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