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.
@return [Class] @private
# File lib/bunny/queue08.rb, line 63 def self.consumer_class # Bunny::Consumer Bunny::Subscription end
# File lib/bunny/queue08.rb, line 15 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 @subscription = 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 }.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 }.merge(opts) client.send_frame(Qrack::Protocol::Queue::Declare.new(opts)) method = client.next_method client.check_response(method, Qrack::Protocol::Queue::DeclareOk, "Error declaring queue #{name}") @name = method.queue client.queues[@name] = self 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.
:delivery_tag
:multiple => true or false (default)
- 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.
# File lib/bunny/queue08.rb, line 85 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::Protocol::Basic::Ack.new(opts)) # reset delivery tag self.delivery_tag = nil 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.
:key => 'routing key'* <tt>:key => 'routing_key'
-
Specifies the routing key for the binding. The routing key is used for
routing messages depending on the exchange configuration.
:nowait => true or false (default)
- Ignored by Bunny, always false.
:bind_ok
if successful.
# File lib/bunny/queue08.rb, line 118 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 }.merge(opts) client.send_frame(Qrack::Protocol::Queue::Bind.new(opts)) method = client.next_method client.check_response(method, Qrack::Protocol::Queue::BindOk, "Error binding queue: #{name} to exchange: #{exchange}") # return message :bind_ok end
@return [Bunny::Consumer] Default consumer associated with this queue (if any), or nil @note Default consumer is the one registered with the convenience {#subscribe} method. It has no special properties of any kind. @see #subscribe @see Bunny::Consumer @api public
# File lib/bunny/queue08.rb, line 56 def default_consumer @default_consumer 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.
:if_unused => true or false (default)
- 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 => true or false (default)
- 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 => true or false (default)
- Ignored by Bunny, always false.
:delete_ok
if successful
# File lib/bunny/queue08.rb, line 165 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 }.merge(opts) client.send_frame(Qrack::Protocol::Queue::Delete.new(opts)) method = client.next_method client.check_response(method, Qrack::Protocol::Queue::DeleteOk, "Error deleting queue #{name}") client.queues.delete(name) # return confirmation :delete_ok end
Gets a message from a queue in a synchronous way. If error occurs, raises Bunny::ProtocolError.
:ack => false (default) or true
- 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.
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 213 def pop(opts = {}, &blk) # do we want to have to provide an acknowledgement? ack = opts.delete(:ack) opts = { :queue => name, :consumer_tag => name, :no_ack => !ack, :nowait => true }.merge(opts) client.send_frame(Qrack::Protocol::Basic::Get.new(opts)) method = client.next_method if method.is_a?(Qrack::Protocol::Basic::GetEmpty) then queue_empty = true elsif !method.is_a?(Qrack::Protocol::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 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
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.
:nowait => true or false (default)
- Ignored by Bunny, always false.
:purge_ok
if successful
# File lib/bunny/queue08.rb, line 274 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 }.merge(opts) client.send_frame(Qrack::Protocol::Queue::Purge.new(opts)) method = client.next_method client.check_response(method, Qrack::Protocol::Queue::PurgeOk, "Error purging queue #{name}") # return confirmation :purge_ok end
Returns hash {:message_count, :consumer_count}.
# File lib/bunny/queue08.rb, line 299 def status client.send_frame(Qrack::Protocol::Queue::Declare.new(:queue => name, :passive => true)) method = client.next_method {:message_count => method.message_count, :consumer_count => method.consumer_count} end
# File lib/bunny/queue08.rb, line 305 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
Removes a queue binding from an exchange. If error occurs, a Bunny::ProtocolError is raised.
:key => 'routing key'* <tt>:key => 'routing_key'
-
Specifies the routing key for the binding.
:nowait => true or false (default)
- Ignored by Bunny, always false.
:unbind_ok
if successful.
# File lib/bunny/queue08.rb, line 370 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 }.merge(opts) client.send_frame(Qrack::Protocol::Queue::Unbind.new(opts)) method = client.next_method client.check_response(method, Qrack::Protocol::Queue::UnbindOk, "Error unbinding queue #{name}") # return message :unbind_ok 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.
:consumer_tag => 'tag'
- Specifies the identifier
for the consumer.
:nowait => true or false (default)
- Ignored by Bunny, always false.
:unsubscribe_ok
if successful
# File lib/bunny/queue08.rb, line 331 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::Protocol::Basic::Cancel.new(:consumer_tag => consumer_tag,:nowait => false)) method = client.next_method client.check_response(method, Qrack::Protocol::Basic::CancelOk, "Error unsubscribing from queue #{name}") # Reset subscription @default_consumer = nil # Return confirmation :unsubscribe_ok end