Using HTTP/1.1 and permanent connections

Iñaki Baz Castillo ibc at aliax.net
Fri Apr 16 14:49:17 EDT 2010


Hi, I know that Unicorn forces TCP disconnection as it's explained at
the top of lib/unicorn/http_response.rb:

  # A design decision was made to force the client to not pipeline or
  # keepalive requests.  HTTP/1.1 pipelining really kills the
  # performance due to how it has to be handled and how unclear the
  # standard is.  To fix this the HttpResponse always gives a
  # "Connection: close" header which forces the client to close right
  # away.  The bonus for this is that it gives a pretty nice speed boost
  # to most clients since they can close their connection immediately.


However I want to try TCP permanent connections from the client (or a
proxy) to Unicorn. I've tryed to modify same file as above by changing
at the end:


        # Remove "Connection: close":
        socket.write("HTTP/1.1 #{status}\r\n" \
                     "Date: #{Time.now.httpdate}\r\n" \
                     "Status: #{status}\r\n" \
                     "#{out.join('')}\r\n")
      end

      body.each { |chunk| socket.write(chunk) }
      # Don't close the socket:
      #socket.close # flushes and uncorks the socket immediately
      ensure
        body.respond_to?(:close) and body.close


But of course this is not enough and it fails. Not sure what exactly
happens, it seems that a Unicorn worker doesn't process requests
anymore until replying the first response.

So I would like to know if it's feasible to make Unicorn work in
persistent mode.
NOTE: I already know that the current design is really good, better
than using persistent connections, but I want to experiment with
persistent connections for other purposes I will explain in a future.


Thanks a lot.


-- 
Iñaki Baz Castillo
<ibc at aliax.net>


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