DESCRIPTION:
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.
| Class | Bunny::Queue |
| In: |
lib/bunny/queue08.rb
|
| Parent: | Qrack::Queue |
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.
# File lib/bunny/queue08.rb, line 14
14: def initialize(client, name, opts = {})
15: # check connection to server
16: raise Bunny::ConnectionError, 'Not connected to server' if client.status == :not_connected
17:
18: @client = client
19: @opts = opts
20: @delivery_tag = nil
21: @subscription = nil
22:
23: # Queues without a given name are named by the server and are generally
24: # bound to the process that created them.
25: if !name
26: opts = {
27: :passive => false,
28: :durable => false,
29: :exclusive => true,
30: :auto_delete => true
31: }.merge(opts)
32: end
33:
34: # ignore the :nowait option if passed, otherwise program will hang waiting for a
35: # response that will not be sent by the server
36: opts.delete(:nowait)
37:
38: client.send_frame(
39: Qrack::Protocol::Queue::Declare.new({ :queue => name || '', :nowait => false }.merge(opts))
40: )
41:
42: method = client.next_method
43:
44: client.check_response(method, Qrack::Protocol::Queue::DeclareOk, "Error declaring queue #{name}")
45:
46: @name = method.queue
47: client.queues[@name] = self
48: end
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.
# File lib/bunny/queue08.rb, line 67
67: def ack(opts={})
68: # Set delivery tag
69: if delivery_tag.nil? and opts[:delivery_tag].nil?
70: raise Bunny::AcknowledgementError, "No delivery tag received"
71: else
72: self.delivery_tag = opts[:delivery_tag] if delivery_tag.nil?
73: end
74:
75: client.send_frame(
76: Qrack::Protocol::Basic::Ack.new({:delivery_tag => delivery_tag, :multiple => false}.merge(opts))
77: )
78:
79: # reset delivery tag
80: self.delivery_tag = nil
81: end
Binds a queue to an exchange. Until a queue is bound it will not receive any messages. Queues are bound to the direct exchange ’’ by default. If error occurs, a Bunny::ProtocolError is raised.
:bind_ok if successful.
# File lib/bunny/queue08.rb, line 100
100: def bind(exchange, opts = {})
101: exchange = exchange.respond_to?(:name) ? exchange.name : exchange
102:
103: # ignore the :nowait option if passed, otherwise program will hang waiting for a
104: # response that will not be sent by the server
105: opts.delete(:nowait)
106:
107: client.send_frame(
108: Qrack::Protocol::Queue::Bind.new({ :queue => name,
109: :exchange => exchange,
110: :routing_key => opts.delete(:key),
111: :nowait => false }.merge(opts))
112: )
113:
114: method = client.next_method
115:
116: client.check_response(method, Qrack::Protocol::Queue::BindOk,
117: "Error binding queue: #{name} to exchange: #{exchange}")
118:
119: # return message
120: :bind_ok
121: end
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.
:delete_ok if successful
# File lib/bunny/queue08.rb, line 146
146: def delete(opts = {})
147: # ignore the :nowait option if passed, otherwise program will hang waiting for a
148: # response that will not be sent by the server
149: opts.delete(:nowait)
150:
151: client.send_frame(
152: Qrack::Protocol::Queue::Delete.new({ :queue => name, :nowait => false }.merge(opts))
153: )
154:
155: method = client.next_method
156:
157: client.check_response(method, Qrack::Protocol::Queue::DeleteOk, "Error deleting queue #{name}")
158:
159: client.queues.delete(name)
160:
161: # return confirmation
162: :delete_ok
163: end
Gets a message from a queue in a synchronous way. If error occurs, raises Bunny::ProtocolError.
Hash {:header, :payload, :delivery_details}. :delivery_details is a hash {:consumer_tag, :delivery_tag, :redelivered, :exchange, :routing_key}.
If the queue is empty the returned hash will contain the values -
: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.
# File lib/bunny/queue08.rb, line 194
194: def pop(opts = {}, &blk)
195:
196: # do we want to have to provide an acknowledgement?
197: ack = opts.delete(:ack)
198:
199: client.send_frame(
200: Qrack::Protocol::Basic::Get.new({ :queue => name,
201: :consumer_tag => name,
202: :no_ack => !ack,
203: :nowait => true }.merge(opts))
204: )
205:
206: method = client.next_method
207:
208: if method.is_a?(Qrack::Protocol::Basic::GetEmpty) then
209: queue_empty = true
210: elsif !method.is_a?(Qrack::Protocol::Basic::GetOk)
211: raise Bunny::ProtocolError, "Error getting message from queue #{name}"
212: end
213:
214: if !queue_empty
215: # get delivery tag to use for acknowledge
216: self.delivery_tag = method.delivery_tag if ack
217:
218: header = client.next_payload
219:
220: # If maximum frame size is smaller than message payload body then message
221: # will have a message header and several message bodies
222: msg = ''
223: while msg.length < header.size
224: msg += client.next_payload
225: end
226:
227: msg_hash = {:header => header, :payload => msg, :delivery_details => method.arguments}
228:
229: else
230: msg_hash = {:header => nil, :payload => :queue_empty, :delivery_details => nil}
231: end
232:
233: # Pass message hash to block or return message hash
234: blk ? blk.call(msg_hash) : msg_hash
235:
236: end
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 Bunny::ProtocolError.
:purge_ok if successful
# File lib/bunny/queue08.rb, line 254
254: def purge(opts = {})
255: # ignore the :nowait option if passed, otherwise program will hang waiting for a
256: # response that will not be sent by the server
257: opts.delete(:nowait)
258:
259: client.send_frame(
260: Qrack::Protocol::Queue::Purge.new({ :queue => name, :nowait => false }.merge(opts))
261: )
262:
263: method = client.next_method
264:
265: client.check_response(method, Qrack::Protocol::Queue::PurgeOk, "Error purging queue #{name}")
266:
267: # return confirmation
268: :purge_ok
269:
270: end
Returns hash {:message_count, :consumer_count}.
# File lib/bunny/queue08.rb, line 280
280: def status
281: client.send_frame(
282: Qrack::Protocol::Queue::Declare.new({ :queue => name, :passive => true })
283: )
284: method = client.next_method
285: {:message_count => method.message_count, :consumer_count => method.consumer_count}
286: end
# File lib/bunny/queue08.rb, line 289
289: def subscribe(opts = {}, &blk)
290: # Create subscription
291: s = Bunny::Subscription.new(client, self, opts)
292: s.start(&blk)
293:
294: # Reset when subscription finished
295: @subscription = nil
296: end
Removes a queue binding from an exchange. If error occurs, a Bunny::ProtocolError is raised.
:unbind_ok if successful.
# File lib/bunny/queue08.rb, line 358
358: def unbind(exchange, opts = {})
359: exchange = exchange.respond_to?(:name) ? exchange.name : exchange
360:
361: # ignore the :nowait option if passed, otherwise program will hang waiting for a
362: # response that will not be sent by the server
363: opts.delete(:nowait)
364:
365: client.send_frame(
366: Qrack::Protocol::Queue::Unbind.new({ :queue => name,
367: :exchange => exchange,
368: :routing_key => opts.delete(:key),
369: :nowait => false }.merge(opts)
370: )
371: )
372:
373: method = client.next_method
374:
375: client.check_response(method, Qrack::Protocol::Queue::UnbindOk, "Error unbinding queue #{name}")
376:
377: # return message
378: :unbind_ok
379: end
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.
:unsubscribe_ok if successful
# File lib/bunny/queue08.rb, line 316
316: def unsubscribe(opts = {})
317: # Default consumer_tag from subscription if not passed in
318: consumer_tag = subscription ? subscription.consumer_tag : opts[:consumer_tag]
319:
320: # Must have consumer tag to tell server what to unsubscribe
321: raise Bunny::UnsubscribeError,
322: "No consumer tag received" if !consumer_tag
323:
324: # Cancel consumer
325: client.send_frame( Qrack::Protocol::Basic::Cancel.new(:consumer_tag => consumer_tag,
326: :nowait => false))
327:
328: method = client.next_method
329:
330: client.check_response(method, Qrack::Protocol::Basic::CancelOk,
331: "Error unsubscribing from queue #{name}")
332:
333: # Reset subscription
334: @subscription = nil
335:
336: # Return confirmation
337: :unsubscribe_ok
338:
339: end