leak.rb

# Minimal example that demonstrates a memory leak in Celluloid.
# Adapted from @debrasetton example: https://github.com/mperham/sidekiq/issues/2107
# Adapted from @grosser example: https://github.com/mperham/sidekiq/blob/master/examples/leak.rb

# Run with LEAK=0 for no memory leak or LEAK=1 for memory leak, like so:
# LEAK=1 ruby ./leak.rb > /dev/null
require 'celluloid/autostart'
Celluloid.logger = nil
$counter = 0
$jobs = 5_000

class MyWorker
  include Celluloid

  def perform
    report_memory
    check_done

    # Normally, we'd perform some work here:
    # ...

    # Now, assume that the something went wrong for whatever reason and
    # we'd like to retry the job.

    if ENV['LEAK'].to_i == 1
      # If the error is raised using this line, it will cause a memory leak.
      raise Exception.new("Exception - Job failed for some reason")
    else
      # On the other hand, if this line is used, memory usage remains ok.
      raise "RuntimeError - Job failed for some reason"
    end
  end

  def report_memory
    $counter += 1
    if $counter % 100 == 0
      GC.start
      memory = `ps -o rss -p #{Process.pid}`.chomp.split("\n").last.to_i
      $stderr.puts "#{$counter.to_s.ljust(5)} - Memory usage: #{memory}"
    end
  end

  def check_done
    if $counter > $jobs
      exit
    end
  end
end

pool = MyWorker.pool

# Enqueue jobs
$jobs.times { pool.async.perform }

while pool.busy_size > 0
  sleep(1)
end

output

 LEAK=0 bundle exec ruby ./script.rb > /dev/null
100   - Memory usage: 25388
200   - Memory usage: 25672
302   - Memory usage: 25704
402   - Memory usage: 25704
502   - Memory usage: 25740
602   - Memory usage: 25984
702   - Memory usage: 26112
801   - Memory usage: 26144
901   - Memory usage: 26136
1000  - Memory usage: 26320
1101  - Memory usage: 26312
1201  - Memory usage: 26312
1301  - Memory usage: 26312
1400  - Memory usage: 26312
1502  - Memory usage: 26320
1602  - Memory usage: 26320
1702  - Memory usage: 26312
1802  - Memory usage: 26312
1902  - Memory usage: 26312
2003  - Memory usage: 26356
2102  - Memory usage: 26388
2200  - Memory usage: 26396
2302  - Memory usage: 26404
2400  - Memory usage: 26412
2500  - Memory usage: 26412
2600  - Memory usage: 26412
2701  - Memory usage: 26432
2802  - Memory usage: 26432
2902  - Memory usage: 26468
3002  - Memory usage: 26460
3101  - Memory usage: 26460
3202  - Memory usage: 26512
3300  - Memory usage: 26512
3402  - Memory usage: 26512
3501  - Memory usage: 26512
3601  - Memory usage: 26520
3702  - Memory usage: 26512
3800  - Memory usage: 26520
3903  - Memory usage: 26520
4001  - Memory usage: 26640
4102  - Memory usage: 26632
4202  - Memory usage: 26640
4303  - Memory usage: 26640
4400  - Memory usage: 26640
4503  - Memory usage: 26640
4600  - Memory usage: 26640
4701  - Memory usage: 26640
4801  - Memory usage: 26632
4904  - Memory usage: 26632
5000  - Memory usage: 26632






LEAK=1 bundle exec ruby ./script.rb > /dev/null
102   - Memory usage: 28120
200   - Memory usage: 33864
302   - Memory usage: 39700
401   - Memory usage: 45352
503   - Memory usage: 51440
600   - Memory usage: 56876
700   - Memory usage: 62920
802   - Memory usage: 68732
901   - Memory usage: 74736
1000  - Memory usage: 80360
1100  - Memory usage: 86220
1201  - Memory usage: 92096
1301  - Memory usage: 97892
1402  - Memory usage: 103660
1502  - Memory usage: 109512
1600  - Memory usage: 114952
1702  - Memory usage: 121052
1801  - Memory usage: 127256
1901  - Memory usage: 132868
2000  - Memory usage: 138472
2101  - Memory usage: 144476
2202  - Memory usage: 150176
2301  - Memory usage: 155796
2400  - Memory usage: 161428
2502  - Memory usage: 167448
2600  - Memory usage: 172836
2701  - Memory usage: 178804
2803  - Memory usage: 184696
2902  - Memory usage: 190484
3002  - Memory usage: 196080
3101  - Memory usage: 201980
3202  - Memory usage: 207812
3300  - Memory usage: 213228
3401  - Memory usage: 219296
3500  - Memory usage: 224936
3600  - Memory usage: 230856
3701  - Memory usage: 237540
3802  - Memory usage: 243492
3900  - Memory usage: 249012
4002  - Memory usage: 255104
4100  - Memory usage: 260792
4201  - Memory usage: 266544
4302  - Memory usage: 272428
4401  - Memory usage: 277904
4502  - Memory usage: 284144
4602  - Memory usage: 289648
4703  - Memory usage: 295508
4801  - Memory usage: 301120
4902  - Memory usage: 307012
5000  - Memory usage: 312684