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fiber_scheduler_socket_server

⚡ High-Concurrency Socket Server with Fiber Scheduler​

Ruby 3 introduces a global scheduler API to integrate blocking I/O into fibers transparently. You can write synchronous‐style socket code while scaling to millions of connections.

require 'socket'
require 'fiber'

# Install an EventMachine‐like reactor
require 'io/wait'
Fiber.set_scheduler(->(fiber, io, event) do
  io.public_send("wait_#{event}")
  fiber.transfer
end)

def handle(client)
  # This appears blocking but uses Fiber scheduler under the hood
  while data = client.gets
    client.write "Echo: ".upcase
  end
  client.close
end

server = TCPServer.new('0.0.0.0', 12345)

loop do
  sock = server.accept
  Fiber.schedule { handle(sock) }
end

# Keep the main fiber alive
Fiber.current.resume

Advanced notes:

  • The scheduler converts io.wait_readable/io.wait_writable into fiber suspensions.
  • You can layer any event library (e.g., libev or nio4r) by supplying a custom scheduler.
  • Monitor file descriptors and timers for timeouts and cancellation via Fiber.schedule.
  • Ideal for building microservices that require massive concurrency with minimal threading overhead.