is_rescaling_needed = false
  low = high = 0
 
- if buckets.counts.empty?
+ if buckets.counts == [0] # special case of empty
  buckets.index_start = bucket_index
  buckets.index_end = bucket_index
  buckets.index_base = bucket_index
@@ -171,12 +169,13 @@ def update(amount, attributes)
  buckets.index_end = bucket_index
  end
 
- bucket_index = bucket_index - buckets.index_base
+ bucket_index -= buckets.index_base
  bucket_index += buckets.counts.size if bucket_index.negative?
 
  buckets.increment_bucket(bucket_index)
  nil
  end
+ # rubocop:enable Metrics/MethodLength, Metrics/CyclomaticComplexity
 
  private
 
@@ -203,7 +202,7 @@ def get_scale_change(low, high)
 
  def downscale(change, positive, negative)
  return if change == 0
- raise "Invalid change of scale" if change.negative?
+ raise 'Invalid change of scale' if change.negative?
 
  positive.downscale(change)
  negative.downscale(change)

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb

@@ -9,9 +9,9 @@ module SDK
  module Metrics
  module Aggregation
  module ExponentialHistogram
+ # Buckets is the fundamental building block of exponential histogram that store bucket/boundary value
  class Buckets
  attr_accessor :index_start, :index_end, :index_base
- attr_reader :counts
 
  def initialize
  @counts = [0]
@@ -30,7 +30,7 @@ def grow(needed, max_size)
  new_positive_limit = new_size - bias
 
  tmp = Array.new(new_size, 0)
- tmp[new_positive_limit..-1] = @counts[old_positive_limit..-1]
+ tmp[new_positive_limit..-1] = @counts[old_positive_limit..]
  tmp[0...old_positive_limit] = @counts[0...old_positive_limit]
  @counts = tmp
  end
@@ -39,11 +39,11 @@ def offset
  @index_start
  end
 
- def get_offset_counts
+ def offset_counts
  bias = @index_base - @index_start
- @counts[-bias..-1] + @counts[0...-bias]
+ @counts[-bias..] + @counts[0...-bias]
  end
- alias_method :counts, :get_offset_counts
+ alias counts offset_counts
 
  def length
  return 0 if @counts.empty?
@@ -67,7 +67,7 @@ def downscale(amount)
  if bias != 0
  @index_base = @index_start
  @counts.reverse!
- @counts = @counts[0...bias].reverse + @counts[bias..-1].reverse
+ @counts = @counts[0...bias].reverse + @counts[bias..].reverse
  end
 
  size = 1 + @index_end - @index_start
@@ -110,4 +110,3 @@ def increment_bucket(bucket_index, increment = 1)
  end
  end
 end
-

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/exponent_mapping.rb

@@ -9,6 +9,7 @@ module SDK
  module Metrics
  module Aggregation
  module ExponentialHistogram
+ # LogarithmMapping for mapping when scale < 0
  class ExponentMapping
  attr_reader :scale
 
@@ -19,7 +20,6 @@ def initialize(scale)
  end
 
  def map_to_index(value)
-
  return @min_normal_lower_boundary_index if value < IEEE754::MIN_NORMAL_VALUE
 
  exponent = IEEE754.get_ieee_754_exponent(value)

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/ieee_754.rb

@@ -11,6 +11,7 @@ module SDK
  module Metrics
  module Aggregation
  module ExponentialHistogram
+ # IEEE754 standard for floating-point calculation
  module IEEE754
  extend Fiddle::Importer
  dlload Fiddle::Handle::DEFAULT
@@ -19,7 +20,7 @@ module IEEE754
  EXPONENT_WIDTH = 11
 
  MANTISSA_MASK = (1 << MANTISSA_WIDTH) - 1
- EXPONENT_BIAS = (2 ** (EXPONENT_WIDTH - 1)) - 1
+ EXPONENT_BIAS = (2**(EXPONENT_WIDTH - 1)) - 1
  EXPONENT_MASK = ((1 << EXPONENT_WIDTH) - 1) << MANTISSA_WIDTH
  SIGN_MASK = 1 << (EXPONENT_WIDTH + MANTISSA_WIDTH)
 

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/log2e_scale_factor.rb

@@ -9,6 +9,7 @@ module SDK
  module Metrics
  module Aggregation
  module ExponentialHistogram
+ # Log2eScaleFactor is precomputed scale factor value
  class Log2eScaleFactor
  MAX_SCALE = 20
 
@@ -25,4 +26,4 @@ def self.log2e_scale_buckets
  end
  end
  end
-end
+end

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/logarithm_mapping.rb

@@ -9,12 +9,13 @@ module SDK
  module Metrics
  module Aggregation
  module ExponentialHistogram
+ # LogarithmMapping for mapping when scale > 0
  class LogarithmMapping
  attr_reader :scale
 
  def initialize(scale)
  @scale = scale
- @scale_factor = Log2eScaleFactor::LOG2E_SCALE_BUCKETS[scale]  # scale_factor is used for mapping the index
+ @scale_factor = Log2eScaleFactor::LOG2E_SCALE_BUCKETS[scale] # scale_factor is used for mapping the index
  @min_normal_lower_boundary_index = IEEE754::MIN_NORMAL_EXPONENT << @scale
  @max_normal_lower_boundary_index = ((IEEE754::MAX_NORMAL_EXPONENT + 1) << @scale) - 1
  end
@@ -33,12 +34,14 @@ def map_to_index(value)
  def get_lower_boundary(inds)
  if inds >= @max_normal_lower_boundary_index
  return 2 * Math.exp((inds - (1 << @scale)) / @scale_factor) if inds == @max_normal_lower_boundary_index
+
  raise StandardError, 'mapping overflow'
  end
 
  if inds <= @min_normal_lower_boundary_index
  return IEEE754::MIN_NORMAL_VALUE if inds == @min_normal_lower_boundary_index
  return Math.exp((inds + (1 << @scale)) / @scale_factor) / 2 if inds == @min_normal_lower_boundary_index - 1
+
  raise StandardError, 'mapping underflow'
  end
 

metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram_data_point.rb

@@ -8,23 +8,22 @@ module OpenTelemetry
  module SDK
  module Metrics
  module Aggregation
- # TODO: Deal with this later
  # rubocop:disable Lint/StructNewOverride
 
- ExponentialHistogramDataPoint = Struct.new(:attributes,  # optional Hash{String => String, Numeric, Boolean, Array<String, Numeric, Boolean>}
- :start_time_unix_nano, # Integer nanoseconds since Epoch
- :time_unix_nano, # Integer nanoseconds since Epoch
- :count, # Integer count is the number of values in the population. Must be non-negative
- :sum, # Integer sum of the values in the population. If count is zero then this field then this field must be zero
- :scale, # Integer scale factor
- :zero_count, # Integer special bucket that count of observations that fall into the zero bucket
- :positive, # Buckets representing the positive range of the histogram.
- :negative, # Buckets representing the negative range of the histogram.
- :flags, # Integer flags associated with the data point.
- :exemplars, # optional List of exemplars collected from measurements that were used to form the data point
- :min, # optional Float min is the minimum value over (start_time, end_time].
- :max, # optional Float max is the maximum value over (start_time, end_time].
- :zero_threshold) # optional Float the threshold for the zero bucket
+ ExponentialHistogramDataPoint = Struct.new(:attributes, # optional Hash{String => String, Numeric, Boolean, Array<String, Numeric, Boolean>}
+  :start_time_unix_nano, # Integer nanoseconds since Epoch
+  :time_unix_nano, # Integer nanoseconds since Epoch
+  :count, # Integer count is the number of values in the population. Must be non-negative
+  :sum, # Integer sum of the values in the population. If count is zero then this field then this field must be zero
+  :scale, # Integer scale factor
+  :zero_count, # Integer special bucket that count of observations that fall into the zero bucket
+  :positive, # Buckets representing the positive range of the histogram.
+  :negative, # Buckets representing the negative range of the histogram.
+  :flags, # Integer flags associated with the data point.
+  :exemplars, # optional List of exemplars collected from measurements that were used to form the data point
+  :min, # optional Float min is the minimum value over (start_time, end_time].
+  :max, # optional Float max is the maximum value over (start_time, end_time].
+  :zero_threshold) # optional Float the threshold for the zero bucket
  # rubocop:enable Lint/StructNewOverride
  end
  end

metrics_sdk/test/opentelemetry/sdk/metrics/aggregation/exponential_bucket_histogram_test.rb

@@ -30,8 +30,8 @@
  expbh.update(1.23, {})
  expbh.update(0, {})
 
- expbh.update(1.45, {'foo' => 'bar'})
- expbh.update(1.67, {'foo' => 'bar'})
+ expbh.update(1.45, { 'foo' => 'bar' })
+ expbh.update(1.67, { 'foo' => 'bar' })
 
  exphdps = expbh.collect(start_time, end_time)
 
@@ -43,7 +43,7 @@
  _(exphdps[0].max).must_equal(1.23)
  _(exphdps[0].scale).must_equal(5)
  _(exphdps[0].zero_count).must_equal(1)
- _(exphdps[0].positive.counts).must_equal([0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0])
+ _(exphdps[0].positive.counts).must_equal([1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0])
  _(exphdps[0].negative.counts).must_equal([0])
  _(exphdps[0].zero_threshold).must_equal(0)
 
@@ -52,9 +52,9 @@
  _(exphdps[1].sum).must_equal(3.12)
  _(exphdps[1].min).must_equal(1.45)
  _(exphdps[1].max).must_equal(1.67)
- _(exphdps[1].scale).must_equal(4)
+ _(exphdps[1].scale).must_equal(5)
  _(exphdps[1].zero_count).must_equal(0)
- _(exphdps[1].positive.counts).must_equal([0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0])
+ _(exphdps[1].positive.counts).must_equal([1, 0, 0, 0, 0, 0, 1, 0])
  _(exphdps[1].negative.counts).must_equal([0])
  _(exphdps[1].zero_threshold).must_equal(0)
  end
@@ -133,6 +133,122 @@
  _(exphdps[0].zero_threshold).must_equal(0)
  end
 
+ it 'test_permutations' do
+ test_cases = [
+ [
+ [0.5, 1.0, 2.0],
+ {
+ scale: -1,
+ offset: -1,
+ len: 2,
+ at_zero: 2,
+ at_one: 1
+ }
+ ],
+ [
+ [1.0, 2.0, 4.0],
+ {
+ scale: -1,
+ offset: -1,
+ len: 2,
+ at_zero: 1,
+ at_one: 2
+ }
+ ],
+ [
+ [0.25, 0.5, 1.0],
+ {
+ scale: -1,
+ offset: -2,
+ len: 2,
+ at_zero: 1,
+ at_one: 2
+ }
+ ]
+ ]
+
+ test_cases.each do |test_values, expected|
+ test_values.permutation.each do |permutation|
+ expbh = OpenTelemetry::SDK::Metrics::Aggregation::ExponentialBucketHistogram.new(
+ aggregation_temporality: aggregation_temporality,
+ record_min_max: record_min_max,
+ max_size: 2,
+ max_scale: 20, # use default value of max scale; should downscale to 0
+ zero_threshold: 0
+ )
+
+ permutation.each do |value|
+ expbh.update(value, {})
+ end
+
+ exphdps = expbh.collect(start_time, end_time)
+
+ assert_equal expected[:scale], exphdps[0].scale
+ assert_equal expected[:offset], exphdps[0].positive.offset
+ assert_equal expected[:len], exphdps[0].positive.length
+ assert_equal expected[:at_zero], exphdps[0].positive.counts[0]
+ assert_equal expected[:at_one], exphdps[0].positive.counts[1]
+ end
+ end
+ end
+
+ it 'test_full_range' do
+ expbh = OpenTelemetry::SDK::Metrics::Aggregation::ExponentialBucketHistogram.new(
+ aggregation_temporality: aggregation_temporality,
+ record_min_max: record_min_max,
+ max_size: 2,
+ max_scale: 20, # use default value of max scale; should downscale to 0
+ zero_threshold: 0
+ )
+
+ expbh.update(Float::MAX, {})
+ expbh.update(1, {})
+ expbh.update(2**-1074, {})
+
+ exphdps = expbh.collect(start_time, end_time)
+
+ assert_equal Float::MAX, exphdps[0].sum
+ assert_equal 3, exphdps[0].count
+ assert_equal(-10, exphdps[0].scale)
+
+ assert_equal 2, exphdps[0].positive.length
+ assert_equal(-1, exphdps[0].positive.offset)
+ assert_operator exphdps[0].positive.counts[0], :<=, 2
+ assert_operator exphdps[0].positive.counts[1], :<=, 1
+ end
+
+ it 'test_aggregator_min_max' do
+ expbh = OpenTelemetry::SDK::Metrics::Aggregation::ExponentialBucketHistogram.new(
+ aggregation_temporality: aggregation_temporality,
+ record_min_max: record_min_max,
+ zero_threshold: 0
+ )
+
+ [1, 3, 5, 7, 9].each do |value|
+ expbh.update(value, {})
+ end
+
+ exphdps = expbh.collect(start_time, end_time)
+
+ assert_equal 1, exphdps[0].min
+ assert_equal 9, exphdps[0].max
+
+ expbh = OpenTelemetry::SDK::Metrics::Aggregation::ExponentialBucketHistogram.new(
+ aggregation_temporality: aggregation_temporality,
+ record_min_max: record_min_max,
+ zero_threshold: 0
+ )
+
+ [-1, -3, -5, -7, -9].each do |value|
+ expbh.update(value, {})
+ end
+
+ exphdps = expbh.collect(start_time, end_time)
+
+ assert_equal(-9, exphdps[0].min)
+ assert_equal(-1, exphdps[0].max)
+ end
+
  it 'test_merge' do
  # TODO
  end