From e184dfc9e6f0e8f142c3fbb0e9d98e8c57f82469 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sat, 15 Aug 2009 01:02:03 -0700 Subject: TODO: remove keep-alive/pipelining The code I was _about_ to commit to support them was too ugly and the performance benefit in real applications/clients is unproven. Support for these things also had the inevitable side effect of adding overhead to non-persistent requests. Worst of all, interaction with people tweaking TCP_CORK/TCP_NOPUSH suddenly becomes an order of magnitude more complex because of the _need_ to flush the socket out in between requests (for most apps). Aggressive pipelining can actually help a lot with a direct connection to Unicorn, not via proxy. But the applications (and clients) that would benefit from it are very few and moving those applications away from HTTP entirely would be an even bigger benefit. The C/Ragel parser will maintain keepalive support for now since I've always intended for that to be used in more general-purpose HTTP servers than Unicorn. For documentation purposes, the keep-alive/pipelining patch is included below in its entirety. I don't have the TCP_CORK/TCP_NOPUSH parts in there because that's when I finally gave up and decided it would not be worth supporting. diff --git a/lib/unicorn.rb b/lib/unicorn.rb index b185b25..cc58997 100644 --- a/lib/unicorn.rb +++ b/lib/unicorn.rb @@ -439,22 +439,24 @@ module Unicorn # once a client is accepted, it is processed in its entirety here # in 3 easy steps: read request, call app, write app response def process_client(client) + response = nil client.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC) - response = app.call(env = REQUEST.read(client)) - - if 100 == response.first.to_i - client.write(Const::EXPECT_100_RESPONSE) - env.delete(Const::HTTP_EXPECT) - response = app.call(env) - end + begin + response = app.call(env = REQUEST.read(client)) - HttpResponse.write(client, response) + if 100 == response.first.to_i + client.write(Const::EXPECT_100_RESPONSE) + env.delete(Const::HTTP_EXPECT) + response = app.call(env) + end + end while HttpResponse.write(client, response, HttpRequest::PARSER.keepalive?) + client.close # if we get any error, try to write something back to the client # assuming we haven't closed the socket, but don't get hung up # if the socket is already closed or broken. We'll always ensure # the socket is closed at the end of this function - rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL,Errno::EBADF - client.write_nonblock(Const::ERROR_500_RESPONSE) rescue nil + rescue EOFError,Errno::ECONNRESET,Errno::EPIPE,Errno::EINVAL, + Errno::EBADF,Errno::ENOTCONN client.close rescue nil rescue HttpParserError # try to tell the client they're bad client.write_nonblock(Const::ERROR_400_RESPONSE) rescue nil diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb index 1358ccc..f73bdd0 100644 --- a/lib/unicorn/http_request.rb +++ b/lib/unicorn/http_request.rb @@ -42,6 +42,7 @@ module Unicorn # to handle any socket errors (e.g. user aborted upload). def read(socket) REQ.clear + pipelined = PARSER.keepalive? && 0 < BUF.size PARSER.reset # From http://www.ietf.org/rfc/rfc3875: @@ -55,7 +56,9 @@ module Unicorn TCPSocket === socket ? socket.peeraddr.last : LOCALHOST # short circuit the common case with small GET requests first - PARSER.headers(REQ, socket.readpartial(Const::CHUNK_SIZE, BUF)) and + PARSER.headers(REQ, + pipelined ? BUF : + socket.readpartial(Const::CHUNK_SIZE, BUF)) and return handle_body(socket) data = BUF.dup # socket.readpartial will clobber data diff --git a/lib/unicorn/http_response.rb b/lib/unicorn/http_response.rb index 5602a43..e22b5f9 100644 --- a/lib/unicorn/http_response.rb +++ b/lib/unicorn/http_response.rb @@ -20,12 +20,15 @@ module Unicorn # to most clients since they can close their connection immediately. class HttpResponse + include Unicorn::SocketHelper # Every standard HTTP code mapped to the appropriate message. CODES = Rack::Utils::HTTP_STATUS_CODES.inject({}) { |hash,(code,msg)| hash[code] = "#{code} #{msg}" hash } + CLOSE = "close".freeze # :nodoc + KEEPALIVE = "keep-alive".freeze # :nodoc # Rack does not set/require a Date: header. We always override the # Connection: and Date: headers no matter what (if anything) our @@ -34,7 +37,7 @@ module Unicorn OUT = [] # :nodoc # writes the rack_response to socket as an HTTP response - def self.write(socket, rack_response) + def self.write(socket, rack_response, keepalive = false) status, headers, body = rack_response status = CODES[status.to_i] || status OUT.clear @@ -50,6 +53,10 @@ module Unicorn end end + if keepalive && (0 == HttpRequest::BUF.size) + keepalive = IO.select([socket], nil, nil, 0.0) + end + # Rack should enforce Content-Length or chunked transfer encoding, # so don't worry or care about them. # Date is required by HTTP/1.1 as long as our clock can be trusted. @@ -57,10 +64,10 @@ module Unicorn socket.write("HTTP/1.1 #{status}\r\n" \ "Date: #{Time.now.httpdate}\r\n" \ "Status: #{status}\r\n" \ - "Connection: close\r\n" \ + "Connection: #{keepalive ? KEEPALIVE : CLOSE}\r\n" \ "#{OUT.join(Z)}\r\n") body.each { |chunk| socket.write(chunk) } - socket.close # flushes and uncorks the socket immediately + keepalive ensure body.respond_to?(:close) and body.close rescue nil end --- TODO | 2 -- 1 file changed, 2 deletions(-) diff --git a/TODO b/TODO index 01e6596..0b73934 100644 --- a/TODO +++ b/TODO @@ -9,5 +9,3 @@ * Rainbows! * Rubinius support - -* keepalive (1 second max) + pipelining support (Ragel bits already done) -- cgit v1.2.3-24-ge0c7