Ruby » Ruby master

Bug #19412

Updated by brodock (Gabriel Mazetto) over 1 year ago

Here is a an example code: 

 ```ruby ``` 
 require 'socket' 

 PORT = 8080 
 BACKLOG = 50 
 LISTEN = '127.0.0.1' 

 def handle_connection(connection, _addrinfo) 
   request = connection.gets 

   puts request 

   connection.write "HTTP/1.1 200\r\n" 
   connection.write "Content-Type: text/html\r\n" 
   connection.write "\r\n" 
   connection.write "Hello world! Current time is #{Time.now}" 

 ensure 
   connection.close 
 end 

 begin 
   socket = Socket.new(:INET, :STREAM) 
   socket.bind(Addrinfo.tcp(LISTEN, PORT)) 
   socket.listen(BACKLOG) 

   puts "Requested queue size: #{BACKLOG} bigger then limit: #{Socket::SOMAXCONN}" if BACKLOG > Socket::SOMAXCONN 

   loop do 
     listening, = IO.select([socket]) 
     io, = listening 
     connection, addrinfo = io.accept 
     handle_connection(connection, addrinfo) 
   end 
 ensure 
   socket.close 
 end 
 ``` 

 This tries to simulate a TCP server that responds as if it was an HTTP server. 

 The amount of requests it can sustain seems to depend on the OS. On a Linux machine running ubuntu 20.04 I get something around 7.6K to 7.8K until it stops responding. 

 ``` 
 $ uname -a 
 Linux ... 5.17.5-x86_64-linode154 #1 SMP PREEMPT Mon May 2 15:07:22 EDT 2022 x86_64 x86_64 x86_64 GNU/Linux 

 $ ab -n 20000 -c 50 http://127.0.0.1:8080/ 
 This is ApacheBench, Version 2.3 <$Revision: 1843412 $> 
 Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ 
 Licensed to The Apache Software Foundation, http://www.apache.org/ 

 Benchmarking 127.0.0.1 (be patient) 
 Completed 2000 requests 
 Completed 4000 requests 
 Completed 6000 requests 
 apr_pollset_poll: The timeout specified has expired (70007) 
 Total of 7883 requests completed 
 ``` 

 on MacOS Ventura I get around 16K: 

 ``` 
 $ uname -a 
 Darwin ... 22.2.0 Darwin Kernel Version 22.2.0: Fri Nov 11 02:04:44 PST 2022; root:xnu-8792.61.2~4/RELEASE_ARM64_T8103 arm64 

 $ ab -n 20000 -c 50 http://127.0.0.1:8080/      
                                                                                                                            
 This is ApacheBench, Version 2.3 <$Revision: 1901567 $> 
 Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ 
 Licensed to The Apache Software Foundation, http://www.apache.org/ 

 Benchmarking 127.0.0.1 (be patient) 
 Completed 2000 requests 
 Completed 4000 requests 
 Completed 6000 requests 
 Completed 8000 requests 
 Completed 10000 requests 
 Completed 12000 requests 
 Completed 14000 requests 
 Completed 16000 requests 
 apr_socket_recv: Operation timed out (60) 
 Total of 16375 requests completed 
 ``` 

 in both cases when that limit reaches, if I abort the program (CTRL-C) and try to run it again it takes a while until the port is released: 

 ``` 
 ... 
 GET / HTTP/1.0 
 GET / HTTP/1.0 
 GET / HTTP/1.0 
 ^Csocketserver.rb:29:in `select': Interrupt 
	 from socketserver.rb:29:in `block in <main>' 
	 from socketserver.rb:28:in `loop' 
	 from socketserver.rb:28:in `<main>' 
 $ ruby socketserver.rb                                                                                                                                                   
 socketserver.rb:23:in `bind': Address already in use - bind(2) for 127.0.0.1:8080 (Errno::EADDRINUSE) 
	 from socketserver.rb:23:in `<main>' 
 ``` 

 After killing the process it seems no process is holding the port: 

 ``` 
 lsof -wni tcp:8080 
 ``` 

 Running the command above does not return anything (it does when the program is still running). 

 I think we may be failing to release something when interacting with the Socket on syscalls/kernel level and we endup filling up some queue/buffer that eventually gets freed.

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