From 7542c8365613d0104b8a3171418bb8c7f1a518cb Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sat, 14 Mar 2015 01:39:23 +0000 Subject: proxy_pass: officially become a part of yahns This will rely on rack.hijack in the future to support asynchronous execution without tying up a thread when waiting for upstreams. For now, this allows simpler code with fewer checks and the use of monotonic time on newer versions of Ruby. --- lib/yahns/proxy_pass.rb | 210 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 lib/yahns/proxy_pass.rb (limited to 'lib') diff --git a/lib/yahns/proxy_pass.rb b/lib/yahns/proxy_pass.rb new file mode 100644 index 0000000..9c12e99 --- /dev/null +++ b/lib/yahns/proxy_pass.rb @@ -0,0 +1,210 @@ +# -*- encoding: binary -*- +# Copyright (C) 2013-2015 all contributors +# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt) +require 'socket' +require 'kgio' +require 'kcar' # gem install kcar +require 'rack/request' +require 'thread' +require 'timeout' + +# Totally synchronous and Rack 1.1-compatible, this will probably be rewritten. +# to take advantage of rack.hijack and use the non-blocking I/O facilities +# in yahns. yahns may have to grow a supported API for that... +# For now, we this blocks a worker thread; fortunately threads are reasonably +# cheap on GNU/Linux... +class Yahns::ProxyPass # :nodoc: + class ConnPool + def initialize + @mtx = Mutex.new + @objs = [] + end + + def get + @mtx.synchronize { @objs.pop } + end + + def put(obj) + @mtx.synchronize { @objs << obj } + end + end + + class UpstreamSocket < Kgio::Socket # :nodoc: + attr_writer :expiry + + # called automatically by kgio_read! + def kgio_wait_readable(timeout = nil) + super(timeout || wait_time) + end + + def wait_time + tout = @expiry ? @expiry - Yahns.now : @timeout + raise Timeout::Error, "request timed out", [] if tout < 0 + tout + end + + def readpartial(bytes, buf = Thread.current[:yahns_rbuf] ||= "") + case rv = kgio_read!(bytes, buf) + when String + @expiry += @timeout # bump expiry when we succeed + end + rv + end + + def req_write(buf, timeout) + @timeout = timeout + @expiry = Yahns.now + timeout + case rv = kgio_trywrite(buf) + when :wait_writable + kgio_wait_writable(wait_time) + when nil + return + when String + buf = rv + end while true + end + end # class UpstreamSocket + + class UpstreamResponse < Kcar::Response # :nodoc: + # Called by the Rack server at the end of a successful response + def close + reusable = @parser.keepalive? && @parser.body_eof? + super + @pool.put(self) if reusable + nil + end + + # req is just a string buffer of HTTP headers + def req_write(req, timeout) + @sock.req_write(req, timeout) + end + + # returns true if the socket is still alive, nil if dead + def sock_alive? + @reused = (:wait_readable == (@sock.kgio_tryread(1) rescue nil)) ? + true : @sock.close + end + + # returns true if the socket was reused and thus retryable + def fail_retryable? + @sock.close + @reused + end + + def initialize(sock, pool) + super(sock) + @reused = false + @pool = pool + end + end # class UpstreamResponse + + # take a responder from the pool, we'll add the object back to the + # pool in UpstreamResponse#close + def responder_get + while obj = @pool.get + return obj if obj.sock_alive? + end + + UpstreamResponse.new(UpstreamSocket.start(@sockaddr), @pool) + end + + def initialize(dest, timeout = 5) + case dest + when %r{\Aunix:([^:]+)(?::(/.*))?\z} + path = $2 + @sockaddr = Socket.sockaddr_un($1) + when %r{\Ahttp://([^/]+)(/.*)?\z} + path = $2 + host, port = $1.split(':') + @sockaddr = Socket.sockaddr_in(port || 80, host) + else + raise ArgumentError, "destination must be an HTTP URL or unix: path" + end + init_path_vars(path) + @pool = ConnPool.new + @timeout = timeout + end + + def init_path_vars(path) + path ||= '$fullpath' + # methods from Rack::Request we want: + allow = %w(fullpath host_with_port host port url path) + want = path.scan(/\$(\w+)/).flatten! || [] + diff = want - allow + diff.empty? or + raise ArgumentError, "vars not allowed: #{diff.uniq.join(' ')}" + + # kill leading slash just in case... + @path = path.gsub(%r{\A/(\$(?:fullpath|path))}, '\1') + end + + def call(env) + request_method = env['REQUEST_METHOD'] + req = Rack::Request.new(env) + path = @path.gsub(/\$(\w+)/) { req.__send__($1) } + req = "#{request_method} #{path} HTTP/1.1\r\n" \ + "X-Forwarded-For: #{env["REMOTE_ADDR"]}\r\n" + + # pass most HTTP_* headers through as-is + chunked = false + env.each do |key, val| + %r{\AHTTP_(\w+)\z} =~ key or next + key = $1 + next if %r{\A(?:VERSION|CONNECTION|KEEP_ALIVE|X_FORWARDED_FOR)} =~ key + chunked = true if %r{\ATRANSFER_ENCODING} =~ key && val =~ /\bchunked\b/i + key.tr!("_", "-") + req << "#{key}: #{val}\r\n" + end + + # special cases which Rack does not prefix: + ctype = env["CONTENT_TYPE"] and req << "Content-Type: #{ctype}\r\n" + clen = env["CONTENT_LENGTH"] and req << "Content-Length: #{clen}\r\n" + req << "\r\n" + + # get an open socket and send the headers + ures = responder_get + ures.req_write(req, @timeout) + + # send the request body if there was one + send_body(env["rack.input"], ures, chunked) if chunked || clen + + # wait for the response here + _, header, body = res = ures.rack + + # don't let the upstream Connection and Keep-Alive headers leak through + header.delete_if do |k,_| + k =~ /\A(?:Connection|Keep-Alive)\z/i + end + + case request_method + when "HEAD" + # kcar doesn't know if it's a HEAD or GET response, and HEAD + # responses have Content-Length in it which fools kcar... + body.parser.body_bytes_left = 0 + res[1] = header.dup + body.close # clobbers original header + res[2] = body = [] + end + res + rescue => e + retry if ures && ures.fail_retryable? && request_method != "POST" + Yahns::Log.exception(env['rack.logger'], 'proxy_pass', e) + [ 502, [ %w(Content-Length 0), %w(Content-Type text/plain) ], [] ] + end + + def send_body(input, ures, chunked) + buf = Thread.current[:yahns_rbuf] ||= "" + + if chunked # unlikely + while input.read(16384, buf) + buf.replace("#{buf.size.to_s(16)}\r\n#{buf}\r\n") + ures.req_write(buf, @timeout) + end + ures.req_write("0\r\n\r\n", @timeout) + else # common if we hit uploads + while input.read(16384, buf) + ures.req_write(buf, @timeout) + end + end + end +end -- cgit v1.2.3-24-ge0c7