Feature #20935: API for Globally Enabling/Disabling Happy Eyeballs Version 2 in the Socket Class

• Status: Closed
• Assignee: -
• Target version: -

[shioimm (Misaki Shioi)]

When introducing Happy Eyeballs Version 2 to Socket.tcp (https://bugs.ruby-lang.org/issues/20108), it was pointed out that there should be a way to disable this feature (https://bugs.ruby-lang.org/issues/20108#note-7).

To address this, I added fast_fallback: true or false keyword argument to both Socket.tcp and TCPSocket.new.
Additionally, I introduced two singleton methods to the Socket class: tcp_fast_fallback= and tcp_fast_fallback.

These can be used as follows:

Socket.tcp(host, port, fast_fallback: true)
TCPSocket.new(host, port, fast_fallback: true)

# Globally controlling HEv2
Socket.tcp_fast_fallback = true # => true
Socket.tcp_fast_fallback # => true

I apologize for this after the implementation, but I would like to discuss whether adding these APIs is appropriate.

[mame (Yusuke Endoh)]

@matz (Yukihiro Matsumoto) approved the new API, and also wanted a configuration to stop happy eyeballs by an environment variable: RUBY_TCP_NO_FAST_FALLBACK=1.

[shioimm (Misaki Shioi)]

• Status changed from Open to Closed

New environment variables added in this PR https://github.com/ruby/ruby/pull/12257 .