Class: EventHub::ActorListener

Inherits:
Object
  • Object
show all
Includes:
Celluloid, Helper
Defined in:
lib/eventhub/actor_listener.rb

Overview

Listner Class

Instance Method Summary collapse

Methods included from Helper

#bunny_connection_properties, #get_name_from_class, #now_stamp

Constructor Details

#initialize(processor_instance) ⇒ ActorListener

Returns a new instance of ActorListener.



9
10
11
12
13
14
 
# File 'lib/eventhub/actor_listener.rb', line 9

def initialize(processor_instance)
  @actor_watchdog = ActorWatchdog.new_link
  @connections= {}
  @processor_instance = processor_instance
  start
end

Instance Method Details

#cleanup ⇒ Object 



152
153
154
155
156
157
158
 
# File 'lib/eventhub/actor_listener.rb', line 152

def cleanup
  EventHub.logger.info('Listener is cleanig up...')
  # close all open connections
  @connections.values.each do |connection|
    connection.close if connection
  end
end

#handle_payload(args = {}) ⇒ Object 



72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
 
# File 'lib/eventhub/actor_listener.rb', line 72

def handle_payload(args = {})
  response_messages = []
  connection = args[:connection]

  # convert to EventHub message
  message = EventHub::Message.from_json(args[:payload])

  # append to execution history
  message.append_to_execution_history(EventHub::Configuration.name)

  # return invalid messages to dispatcher
  if message.invalid?
    response_messages << message
    EventHub.logger.info("-> #{message.to_s} => return invalid to dispatcher")
  else
    begin
      response_messages = @processor_instance.send(:handle_message,
                                                   message,
                                                   pass_arguments(args))
    rescue => exception
      # this catches unexpected exceptions in handle message method
      # deadletter the message via dispatcher
      message.status_code = EventHub::STATUS_DEADLETTER
      message.status_message = exception
      EventHub.logger.info("-> #{message.to_s} => return exception to diaptcher")
      response_messages << message
    end
  end

  Array(response_messages).each do |message|
    publish(message: message.to_json, connection: connection)
  end
end

#listen(args = {}) ⇒ Object 



27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
 
# File 'lib/eventhub/actor_listener.rb', line 27

def listen(args = {})
  with_listen(args) do |connection, channel, consumer, queue, queue_name|
    EventHub.logger.info("Listening to queue [#{queue_name}]")
    consumer.on_delivery do |delivery_info, metadata, payload|
      EventHub.logger.info("#{queue_name}: [#{delivery_info.delivery_tag}]"\
                             ' delivery')

      # EventHub::logger.debug("delivery_info: #{delivery_info.inspect}")
      # EventHub::logger.debug("metadata: #{metadata.inspect}")

      @processor_instance.statistics.measure(payload.size) do
        handle_payload(payload: payload,
                       connection: connection,
                       queue_name: queue_name,
                       content_type: metadata[:content_type],
                       priority: metadata[:priority],
                       delivery_tag: delivery_info.delivery_tag
                       )
        channel.acknowledge(delivery_info.delivery_tag, false)
      end

      EventHub.logger.info("#{queue_name}: [#{delivery_info.delivery_tag}]"\
                           ' acknowledged')
    end
    queue.subscribe_with(consumer, block: false)
  end
end

#pass_arguments(args = {}) ⇒ Object 



106
107
108
109
 
# File 'lib/eventhub/actor_listener.rb', line 106

def pass_arguments(args = {})
  keys_to_pass = [:queue_name, :content_type, :priority, :delivery_tag]
  args.select{ |key| keys_to_pass.include?(key) }
end

#publish(args = {}) ⇒ Object 



111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
 
# File 'lib/eventhub/actor_listener.rb', line 111

def publish(args = {})
  with_publish(args) do |connection, exchange_name, message|
    begin
      channel = connection.create_channel
      channel.confirm_select
      exchange = channel.direct(exchange_name, durable: true)
      exchange.publish(message, persistent: true)

      success = channel.wait_for_confirms

      unless success
        raise 'Published message from Listener actor '\
          'has not been confirmed by the server'
      end
    ensure
      channel.close if channel
    end
  end
end

#restart ⇒ Object 



23
24
25
 
# File 'lib/eventhub/actor_listener.rb', line 23

def restart
  raise 'Listener is restarting...'
end

#start ⇒ Object 



16
17
18
19
20
21
 
# File 'lib/eventhub/actor_listener.rb', line 16

def start
  EventHub.logger.info('Listener is starting...')
  EventHub::Configuration.processor[:listener_queues].each_with_index do |queue_name, index|
    async.listen(queue_name: queue_name, index: index)
  end
end

#with_listen(args = {}) {|connection, channel, consumer, queue, queue_name| ... } ⇒ Object

Yields:

  • (connection, channel, consumer, queue, queue_name) 


55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
 
# File 'lib/eventhub/actor_listener.rb', line 55

def with_listen(args = {}, &block)
  connection = Bunny.new(bunny_connection_properties)
  connection.start
  queue_name = args[:queue_name]
  @connections[queue_name] = connection
  channel = connection.create_channel
  channel.prefetch(1)
  queue = channel.queue(queue_name, durable: true)
  consumer = EventHub::Consumer.new(channel,
                                    queue,
                                    EventHub::Configuration.name +
                                      '-' +
                                      args[:index].to_s,
                                    false)
  yield connection, channel, consumer, queue, queue_name
end

#with_publish(args = {}, &block) ⇒ Object 



132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
 
# File 'lib/eventhub/actor_listener.rb', line 132

def with_publish(args = {}, &block)
  message = args[:message]
  return if message.nil?

  need_to_close = false
  connection = args[:connection]
  if connection.nil?
    connection = Bunny.new(bunny_connection_properties)
    connection.start
    need_to_close = true
  end

  exchange_name = args[:exchange_name] || EH_X_INBOUND

  yield connection, exchange_name, message
ensure
  connection.close if connection && need_to_close
end