Async HTTP Server does not respond on Windows if cool.io gem is loaded

[Watson1978]

I'm trying to update the async gem from v1.x to v2.x, which async-http gem depends on.
fluent/fluentd#3842

Then, I found a problem that Async HTTP Server stops responding If I use the async gem and cool.io gem under Windows.
It works well under Linux and macOS even if I use them.

Curiously, if I removed https://github.com/socketry/cool.io/blame/2735948698687b087f31c0e0056078dbf6d73a7f/ext/iobuffer/iobuffer.c#L104 line from cool.io gem, then Async HTTP server works.

Looks for me that async will change the behavior at https://github.com/socketry/async/blob/10fa816bb229d4df3433d337ded3421b43d161fe/lib/async/scheduler.rb#L253-L266 if cool.io is loaded.

Environment

• Windows 11
• Ruby 3.3.4
• async 2.16.1
• async-http 0.71.0
• cool.io 1.8.1

Reproduce code

require 'bundler/inline'
gemfile do
  source 'https://rubygems.org'
  gem 'async-http'
  gem 'cool.io' # A problem is occurred if cool.io gem is loaded
end

require 'net/http'
require 'async/http/protocol'
require 'timeout'

module HttpServer
  class Router
    def initialize
      @router = { get: {} }
    end

    def mount(method, path, app)
      @router[method][path] = app
    end

    def route!(method, path, request)
      @router.fetch(method).fetch(path).call(request)
    end
  end

  class Server
    class App
      def initialize(router)
        @router = router
      end

      def call(request)
        method = request.method
        resp = get(request)

        Protocol::HTTP::Response[*resp]
      rescue => e
        Protocol::HTTP::Response[500, { 'Content-Type' => 'text/plain' }, 'Internal Server Error']
      end

      def get(request)
        @router.route!(:get, request.path, request)
      end
    end

    def initialize(addr:, port:, tls_context: nil)
      @uri = URI("http://#{addr}:#{port}").to_s
      @router = Router.new
      @server_task = nil

      @server = Async::HTTP::Server.new(App.new(@router), Async::HTTP::Endpoint.parse(@uri))
    end

    def start
      Async do |task|
        @server_task = task.async do
          @server.run
        end
      end
    end

    def stop
      @server_task&.stop
    end

    def get(path, app = nil, &block)
      @router.mount(:get, path, app || block)
    end
  end
end


def http_server_start(addr:, port:)
  server = HttpServer::Server.new(addr: addr, port: port)
  server.get('/api/plugins.json') { |req| [200, { 'Content-Type' => 'text/html' }, "Hello"] }

  Thread.new do
    server.start
  end

  sleep 1 # Wait until the server starts up.
end

#################################################

puts "[http server start]"
http_server_start(addr: "127.0.0.1", port: "8080")

puts "-" * 80
puts "[client request]"

Timeout.timeout(10) {
  p Net::HTTP.get(URI.parse("http://127.0.0.1:8080/api/plugins.json"))
}

Result on Windows

C:\tmp> ruby .\async-http.rb
[http server start]
--------------------------------------------------------------------------------
[client request]
C:/Ruby33-x64/lib/ruby/3.3.0/timeout.rb:43:in `rescue in handle_timeout': execution expired (Timeout::Error)
        from C:/Ruby33-x64/lib/ruby/3.3.0/timeout.rb:40:in `handle_timeout'
        from C:/Ruby33-x64/lib/ruby/3.3.0/timeout.rb:195:in `timeout'
        from ./async-http.rb:93:in `<main>'
C:/Ruby33-x64/lib/ruby/3.3.0/net/protocol.rb:229:in `wait_readable': execution expired (Timeout::ExitException)
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/protocol.rb:229:in `rbuf_fill'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/protocol.rb:199:in `readuntil'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/protocol.rb:209:in `readline'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http/response.rb:158:in `read_status_line'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http/response.rb:147:in `read_new'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:2342:in `block in transport_request'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:2333:in `catch'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:2333:in `transport_request'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:2306:in `request'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:2177:in `request_get'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:824:in `block in get_response'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:1570:in `start'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:1029:in `start'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:822:in `get_response'
        from C:/Ruby33-x64/lib/ruby/3.3.0/net/http.rb:803:in `get'
        from ./async-http.rb:94:in `block in <main>'
        from C:/Ruby33-x64/lib/ruby/3.3.0/timeout.rb:186:in `block in timeout'
        from C:/Ruby33-x64/lib/ruby/3.3.0/timeout.rb:41:in `handle_timeout'
        from C:/Ruby33-x64/lib/ruby/3.3.0/timeout.rb:195:in `timeout'
        from ./async-http.rb:93:in `<main>'

It got a timeout error because Async HTTP Server does not return any response.

Can you have any idea to solve this issue?

[ioquatix]

It looks like cool.io is unlikely to be compatible with Ruby 3.1+ as it introduces a class IO::Buffer which conflicts with Ruby's IO::Buffer (introduced in 3.1).

Unfortunately, cool.io should be considered legacy/deprecated and removed/replaced.

[Watson1978]

Thank you for quick reply.
OK, I see...
We have to plan to replace cool.io or something....