# frozen_string_literal: false
#
# Note: Rinda::Ring API is unstable.
#
require 'drb/drb'
require_relative 'rinda'
require 'ipaddr'
module Rinda
##
# The default port Ring discovery will use.
Ring_PORT = 7647
##
# A RingServer allows a Rinda::TupleSpace to be located via UDP broadcasts.
# Default service location uses the following steps:
#
# 1. A RingServer begins listening on the network broadcast UDP address.
# 2. A RingFinger sends a UDP packet containing the DRb URI where it will
# listen for a reply.
# 3. The RingServer receives the UDP packet and connects back to the
# provided DRb URI with the DRb service.
#
# A RingServer requires a TupleSpace:
#
# ts = Rinda::TupleSpace.new
# rs = Rinda::RingServer.new
#
# RingServer can also listen on multicast addresses for announcements. This
# allows multiple RingServers to run on the same host. To use network
# broadcast and multicast:
#
# ts = Rinda::TupleSpace.new
# rs = Rinda::RingServer.new ts, %w[Socket::INADDR_ANY, 239.0.0.1 ff02::1]
class RingServer
include DRbUndumped
##
# Special renewer for the RingServer to allow shutdown
class Renewer # :nodoc:
include DRbUndumped
##
# Set to false to shutdown future requests using this Renewer
attr_writer :renew
def initialize # :nodoc:
@renew = true
end
def renew # :nodoc:
@renew ? 1 : true
end
end
##
# Advertises +ts+ on the given +addresses+ at +port+.
#
# If +addresses+ is omitted only the UDP broadcast address is used.
#
# +addresses+ can contain multiple addresses. If a multicast address is
# given in +addresses+ then the RingServer will listen for multicast
# queries.
#
# If you use IPv4 multicast you may need to set an address of the inbound
# interface which joins a multicast group.
#
# ts = Rinda::TupleSpace.new
# rs = Rinda::RingServer.new(ts, [['239.0.0.1', '9.5.1.1']])
#
# You can set addresses as an Array Object. The first element of the
# Array is a multicast address and the second is an inbound interface
# address. If the second is omitted then '0.0.0.0' is used.
#
# If you use IPv6 multicast you may need to set both the local interface
# address and the inbound interface index:
#
# rs = Rinda::RingServer.new(ts, [['ff02::1', '::1', 1]])
#
# The first element is a multicast address and the second is an inbound
# interface address. The third is an inbound interface index.
#
# At this time there is no easy way to get an interface index by name.
#
# If the second is omitted then '::1' is used.
# If the third is omitted then 0 (default interface) is used.
def initialize(ts, addresses=[Socket::INADDR_ANY], port=Ring_PORT)
@port = port
if Integer === addresses then
addresses, @port = [Socket::INADDR_ANY], addresses
end
@renewer = Renewer.new
@ts = ts
@sockets = []
addresses.each do |address|
if Array === address
make_socket(*address)
else
make_socket(address)
end
end
@w_services = write_services
@r_service = reply_service
end
##
# Creates a socket at +address+
#
# If +address+ is multicast address then +interface_address+ and
# +multicast_interface+ can be set as optional.
#
# A created socket is bound to +interface_address+. If you use IPv4
# multicast then the interface of +interface_address+ is used as the
# inbound interface. If +interface_address+ is omitted or nil then
# '0.0.0.0' or '::1' is used.
#
# If you use IPv6 multicast then +multicast_interface+ is used as the
# inbound interface. +multicast_interface+ is a network interface index.
# If +multicast_interface+ is omitted then 0 (default interface) is used.
def make_socket(address, interface_address=nil, multicast_interface=0)
addrinfo = Addrinfo.udp(address, @port)
socket = Socket.new(addrinfo.pfamily, addrinfo.socktype,
addrinfo.protocol)
if addrinfo.ipv4_multicast? or addrinfo.ipv6_multicast? then
if Socket.const_defined?(:SO_REUSEPORT) then
socket.setsockopt(:SOCKET, :SO_REUSEPORT, true)
else
socket.setsockopt(:SOCKET, :SO_REUSEADDR, true)
end
if addrinfo.ipv4_multicast? then
interface_address = '0.0.0.0' if interface_address.nil?
socket.bind(Addrinfo.udp(interface_address, @port))
mreq = IPAddr.new(addrinfo.ip_address).hton +
IPAddr.new(interface_address).hton
socket.setsockopt(:IPPROTO_IP, :IP_ADD_MEMBERSHIP, mreq)
else
interface_address = '::1' if interface_address.nil?
socket.bind(Addrinfo.udp(interface_address, @port))
mreq = IPAddr.new(addrinfo.ip_address).hton +
[multicast_interface].pack('I')
socket.setsockopt(:IPPROTO_IPV6, :IPV6_JOIN_GROUP, mreq)
end
else
socket.bind(addrinfo)
end
socket
rescue
socket = socket.close if socket
raise
ensure
@sockets << socket if socket
end
##
# Creates threads that pick up UDP packets and passes them to do_write for
# decoding.
def write_services
@sockets.map do |s|
Thread.new(s) do |socket|
loop do
msg = socket.recv(1024)
do_write(msg)
end
end
end
end
##
# Extracts the response URI from +msg+ and adds it to TupleSpace where it
# will be picked up by +reply_service+ for notification.
def do_write(msg)
Thread.new do
begin
tuple, sec = Marshal.load(msg)
@ts.write(tuple, sec)
rescue
end
end
end
##
# Creates a thread that notifies waiting clients from the TupleSpace.
def reply_service
Thread.new do
loop do
do_reply
end
end
end
##
# Pulls lookup tuples out of the TupleSpace and sends their DRb object the
# address of the local TupleSpace.
def do_reply
tuple = @ts.take([:lookup_ring, nil], @renewer)
Thread.new { tuple[1].call(@ts) rescue nil}
rescue
end
##
# Shuts down the RingServer
def shutdown
@renewer.renew = false
@w_services.each do |thread|
thread.kill
thread.join
end
@sockets.each do |socket|
socket.close
end
@r_service.kill
@r_service.join
end
end
##
# RingFinger is used by RingServer clients to discover the RingServer's
# TupleSpace. Typically, all a client needs to do is call
# RingFinger.primary to retrieve the remote TupleSpace, which it can then
# begin using.
#
# To find the first available remote TupleSpace:
#
# Rinda::RingFinger.primary
#
# To create a RingFinger that broadcasts to a custom list:
#
# rf = Rinda::RingFinger.new ['localhost', '192.0.2.1']
# rf.primary
#
# Rinda::RingFinger also understands multicast addresses and sets them up
# properly. This allows you to run multiple RingServers on the same host:
#
# rf = Rinda::RingFinger.new ['239.0.0.1']
# rf.primary
#
# You can set the hop count (or TTL) for multicast searches using
# #multicast_hops.
#
# If you use IPv6 multicast you may need to set both an address and the
# outbound interface index:
#
# rf = Rinda::RingFinger.new ['ff02::1']
# rf.multicast_interface = 1
# rf.primary
#
# At this time there is no easy way to get an interface index by name.
class RingFinger
@@broadcast_list = ['<broadcast>', 'localhost']
@@finger = nil
##
# Creates a singleton RingFinger and looks for a RingServer. Returns the
# created RingFinger.
def self.finger
unless @@finger
@@finger = self.new
@@finger.lookup_ring_any
end
@@finger
end
##
# Returns the first advertised TupleSpace.
def self.primary
finger.primary
end
##
# Contains all discovered TupleSpaces except for the primary.
def self.to_a
finger.to_a
end
##
# The list of addresses where RingFinger will send query packets.
attr_accessor :broadcast_list
##
# Maximum number of hops for sent multicast packets (if using a multicast
# address in the broadcast list). The default is 1 (same as UDP
# broadcast).
attr_accessor :multicast_hops
##
# The interface index to send IPv6 multicast packets from.
attr_accessor :multicast_interface
##
# The port that RingFinger will send query packets to.
attr_accessor :port
##
# Contain the first advertised TupleSpace after lookup_ring_any is called.
attr_accessor :primary
##
# Creates a new RingFinger that will look for RingServers at +port+ on
# the addresses in +broadcast_list+.
#
# If +broadcast_list+ contains a multicast address then multicast queries
# will be made using the given multicast_hops and multicast_interface.
def initialize(broadcast_list=@@broadcast_list, port=Ring_PORT)
@broadcast_list = broadcast_list || ['localhost']
@port = port
@primary = nil
@rings = []
@multicast_hops = 1
@multicast_interface = 0
end
##
# Contains all discovered TupleSpaces except for the primary.
def to_a
@rings
end
##
# Iterates over all discovered TupleSpaces starting with the primary.
def each
lookup_ring_any unless @primary
return unless @primary
yield(@primary)
@rings.each { |x| yield(x) }
end
##
# Looks up RingServers waiting +timeout+ seconds. RingServers will be
# given +block+ as a callback, which will be called with the remote
# TupleSpace.
def lookup_ring(timeout=5, &block)
return lookup_ring_any(timeout) unless block_given?
msg = Marshal.dump([[:lookup_ring, DRbObject.new(block)], timeout])
@broadcast_list.each do |it|
send_message(it, msg)
end
sleep(timeout)
end
##
# Returns the first found remote TupleSpace. Any further recovered
# TupleSpaces can be found by calling +to_a+.
def lookup_ring_any(timeout=5)
queue = Thread::Queue.new
Thread.new do
self.lookup_ring(timeout) do |ts|
queue.push(ts)
end
queue.push(nil)
end
@primary = queue.pop
raise('RingNotFound') if @primary.nil?
Thread.new do
while it = queue.pop
@rings.push(it)
end
end
@primary
end
##
# Creates a socket for +address+ with the appropriate multicast options
# for multicast addresses.
def make_socket(address) # :nodoc:
addrinfo = Addrinfo.udp(address, @port)
soc = Socket.new(addrinfo.pfamily, addrinfo.socktype, addrinfo.protocol)
begin
if addrinfo.ipv4_multicast? then
soc.setsockopt(Socket::Option.ipv4_multicast_loop(1))
soc.setsockopt(Socket::Option.ipv4_multicast_ttl(@multicast_hops))
elsif addrinfo.ipv6_multicast? then
soc.setsockopt(:IPPROTO_IPV6, :IPV6_MULTICAST_LOOP, true)
soc.setsockopt(:IPPROTO_IPV6, :IPV6_MULTICAST_HOPS,
[@multicast_hops].pack('I'))
soc.setsockopt(:IPPROTO_IPV6, :IPV6_MULTICAST_IF,
[@multicast_interface].pack('I'))
else
soc.setsockopt(:SOL_SOCKET, :SO_BROADCAST, true)
end
soc.connect(addrinfo)
rescue Exception
soc.close
raise
end
soc
end
def send_message(address, message) # :nodoc:
soc = make_socket(address)
soc.send(message, 0)
rescue
nil
ensure
soc.close if soc
end
end
##
# RingProvider uses a RingServer advertised TupleSpace as a name service.
# TupleSpace clients can register themselves with the remote TupleSpace and
# look up other provided services via the remote TupleSpace.
#
# Services are registered with a tuple of the format [:name, klass,
# DRbObject, description].
class RingProvider
##
# Creates a RingProvider that will provide a +klass+ service running on
# +front+, with a +description+. +renewer+ is optional.
def initialize(klass, front, desc, renewer = nil)
@tuple = [:name, klass, front, desc]
@renewer = renewer || Rinda::SimpleRenewer.new
end
##
# Advertises this service on the primary remote TupleSpace.
def provide
ts = Rinda::RingFinger.primary
ts.write(@tuple, @renewer)
end
end
end