Feature #17528


Make Addrinfo.getaddrinfo fall back to Timeout.timeout for :resolv_timeout

Added by mohamedhafez (Mohamed Hafez) over 1 year ago. Updated over 1 year ago.

Target version:


Currently, Addrinfo.getaddrinfo ignores the :resolv_timeout option if we are on a system without getaddrinfo_a. It would be great if instead it would fall back to using Timeout.timeout.

That way, we could get rid of a lot of the usage of Timeout.timeout for systems that do have getaddrinfo_a. For example, for Net::HTTP#connect we could easily then do something like this:

The motivation for this is that the usage of Timeout.timeout is inherently unsafe, and it would be great to stop using it where we can (see and

Updated by akr (Akira Tanaka) over 1 year ago

I think Timeout.timeout doesn't work for Addrinfo.getaddrinfo
because Timeout.timeout cannot interrupt getaddrinfo function in C.

Updated by mohamedhafez (Mohamed Hafez) over 1 year ago

According to, the only reason we are using Timeout.timeout in Net::HTTP#connect instead of using nonblocking io and is so that we can place a timeout on the getaddrinfo function, @normalperson (Eric Wong) can you clarify here?

Updated by akr (Akira Tanaka) over 1 year ago

How to test:

% vi /etc/resolv.conf      # specify non-existing nameserver
% time ./ruby -rtimeout -rsocket -e 'Timeout.timeout(2) { Addrinfo.getaddrinfo("",nil) }'
-e:1:in `getaddrinfo': execution expired (Timeout::Error)
	from -e:1:in `block in <main>'
	from /home/akr/o0/lib/ruby/3.1.0/timeout.rb:112:in `timeout'
	from -e:1:in `<main>'
./ruby -rtimeout -rsocket -e   0.14s user 0.00s system 0% cpu 20.136 total

This needs 20 second instead of 2 second.

Updated by mohamedhafez (Mohamed Hafez) over 1 year ago

I was just doing a similar test actually, I think you're correct! I'll close this issue and re-submit a patch to Net::HTTP to replace Timeout::timeout there, since it's not doing anything for DNS lookups anyway. Thank you!


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