Class: RequireProfiler::Printer::JSON

Inherits:
CallStack show all
Defined in:
lib/require_profiler/printer/json.rb

Overview

JSON formatter converts call tacks into Speedscope compatible JSON on finish.

Can only be used with rewindable IO.

Instance Method Summary collapse

Methods inherited from CallStack

#flush

Methods inherited from Base

#flush, #initialize

Constructor Details

This class inherits a constructor from RequireProfiler::Printer::Base

Instance Method Details

#finish ⇒ Object 



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# File 'lib/require_profiler/printer/json.rb', line 12

def finish
  output.rewind
  stacks = output.read
  output.rewind

  frames = []
  frame_index = {}

  samples = []
  weights = []

  stacks.each_line do |line|
    line = line.strip
    next if line.empty?

    sep = line.rindex(" ")
    next unless sep

    stack = line[0...sep]
    weight = line[(sep + 1)..].to_f

    sample = stack.split(";").map do |name|
      frame_index[name] ||= begin
        frames << {name: name}
        frames.size - 1
      end
    end

    samples << sample
    weights << weight
  end

  total = weights.sum

  profile = {
    "$schema" => "https://www.speedscope.app/file-format-schema.json",
    :shared => {frames: frames},
    :profiles => [
      {
        type: "sampled",
        unit: "milliseconds",
        startValue: 0,
        endValue: total,
        samples:,
        weights:
      }
    ]
  }

  output.write(::JSON.pretty_generate(profile))
  super
end