Class: Bunny::Consumer

Inherits:
Object
  • Object
show all
Defined in:
lib/bunny/consumer.rb

Overview

Base class that represents consumer interface. Subclasses of this class implement specific logic of handling consumer life cycle events. Note that when the only event you are interested in is message deliveries, it is recommended to just use Queue#subscribe instead of subclassing this class.

See Also:

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(channel, queue, consumer_tag = channel.generate_consumer_tag, no_ack = true, exclusive = false, arguments = {}) ⇒ Consumer

Returns a new instance of Consumer.

Parameters:

  • channel (Bunny::Channel) —

    Channel this consumer will use

  • queue (Bunny::Queue, String) —

    Queue messages will be consumed from

  • consumer_tag (String) (defaults to: channel.generate_consumer_tag) —

    Consumer tag (unique identifier). Generally it is better to let Bunny generate one. Empty string means RabbitMQ will generate consumer tag.

  • no_ack (Boolean) (defaults to: true) —

    (true) If true, delivered messages will be automatically acknowledged. If false, manual acknowledgements will be necessary.

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

    (false) Should this consumer be exclusive?

  • arguments (Hash) (defaults to: {}) —

    (nil) Optional arguments that may be used by RabbitMQ extensions, etc



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# File 'lib/bunny/consumer.rb', line 34

def initialize(channel, queue, consumer_tag = channel.generate_consumer_tag, no_ack = true, exclusive = false, arguments = {})
  @channel       = channel || raise(ArgumentError, "channel is nil")
  @queue         = queue   || raise(ArgumentError, "queue is nil")
  @consumer_tag  = consumer_tag
  @exclusive     = exclusive
  @arguments     = arguments
  # no_ack set to true = no manual ack = automatic ack. MK.
  @no_ack        = no_ack

  @on_cancellation = []
end

Instance Attribute Details

#arguments ⇒ Object (readonly) 



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# File 'lib/bunny/consumer.rb', line 20

def arguments
  @arguments
end

#channel ⇒ Object (readonly)

API



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# File 'lib/bunny/consumer.rb', line 17

def channel
  @channel
end

#consumer_tag ⇒ Object 



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# File 'lib/bunny/consumer.rb', line 19

def consumer_tag
  @consumer_tag
end

#exclusive ⇒ Object (readonly) 



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# File 'lib/bunny/consumer.rb', line 22

def exclusive
  @exclusive
end

#no_ack ⇒ Object (readonly) 



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# File 'lib/bunny/consumer.rb', line 21

def no_ack
  @no_ack
end

#queue ⇒ Object (readonly) 



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# File 'lib/bunny/consumer.rb', line 18

def queue
  @queue
end

Instance Method Details

#automatic_acknowledgement? ⇒ Boolean

Returns true if this consumer uses automatic acknowledgement mode.

Returns:

  • (Boolean) —

    true if this consumer uses automatic acknowledgement mode



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# File 'lib/bunny/consumer.rb', line 99

def automatic_acknowledgement?
  @no_ack == true
end

#call(*args) ⇒ Object Also known as: handle_delivery

Invokes message delivery handler



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# File 'lib/bunny/consumer.rb', line 55

def call(*args)
  @on_delivery.call(*args) if @on_delivery
end

#cancel ⇒ Object

Cancels this consumer. Messages for this consumer will no longer be delivered. If the queue it was on is auto-deleted and this consumer was the last one, the queue will be deleted.

See Also:



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# File 'lib/bunny/consumer.rb', line 83

def cancel
  @channel.basic_cancel(@consumer_tag)
end

#handle_cancellation(basic_cancel) ⇒ Object

Invokes consumer cancellation notification handler



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# File 'lib/bunny/consumer.rb', line 72

def handle_cancellation(basic_cancel)
  @on_cancellation.each do |fn|
    fn.call(basic_cancel)
  end
end

#inspect ⇒ String

Returns More detailed human-readable string representation of this consumer.

Returns:

  • (String) —

    More detailed human-readable string representation of this consumer



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# File 'lib/bunny/consumer.rb', line 88

def inspect
  "#<#{self.class.name}:#{object_id} @channel_id=#{@channel.number} @queue=#{self.queue_name} @consumer_tag=#{@consumer_tag} @exclusive=#{@exclusive} @no_ack=#{@no_ack}>"
end

#manual_acknowledgement? ⇒ Boolean

Returns true if this consumer uses manual (explicit) acknowledgement mode.

Returns:

  • (Boolean) —

    true if this consumer uses manual (explicit) acknowledgement mode



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# File 'lib/bunny/consumer.rb', line 105

def manual_acknowledgement?
  @no_ack == false
end

#on_cancellation(&block) ⇒ Object

Defines consumer cancellation notification handler

See Also:



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# File 'lib/bunny/consumer.rb', line 65

def on_cancellation(&block)
  @on_cancellation << block
  self
end

#on_delivery(&block) ⇒ Object

Defines message delivery handler



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# File 'lib/bunny/consumer.rb', line 48

def on_delivery(&block)
  @on_delivery = block
  self
end

#queue_name ⇒ String

Returns Name of the queue this consumer is on.

Returns:

  • (String) —

    Name of the queue this consumer is on



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# File 'lib/bunny/consumer.rb', line 111

def queue_name
  if @queue.respond_to?(:name)
    @queue.name
  else
    @queue
  end
end

#recover_from_network_failure ⇒ Object 



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# File 'lib/bunny/consumer.rb', line 124

def recover_from_network_failure
  @channel.basic_consume_with(self)
end

#to_s ⇒ String

Returns Brief human-readable string representation of this consumer.

Returns:

  • (String) —

    Brief human-readable string representation of this consumer



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# File 'lib/bunny/consumer.rb', line 93

def to_s
  "#<#{self.class.name}:#{object_id} @channel_id=#{@channel.number} @queue=#{self.queue_name} @consumer_tag=#{@consumer_tag}>"
end