Class: Bunny::Queue09

Inherits:
Qrack::Queue show all
Defined in:
lib/bunny/queue09.rb

Overview

Queues store and forward messages. Queues can be configured in the server or created at runtime. Queues must be attached to at least one exchange in order to receive messages from publishers.

Instance Attribute Summary

Attributes inherited from Qrack::Queue

#client, #delivery_tag, #name

Instance Method Summary collapse

Methods inherited from Qrack::Queue

#consumer_count, #message_count, #publish

Constructor Details

#initialize(client, name, opts = {}) ⇒ Queue09

Returns a new instance of Queue09.

Raises:



8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
 
# File 'lib/bunny/queue09.rb', line 8

def initialize(client, name, opts = {})
  # check connection to server
  raise Bunny::ConnectionError, 'Not connected to server' if client.status == :not_connected

  @client = client
  @opts   = opts
  @delivery_tag = nil

  # Queues without a given name are named by the server and are generally
  # bound to the process that created them.
  if !name
    opts = {
      :passive => false,
      :durable => false,
      :exclusive => true,
      :auto_delete => true,
      :deprecated_ticket => 0
    }.merge(opts)
  end

  # ignore the :nowait option if passed, otherwise program will hang waiting for a
  # response that will not be sent by the server
  opts.delete(:nowait)

  opts = { :queue => name || '', :nowait => false, :deprecated_ticket => 0 }.merge(opts)

  client.send_frame(Qrack::Protocol09::Queue::Declare.new(opts))

  method = client.next_method

  client.check_response(method, Qrack::Protocol09::Queue::DeclareOk, "Error declaring queue #{name}")

  @name = method.queue
  client.queues[@name] = self
end

Instance Method Details

#ack(opts = {}) ⇒ Object

Acknowledges one or more messages delivered via the Deliver or Get_-_Ok methods. The client can ask to confirm a single message or a set of messages up to and including a specific message.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :delivery_tag (String)
  • :multiple (Boolean) — default: false —

    If set to true, the delivery tag is treated as “up to and including”, so that the client can acknowledge multiple messages with a single method. If set to false, the delivery tag refers to a single message. If the multiple field is true, and the delivery tag is zero, tells the server to acknowledge all outstanding messages.



71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
 
# File 'lib/bunny/queue09.rb', line 71

def ack(opts = {})
  # Set delivery tag
  if delivery_tag.nil? and opts[:delivery_tag].nil?
    raise Bunny::AcknowledgementError, "No delivery tag received"
  else
    self.delivery_tag = opts[:delivery_tag] if delivery_tag.nil?
  end

  opts = {:delivery_tag => delivery_tag, :multiple => false}.merge(opts)

  client.send_frame(Qrack::Protocol09::Basic::Ack.new(opts))

  # reset delivery tag
  self.delivery_tag = nil
end

#bind(exchange, opts = {}) ⇒ Symbol

Binds a queue to an exchange. Until a queue is bound it won’t receive any messages. Queues are bound to the direct exchange ’’ by default. If error occurs, a ProtocolError is raised.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :key (String) —

    Specifies the routing key for the binding. The routing key is used for routing messages depending on the exchange configuration.

  • :nowait (Boolean) — default: false —

    Ignored by Bunny, always false.

Returns:

  • (Symbol) —

    :bind_ok if successful.



99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
 
# File 'lib/bunny/queue09.rb', line 99

def bind(exchange, opts = {})
  exchange = exchange.respond_to?(:name) ? exchange.name : exchange

  # ignore the :nowait option if passed, otherwise program will hang waiting for a
  # response that will not be sent by the server
  opts.delete(:nowait)

  opts = {
    :queue => name,
    :exchange => exchange,
    :routing_key => opts.delete(:key),
    :nowait => false,
    :deprecated_ticket => 0
  }.merge(opts)

  client.send_frame(Qrack::Protocol09::Queue::Bind.new(opts))

  method = client.next_method

  client.check_response(method, Qrack::Protocol09::Queue::BindOk, "Error binding queue: #{name} to exchange: #{exchange}")

  # return message
  :bind_ok
end

#default_consumer ⇒ Bunny::Consumer

Note:

Default consumer is the one registered with the convenience Bunny::Queue#subscribe method. It has no special properties of any kind.

Returns Default consumer associated with this queue (if any), or nil.

Returns:

  • (Bunny::Consumer) —

    Default consumer associated with this queue (if any), or nil

See Also:



49
50
51
 
# File 'lib/bunny/queue09.rb', line 49

def default_consumer
  @default_consumer
end

#delete(opts = {}) ⇒ Symbol

Requests that a queue is deleted from broker/server. When a queue is deleted any pending messages are sent to a dead-letter queue if this is defined in the server configuration. Removes reference from queues if successful. If an error occurs raises Bunny::ProtocolError.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :if_unused (Boolean) — default: false —

    If set to true, the server will only delete the queue if it has no consumers. If the queue has consumers the server does not delete it but raises a channel exception instead.

  • :if_empty (Boolean) — default: false —

    If set to true, the server will only delete the queue if it has no messages. If the queue is not empty the server raises a channel exception.

  • :nowait (Boolean) — default: false —

    Ignored by Bunny, always false.

Returns:

  • (Symbol) —

    :delete_ok if successful



140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
 
# File 'lib/bunny/queue09.rb', line 140

def delete(opts = {})
  # ignore the :nowait option if passed, otherwise program will hang waiting for a
  # response that will not be sent by the server
  opts.delete(:nowait)

  opts = { :queue => name, :nowait => false, :deprecated_ticket => 0 }.merge(opts)

  client.send_frame(Qrack::Protocol09::Queue::Delete.new(opts))

  method = client.next_method

  client.check_response(method, Qrack::Protocol09::Queue::DeleteOk, "Error deleting queue #{name}")

  client.queues.delete(name)

  # return confirmation
  :delete_ok
end

#pop(opts = {}, &blk) ⇒ Hash

Gets a message from a queue in a synchronous way. If error occurs, raises Bunny_::_ProtocolError.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :ack (Boolean) — default: false —

    If set to false, the server does not expect an acknowledgement message from the client. If set to true, the server expects an acknowledgement message from the client and will re-queue the message if it does not receive one within a time specified by the server.

Returns:

  • (Hash) —

    Hash with :header, :payload and :delivery_details keys. :delivery_details is a hash :consumer_tag, :delivery_tag, :redelivered, :exchange and :routing_key. If the queue is empty the returned hash will contain: {:header => nil, :payload => :queue_empty, :delivery_details => nil}. N.B. If a block is provided then the hash will be passed into the block and the return value will be nil.



168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
 
# File 'lib/bunny/queue09.rb', line 168

def pop(opts = {}, &blk)
  opts = {
    :queue => name,
    :consumer_tag => name,
    :no_ack => !opts[:ack],
    :nowait => true,
    :deprecated_ticket => 0
  }.merge(opts)

  client.send_frame(Qrack::Protocol09::Basic::Get.new(opts))

  method = client.next_method

  if method.is_a?(Qrack::Protocol09::Basic::GetEmpty) then
    queue_empty = true
  elsif !method.is_a?(Qrack::Protocol09::Basic::GetOk)
    raise Bunny::ProtocolError, "Error getting message from queue #{name}"
  end

  if !queue_empty
    # get delivery tag to use for acknowledge
    self.delivery_tag = method.delivery_tag if opts[:ack]

    header = client.next_payload

    # If maximum frame size is smaller than message payload body then message
    # will have a message header and several message bodies
    msg = ''
    while msg.length < header.size
      msg << client.next_payload
    end

    msg_hash = {:header => header, :payload => msg, :delivery_details => method.arguments}

  else
    msg_hash = {:header => nil, :payload => :queue_empty, :delivery_details => nil}
  end

  # Pass message hash to block or return message hash
  blk ? blk.call(msg_hash) : msg_hash
end

#purge(opts = {}) ⇒ Symbol

Removes all messages from a queue. It does not cancel consumers. Purged messages are deleted without any formal “undo” mechanism. If an error occurs raises ProtocolError.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :nowait (Boolean) — default: false —

    Ignored by Bunny, always false.

Returns:

  • (Symbol) —

    :purge_ok if successful



217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
 
# File 'lib/bunny/queue09.rb', line 217

def purge(opts = {})
  # ignore the :nowait option if passed, otherwise program will hang waiting for a
  # response that will not be sent by the server
  opts.delete(:nowait)

  opts = { :queue => name, :nowait => false, :deprecated_ticket => 0 }.merge(opts)

  client.send_frame(Qrack::Protocol09::Queue::Purge.new(opts))

  method = client.next_method

  client.check_response(method,   Qrack::Protocol09::Queue::PurgeOk, "Error purging queue #{name}")

  # return confirmation
  :purge_ok
end

#status ⇒ Hash

Returns Hash with keys :message_count and consumer_count.

Returns:

  • (Hash) —

    Hash with keys :message_count and consumer_count.



235
236
237
238
239
240
241
 
# File 'lib/bunny/queue09.rb', line 235

def status
  opts = { :queue => name, :passive => true, :deprecated_ticket => 0 }
  client.send_frame(Qrack::Protocol09::Queue::Declare.new(opts))

  method = client.next_method
  {:message_count => method.message_count, :consumer_count => method.consumer_count}
end

#subscribe(opts = {}, &blk) ⇒ Object

Raises:

  • (RuntimeError) 


243
244
245
246
247
248
249
 
# File 'lib/bunny/queue09.rb', line 243

def subscribe(opts = {}, &blk)
  raise RuntimeError.new("This queue already has default consumer. Please instantiate Bunny::Consumer directly and call its #consume method to register additional consumers.") if @default_consumer && ! opts[:consumer_tag]

  # Create a subscription.
  @default_consumer = self.class.consumer_class.new(client, self, opts)
  @default_consumer.consume(&blk)
end

#unbind(exchange, opts = {}) ⇒ Symbol

Removes a queue binding from an exchange. If error occurs, a Bunny_::_ProtocolError is raised.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :key (String) —

    Specifies the routing key for the binding.

  • :nowait (Boolean) — default: false —

    Ignored by Bunny, always false.

Returns:

  • (Symbol) —

    :unbind_ok if successful.



260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
 
# File 'lib/bunny/queue09.rb', line 260

def unbind(exchange, opts = {})
  exchange = exchange.respond_to?(:name) ? exchange.name : exchange

  # ignore the :nowait option if passed, otherwise program will hang waiting for a
  # response that will not be sent by the server
  opts.delete(:nowait)

  opts = {
    :queue => name,
    :exchange => exchange,
    :routing_key => opts.delete(:key),
    :nowait => false,
    :deprecated_ticket => 0
  }.merge(opts)

  client.send_frame(Qrack::Protocol09::Queue::Unbind.new(opts))

  method = client.next_method

  client.check_response(method, Qrack::Protocol09::Queue::UnbindOk, "Error unbinding queue #{name}")

  # return message
  :unbind_ok
end

#unsubscribe(opts = {}) ⇒ Symbol

Cancels a consumer. This does not affect already delivered messages, but it does mean the server will not send any more messages for that consumer.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :consumer_tag (String) —

    Specifies the identifier for the consumer.

  • :nowait (Boolean) — default: false —

    Ignored by Bunny, always false.

Returns:

  • (Symbol) —

    :unsubscribe_ok if successful

Raises:



295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
 
# File 'lib/bunny/queue09.rb', line 295

def unsubscribe(opts = {})
  # Default consumer_tag from subscription if not passed in
  consumer_tag = @default_consumer ? @default_consumer.consumer_tag : opts[:consumer_tag]

  # Must have consumer tag to tell server what to unsubscribe
  raise Bunny::UnsubscribeError,
  "No consumer tag received" if !consumer_tag

  # Cancel consumer
  client.send_frame(Qrack::Protocol09::Basic::Cancel.new(:consumer_tag => consumer_tag, :nowait => false))

  method = client.next_method

  client.check_response(method, Qrack::Protocol09::Basic::CancelOk, "Error unsubscribing from queue #{name}")

  # Reset subscription
  @default_consumer = nil

  # Return confirmation
  :unsubscribe_ok
end