diff_heaps.rb

require 'set'
require 'json'

if ARGV.length != 2
  puts 'Usage diff_heaps [ORIG.json] [AFTER.json]'
  exit 1
end

origs = Set.new

File.open(ARGV[0], 'r').each_line do |line|
  parsed = JSON.parse(line)
  origs << parsed['address'] if parsed && parsed['address']
end

diff = []

File.open(ARGV[1], 'r').each_line do |line|
  parsed = JSON.parse(line)

  if parsed && parsed['address']
    diff << parsed unless origs.include? parsed['address']
  end
end

#diff.select{|d|
  #d['file'] =~ /template/ &&
    #d['type'] == 'STRING' &&
    #d['value'] =~ /j____com_posts_shared__featured_html_erb/
#}.each do |d|
  #puts d['value']
#end

diff = diff.select {|d| d['file'] =~ /template/}
diff.group_by do |x|
  [x['type'], x['file'], x['line']]
end.map { |x,y|
  [x, y.count]
}.sort { |a,b|
  b[1] <=> a[1]
}.each {|x,y|
  if y >= 5
    puts "Leaked #{y} #{x[0]} objects at: #{x[1]}:#{x[2]}"
  end
}

dump_heaps.rake

task :one_request => :environment do
  s = ActionDispatch::Integration::Session.new(Rails.application)
  3.times { s.get('/')}
end

task :heaps => :environment do
  s = ActionDispatch::Integration::Session.new(Rails.application)
  s.get('/')
  if s.response.body =~ /ActionView::Template::Error/
    puts 'Whoops, that resulted in an error'
    raise
  else
    puts 'Sending 100 requests'
    100.times { s.get('/') }
    puts 'Dumping heap 1'
    dump_stuff('1')

    puts 'Sending 100 more requests'
    100.times { s.get('/') }
    puts 'Dumping heap 2'
    dump_stuff('2')
  end
end

def dump_stuff(id)
  Thread.new {
    require "objspace";
    ObjectSpace.trace_object_allocations_start;
    GC.start(full_mark: true);
    ObjectSpace.dump_all(output: File.open("heap#{id}.json", 'w'))
  }.join
end