Module: Etalon

Defined in:
lib/etalon.rb,
lib/etalon/version.rb

Overview

Etalon is a simple tool to instrument Ruby code and output basic metrics to a logger or store them in a hash.

Constant Summary collapse

VERSION =

:no-doc

"1.0.0"

Class Method Summary collapse

Class Method Details

.activate ⇒ Boolean

Activates Etalon.

Returns:

  • (Boolean) —

    Etalon’s current activation status



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# File 'lib/etalon.rb', line 93

def activate
  !!ENV["ETALON_ACTIVE"] = "true"
end

.active? ⇒ Boolean

Returns whether Etalon is active and recording metrics.

Returns:

  • (Boolean) —

    whether Etalon is active and recording metrics.



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# File 'lib/etalon.rb', line 10

def active?
  # rubocop:disable Style/DoubleNegation
  !!ENV["ETALON_ACTIVE"]
  # rubocop:enable Style/DoubleNegation
end

.deactivate ⇒ Boolean

Deactivates Etalon.

Returns:

  • (Boolean) —

    Etalon’s current activation status



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# File 'lib/etalon.rb', line 101

def deactivate
  !!ENV["ETALON_ACTIVE"] = nil
end

.print_timings ⇒ Hash

Uses either Rails.logger or a Syslog::Logger instance to print out iteration count, minimum, maximum, average and standard deviation timings for each individual call instrumented by #time.

Returns:

  • (Hash) —

    all stored metrics indexed by identifier



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# File 'lib/etalon.rb', line 55

def print_timings
  if active?
    instrument_store.each_with_object({}) do |(key, metrics), memo|
      count, min, max, all = metrics.values_at(:count, :min, :max, :all)
      top = all.sort.reverse.take(5)
      mean = mean(all).floor(2)
      deviation = standard_deviation(all).floor(2)

      title = key.to_s.titleize

      output = [
        "count: #{count}",
        "min: #{min}",
        "max: #{max}",
        "mean: #{mean}",
        "deviation: ±#{deviation}%",
        "top 5: #{top}",
      ]

      logger.debug("#{title} - #{output.join(" | ")}")

      memo[key] = output
    end
  end
end

.reset_timings ⇒ type

Resets Etalon’s internal storage to remove all stored timings.

Returns:

  • (type) —
    description


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# File 'lib/etalon.rb', line 85

def reset_timings
  @instrument_store = nil
end

.time(identifier) ⇒ Object

Runs timing metrics on the supplied block of code and stores those metrics for later logging or analysis using the supplied @identifier.

Parameters:

  • identifier (String) —

    A unique identifier used to store calls to the supplied block and report them later.

Returns:

  • the supplied block’s return value



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# File 'lib/etalon.rb', line 23

def time(identifier)
  if active?
    unless block_given?
      raise "Please supply a block of code for Etalon to instrument"
    end

    start = Time.now

    return_value = yield

    duration = elapsed(start)

    key = key_from(identifier: identifier)
    store = instrument_store_for(key: key)

    store[:count] += 1
    store[:min] = duration if duration < store[:min]
    store[:max] = duration if duration > store[:max]
    store[:all] << duration

    return_value
  else
    yield
  end
end