Profiling Sinatra with rack-perftools_profiler (using net/http) - ruby

Question

One of my Sinatra actions performs another request using net/http and computes something based on the response:
api_response = Net::HTTP.get_response(uri)
It works like a charm, but when I try to profile this:
configure do
use ::Rack::PerftoolsProfiler, default_printer: 'pdf', frequency: 4000, mode: :walltime
end
(and put ?profile=true into the params of the request I get this:
Errno::EADDRINUSE - Address already in use - connect(2):
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:762:in `initialize'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:762:in `open'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:762:in `block in connect'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/timeout.rb:54:in `timeout'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/timeout.rb:99:in `timeout'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:762:in `connect'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:755:in `do_start'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:744:in `start'
/Users/tomek/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/net/http.rb:454:in `get_response'
Any idea what's happening?

Answer 1

I try to setup these the same way as you.
require 'sinatra'
require 'rack/perftools_profiler'
require 'net/http'
configure do
use ::Rack::PerftoolsProfiler, default_printer: 'pdf', frequency: 4000, mode: :walltime
end
get "/" do
uri = URI('http://google.com')
api_response = Net::HTTP.get_response(uri)
end
And it run with out a problem on ruby 1.9.3-p286 and with rack-perftools_profiler (0.6.1).
Two recommendations:
update your ruby version
update your gems
If these don't help check which program has bound your port with sudo netstat -nlp
If these all don't help please tell us more about your setup.