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@seki /drb.rb
Created Jun 5, 2013

1st druby. [ruby-list:15406]
drb.rb
#!/usr/local/bin/ruby
=begin
Tiny distributed Ruby --- dRuby
DRb --- dRuby module.
DRbProtocol --- Mixin class.
DRbObject --- dRuby remote object.
DRbConn ---
DRbServer --- dRuby message handler.
=end
require 'socket'
require 'marshal'
module DRb
def start_service(uri, front=nil)
@uri = uri.to_s
@front = front
@server = DRbServer.new(@uri)
@thread = @server.run
end
module_function :start_service
attr :uri
module_function :uri
attr :thread
module_function :thread
attr :front
module_function :front
end
module DRbProtocol
def parse_uri(uri)
if uri =~ /^druby:\/\/(.+?):(\d+)/
host = $1
port = $2.to_i
[host, port]
else
raise RuntimeError, 'can\'t parse uri'
end
end
def dump(obj, soc)
begin
str = Marshal::dump(obj)
rescue
ro = DRbObject.new(obj)
str = Marshal::dump(ro)
end
soc.write(str) if soc
return str
end
def send_request(soc, ref,msg_id, *arg)
dump(ref, soc)
dump(msg_id.id2name, soc)
dump(arg.length, soc)
arg.each do |e|
dump(e, soc)
end
end
def recv_reply(soc)
succ = Marshal::load(soc)
result = Marshal::load(soc)
[succ, result]
end
def recv_request(soc)
ro = Marshal::load(soc)
msg = Marshal::load(soc)
argc = Marshal::load(soc)
argv = []
argc.times do
argv.push Marshal::load(soc)
end
[ro, msg, argv]
end
def send_reply(soc, succ, result)
dump(succ, soc)
dump(result, soc)
end
end
class DRbObject
def initialize(obj, uri=nil)
@uri = uri || DRb.uri
@ref = obj.id if obj
end
def method_missing(msg_id, *a)
succ, result = DRbConn.new(@uri).send_message(self, msg_id, *a)
raise result if ! succ
result
end
attr :ref
end
class DRbConn
include DRbProtocol
def initialize(remote_uri)
@host, @port = parse_uri(remote_uri)
end
def send_message(ref, msg_id, *arg)
begin
soc = TCPSocket.open(@host, @port)
send_request(soc, ref, msg_id, *arg)
recv_reply(soc)
ensure
soc.close if soc
# ObjectSpace.garbage_collect
end
end
end
class DRbServer
include DRbProtocol
def initialize(uri)
@host, @port = parse_uri(uri)
@soc = TCPServer.open(@port)
@uri = uri.dup
end
def run
Thread.start do
while true
proc
end
end
end
def proc
ns = @soc.accept
Thread.start do
begin
s = ns
begin
ro, msg, argv = recv_request(s)
if ro and ro.ref
obj = ObjectSpace._id2ref(ro.ref)
else
obj = DRb.front
end
result = obj.__send__(msg.intern, *argv)
succ = true
rescue
result = $!
succ = false
end
send_reply(s, succ, result)
ensure
close s if s
# ObjectSpace.garbage_collect
end
end
end
end
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