ruby restclient timeout does not work properly, it throws exception after double the defined timeout

Question

Noticed that Ruby RestClient does not follow the given timeout parameter precisely, however it works by doubling the current timeout setting.

Has anyone noticed the same? attached a test code example below.

As httpbin.org is having max delay 10, we need to use small timeouts:

  def test_timeout(delay)
    start = Time.now.to_i
    RestClient::Request.execute(url:     "http://httpbin.org/delay/10",
                                method:  'GET',
                                timeout: delay)
    return 0
  rescue RestClient::Exceptions::ReadTimeout => exception
    endtime = Time.now.to_i
    return endtime - start
  end

pry(main)> test_timeout 1
RestClient.get "http://httpbin.org/delay/10", "Accept"=>"*/*", "Accept-Encoding"=>"gzip, deflate"

=> 3

pry(main)> test_timeout 5
RestClient.get "http://httpbin.org/delay/10", "Accept"=>"*/*", "Accept-Encoding"=>"gzip, deflate"

=> 10

Using Ruby RestClient 2.0.2 and also tested with 2.1.0.rc1

Also tested with read_timeout and open_timeout parameters, which had the same

  def test_timeout(delay)
    start = Time.now.to_i
    RestClient::Request.execute(url: "http://httpbin.org/delay/10",
                                method: 'GET',
                                open_timeout: 1,
                                read_timeout: delay)
    return 0
  rescue RestClient::Exceptions::ReadTimeout => exception
    endtime = Time.now.to_i
    return endtime - start
  end

pry(main)> test_timeout 2
RestClient.get "http://httpbin.org/delay/10", "Accept"=>"*/*", "Accept-Encoding"=>"gzip, deflate"

=> 4
pry(main)> test_timeout 3
RestClient.get "http://httpbin.org/delay/10", "Accept"=>"*/*", "Accept-Encoding"=>"gzip, deflate"

=> 6

Potentially of note: httpbin.org/delay has a max delay of 10seconds. — Sean, Oct 12 '18 at 15:20
You might want to read [this](https://engineering.wework.com/ruby-users-be-wary-of-net-http-f284747288b2) — Marcin Kołodziej, Oct 12 '18 at 15:23
Thank you Sean, you are right regarding the httpbin.org max delay. Its 10 secs. — jaluke, Oct 15 '18 at 05:42
I modified a bit the examples above. Now using smaller timeouts (below 10). The effect is the same. — jaluke, Oct 15 '18 at 06:01
Thank you Marcin! Seem that's its a wanted feature on Net::HTTP library. Ruby 2.5 should have a parameter to over ride the feature. — jaluke, Oct 17 '18 at 10:22

score 1 · Answer 1 · answered Oct 12 '18 at 17:12

1

Timeout = read_timeout + open_timeout

open_timeout: is the time after which if the connection fails to establish, the request will be rejected

read_timeout: the time you are willing to wait for some data to be received from the server

  RestClient::Request.execute(url: "http://httpbin.org/delay/#{delay * 10}",
                            method: 'GET',
                            timeout: 1)

answered Oct 12 '18 at 17:12

arjunsv3691

791
6
19

The initial examples shows that RestClient doubles the time we shall wait, even if the open_timeout is 1 and read_timeout is 3 then the actual timeout occurs at ~6seconds. – jaluke Oct 15 '18 at 05:58

score 1 · Accepted Answer · answered Oct 17 '18 at 10:57

As a summary,

its a wanted feature on Net::HTTP library. Ruby 2.5 should have a parameter to over ride the feature.

More information from https://engineering.wework.com/ruby-users-be-wary-of-net-http-f284747288b2

Thank you all regarding you replies!

ruby restclient timeout does not work properly, it throws exception after double the defined timeout

2 Answers2