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Celluloid::IO-based web server

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Build Status

Reel is a fast, non-blocking "evented" web server built on http_parser.rb and Celluloid::IO. It's probably most similar to Goliath, but thanks to Celluloid can be easily composed with multithreaded applications.

Connections to Reel can be either non-blocking and handled entirely within the Reel::Server thread, or the same connections can be dispatched to worker threads where they will perform ordinary blocking IO. Reel provides no built-in thread pool, however you can build one yourself using Celluloid::Pool, or because Celluloid already pools threads to begin with, you can simply use an actor per connection.

This gives you the best of both worlds: non-blocking I/O for when you're primarily I/O bound, and threads for where you're compute bound.

Is It Good?

Yes, but it has room for improvement. A "hello world" web server benchmark, done on a 2GHz i7 w\ ApacheBench, 64 concurrent connections:

Reel    (HEAD)        5189 reqs/s (6.1 ms/req)
Goliath (0.9.4)       3495 reqs/s (18.3 ms/req)
Thin    (1.2.11)      8747 reqs/s (7.3 ms/req)
Node.js (0.6.5)       9023 reqs/s (7.1 ms/req)

All Ruby benchmarks done on Ruby 1.9.3. Means given are average-per-request and are not amortized across all concurrent requests.


Reel provides an extremely simple API:

require 'reel'

Reel::Server.supervise("", 3000) do |connection|
  request = connection.request
  puts "Client requested: #{request.method} #{request.url}"
  connection.respond :ok, "hello, world"


Reel is mostly in the proof of concept stage, working well enough you can point your favorite benchmarking utility at it, but not exactly speaking valid HTTP yet.


  • Fork this repository on github
  • Make your changes and send me a pull request
  • If I like them I'll merge them
  • If I've accepted a patch, feel free to ask for commit access


Copyright (c) 2012 Tony Arcieri. Distributed under the MIT License. See LICENSE.txt for further details.

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