Class: RServiceBus2::Host

Inherits:
Object
  • Object
show all
Defined in:
lib/rservicebus2/host.rb

Overview

Host process for rservicebus

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Host

Returns a new instance of Host.



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# File 'lib/rservicebus2/host.rb', line 151

def initialize
  RServiceBus2.rlog "Current directory: #{Dir.pwd}"
  @config = ConfigFromEnv.new.load_host_section
                              .load_contracts
                              .load_handler_path_list
                              .load_saga_path_list
                              .load_libs
                              .load_working_dir_list

  connect_to_mq

  @endpoint_mapping = EndpointMapping.new.configure(@mq.local_queue_name)

  self.configure_statistics
      .load_contracts
      .load_libs
      .configure_send_at_manager
      .configure_state_manager
      .configure_saga_storage
      .configure_app_resource
      .configure_circuit_breaker
      .configure_monitors
      .load_handlers
      .load_sagas
      .configure_cron_manager
      .configure_subscriptions
      .send_subscriptions

  self
end

Instance Attribute Details

#saga_data ⇒ Object

Returns the value of attribute saga_data.



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# File 'lib/rservicebus2/host.rb', line 13

def saga_data
  @saga_data
end

Instance Method Details

#_send_already_wrapped_and_serialised(serialized_object, queue_name) ⇒ Object

Sends a msg across the bus

Parameters:

  • serialized_object (String) —

    serialized RServiceBus2::Message

  • queue_name (String) —

    endpoint to which the msg will be sent



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# File 'lib/rservicebus2/host.rb', line 381

def _send_already_wrapped_and_serialised(serialized_object, queue_name)
  RServiceBus2.rlog 'Bus._send_already_wrapped_and_serialised'

  unless @config.forward_sent_messages_to.nil?
    @mq.send(@config.forward_sent_messages_to, serialized_object)
  end

  @mq.send(queue_name, serialized_object)
end

#_send_needs_wrapping(msg, queue_name, correlation_id) ⇒ Object

Sends a msg across the bus

Parameters:

  • msg (RServiceBus2::Message) —

    msg to be sent

  • queueName (String) —

    endpoint to which the msg will be sent



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# File 'lib/rservicebus2/host.rb', line 394

def _send_needs_wrapping(msg, queue_name, correlation_id)
  RServiceBus2.rlog 'Bus._send_needs_wrapping'

  r_msg = RServiceBus2::Message.new(msg, @mq.local_queue_name, correlation_id)
  if queue_name.index('@').nil?
    q = queue_name
    RServiceBus2.rlog "Sending, #{msg.class.name} to, #{queue_name}"
  else
    parts = queue_name.split('@')
    r_msg.set_remote_queue_name(parts[0])
    r_msg.set_remote_host_name(parts[1])
    q = 'transport-out'
    RServiceBus2.rlog "Sending, #{msg.class.name} to, #{queue_name}, via #{q}"
  end

  serialized_object = YAML.dump(r_msg)
  _send_already_wrapped_and_serialised(serialized_object, q)
end

#configure_app_resource ⇒ Object

Thin veneer for Configuring external resources



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# File 'lib/rservicebus2/host.rb', line 23

def configure_app_resource
  @resource_manager = ConfigureAppResource.new
                                          .get_resources(ENV,
                                                         self,
                                                         @state_manager,
                                                         @saga_storage)
  self
end

#configure_circuit_breaker ⇒ Object

Thin veneer for Configuring Cron



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# File 'lib/rservicebus2/host.rb', line 55

def configure_circuit_breaker
  @circuit_breaker = CircuitBreaker.new(self)
  self
end

#configure_cron_manager ⇒ Object

Thin veneer for Configuring Cron



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# File 'lib/rservicebus2/host.rb', line 111

def configure_cron_manager
  @cron_manager = CronManager.new(self, @handler_manager.get_list_of_msg_names)
  self
end

#configure_monitors ⇒ Object

Thin veneer for Configuring external resources



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# File 'lib/rservicebus2/host.rb', line 61

def configure_monitors
  @monitors = ConfigureMonitor.new(self, @resource_manager).get_monitors(ENV)
  self
end

#configure_saga_storage ⇒ Object

Thin veneer for Configuring state



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# File 'lib/rservicebus2/host.rb', line 45

def configure_saga_storage
  string = RServiceBus2.get_value('SAGA_URI')
  string = 'dir:///tmp' if string.nil?

  uri = URI.parse(string)
  @saga_storage = SagaStorage.get(uri)
  self
end

#configure_send_at_manager ⇒ Object

Thin veneer for Configuring SendAt



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# File 'lib/rservicebus2/host.rb', line 33

def configure_send_at_manager
  @send_at_manager = SendAtManager.new(self)
  self
end

#configure_state_manager ⇒ Object

Thin veneer for Configuring state



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# File 'lib/rservicebus2/host.rb', line 39

def configure_state_manager
  @state_manager = StateManager.new
  self
end

#configure_statistics ⇒ Object

Initialise statistics monitor



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# File 'lib/rservicebus2/host.rb', line 146

def configure_statistics
  @stats = StatisticManager.new( self )
  self
end

#configure_subscriptions ⇒ Object

Load, configure and initialise Subscriptions



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# File 'lib/rservicebus2/host.rb', line 139

def configure_subscriptions
  subscription_storage = ConfigureSubscriptionStorage.new.get(@config.app_name, @config.subscription_uri)
  @subscription_manager = SubscriptionManager.new(subscription_storage)
  self
end

#connect_to_mq ⇒ Object

Thin veneer for Configuring the Message Queue



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# File 'lib/rservicebus2/host.rb', line 67

def connect_to_mq
  @mq = MQ.get
  self
end

#get_endpoint_for_msg(msg_name) ⇒ Object 



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# File 'lib/rservicebus2/host.rb', line 440

def get_endpoint_for_msg(msg_name)
  queue_name = @endpoint_mapping.get(msg_name)
  return queue_name unless queue_name.nil?

  return @mq.local_queue_name if @handler_manager.can_msg_be_handled_locally(msg_name)

  log 'No end point mapping found for: ' + msg_name
  log '**** Check environment variable MessageEndpointMappings contains an entry named : ' + msg_name
  raise 'No end point mapping found for: ' + msg_name
end

#handle_message ⇒ Object

Send the current msg to the appropriate handlers



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# File 'lib/rservicebus2/host.rb', line 337

def handle_message
  @resource_manager.begin
  msg_name = @msg.msg.class.name
  handler_list = @handler_manager.get_handler_list_for_msg(msg_name)
  RServiceBus2.rlog 'Handler found for: ' + msg_name
  begin
    @queue_for_msgs_to_be_sent_on_complete = []

    log "Started processing msg, #{msg_name}"
    handler_list.each do |handler|
      begin
        log "Handler, #{handler.class.name}, Started"
        handler.handle(@msg.msg)
        log "Handler, #{handler.class.name}, Finished"
      rescue PropertyNotSet => e
        raise PropertyNotSet.new( "Property, #{e.message}, not set for, #{handler.class.name}" )
      rescue StandardError => e
        puts "E #{e.message}"
        log 'An error occurred in Handler: ' + handler.class.name
        raise e
      end
    end

    if @saga_manager.handle(@msg) == false && handler_list.length == 0
      fail NoHandlerFound, msg_name
    end
    @resource_manager.commit(msg_name)

    send_queued_msgs
    log "Finished processing msg, #{msg_name}"

  rescue StandardError => e
    @resource_manager.rollback(msg_name)
    @queue_for_msgs_to_be_sent_on_complete = nil
    raise e
  end
end

#load_contracts ⇒ Object

Load Contracts



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# File 'lib/rservicebus2/host.rb', line 117

def load_contracts
  log 'Load Contracts'

  @config.contract_list.each do |path|
    require path
    RServiceBus2.rlog "Loaded Contract: #{path}"
  end

  self
end

#load_handlers ⇒ Object

Load and configure Message Handlers



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# File 'lib/rservicebus2/host.rb', line 85

def load_handlers
  log 'Load Message Handlers'
  @handler_manager = HandlerManager.new(self, @resource_manager, @state_manager)
  @handler_loader = HandlerLoader.new(self, @handler_manager)

  @config.handler_path_list.each do |path|
    @handler_loader.load_handlers_from_path(path)
  end

  self
end

#load_libs ⇒ Object

For each directory given, find and load all librarys



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# File 'lib/rservicebus2/host.rb', line 129

def load_libs
  log 'Load Libs'
  @config.lib_list.each do |path|
    $:.unshift path
  end

  self
end

#load_sagas ⇒ Object

Load and configure Sagas



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# File 'lib/rservicebus2/host.rb', line 98

def load_sagas
  log 'Load Sagas'
  @saga_manager = SagaManager.new(self, @resource_manager, @saga_storage)
  @saga_loader = SagaLoader.new(self, @saga_manager)

  @config.saga_path_list.each do |path|
    @saga_loader.load_sagas_from_path(path)
  end

  self
end

#log(string, ver = false) ⇒ Object

Provides a thin logging veneer

Parameters:

  • string (String) —

    Log entry

  • ver (Boolean) (defaults to: false) —

    Indicator for a verbose log entry



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# File 'lib/rservicebus2/host.rb', line 18

def log(string, ver = false)
  RServiceBus2.log(string, ver)
end

#publish(msg) ⇒ Object

Sends an event to all subscribers across the bus

Parameters:



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# File 'lib/rservicebus2/host.rb', line 466

def publish(msg)
  RServiceBus2.rlog 'Bus.Publish'
  @stats.inc_total_published

  subscriptions = @subscription_manager.get(msg.class.name)
  subscriptions.each do |subscriber|
    queue_msg_for_send_on_complete(msg, subscriber)
  end
end

#queue_msg_for_send_on_complete(msg, queue_name, timestamp = nil) ⇒ Object 



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# File 'lib/rservicebus2/host.rb', line 423

def queue_msg_for_send_on_complete(msg, queue_name, timestamp = nil)
  correlation_id = @saga_data.nil? ? nil : @saga_data.correlation_id
  correlation_id = (!@msg.nil? && !@msg.correlation_id.nil?) ? @msg.correlation_id : correlation_id
  @queue_for_msgs_to_be_sent_on_complete << Hash['msg', msg, 'queue_name', queue_name, 'correlation_id', correlation_id, 'timestamp',timestamp ]
end

#reply(msg) ⇒ Object

Sends a msg back across the bus Reply queues are specified in each msg. It works like email, where the reply address can actually be anywhere

Parameters:



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# File 'lib/rservicebus2/host.rb', line 433

def reply(msg)
  RServiceBus2.rlog 'Reply with: ' + msg.class.name + ' To: ' + @msg.return_address
  @stats.inc_total_reply

  queue_msg_for_send_on_complete(msg, @msg.return_address)
end

#run ⇒ Object

Ignition



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# File 'lib/rservicebus2/host.rb', line 183

def run
  log 'Starting the Host'
  log "Watching, #{@mq.local_queue_name}"
  $0 = "rservicebus - #{@mq.local_queue_name}"
  unless @config.forward_received_messages_to.nil?
    log 'Forwarding all received messages to: ' + @config.forward_received_messages_to.to_s
  end
  unless @config.forward_sent_messages_to.nil?
    log 'Forwarding all sent messages to: ' + @config.forward_sent_messages_to.to_s
  end

  start_listening_to_endpoints
end

#send(msg, timestamp = nil) ⇒ Object

Send a msg across the bus msg destination is specified at the infrastructure level

Parameters:



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# File 'lib/rservicebus2/host.rb', line 455

def send( msg, timestamp=nil )
  RServiceBus2.rlog 'Bus.Send'
  @stats.inc_total_sent

  msg_name = msg.class.name
  queue_name = self.get_endpoint_for_msg(msg_name)
  queue_msg_for_send_on_complete(msg, queue_name, timestamp)
end

#send_queued_msgs ⇒ Object 



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# File 'lib/rservicebus2/host.rb', line 413

def send_queued_msgs
  @queue_for_msgs_to_be_sent_on_complete.each do |row|
    if row['timestamp'].nil?
      _send_needs_wrapping(row['msg'], row['queue_name'], row['correlation_id'])
    else
      @send_at_manager.add(row)
    end
  end
end

#send_subscriptions ⇒ Object

Subscriptions are specified by adding events to the msg endpoint mapping



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# File 'lib/rservicebus2/host.rb', line 74

def send_subscriptions
  log 'Send Subscriptions'

  @endpoint_mapping.get_subscription_endpoints.each do |event_name|
    subscribe(event_name)
  end

  self
end

#start_listening_to_endpoints ⇒ Object

Receive a msg, prep it, and handle any errors that may occur

  • Most of this should be queue independant



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# File 'lib/rservicebus2/host.rb', line 199

def start_listening_to_endpoints
  log 'Waiting for messages. To exit press CTRL+C'
  message_loop = true
  retries = @config.max_retries

  while message_loop
    # Popping a msg off the queue should not be in the message handler,
    #  as it affects retry
    begin
      @stats.tick
      if @circuit_breaker.broken
        sleep 0.5
        next
      end

      body = @mq.pop
      begin
        @stats.inc_total_processed
        @msg = YAML.load(body)
        case @msg.msg.class.name
        when 'RServiceBus2::MessageSubscription'
          @subscription_manager.add(@msg.msg.event_name,
                                    @msg.return_address)
        when 'RServiceBus2::MessageStatisticOutputOn'
          @stats.output = true
          log 'Turn on Stats logging'
        when 'RServiceBus2::MessageStatisticOutputOff'
          @stats.output = false
          log 'Turn off Stats logging'
        when 'RServiceBus2::MessageVerboseOutputOn'
          ENV['VERBOSE'] = 'true'
          log 'Turn on Verbose logging'
        when 'RServiceBus2::MessageVerboseOutputOff'
          ENV.delete('VERBOSE')
          log 'Turn off Verbose logging'
        else
          handle_message
          unless @config.forward_received_messages_to.nil?
            _send_already_wrapped_and_serialised(body, @config.forward_received_messages_to)
          end
        end
        @mq.ack
      rescue ClassNotFoundForMsg => e
        puts "*** Class not found for msg, #{e.message}"
        puts "*** Ensure, #{e.message}, is defined in contract.rb, most
          likely as 'Class #{e.message} end"

        @msg.add_error_msg(@mq.local_queue_name, e.message)
        serialized_object = YAML.dump(@msg)
        _send_already_wrapped_and_serialised(serialized_object,
                                             @config.error_queue_name)
        @mq.ack
      rescue NoHandlerFound => e
        puts "*** Handler not found for msg, #{e.message}"
        puts "*** Ensure a handler named, #{e.message}, is present in the
          messagehandler directory."

        @msg.add_error_msg(@mq.local_queue_name, e.message)
        serialized_object = YAML.dump(@msg)
        _send_already_wrapped_and_serialised(serialized_object,
                                             @config.error_queue_name)
        @mq.ack

      rescue PropertyNotSet => e
        # This has been re-rasied from a rescue in the handler
        puts "*** #{e.message}"
        # "Property, #{e.message}, not set for, #{handler.class.name}"
        property_name = e.message[10, e.message.index(',', 10) - 10]
        puts "*** Ensure the environment variable, RSB_#{property_name},
          has been set at startup."

      rescue StandardError => e
        sleep 0.5

        puts '*** Exception occurred'
        puts e.message
        puts e.backtrace
        puts '***'

        if retries > 0
          retries -= 1
          @mq.return_to_queue
        else
          @circuit_breaker.failure
          @stats.inc_total_errored
          if e.class.name == 'Beanstalk::NotConnected'
            puts 'Lost connection to beanstalkd.'
            puts '*** Start or Restart beanstalkd and try again.'
            abort
          end

          if e.class.name == 'Redis::CannotConnectError'
            puts 'Lost connection to redis.'
            puts '*** Start or Restart redis and try again.'
            abort
          end

          error_string = e.message + '. ' + e.backtrace.join('. ')
          @msg.add_error_msg(@mq.local_queue_name, error_string)
          serialized_object = YAML.dump(@msg)
          _send_already_wrapped_and_serialised(serialized_object, @config.error_queue_name)
          @mq.ack
          retries = @config.max_retries
        end
      end
    rescue SystemExit, Interrupt
      puts 'Exiting on request ...'
      message_loop = false
    rescue NoMsgToProcess => e
      # This exception is just saying there are no messages to process
      @queue_for_msgs_to_be_sent_on_complete = []
      @monitors.each(&:look)
      send_queued_msgs
      @queue_for_msgs_to_be_sent_on_complete = nil

      @queue_for_msgs_to_be_sent_on_complete = []
      @cron_manager.run
      send_queued_msgs
      @queue_for_msgs_to_be_sent_on_complete = nil

      @send_at_manager.process
      @circuit_breaker.success

    rescue StandardError => e
      if e.message == 'SIGTERM' || e.message == 'SIGINT'
        puts 'Exiting on request ...'
        message_loop = false
      else
        puts '*** This is really unexpected.'
        message_loop = false
        puts 'Message: ' + e.message
        puts e.backtrace
      end
    end
  end
end

#subscribe(event_name) ⇒ Object

Sends a subscription request across the Bus

Parameters:

  • eventName (String) —

    event to be subscribes to



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# File 'lib/rservicebus2/host.rb', line 478

def subscribe(event_name)
  RServiceBus2.rlog 'Bus.Subscribe: ' + event_name

  queue_name = get_endpoint_for_msg(event_name)
  subscription = MessageSubscription.new(event_name)

  _send_needs_wrapping(subscription, queue_name, nil)
end