Class: Archipelago::Disco::Jockey

Inherits:
Object
  • Object
show all
Defined in:
lib/archipelago/disco.rb

Overview

The main discovery class used to both publish and lookup services.

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Jockey

Will create a Jockey service running on :address and :port or ADDRESS and PORT if none are given.

Will the first available unicast port within :uniports or if not given UNIPORTS for receiving unicast messages.

Will have a default :lookup_timeout of LOOKUP_TIMEOUT, a default :initial_lookup_standoff of INITIAL_LOOKUP_STANDOFF and a default :validation_interval of VALIDATION_INTERVAL.

Will only cache (and validate, which saves network traffic) stuff that has been looked up before if :thrifty_caching, or THRIFTY_CACHING if not given.

Will only reply to the one that sent out the query (and therefore save lots of network traffic) if :thrifty_replying, or THRIFTY_REPLYING if not given.

Will send out a multicast when a new service is published unless :thrifty_publishing, or THRIFTY_PUBLISHING if not given.

Will reply to all queries to which it has matching local services with a unicast message if :thrifty_replying, or if not given THRIFTY_REPLYING. Otherwise will reply with multicasts.



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# File 'lib/archipelago/disco.rb', line 493

def initialize(options = {})
  @valid = true
  @remote_services = ServiceLocker.new(:jockey => self)
  @local_services = ServiceLocker.new(:jockey => self)
  @subscribed_services = Set.new

  @incoming = Queue.new
  @outgoing = Queue.new

  @new_service_semaphore = MonitorMixin::ConditionVariable.new(Archipelago::Current::Lock.new)
  @service_change_subscribers_by_event_type = {:found => {}, :lost => {}}
  
  @validation_interval = options[:validation_interval] || VALIDATION_INTERVAL

  setup(options)
  
  start!
end

Instance Method Details

#clear! ⇒ Object

Clears our local and remote services.



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# File 'lib/archipelago/disco.rb', line 586

def clear!
  @local_services = ServiceLocker.new(:jockey => self)
  @remote_services = ServiceLocker.new(:jockey => self)
end

#lookup(match, options = {}) ⇒ Object

Lookup any services matching match, optionally with a :timeout and optionally :silent.

Will immediately return if we know of matching and valid services, will otherwise send out regular Queries and return as soon as matching services are found, or when the timeout runs out.



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# File 'lib/archipelago/disco.rb', line 630

def lookup(match, options = {})
  timeout = options[:timeout] || @lookup_timeout
  silent = options[:silent] || false

  match[:unicast_reply] = @unicast_address
  @subscribed_services << match if @thrifty_caching
  standoff = @initial_lookup_standoff

  @outgoing << [nil, match] unless silent
  known_services = @remote_services.get_services(match).merge(@local_services.get_services(match))
  return known_services if timeout == 0 || !known_services.empty?

  t = Time.new
  @new_service_semaphore.wait([standoff, timeout].min)
  standoff *= 2

  while Time.new < t + timeout
    known_services = @remote_services.get_services(match).merge(@local_services.get_services(match))
    return known_services unless known_services.empty?

    wait_time = [standoff, (t + timeout) - Time.new].min
    @new_service_semaphore.wait(wait_time)
    standoff *= 2

    @outgoing << [nil, match] unless silent
  end

  return ServiceLocker.new
end

#publish(service) ⇒ Object

Record the given service and broadcast about it.



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# File 'lib/archipelago/disco.rb', line 663

def publish(service)
  if service.valid?
    service[:published_at] = Time.now
    @local_services[service[:service_id]] = service
    @new_service_semaphore.broadcast
    unless @thrifty_publishing
      @outgoing << [nil, service]
    end
  end
end

#setup(options = {}) ⇒ Object

Sets up this instance according to the given options.



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# File 'lib/archipelago/disco.rb', line 535

def setup(options = {})
  @thrifty_caching = options.include?(:thrifty_caching) ? options[:thrifty_caching] : THRIFTY_CACHING
  @thrifty_replying = options.include?(:thrifty_replying) ? options[:thrifty_replying] : THRIFTY_REPLYING
  @thrifty_publishing = options.include?(:thrifty_publishing) ? options[:thrifty_publishing] : THRIFTY_PUBLISHING
  @lookup_timeout = options[:lookup_timeout] || LOOKUP_TIMEOUT
  @initial_lookup_standoff = options[:initial_lookup_standoff] || INITIAL_LOOKUP_STANDOFF

  @listener = UDPSocket.new
  @unilistener = UDPSocket.new
  
  @listener.setsockopt(Socket::IPPROTO_IP, 
                       Socket::IP_ADD_MEMBERSHIP, 
                       IPAddr.new(options[:address] || ADDRESS).hton + Socket.gethostbyname("0.0.0.0")[3])
  
  @listener.setsockopt(Socket::SOL_SOCKET, 
                       Socket::SO_REUSEADDR, 
                       true)
  begin
    @listener.setsockopt(Socket::SOL_SOCKET, 
                         Socket::SO_REUSEPORT, 
                         true)
  rescue
    # /moo
  end
  @listener.bind('', options[:port] || PORT)

  uniports = options[:uniports] || UNIPORTS
  this_port = uniports.min
  begin
    @unilistener.bind('', this_port)
  rescue Errno::EADDRINUSE => e
    if this_port < uniports.max
      this_port += 1
      retry
    else
      raise e
    end
  end
  @unicast_address = "#{HOST}:#{this_port}"
  
  @sender = UDPSocket.new
  @multiaddress = options[:address] || ADDRESS
  @multiport = options[:port] || PORT
  @sender.connect(@multiaddress, @multiport)

  @unisender = UDPSocket.new
end

#stop! ⇒ Object

Stops all the threads and closes all sockets in this instance.



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# File 'lib/archipelago/disco.rb', line 594

def stop!
  if @valid
    @valid = false
    @local_services.each do |service_id, service_description|
      self.unpublish(service_id)
    end

    @listener_thread.kill
    @unilistener_thread.kill

    @listener.close
    @unilistener.close
    while !@incoming.empty?
      sleep 0.1
    end
    @picker_thread.kill
    
    while !@outgoing.empty?
      sleep 0.1
    end
    @shouter_thread.kill
    @sender.close
    @unisender.close

    @validator_thread.kill
  end
end

#subscribe(event_type, match, identity, &block) ⇒ Object

Will listen for event_types matching the Query match and do block.call with the matching Record.

identity is used to determine what subscription to remove when doing unsubscribe.

Recognized event_types: :found, :lost



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# File 'lib/archipelago/disco.rb', line 521

def subscribe(event_type, match, identity, &block)
  @service_change_subscribers_by_event_type[event_type][[match, identity]] = block
end

#unpublish(service_id) ⇒ Object

Removes the service with given service_id from the published services.



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# File 'lib/archipelago/disco.rb', line 677

def unpublish(service_id)
  @local_services.delete(service_id)
  @new_service_semaphore.broadcast
  unless @thrifty_publishing
    @outgoing << [nil, UnPublish.new(service_id)]
  end
end

#unsubscribe(event_type, match, identity) ⇒ Object

Will stop listening for event_type and match with identity.



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# File 'lib/archipelago/disco.rb', line 528

def unsubscribe(event_type, match, identity)
  @service_change_subscribers_by_event_type[event_type].delete([match, identity])
end

#validate! ⇒ Object

Validate all our known services.



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# File 'lib/archipelago/disco.rb', line 688

def validate!
  @local_services.validate!
  @remote_services.validate!
end