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/queue.rb, line 54 def self.consumer_class # Bunny::Consumer Bunny::Subscription end
# File lib/bunny/queue.rb, line 7 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::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.
@option opts [String] :delivery_tag
@option opts [Boolean] :multiple (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.
# File lib/bunny/queue.rb, line 70 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 won't receive any messages. Queues are bound to the direct exchange " by default. If error occurs, a {Bunny::ProtocolError} is raised.
@option opts [String] :key
Specifies the routing key for the binding. The routing key is used for routing messages depending on the exchange configuration.
@option opts [Boolean] :nowait (false)
Ignored by Bunny, always @false@.
@return [Symbol] @:bind_ok@ if successful.
# File lib/bunny/queue.rb, line 98 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::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 {Bunny::Queue#subscribe} method. It has no special properties of any kind. @see Queue#subscribe @see Bunny::Consumer @api public
# File lib/bunny/queue.rb, line 48 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@.
@option opts [Boolean] :if_unused (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.
@option opts [Boolean] :if_empty (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.
@option opts [Boolean] :nowait (false)
Ignored by Bunny, always @false@.
@return [Symbol] @:delete_ok@ if successful
# File lib/bunny/queue.rb, line 139 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::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.
@option opts [Boolean] :ack (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.
@return [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.
# File lib/bunny/queue.rb, line 167 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::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 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
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}.
@option opts [Boolean] :nowait (false)
Ignored by Bunny, always @false@.
@return [Symbol] @:purge_ok@ if successful
# File lib/bunny/queue.rb, line 216 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::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
@return [Hash] Hash with keys @:message_count@ and @consumer_count@.
# File lib/bunny/queue.rb, line 234 def status opts = { :queue => name, :passive => true, :deprecated_ticket => 0 } client.send_frame(Qrack::Protocol::Queue::Declare.new(opts)) method = client.next_method {:message_count => method.message_count, :consumer_count => method.consumer_count} end
# File lib/bunny/queue.rb, line 242 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.
@option opts [String] :key
Specifies the routing key for the binding.
@option opts [Boolean] :nowait (false)
Ignored by Bunny, always @false@.
@return [Symbol] @:unbind_ok@ if successful.
# File lib/bunny/queue.rb, line 259 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::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.
@option opts [String] :consumer_tag
Specifies the identifier for the consumer.
@option opts [Boolean] :nowait (false)
Ignored by Bunny, always @false@.
@option opts [Boolean] :nowait (false)
Ignored by Bunny, always @false@.
@return [Symbol] @:unsubscribe_ok@ if successful
# File lib/bunny/queue.rb, line 297 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)) # Reset subscription @default_consumer = nil method = client.next_method client.check_response(method, Qrack::Protocol::Basic::CancelOk, "Error unsubscribing from queue #{name}, got #{method.class}") # Return confirmation :unsubscribe_ok end
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