tokoroten

tokoroten is one of the approach to use multiple processes in Crystal.

spawn is a good feature for executing light tasks concurrently.

For heavy tasks, tokoroten has an advantage compared to spawn.

See the below Performance evaluation.

Performance evaluation

Compare the execution time of spawn and tokoroten By using sample/benchmark.cr.

In this example, tokoroten uses 4 processes.

Start benchmarking...

----- Tokoroten
=> 2.822[sec]

----- `spawn`
=> 10.704[sec]

tokoroten is about 4.0x faster than spawn

Installation

Add this to your application's shard.yml:

dependencies:
  tokoroten:
    github: tbrand/tokoroten

Usage

Requirement

require "tokoroten"

Define woker

class MyWorker < Tokoroten::Worker
  def task(message : String)
    #
    # Write your task using the `message`.
    # In this sample, just return a message with "-ok" prefix.
    # Use `response` when you create responses.
    #
    response("#{message}-ok")
  end
end

Execute workers

# Create 4 workers. (Using 4 processes)
workers = MyWorker.create(4)

# Execute each worker
workers.each_with_index do |w, i|
  w.exec(i.to_s)
end

# Join every workers (Syncronize point)
workers.each do |w|
  #
  # Receive result from a worker
  # The below `r` will be "0-ok", "1-ok"...
  #
  r = w.receive.try &.to_s || ""
end

# Clean up workers
workers.each do |w|
  w.kill
end

Current restriction

Currently, communication between main process and worker processes are done by String.

So you can not pass arbitrary objects directly. (have to convert to string and re-convert from it.)

JSON serialization is one of the way to pass the objects.

# main process => worker process
worker.exec(my_obj.to_json)

# worker process => main process
MyObj.from_json(worker.receive.to_s)

Contributing

1. Fork it ( https://github.com/tbrand/tokoroten/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• tbrand Taichiro Suzuki - creator, maintainer