1 # -*- encoding: binary -*-
3 # This concurrency model implements a single-threaded app dispatch
4 # with a separate thread pool for writing responses.
6 # Unlike most \Rainbows! concurrency models, WriterThreadPool is
7 # designed to run behind nginx just like Unicorn is. This concurrency
8 # model may be useful for existing Unicorn users looking for more
9 # output concurrency than socket buffers can provide while still
10 # maintaining a single-threaded application dispatch (though if the
11 # response body is dynamically generated, it must be thread safe).
13 # For serving large or streaming responses, using more threads (via
14 # the +worker_connections+ setting) and setting "proxy_buffering off"
15 # in nginx is recommended. If your application does not handle
16 # uploads, then using any HTTP-aware proxy like haproxy is fine.
17 # Using a non-HTTP-aware proxy will leave you vulnerable to
18 # slow client denial-of-service attacks.
19 module Rainbows::WriterThreadPool
21 include Rainbows::Base
23 # used to wrap a BasicSocket to use with +q+ for all writes
24 # this is compatible with IO.select
25 class QueueSocket < Struct.new(:to_io, :q) # :nodoc:
30 def kgio_read(size, buf = "")
31 to_io.kgio_read(size, buf)
34 def kgio_read!(size, buf = "")
35 to_io.kgio_read!(size, buf)
38 def kgio_trywrite(buf)
39 to_io.kgio_trywrite(buf)
51 q << [ to_io, :close ]
62 def async_write_body(qclient, body, range)
63 qclient.q << [ qclient.to_io, :body, body, range ]
66 def process_client(client) # :nodoc:
68 super(QueueSocket.new(client, @@q[@@nr %= @@q.size]))
71 def init_worker_process(worker)
73 self.class.__send__(:alias_method, :sync_write_body, :write_body)
74 Rainbows::WriterThreadPool.__send__(
75 :alias_method, :write_body, :async_write_body)
78 def worker_loop(worker) # :nodoc:
79 # we have multiple, single-thread queues since we don't want to
80 # interleave writes from the same client
81 qp = (1..worker_connections).map do |n|
82 Rainbows::QueuePool.new(1) do |response|
84 io, arg1, arg2, arg3 = response
86 when :body then sync_write_body(io, arg2, arg3)
87 when :close then io.close unless io.closed?
92 Rainbows::Error.write(io, err)
97 @@q = qp.map { |q| q.queue }
98 super(worker) # accept loop from Unicorn
99 qp.map { |q| q.quit! }