Class: EventHub::Processor

Inherits:
Object
  • Object
show all
Includes:
Helper
Defined in:
lib/eventhub/processor.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Helper

#class_to_array, #duration, #format_string, #now_stamp

Constructor Details

#initialize(name = nil) ⇒ Processor

Returns a new instance of Processor.



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# File 'lib/eventhub/processor.rb', line 11

def initialize(name=nil)
  @name = name || class_to_array(self.class)[1..-1].join('.')
  @pidfile = EventHub::Components::Pidfile.new(File.join(Dir.pwd, 'pids', "#{@name}.pid"))
  @exception_writer = EventHub::Components::ExceptionWriter.new
  @statistics = EventHub::Statistics.new
  @heartbeat = EventHub::Heartbeat.new(self)
  @message_processor = EventHub::MessageProcessor.new(self)

  @channel_receiver = nil
  @channel_sender   = nil
  @restart = true
end

Instance Attribute Details

#exception_writer ⇒ Object (readonly)

Returns the value of attribute exception_writer.



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# File 'lib/eventhub/processor.rb', line 3

def exception_writer
  @exception_writer
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/eventhub/processor.rb', line 3

def name
  @name
end

#pidfile ⇒ Object (readonly)

Returns the value of attribute pidfile.



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# File 'lib/eventhub/processor.rb', line 3

def pidfile
  @pidfile
end

#statistics ⇒ Object (readonly)

Returns the value of attribute statistics.



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# File 'lib/eventhub/processor.rb', line 3

def statistics
  @statistics
end

Instance Method Details

#configuration ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 24

def configuration
  EventHub::Configuration.instance.data
end

#connection_settings ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 48

def connection_settings
  { user: server_user, password: server_password, host: server_host, vhost: server_vhost }
end

#handle_message(metadata, payload) ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 103

def handle_message(metadata, payload)
  raise 'Please implement method in derived class'
end

#heartbeat_cycle_in_s ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 68

def heartbeat_cycle_in_s
  configuration.get('processor.heartbeat_cycle_in_s') || 300
end

#listener_queues ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 52

def listener_queues
  Array(
    configuration.get('processor.listener_queue') ||
    configuration.get('processor.listener_queues') ||
    'undefined_listener_queues'
  )
end

#restart_in_s ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 64

def restart_in_s
  configuration.get('processor.restart_in_s') || 15
end

#send_message(message, exchange_name = EventHub::EH_X_INBOUND) ⇒ Object

send message



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# File 'lib/eventhub/processor.rb', line 134

def send_message(message, exchange_name = EventHub::EH_X_INBOUND)

  if @channel_sender.nil? || !@channel_sender.open?
    @channel_sender = AMQP::Channel.new(@connection, prefetch: 1)

    # use publisher confirm
    @channel_sender.confirm_select

    # @channel.on_error { |ch, channel_close| EventHub.logger.error "Oops! a channel-level exception: #{channel_close.reply_text}" }
    # @channel.on_ack   { |basic_ack| EventHub.logger.info "Received basic_ack: multiple = #{basic_ack.multiple}, delivery_tag = #{basic_ack.delivery_tag}" }
  end

  exchange = @channel_sender.direct(exchange_name, :durable => true, :auto_delete => false)
  exchange.publish(message.to_json, :persistent => true)
end

#server_host ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 28

def server_host
  configuration.get('server.host') || 'localhost'
end

#server_management_port ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 40

def server_management_port
  configuration.get('server.management_port') || 15672
end

#server_password ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 36

def server_password
  configuration.get('server.password') || 'admin'
end

#server_user ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 32

def server_user
  configuration.get('server.user') || 'admin'
end

#server_vhost ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 44

def server_vhost
  configuration.get('server.vhost') || 'event_hub'
end

#sleep_break(seconds) ⇒ Object

breaks after n seconds or after interrupt



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# File 'lib/eventhub/processor.rb', line 150

def sleep_break(seconds) # breaks after n seconds or after interrupt
  while (seconds > 0)
    sleep(1)
    seconds -= 1
    break unless @restart
  end
end

#start(detached = false) ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 72

def start(detached = false)
  daemonize if detached

  EventHub.logger.info("Processor [#{@name}] base folder [#{Dir.pwd}]")

  # use timer here to have last heartbeat message working
  Signal.trap('TERM') { EventMachine.add_timer(0) { about_to_stop } }
  Signal.trap('INT')  { EventMachine.add_timer(0) { about_to_stop } }

  while @restart
    begin
      handle_start_internal

      # custom post start method to be overwritten
      post_start

    rescue => e
      id = @exception_writer.write(e)
      EventHub.logger.error("Unexpected exception: #{e}, see => #{id}. Trying to restart in #{self.restart_in_s} seconds...")
      sleep_break self.restart_in_s
    end
  end # while

  # custon post stop method to be overwritten
  post_stop

  EventHub.logger.info("Processor [#{@name}] has been stopped")
ensure
  pidfile.delete
end

#version ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 7

def version
  '1.0.0'
end

#watchdog ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 107

def watchdog
  self.listener_queues.each do |queue_name|
    begin
      response = RestClient.get "http://#{self.server_user}:#{self.server_password}@#{self.server_host}:#{self.server_management_port}/api/queues/#{self.server_vhost}/#{queue_name}/bindings", { :content_type => :json}
      data = JSON.parse(response.body)

      if response.code != 200
        EventHub.logger.warn("Watchdog: Server did not answered properly. Trying to restart in #{self.restart_in_s} seconds...")
        EventMachine.add_timer(self.restart_in_s) { stop_processor(true) }
      elsif data.size == 0
        EventHub.logger.warn("Watchdog: Something is wrong with the vhost, queue [#{queue_name}], and/or bindings. Trying to restart in #{self.restart_in_s} seconds...")
        EventMachine.add_timer(self.restart_in_s) { stop_processor(true) }
        # does it make sence ? Needs maybe more checks in future
      else
        # Watchdog is happy :-)
        # add timer for next check
        EventMachine.add_timer(self.watchdog_cycle_in_s) { watchdog }
      end

    rescue => e
      EventHub.logger.error("Watchdog: Unexpected exception: #{e}. Trying to restart in #{self.restart_in_s} seconds...")
      stop_processor
    end
  end
end

#watchdog_cycle_in_s ⇒ Object 



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# File 'lib/eventhub/processor.rb', line 60

def watchdog_cycle_in_s
  configuration.get('processor.watchdog_cycle_is_s') || 15
end