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Replace Timeout.timeout with TCPSocket.open(open_timeout:) when available #224

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Replace Timeout.timeout with TCPSocket.open(open_timeout:) when available #224

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728eb8f
Replace Timeout.timeout with TCPSocket.open(open_timeout:) when avail…
osyoyu Jul 16, 2025
09bf573
Ruby 2 compat
osyoyu Jul 22, 2025
06d982f
Remember if TCPSocket impl supports open_timeout
osyoyu Nov 6, 2025
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22 changes: 15 additions & 7 deletions lib/net/http.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -1654,14 +1654,22 @@ def connect
end

debug "opening connection to #{conn_addr}:#{conn_port}..."
s = Timeout.timeout(@open_timeout, Net::OpenTimeout) {
begin
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
rescue => e
raise e, "Failed to open TCP connection to " +
"#{conn_addr}:#{conn_port} (#{e.message})"
begin
s = begin
# Use built-in timeout in TCPSocket.open if available
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port, open_timeout: @open_timeout)
rescue ArgumentError => e
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@osyoyu osyoyu Jul 19, 2025

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I couldn't come up with a better way to detect the absence of open_timeout: option. Is this a acceptable solution?

TCPSocket.open is basically (**args) from the perspective of Ruby, so Method#parameters wasn't an option:

irb(main):001> require 'socket'
=> true
irb(main):002> TCPSocket.method(:open).parameters
=> [[:rest]]

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@deivid-rodriguez deivid-rodriguez Jul 29, 2025

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I think it's fine, given this is only to keep things working for very old rubies, right, and the error message is not going to change for those rubies anyways.

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@osyoyu osyoyu Jul 29, 2025

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Actually it's not only very old Rubies, but even 3.4 raises on a TCPSocket.open call with open_timeout. It is true that the situation is different in Ruby 2.x, where keyword arguments were not a argument of its own kind (workaround in 09bf573).

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@deivid-rodriguez deivid-rodriguez Jul 29, 2025

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Oh, I thought your question was specifically for the Ruby 2.x workaround, since you need to parse a very generic error message, but I see how the detection for Ruby 3.4 is also brittle since it also involves parsing the error message, even if more specific. Unfortunately, I don't know of a better way, but I'd say this way is acceptable.

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@mohamedhafez mohamedhafez Aug 9, 2025

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Considering that every single new HTTP request is going to go through this raise/rescue flow on ruby < 3.5, and that exceptions are kind of expensive, personally I think a better option is just to have test for RUBY_VERSION.to_f < 3.5 directly to see if we use the old Timeout.timeout. I get that testing version numbers directly is a bit distasteful, but when there's actual performance issues and brittleness issues on the line... I'd say its merited

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@osyoyu osyoyu Nov 6, 2025

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I've took @eregon's idea. Pushed in 06d982f. (thanks: @niku)

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@mohamedhafez mohamedhafez Nov 6, 2025

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Regarding 06d982f:

Since it's going to affect all instances of this class, can you make it a class variable, i.e. @@tcpsocket_supports_open_timeout? My code for example makes tons of new instances of this class, and it would be great if they didn't all have to individually figure out that they couldn't use open_timeout.

We wouldn't need any synchronization for a @@tcpsocket_supports_open_timeout I believe: the worst that would happen is a different thread might read an old value and try to use open_timeout again unnecessarily. Writing a boolean value should be atomic on all Rubies as well since it's going to be just a byte, and can never be in a state where it's partially written... right @eregon?

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@mohamedhafez mohamedhafez Nov 6, 2025 •
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ah Christ. Ractors. Yeah nevermind my suggestion above won't work any more, since it would make it so instances of Net::HTTP wouldn't work inside anything but the main Ractor.

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@osyoyu osyoyu Nov 6, 2025

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Yes, that’s exactly right. Using class variables would unfortunately kill Ractors.

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@mohamedhafez mohamedhafez Nov 6, 2025 •
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In that case I'd still argue that simply testing RUBY_VERSION.to_f >= 3.5 is the more straightforward and efficient way to do it - to address @eregon's arguments: Regarding alternative Rubies, I'd say its their responsibility to implement Ruby 3.5 functionality before advertising compatibility with it in RUBY_VERSION (unless there's some reason why open_timeout specifically would be difficult to implemented in Java?). And in the unlikely case that open_timeout is removed in a future Ruby version, well then an update to this library would be necessary, which is to be expected when behavior is deprecated/removed, and isn't something we usually guard against no? Things would get pretty messy if we did that all over the place.

Just my two cents, and yeah an exception raised on first use of every Net::HTTP instance probably isn't a performance hit we need to be debating a ton. I'll just be happy either way if this hopefully gets merged, and i appreciate the work!! 🙏

raise if !(e.message.include?('unknown keyword: :open_timeout') || e.message.include?('wrong number of arguments (given 5, expected 2..4)'))
# Fallback to Timeout.timeout if TCPSocket.open does not support open_timeout
Timeout.timeout(@open_timeout, Net::OpenTimeout) {
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
}
end
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@niku niku Oct 24, 2025

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Based on @eregon's idea(https://github.com/ruby/net-http/pull/224/files#r2411676663) , I wrote this code.
It's a little verbose, but I feel I've kept it understandable.

Feel free to use it if you need it, @osyoyu

Suggested change
s = begin
# Use built-in timeout in TCPSocket.open if available
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port, open_timeout: @open_timeout)
rescue ArgumentError => e
raise if !(e.message.include?('unknown keyword: :open_timeout') || e.message.include?('wrong number of arguments (given 5, expected 2..4)'))
# Fallback to Timeout.timeout if TCPSocket.open does not support open_timeout
Timeout.timeout(@open_timeout, Net::OpenTimeout) {
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
}
end
s = begin
# Determine once whether TCPSocket.open supports open_timeout keyword argument
case @tcpsocket_open_timeout_supported
when nil
begin
# Try using open_timeout keyword argument
sock = TCPSocket.open(conn_addr, conn_port, @local_host, @local_port, open_timeout: @open_timeout)
@tcpsocket_open_timeout_supported = true
sock
rescue ArgumentError => e
if e.message.include?('unknown keyword: :open_timeout') || e.message.include?('wrong number of arguments (given 5, expected 2..4)')
# TCPSocket.open does not support open_timeout keyword argument
@tcpsocket_open_timeout_supported = false
# Fallback to Timeout.timeout
Timeout.timeout(@open_timeout, Net::OpenTimeout) {
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
}
else
raise
end
end
when true
# Use open_timeout keyword argument (known to be supported)
# assume Ruby >= 3.5
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port, open_timeout: @open_timeout)
when false
# Use Timeout.timeout (known that open_timeout is not supported)
# assume Ruby < 3.5
Timeout.timeout(@open_timeout, Net::OpenTimeout) {
TCPSocket.open(conn_addr, conn_port, @local_host, @local_port)
}
end
end

}
rescue => e
e = Net::OpenTimeout.new(e) if e.is_a?(Errno::ETIMEDOUT) # for compatibility with previous versions
raise e, "Failed to open TCP connection to " +
"#{conn_addr}:#{conn_port} (#{e.message})"
end
s.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
debug "opened"
if use_ssl?
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