Using HTTP/1.1 and permanent connections

Using HTTP/1.1 and permanent connections

[Iñaki Baz Castillo]

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@aliax.net>
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Re: Using HTTP/1.1 and permanent connections

[Eric Wong]

Iñaki Baz Castillo <ibc@aliax.net> wrote:
> 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:

<snip>

> 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.

Hi Iñaki,

Unicorn won't try to read further requests from the socket (see
process_client() in lib/unicorn.rb).

However, you can use Rainbows! without specifying a concurrency model at
all (or "use :Base").  That way you'll get proper HTTP/1.1 keepalive
support and you can control keepalive_timeout:

# both of these values are the defaults for unconfigured Rainbows!
Rainbows! do
  use :Base
  keepalive_timeout 5
end

-- 
Eric Wong
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Re: Using HTTP/1.1 and permanent connections

[Iñaki Baz Castillo]

2010/4/16 Eric Wong <normalperson@yhbt.net>:
> Hi Iñaki,
>
> Unicorn won't try to read further requests from the socket (see
> process_client() in lib/unicorn.rb).

Ok, understood now.


> However, you can use Rainbows! without specifying a concurrency model at
> all (or "use :Base").  That way you'll get proper HTTP/1.1 keepalive
> support and you can control keepalive_timeout:
>
> # both of these values are the defaults for unconfigured Rainbows!
> Rainbows! do
>  use :Base
>  keepalive_timeout 5
> end


Great! Thanks a lot.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>
_______________________________________________
Unicorn mailing list - mongrel-unicorn@rubyforge.org
http://rubyforge.org/mailman/listinfo/mongrel-unicorn
Do not quote signatures (like this one) or top post when replying