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#:main: README
#
$:.unshift File.expand_path(File.dirname(File.expand_path(__FILE__)))
require 'amqp'
require 'mq/collection'
class MQ
%w[ exchange queue rpc header ].each do |file|
require "mq/#{file}"
end
class << self
@logging = false
attr_accessor :logging
end
# Raised whenever an illegal operation is attempted.
class Error < StandardError; end
end
# The top-level class for building AMQP clients. This class contains several
# convenience methods for working with queues and exchanges. Many calls
# delegate/forward to subclasses, but this is the preferred API. The subclass
# API is subject to change while this high-level API will likely remain
# unchanged as the library evolves. All code examples will be written using
# the MQ API.
#
# Below is a somewhat complex example that demonstrates several capabilities
# of the library. The example starts a clock using a +fanout+ exchange which
# is used for 1 to many communications. Each consumer generates a queue to
# receive messages and do some operation (in this case, print the time).
# One consumer prints messages every second while the second consumer prints
# messages every 2 seconds. After 5 seconds has elapsed, the 1 second
# consumer is deleted.
#
# Of interest is the relationship of EventMachine to the process. All MQ
# operations must occur within the context of an EM.run block. We start
# EventMachine in its own thread with an empty block; all subsequent calls
# to the MQ API add their blocks to the EM.run block. This demonstrates how
# the library could be used to build up and tear down communications outside
# the context of an EventMachine block and/or integrate the library with
# other synchronous operations. See the EventMachine documentation for
# more information.
#
# require 'rubygems'
# require 'mq'
#
# thr = Thread.new { EM.run }
#
# # turns on extreme logging
# #AMQP.logging = true
#
# def log *args
# p args
# end
#
# def publisher
# clock = MQ.fanout('clock')
# EM.add_periodic_timer(1) do
# puts
#
# log :publishing, time = Time.now
# clock.publish(Marshal.dump(time))
# end
# end
#
# def one_second_consumer
# MQ.queue('every second').bind(MQ.fanout('clock')).subscribe do |time|
# log 'every second', :received, Marshal.load(time)
# end
# end
#
# def two_second_consumer
# MQ.queue('every 2 seconds').bind('clock').subscribe do |time|
# time = Marshal.load(time)
# log 'every 2 seconds', :received, time if time.sec % 2 == 0
# end
# end
#
# def delete_one_second
# EM.add_timer(5) do
# # delete the 'every second' queue
# log 'Deleting [every second] queue'
# MQ.queue('every second').delete
# end
# end
#
# publisher
# one_second_consumer
# two_second_consumer
# delete_one_second
# thr.join
#
# __END__
#
# [:publishing, Tue Jan 06 22:46:14 -0600 2009]
# ["every second", :received, Tue Jan 06 22:46:14 -0600 2009]
# ["every 2 seconds", :received, Tue Jan 06 22:46:14 -0600 2009]
#
# [:publishing, Tue Jan 06 22:46:16 -0600 2009]
# ["every second", :received, Tue Jan 06 22:46:16 -0600 2009]
# ["every 2 seconds", :received, Tue Jan 06 22:46:16 -0600 2009]
#
# [:publishing, Tue Jan 06 22:46:17 -0600 2009]
# ["every second", :received, Tue Jan 06 22:46:17 -0600 2009]
#
# [:publishing, Tue Jan 06 22:46:18 -0600 2009]
# ["every second", :received, Tue Jan 06 22:46:18 -0600 2009]
# ["every 2 seconds", :received, Tue Jan 06 22:46:18 -0600 2009]
# ["Deleting [every second] queue"]
#
# [:publishing, Tue Jan 06 22:46:19 -0600 2009]
#
# [:publishing, Tue Jan 06 22:46:20 -0600 2009]
# ["every 2 seconds", :received, Tue Jan 06 22:46:20 -0600 2009]
#
class MQ
include AMQP
include EM::Deferrable
# Returns a new channel. A channel is a bidirectional virtual
# connection between the client and the AMQP server. Elsewhere in the
# library the channel is referred to in parameter lists as +mq+.
#
# Optionally takes the result from calling AMQP::connect.
#
# Rarely called directly by client code. This is implicitly called
# by most instance methods. See #method_missing.
#
# EM.run do
# channel = MQ.new
# end
#
# EM.run do
# channel = MQ.new AMQP::connect
# end
#
def initialize connection = nil
raise 'MQ can only be used from within EM.run{}' unless EM.reactor_running?
@connection = connection || AMQP.start
conn.callback{ |c|
@channel = c.add_channel(self)
send Protocol::Channel::Open.new
}
end
attr_reader :channel, :connection
def check_content_completion
if @body.length >= @header.size
@header.properties.update(@method.arguments)
@consumer.receive @header, @body if @consumer
@body = @header = @consumer = @method = nil
end
end
# May raise a MQ::Error exception when the frame payload contains a
# Protocol::Channel::Close object.
#
# This usually occurs when a client attempts to perform an illegal
# operation. A short, and incomplete, list of potential illegal operations
# follows:
# * publish a message to a deleted exchange (NOT_FOUND)
# * declare an exchange using the reserved 'amq.' naming structure (ACCESS_REFUSED)
#
def process_frame frame
log :received, frame
case frame
when Frame::Header
@header = frame.payload
@body = ''
check_content_completion
when Frame::Body
@body << frame.payload
check_content_completion
when Frame::Method
case method = frame.payload
when Protocol::Channel::OpenOk
send Protocol::Access::Request.new(:realm => '/data',
:read => true,
:write => true,
:active => true,
:passive => true)
when Protocol::Access::RequestOk
@ticket = method.ticket
callback{
send Protocol::Channel::Close.new(:reply_code => 200,
:reply_text => 'bye',
:method_id => 0,
:class_id => 0)
} if @closing
succeed
when Protocol::Basic::CancelOk
if @consumer = consumers[ method.consumer_tag ]
@consumer.cancelled
else
MQ.error "Basic.CancelOk for invalid consumer tag: #{method.consumer_tag}"
end
when Protocol::Exchange::DeclareOk
# We can't use exchanges[method.exchange] because if the name would
# be an empty string, then AMQP broker generated a random one.
exchanges = self.exchanges.select { |exchange| exchange.opts[:nowait].eql?(false) }
exchange = exchanges.reverse.find { |exchange| exchange.status.eql?(:unfinished) }
exchange.receive_response method
when Protocol::Queue::DeclareOk
# We can't use queues[method.queue] because if the name would
# be an empty string, then AMQP broker generated a random one.
queues = self.queues.select { |queue| queue.opts[:nowait].eql?(false) }
queue = queues.reverse.find { |queue| queue.status.eql?(:unfinished) }
queue.receive_status method
when Protocol::Queue::BindOk
# We can't use queues[method.queue] because if the name would
# be an empty string, then AMQP broker generated a random one.
queues = self.queues.select { |queue| queue.opts[:nowait].eql?(false) }
queue = queues.reverse.find { |queue| queue.status.eql?(:unbound) }
queue.after_bind method
when Protocol::Basic::Deliver, Protocol::Basic::GetOk
@method = method
@header = nil
@body = ''
if method.is_a? Protocol::Basic::GetOk
@consumer = get_queue{|q| q.shift }
MQ.error "No pending Basic.GetOk requests" unless @consumer
else
@consumer = consumers[ method.consumer_tag ]
MQ.error "Basic.Deliver for invalid consumer tag: #{method.consumer_tag}" unless @consumer
end
when Protocol::Basic::GetEmpty
if @consumer = get_queue{|q| q.shift }
@consumer.receive nil, nil
else
MQ.error "Basic.GetEmpty for invalid consumer"
end
when Protocol::Channel::Close
raise Error, "#{method.reply_text} in #{Protocol.classes[method.class_id].methods[method.method_id]} on #{@channel}"
when Protocol::Channel::CloseOk
@on_close && @on_close.call(self)
@closing = false
conn.callback{ |c|
c.channels.delete @channel
c.close if c.channels.empty?
}
when Protocol::Basic::ConsumeOk
if @consumer = consumers[ method.consumer_tag ]
@consumer.confirm_subscribe
else
MQ.error "Basic.ConsumeOk for invalid consumer tag: #{method.consumer_tag}"
end
end
end
end
def send *args
conn.callback{ |c|
(@_send_mutex ||= Mutex.new).synchronize do
args.each do |data|
data.ticket = @ticket if @ticket and data.respond_to? :ticket=
log :sending, data
c.send data, :channel => @channel
end
end
}
end
# Defines, intializes and returns an Exchange to act as an ingress
# point for all published messages.
#
# == Direct
# A direct exchange is useful for 1:1 communication between a publisher and
# subscriber. Messages are routed to the queue with a binding that shares
# the same name as the exchange. Alternately, the messages are routed to
# the bound queue that shares the same name as the routing key used for
# defining the exchange. This exchange type does not honor the +:key+ option
# when defining a new instance with a name. It _will_ honor the +:key+ option
# if the exchange name is the empty string.
# Allocating this exchange without a name _or_ with the empty string
# will use the internal 'amq.direct' exchange.
#
# Any published message, regardless of its persistence setting, is thrown
# away by the exchange when there are no queues bound to it.
#
# # exchange is named 'foo'
# exchange = MQ.direct('foo')
#
# # or, the exchange can use the default name (amq.direct) and perform
# # routing comparisons using the :key
# exchange = MQ.direct("", :key => 'foo')
# exchange.publish('some data') # will be delivered to queue bound to 'foo'
#
# queue = MQ.queue('foo')
# # can receive data since the queue name and the exchange key match exactly
# queue.pop { |data| puts "received data [#{data}]" }
#
# == Options
# * :passive => true | false (default false)
# If set, the server will not create the exchange if it does not
# already exist. The client can use this to check whether an exchange
# exists without modifying the server state.
#
# * :durable => true | false (default false)
# If set when creating a new exchange, the exchange will be marked as
# durable. Durable exchanges remain active when a server restarts.
# Non-durable exchanges (transient exchanges) are purged if/when a
# server restarts.
#
# A transient exchange (the default) is stored in memory-only. The
# exchange and all bindings will be lost on a server restart.
# It makes no sense to publish a persistent message to a transient
# exchange.
#
# Durable exchanges and their bindings are recreated upon a server
# restart. Any published messages not routed to a bound queue are lost.
#
# * :auto_delete => true | false (default false)
# If set, the exchange is deleted when all queues have finished
# using it. The server waits for a short period of time before
# determining the exchange is unused to give time to the client code
# to bind a queue to it.
#
# If the exchange has been previously declared, this option is ignored
# on subsequent declarations.
#
# * :internal => true | false (default false)
# If set, the exchange may not be used directly by publishers, but
# only when bound to other exchanges. Internal exchanges are used to
# construct wiring that is not visible to applications.
#
# * :nowait => true | false (default true)
# If set, the server will not respond to the method. The client should
# not wait for a reply method. If the server could not complete the
# method it will raise a channel or connection exception.
#
# == Exceptions
# Doing any of these activities are illegal and will raise MQ:Error.
# * redeclare an already-declared exchange to a different type
# * :passive => true and the exchange does not exist (NOT_FOUND)
#
def direct name = 'amq.direct', opts = {}, &block
self.exchanges << Exchange.new(self, :direct, name, opts, &block)
end
# Defines, intializes and returns an Exchange to act as an ingress
# point for all published messages.
#
# == Fanout
# A fanout exchange is useful for 1:N communication where one publisher
# feeds multiple subscribers. Like direct exchanges, messages published
# to a fanout exchange are delivered to queues whose name matches the
# exchange name (or are bound to that exchange name). Each queue gets
# its own copy of the message.
#
# Any published message, regardless of its persistence setting, is thrown
# away by the exchange when there are no queues bound to it.
#
# Like the direct exchange type, this exchange type does not honor the
# +:key+ option when defining a new instance with a name. It _will_ honor
# the +:key+ option if the exchange name is the empty string.
# Allocating this exchange without a name _or_ with the empty string
# will use the internal 'amq.fanout' exchange.
#
# EM.run do
# clock = MQ.fanout('clock')
# EM.add_periodic_timer(1) do
# puts "\npublishing #{time = Time.now}"
# clock.publish(Marshal.dump(time))
# end
#
# amq = MQ.queue('every second')
# amq.bind(MQ.fanout('clock')).subscribe do |time|
# puts "every second received #{Marshal.load(time)}"
# end
#
# # note the string passed to #bind
# MQ.queue('every 5 seconds').bind('clock').subscribe do |time|
# time = Marshal.load(time)
# puts "every 5 seconds received #{time}" if time.strftime('%S').to_i%5 == 0
# end
# end
#
# == Options
# * :passive => true | false (default false)
# If set, the server will not create the exchange if it does not
# already exist. The client can use this to check whether an exchange
# exists without modifying the server state.
#
# * :durable => true | false (default false)
# If set when creating a new exchange, the exchange will be marked as
# durable. Durable exchanges remain active when a server restarts.
# Non-durable exchanges (transient exchanges) are purged if/when a
# server restarts.
#
# A transient exchange (the default) is stored in memory-only. The
# exchange and all bindings will be lost on a server restart.
# It makes no sense to publish a persistent message to a transient
# exchange.
#
# Durable exchanges and their bindings are recreated upon a server
# restart. Any published messages not routed to a bound queue are lost.
#
# * :auto_delete => true | false (default false)
# If set, the exchange is deleted when all queues have finished
# using it. The server waits for a short period of time before
# determining the exchange is unused to give time to the client code
# to bind a queue to it.
#
# If the exchange has been previously declared, this option is ignored
# on subsequent declarations.
#
# * :internal => true | false (default false)
# If set, the exchange may not be used directly by publishers, but
# only when bound to other exchanges. Internal exchanges are used to
# construct wiring that is not visible to applications.
#
# * :nowait => true | false (default true)
# If set, the server will not respond to the method. The client should
# not wait for a reply method. If the server could not complete the
# method it will raise a channel or connection exception.
#
# == Exceptions
# Doing any of these activities are illegal and will raise MQ:Error.
# * redeclare an already-declared exchange to a different type
# * :passive => true and the exchange does not exist (NOT_FOUND)
#
def fanout name = 'amq.fanout', opts = {}, &block
self.exchanges << Exchange.new(self, :fanout, name, opts, &block)
end
# Defines, intializes and returns an Exchange to act as an ingress
# point for all published messages.
#
# == Topic
# A topic exchange allows for messages to be published to an exchange
# tagged with a specific routing key. The Exchange uses the routing key
# to determine which queues to deliver the message. Wildcard matching
# is allowed. The topic must be declared using dot notation to separate
# each subtopic.
#
# This is the only exchange type to honor the +key+ hash key for all
# cases.
#
# Any published message, regardless of its persistence setting, is thrown
# away by the exchange when there are no queues bound to it.
#
# As part of the AMQP standard, each server _should_ predeclare a topic
# exchange called 'amq.topic' (this is not required by the standard).
# Allocating this exchange without a name _or_ with the empty string
# will use the internal 'amq.topic' exchange.
#
# The classic example is delivering market data. When publishing market
# data for stocks, we may subdivide the stream based on 2
# characteristics: nation code and trading symbol. The topic tree for
# Apple Computer would look like:
# 'stock.us.aapl'
# For a foreign stock, it may look like:
# 'stock.de.dax'
#
# When publishing data to the exchange, bound queues subscribing to the
# exchange indicate which data interests them by passing a routing key
# for matching against the published routing key.
#
# EM.run do
# exch = MQ.topic("stocks")
# keys = ['stock.us.aapl', 'stock.de.dax']
#
# EM.add_periodic_timer(1) do # every second
# puts
# exch.publish(10+rand(10), :routing_key => keys[rand(2)])
# end
#
# # match against one dot-separated item
# MQ.queue('us stocks').bind(exch, :key => 'stock.us.*').subscribe do |price|
# puts "us stock price [#{price}]"
# end
#
# # match against multiple dot-separated items
# MQ.queue('all stocks').bind(exch, :key => 'stock.#').subscribe do |price|
# puts "all stocks: price [#{price}]"
# end
#
# # require exact match
# MQ.queue('only dax').bind(exch, :key => 'stock.de.dax').subscribe do |price|
# puts "dax price [#{price}]"
# end
# end
#
# For matching, the '*' (asterisk) wildcard matches against one
# dot-separated item only. The '#' wildcard (hash or pound symbol)
# matches against 0 or more dot-separated items. If none of these
# symbols are used, the exchange performs a comparison looking for an
# exact match.
#
# == Options
# * :passive => true | false (default false)
# If set, the server will not create the exchange if it does not
# already exist. The client can use this to check whether an exchange
# exists without modifying the server state.
#
# * :durable => true | false (default false)
# If set when creating a new exchange, the exchange will be marked as
# durable. Durable exchanges remain active when a server restarts.
# Non-durable exchanges (transient exchanges) are purged if/when a
# server restarts.
#
# A transient exchange (the default) is stored in memory-only. The
# exchange and all bindings will be lost on a server restart.
# It makes no sense to publish a persistent message to a transient
# exchange.
#
# Durable exchanges and their bindings are recreated upon a server
# restart. Any published messages not routed to a bound queue are lost.
#
# * :auto_delete => true | false (default false)
# If set, the exchange is deleted when all queues have finished
# using it. The server waits for a short period of time before
# determining the exchange is unused to give time to the client code
# to bind a queue to it.
#
# If the exchange has been previously declared, this option is ignored
# on subsequent declarations.
#
# * :internal => true | false (default false)
# If set, the exchange may not be used directly by publishers, but
# only when bound to other exchanges. Internal exchanges are used to
# construct wiring that is not visible to applications.
#
# * :nowait => true | false (default true)
# If set, the server will not respond to the method. The client should
# not wait for a reply method. If the server could not complete the
# method it will raise a channel or connection exception.
#
# == Exceptions
# Doing any of these activities are illegal and will raise MQ:Error.
# * redeclare an already-declared exchange to a different type
# * :passive => true and the exchange does not exist (NOT_FOUND)
#
def topic name = 'amq.topic', opts = {}, &block
self.exchanges << Exchange.new(self, :topic, name, opts, &block)
end
# Defines, intializes and returns an Exchange to act as an ingress
# point for all published messages.
#
# == Headers
# A headers exchange allows for messages to be published to an exchange
#
# Any published message, regardless of its persistence setting, is thrown
# away by the exchange when there are no queues bound to it.
#
# As part of the AMQP standard, each server _should_ predeclare a headers
# exchange called 'amq.match' (this is not required by the standard).
# Allocating this exchange without a name _or_ with the empty string
# will use the internal 'amq.match' exchange.
#
# TODO: The classic example is ...
#
# When publishing data to the exchange, bound queues subscribing to the
# exchange indicate which data interests them by passing arguments
# for matching against the headers in published messages. The
# form of the matching can be controlled by the 'x-match' argument, which
# may be 'any' or 'all'. If unspecified (in RabbitMQ at least), it defaults
# to "all".
#
# A value of 'all' for 'x-match' implies that all values must match (i.e.
# it does an AND of the headers ), while a value of 'any' implies that
# at least one should match (ie. it does an OR).
#
# TODO: document behavior when either the binding or the message is missing
# a header present in the other
#
# TODO: insert example
#
# == Options
# * :passive => true | false (default false)
# If set, the server will not create the exchange if it does not
# already exist. The client can use this to check whether an exchange
# exists without modifying the server state.
#
# * :durable => true | false (default false)
# If set when creating a new exchange, the exchange will be marked as
# durable. Durable exchanges remain active when a server restarts.
# Non-durable exchanges (transient exchanges) are purged if/when a
# server restarts.
#
# A transient exchange (the default) is stored in memory-only. The
# exchange and all bindings will be lost on a server restart.
# It makes no sense to publish a persistent message to a transient
# exchange.
#
# Durable exchanges and their bindings are recreated upon a server
# restart. Any published messages not routed to a bound queue are lost.
#
# * :auto_delete => true | false (default false)
# If set, the exchange is deleted when all queues have finished
# using it. The server waits for a short period of time before
# determining the exchange is unused to give time to the client code
# to bind a queue to it.
#
# If the exchange has been previously declared, this option is ignored
# on subsequent declarations.
#
# * :internal => true | false (default false)
# If set, the exchange may not be used directly by publishers, but
# only when bound to other exchanges. Internal exchanges are used to
# construct wiring that is not visible to applications.
#
# * :nowait => true | false (default true)
# If set, the server will not respond to the method. The client should
# not wait for a reply method. If the server could not complete the
# method it will raise a channel or connection exception.
#
# == Exceptions
# Doing any of these activities are illegal and will raise MQ:Error.
# * redeclare an already-declared exchange to a different type
# * :passive => true and the exchange does not exist (NOT_FOUND)
# * using a value other than "any" or "all" for "x-match"
def headers name = 'amq.match', opts = {}, &block
self.exchanges << Exchange.new(self, :headers, name, opts, &block)
end
# 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.
#
# Like an Exchange, queue names starting with 'amq.' are reserved for
# internal use. Attempts to create queue names in violation of this
# reservation will raise MQ:Error (ACCESS_REFUSED).
#
# It is not supported to create a queue without a name; some string
# (even the empty string) must be passed in the +name+ parameter.
#
# == Options
# * :passive => true | false (default false)
# If set, the server will not create the exchange if it does not
# already exist. The client can use this to check whether an exchange
# exists without modifying the server state.
#
# * :durable => true | false (default false)
# If set when creating a new queue, the queue will be marked as
# durable. Durable queues remain active when a server restarts.
# Non-durable queues (transient queues) are purged if/when a
# server restarts. Note that durable queues do not necessarily
# hold persistent messages, although it does not make sense to
# send persistent messages to a transient queue (though it is
# allowed).
#
# Again, note the durability property on a queue has no influence on
# the persistence of published messages. A durable queue containing
# transient messages will flush those messages on a restart.
#
# If the queue has already been declared, any redeclaration will
# ignore this setting. A queue may only be declared durable the
# first time when it is created.
#
# * :exclusive => true | false (default false)
# Exclusive queues may only be consumed from by the current connection.
# Setting the 'exclusive' flag always implies 'auto-delete'. Only a
# single consumer is allowed to remove messages from this queue.
#
# The default is a shared queue. Multiple clients may consume messages
# from this queue.
#
# Attempting to redeclare an already-declared queue as :exclusive => true
# will raise MQ:Error.
#
# * :auto_delete = true | false (default false)
# If set, the queue is deleted when all consumers have finished
# using it. Last consumer can be cancelled either explicitly or because
# its channel is closed. If there was no consumer ever on the queue, it
# won't be deleted.
#
# The server waits for a short period of time before
# determining the queue is unused to give time to the client code
# to bind an exchange to it.
#
# If the queue has been previously declared, this option is ignored
# on subsequent declarations.
#
# Any remaining messages in the queue will be purged when the queue
# is deleted regardless of the message's persistence setting.
#
# * :nowait => true | false (default true)
# If set, the server will not respond to the method. The client should
# not wait for a reply method. If the server could not complete the
# method it will raise a channel or connection exception.
#
def queue name, opts = {}, &block
self.queues << Queue.new(self, name, opts, &block)
end
def queue! name, opts = {}, &block
self.queues.add! Queue.new(self, name, opts, &block)
end
# Takes a channel, queue and optional object.
#
# The optional object may be a class name, module name or object
# instance. When given a class or module name, the object is instantiated
# during this setup. The passed queue is automatically subscribed to so
# it passes all messages (and their arguments) to the object.
#
# Marshalling and unmarshalling the objects is handled internally. This
# marshalling is subject to the same restrictions as defined in the
# Marshal[http://ruby-doc.org/core/classes/Marshal.html] standard
# library. See that documentation for further reference.
#
# When the optional object is not passed, the returned rpc reference is
# used to send messages and arguments to the queue. See #method_missing
# which does all of the heavy lifting with the proxy. Some client
# elsewhere must call this method *with* the optional block so that
# there is a valid destination. Failure to do so will just enqueue
# marshalled messages that are never consumed.
#
# EM.run do
# server = MQ.rpc('hash table node', Hash)
#
# client = MQ.rpc('hash table node')
# client[:now] = Time.now
# client[:one] = 1
#
# client.values do |res|
# p 'client', :values => res
# end
#
# client.keys do |res|
# p 'client', :keys => res
# EM.stop_event_loop
# end
# end
#
def rpc name, obj = nil
rpcs[name] ||= RPC.new(self, name, obj)
end
def close(&block)
@on_close = block
if @deferred_status == :succeeded
send Protocol::Channel::Close.new(:reply_code => 200,
:reply_text => 'bye',
:method_id => 0,
:class_id => 0)
else
@closing = true
end
end
# Define a message and callback block to be executed on all
# errors.
def self.error msg = nil, &blk
if blk
@error_callback = blk
else
@error_callback.call(msg) if @error_callback and msg
end
end
def prefetch(size)
@prefetch_size = size
send Protocol::Basic::Qos.new(:prefetch_size => 0, :prefetch_count => size, :global => false)
self
end
# Asks the broker to redeliver all unacknowledged messages on this
# channel.
#
# * requeue (default false)
# If this parameter is false, the message will be redelivered to the original recipient.
# If this flag is true, the server will attempt to requeue the message, potentially then
# delivering it to an alternative subscriber.
#
def recover requeue = false
send Protocol::Basic::Recover.new(:requeue => requeue)
self
end
# Returns a hash of all the exchange proxy objects.
#
# Not typically called by client code.
def exchanges
@exchanges ||= MQ::Collection.new
end
# Returns a hash of all the queue proxy objects.
#
# Not typically called by client code.
def queues
@queues ||= MQ::Collection.new
end
def get_queue
if block_given?
(@get_queue_mutex ||= Mutex.new).synchronize{
yield( @get_queue ||= [] )
}
end
end
# Returns a hash of all rpc proxy objects.
#
# Not typically called by client code.
def rpcs
@rcps ||= {}
end
# Queue objects keyed on their consumer tags.
#
# Not typically called by client code.
def consumers
@consumers ||= {}
end
def reset
@deferred_status = nil
@channel = nil
initialize @connection
@consumers = {}
exs = @exchanges
@exchanges = {}
exs.each{ |_,e| e.reset } if exs
qus = @queues
@queues = {}
qus.each{ |_,q| q.reset } if qus
prefetch(@prefetch_size) if @prefetch_size
end
private
def log *args
return unless MQ.logging
pp args
puts
end
attr_reader :connection
alias :conn :connection
end
#-- convenience wrapper (read: HACK) for thread-local MQ object
class MQ
def MQ.default
#-- XXX clear this when connection is closed
Thread.current[:mq] ||= MQ.new
end
# Allows for calls to all MQ instance methods. This implicitly calls
# MQ.new so that a new channel is allocated for subsequent operations.
def MQ.method_missing meth, *args, &blk
MQ.default.__send__(meth, *args, &blk)
end
end
class MQ
# unique identifier
def MQ.id
Thread.current[:mq_id] ||= "#{`hostname`.strip}-#{Process.pid}-#{Thread.current.object_id}"
end
end
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