我正在编写的 API 有一个奇怪的问题。API 已向其他服务发出 http get 请求，并在某些情况下超时 - 在大多数情况下，另一个服务关闭/无法访问。
我正在尝试完全在 AWS 上运行系统，但是当在那里运行 API 时，尝试访问同一实例上的服务时经常出现超时。API 是用 ruby+sinatra 编写的；我从来没有遇到过它的 python 前身的问题。如果我从 AWS 实例命令行 curl 其他服务的 url，我永远不会超时。当我在本地运行 API（AWS 上的其他服务）时，它每次都运行良好。
最初我认为这可能是我使用的 http 库-net/http，结果证明即使在本地也有问题。切换到 open-uri 或 rest-client 解决了所有本地问题，但是当我在 AWS 上运行时，我仍然有 20% 的时间出现超时。
API 是 ruby+sinatra，使用 open-uri 来做 http 请求。其他服务是 ruby+sinatra 或 java。我在 32 位 Amazon Linux 小型实例上运行，ruby 1.9.3，java 1.6；我的本地机器是 Mac，带有 Snow Leopard，带有 ruby 1.9.3 和 java 1.6。
有什么想法或提示可以进一步缩小可能发生的情况吗？
更新：我的大 sinatra 应用程序和小 sinatra 应用程序的行为不同！？
我的 sinatra 应用程序的测试版本调用我的 java 服务，都在 AWS 上运行......工作正常。
require 'rubygems'
require 'uri'
require 'open-uri'
require 'sinatra'
set :port, 6969
get '/wtf' do
xid = params[:xid]
state = params[:state]
service_addr = 'http://prod.myserver.com'
rid = 'xxx'
json = "{\"state\":\"#{state}\",\"sid\":\"0xac99d8929a89e6c01b56378336dec3a8L\",\"m\":\"set\",\"rid\":\"#{rid}\",\"id\":\"#{xid}\"}"
paramStr = URI.escape("rid=#{rid}&id=#{xid}&json=#{json}")
response = open(service_addr+"?"+paramStr)
status = response.status[0]
body = response.read
body
end
大版本，使用 Rack + 作为结构更好的 sinatra 应用程序运行...... 20+% 的时间失败！
require 'uri'
require 'open-uri'
class MyApp < Sinatra::Base
get '/wtf' do
xid = params[:xid]
state = params[:state]
service_addr = 'http://prod.myserver.com'
rid = 'xxx'
json = "{\"state\":\"#{state}\",\"sid\":\"0xac99d8929a89e6c01b56378336dec3a8L\",\"m\":\"set\",\"rid\":\"#{rid}\",\"id\":\"#{xid}\"}"
paramStr = URI.escape("rid=#{rid}&id=#{xid}&json=#{json}")
response = open(service_addr+"?"+paramStr)
status = response.status[0]
body = response.read
body
end
end
更新 2：使用 mechanize 的详细错误读数 - 总是网关超时
对于简单版本，它每次都有效（没有超时）。对于复杂的版本，这里有 mechanize 的读数，当它工作时，而不是。
当它工作时：
I, [2012-05-22T22:45:53.267464 #11610] INFO -- : Net::HTTP::Get: /? ### big long get str
D, [2012-05-22T22:45:53.267587 #11610] DEBUG -- : request-header: accept => */*
D, [2012-05-22T22:45:53.267630 #11610] DEBUG -- : request-header: user-agent => Mechanize/2.5.1 Ruby/1.9.3p125 (http://github.com/tenderlove/mechanize/)
D, [2012-05-22T22:45:53.267676 #11610] DEBUG -- : request-header: accept-encoding => gzip,deflate,identity
D, [2012-05-22T22:45:53.267713 #11610] DEBUG -- : request-header: accept-charset => ISO-8859-1,utf-8;q=0.7,*;q=0.7
D, [2012-05-22T22:45:53.267750 #11610] DEBUG -- : request-header: accept-language => en-us,en;q=0.5
D, [2012-05-22T22:45:53.267787 #11610] DEBUG -- : request-header: host => prod.pixieplug.com:9001
I, [2012-05-22T22:45:53.341814 #11610] INFO -- : status: Net::HTTPOK 1.1 200 OK
D, [2012-05-22T22:45:53.341916 #11610] DEBUG -- : response-header: content-type => application/json;charset=ISO-8859-1
D, [2012-05-22T22:45:53.341962 #11610] DEBUG -- : response-header: transfer-encoding => chunked
D, [2012-05-22T22:45:53.342009 #11610] DEBUG -- : response-header: server => Jetty(8.0.y.z-SNAPSHOT)
D, [2012-05-22T22:45:53.342137 #11610] DEBUG -- : Read 167 bytes (167 total)
98.247.240.63 - - [22/May/2012 22:45:53] "GET /wtf?xid=00:00:00:00:00:17&state=255 HTTP/1.1" 200 167 0.0777
当它没有时：
I, [2012-05-22T22:46:23.665908 #11610] INFO -- : Net::HTTP::Get: /?# long list of params
D, [2012-05-22T22:46:23.666014 #11610] DEBUG -- : request-header: accept => */*
D, [2012-05-22T22:46:23.666053 #11610] DEBUG -- : request-header: user-agent => Mechanize/2.5.1 Ruby/1.9.3p125 (http://github.com/tenderlove/mechanize/)
D, [2012-05-22T22:46:23.666090 #11610] DEBUG -- : request-header: accept-encoding => gzip,deflate,identity
D, [2012-05-22T22:46:23.666125 #11610] DEBUG -- : request-header: accept-charset => ISO-8859-1,utf-8;q=0.7,*;q=0.7
D, [2012-05-22T22:46:23.666161 #11610] DEBUG -- : request-header: accept-language => en-us,en;q=0.5
D, [2012-05-22T22:46:23.666233 #11610] DEBUG -- : request-header: host => prod.pixieplug.com:9001
I, [2012-05-22T22:46:28.675045 #11610] INFO -- : status: Net::HTTPGatewayTimeOut 1.1 504 Gateway Timeout
D, [2012-05-22T22:46:28.675156 #11610] DEBUG -- : response-header: content-type => application/json;charset=ISO-8859-1
D, [2012-05-22T22:46:28.675195 #11610] DEBUG -- : response-header: transfer-encoding => chunked
D, [2012-05-22T22:46:28.675232 #11610] DEBUG -- : response-header: server => Jetty(8.0.y.z-SNAPSHOT)
D, [2012-05-22T22:46:28.675332 #11610] DEBUG -- : Read 48 bytes (48 total)
Mechanize::ResponseCodeError - 504 => Net::HTTPGatewayTimeOut for http://prod.pixieplug.com:9001/?# long list of params -- unhandled response:
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/mechanize-2.5.1/lib/mechanize/http/agent.rb:304:in `fetch'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/mechanize-2.5.1/lib/mechanize.rb:407:in `get'
/home/ec2-user/elphi-api/routes/sandbox.rb:15:in `block in <class:MyApp>'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:1212:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:1212:in `block in compile!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `[]'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `block (3 levels) in route!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:801:in `route_eval'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `block (2 levels) in route!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:822:in `block in process_route'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:820:in `catch'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:820:in `process_route'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:784:in `block in route!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:783:in `each'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:783:in `route!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:886:in `dispatch!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:719:in `block in call!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `block in invoke'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `catch'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `invoke'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:719:in `call!'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/base.rb:705:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/xss_header.rb:22:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/base.rb:47:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/base.rb:47:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/path_traversal.rb:16:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/json_csrf.rb:17:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/base.rb:47:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-protection-1.2.0/lib/rack/protection/xss_header.rb:22:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:205:in `context'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:200:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/logger.rb:15:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/head.rb:9:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/methodoverride.rb:21:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/sinatra-1.3.2/lib/sinatra/showexceptions.rb:21:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/lint.rb:48:in `_call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/lint.rb:36:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/showexceptions.rb:24:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/commonlogger.rb:20:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/chunked.rb:43:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/content_length.rb:14:in `call'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/connection.rb:80:in `block in pre_process'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/connection.rb:78:in `catch'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/connection.rb:78:in `pre_process'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/connection.rb:53:in `process'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/connection.rb:38:in `receive_data'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run_machine'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/backends/base.rb:61:in `start'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/server.rb:159:in `start'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/handler/thin.rb:13:in `run'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/server.rb:265:in `start'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/server.rb:137:in `start'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/bin/rackup:4:in `<top (required)>'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/bin/rackup:19:in `load'
/home/ec2-user/.rvm/gems/ruby-1.9.3-p125/bin/rackup:19:in `<main>'
98.247.240.63 - - [22/May/2012 22:46:28] "GET /wtf?xid=00:00:00:00:00:17&state=255 HTTP/1.1" 500 157221 5.1385