HttpServer plugin helper can not work well with io-stream 0.8 on Windows and Ruby 3.3/3.4/HEAD

[daipom]

Describe the bug

HttpServer plugin helper can not work well with io-stream 0.8 on Windows and Ruby 3.3/3.4.

Currently, CI fails because of this: https://github.com/fluent/fluentd/actions/runs/15821469461/job/44646852748?pr=5008

This change causes this.

https://github.com/socketry/io-stream/pull/5/files#diff-aa450f7b0f2b1c4e53685e572dc8eaf991d7e0c2814d95ed5cd7c48f41e33837R109-R113

I'm not sure yet whether the problem is with Fluentd or async, or with net/http or io-stream.

I'm not sure yet whether it is simply a CI issue or not.

To Reproduce

• Ruby 3.3 or 3.4
• io-stream 0.8

$ bundle exec rake test TESTOPTS="-t'HttpHelperTest'"

Some tests fail as follows:

Error: test: mount frozen path(HttpHelperTest::Create a HTTP server): EOFError: end of file reached
C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:237:in 'Net::BufferedIO#rbuf_fill'
C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:199:in 'Net::BufferedIO#readuntil'
C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:209:in 'Net::BufferedIO#readline'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http/response.rb:158:in 'Net::HTTPResponse.read_status_line'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http/response.rb:147:in 'Net::HTTPResponse.read_new'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2414:in 'block in Net::HTTP#transport_request'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2405:in 'Kernel#catch'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2405:in 'Net::HTTP#transport_request'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2378:in 'Net::HTTP#request'
C:/Users/reang/Documents/work/fluentd/fluentd/test/plugin_helper/test_http_server_helper.rb:75:in 'block (3 levels) in <class:HttpHelperTest>'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:1626:in 'Net::HTTP#start'
C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:1064:in 'Net::HTTP.start'
C:/Users/reang/Documents/work/fluentd/fluentd/test/plugin_helper/test_http_server_helper.rb:74:in 'block (2 levels) in <class:HttpHelperTest>'
C:/Users/reang/Documents/work/fluentd/fluentd/test/plugin_helper/test_http_server_helper.rb:189:in 'block (3 levels) in <class:HttpHelperTest>'
C:/Users/reang/Documents/work/fluentd/fluentd/test/plugin_helper/test_http_server_helper.rb:36:in 'HttpHelperTest#on_driver'
C:/Users/reang/Documents/work/fluentd/fluentd/test/plugin_helper/test_http_server_helper.rb:184:in 'block (2 levels) in <class:HttpHelperTest>'

...

Expected behavior

CI passes.

Your Environment

- Fluentd version: Current master (6821e4bb4b80bf99473541dc6a5779dbc3784c70)
- Package version:
- Operating system: Windows 10 Home
- Kernel version:

Your Configuration

Not related.

Maybe we can reproduce this with the following conf.

<source>
  @type monitor_agent
</source>

Your Error Log

See To Reproduce.

Additional context

No response

[Watson1978]

Reproduce

require 'bundler/inline'
gemfile do
  source 'https://rubygems.org'
#  gem 'io-stream', '= 0.7.0'
  gem 'io-stream', '= 0.8.0'
  gem 'async'
  gem 'async-http'
end

require 'net/http'
require 'uri'

endpoint = Async::HTTP::Endpoint.parse('http://127.0.0.1:8080/hello')

Thread.new do
  Sync do |task|
    Async do
      server = Async::HTTP::Server.for(endpoint) do |request|
        ::Protocol::HTTP::Response[200, {}, ["Hello World"]]
      end

      server.run
    end
  end
end

sleep 1

url = URI.parse("http://127.0.0.1:8080/hello")
req = Net::HTTP::Get.new(url)
Net::HTTP.start(url.host, url.port) do |http|
  puts "-" * 80
  puts "[debug] Requesting #{url}"
  puts http.request(req).body
end

sleep 1

• Result with io-stream v0.8.0

PS C:\src\sandbox\ruby> ruby net.rb
C:/Ruby34-x64/lib/ruby/3.4.0/win32/registry.rb:2: warning: fiddle/import is found in fiddle, which will no longer be part of the default gems starting from Ruby 3.5.0.
You can add fiddle to your Gemfile or gemspec to silence this warning.
--------------------------------------------------------------------------------
[debug] Requesting http://127.0.0.1:8080/hello
  0.0s     warn: Async::Task: Reading HTTP/1.1 requests for Async::HTTP::Protocol::HTTP1::Server. [oid=0x318] [ec=0x320] [pid=9604] [2025-06-24 17:03:08 +0900]
               | Task may have ended with unhandled exception.
               |   Errno::EBADF: Bad file descriptor
               |   → C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO#write'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO::Stream::Buffered#syswrite'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 85:in 'IO::Stream::Writable#drain'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 33:in 'block in IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'Thread::Mutex#synchronize'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 623:in 'Protocol::HTTP1::Connection#write_fixed_length_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 751:in 'Protocol::HTTP1::Connection#write_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 134:in 'block in Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 331:in 'Async::Task#defer_stop'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 81:in 'Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/server.rb 50:in 'Async::HTTP::Server#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-endpoint-0.15.2/lib/io/endpoint/wrapper.rb 216:in 'block (2 levels) in IO::Endpoint::Wrapper#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 201:in 'block in Async::Task#run'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 439:in 'block in Async::Task#schedule'
 0.03s     warn: Async::Task: Reading HTTP/1.1 requests for Async::HTTP::Protocol::HTTP1::Server. [oid=0x328] [ec=0x330] [pid=9604] [2025-06-24 17:03:08 +0900]
               | Task may have ended with unhandled exception.
               |   Errno::EBADF: Bad file descriptor
               |   → C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO#write'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO::Stream::Buffered#syswrite'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 85:in 'IO::Stream::Writable#drain'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 33:in 'block in IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'Thread::Mutex#synchronize'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 623:in 'Protocol::HTTP1::Connection#write_fixed_length_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 751:in 'Protocol::HTTP1::Connection#write_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 134:in 'block in Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 331:in 'Async::Task#defer_stop'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 81:in 'Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/server.rb 50:in 'Async::HTTP::Server#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-endpoint-0.15.2/lib/io/endpoint/wrapper.rb 216:in 'block (2 levels) in IO::Endpoint::Wrapper#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 201:in 'block in Async::Task#run'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 439:in 'block in Async::Task#schedule'
C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:237:in 'Net::BufferedIO#rbuf_fill': end of file reached (EOFError)
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:199:in 'Net::BufferedIO#readuntil'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:209:in 'Net::BufferedIO#readline'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http/response.rb:158:in 'Net::HTTPResponse.read_status_line'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http/response.rb:147:in 'Net::HTTPResponse.read_new'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2414:in 'block in Net::HTTP#transport_request'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2405:in 'Kernel#catch'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2405:in 'Net::HTTP#transport_request'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2378:in 'Net::HTTP#request'
	from net.rb:32:in 'block in <main>'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:1626:in 'Net::HTTP#start'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:1064:in 'Net::HTTP.start'
	from net.rb:29:in '<main>'

it causes error with same net/http stacktrace.

• Result with io-stream v0.7.0

PS C:\src\sandbox\ruby> ruby net.rb
C:/Ruby34-x64/lib/ruby/3.4.0/win32/registry.rb:2: warning: fiddle/import is found in fiddle, which will no longer be part of the default gems starting from Ruby 3.5.0.
You can add fiddle to your Gemfile or gemspec to silence this warning.
--------------------------------------------------------------------------------
[debug] Requesting http://127.0.0.1:8080/hello
Hello World

it works well

So, I think this is io-stream issue.

[Watson1978]

Reported to socketry/io-stream#8

[daipom]

Thanks @Watson1978 !