Class: MarchHare::Channel

Inherits:
Object
  • Object
show all
Defined in:
lib/march_hare/channel.rb

Overview

## Channels in RabbitMQ

To quote AMQP 0.9.1 specification:

AMQP 0.9.1 is a multi-channelled protocol. Channels provide a way to multiplex a heavyweight TCP/IP connection into several light weight connections. This makes the protocol more “firewall friendly” since port usage is predictable. It also means that traffic shaping and other network QoS features can be easily employed. Channels are independent of each other and can perform different functions simultaneously with other channels, the available bandwidth being shared between the concurrent activities.

## Opening Channels

Channels can be opened either via ‘MarchHare::Session#create_channel` (sufficient in the majority of cases) or by instantiating `MarchHare::Channel` directly:

This will automatically allocate a channel id.

## Closing Channels

Channels are closed via #close. Channels that get a channel-level exception are closed, too. Closed channels can no longer be used. Attempts to use them will raise ChannelAlreadyClosed.

## Higher-level API

MarchHare offers two sets of methods on Channel: known as higher-level and lower-level APIs, respectively. Higher-level API mimics amqp gem API where exchanges and queues are objects (instance of Exchange and Queue, respectively). Lower-level API is built around AMQP 0.9.1 methods (commands), where queues and exchanges are passed as strings (à la RabbitMQ Java client, Langohr and Pika).

### Queue Operations In Higher-level API

  • #queue is used to declare queues. The rest of the API is in Queue.

### Exchange Operations In Higher-level API

## Channel Qos (Prefetch Level)

It is possible to control how many messages at most a consumer will be given (before it acknowledges or rejects previously consumed ones). This setting is per channel and controlled via #prefetch.

## Channel IDs

Channels are identified by their ids which are integers. MarchHare takes care of allocating and releasing them as channels are opened and closed. It is almost never necessary to specify channel ids explicitly.

There is a limit on the maximum number of channels per connection, usually 65536. Note that allocating channels is very cheap on both client and server so having tens, hundreds or even thousands of channels is possible.

## Channels and Error Handling

Channel-level exceptions are more common than connection-level ones and often indicate issues applications can recover from (such as consuming from or trying to delete a queue that does not exist).

With MarchHare, channel-level exceptions are raised as Ruby exceptions, for example, NotFound, that provide access to the underlying ‘channel.close` method information.

Examples:

Using Session#create_channel:

conn = MarchHare.new
conn.start

ch   = conn.create_channel

ch  = conn.create_channel
ch.close

Handling 404 NOT_FOUND

begin
  ch.queue_delete("queue_that_should_not_exist#{rand}")
rescue MarchHare::NotFound => e
  puts "Channel-level exception! Code: #{e.channel_close.reply_code}, message: #{e.channel_close.reply_text}"
end

Handling 406 PRECONDITION_FAILED

begin
  ch2 = conn.create_channel
  q   = "rubymarchhare.examples.recovery.q#{rand}"

  ch2.queue_declare(q, :durable => false)
  ch2.queue_declare(q, :durable => true)
rescue MarchHare::PreconditionFailed => e
  puts "Channel-level exception! Code: #{e.channel_close.reply_code}, message: #{e.channel_close.reply_text}"
ensure
  conn.create_channel.queue_delete(q)
end

See Also:

Defined Under Namespace

Classes: BlockConfirmListener, BlockReturnListener

Instance Attribute Summary collapse

Exchanges collapse

Queues collapse

basic.* collapse

Instance Method Summary collapse

Constructor Details

#initialize(session, delegate) ⇒ Channel

Returns a new instance of Channel.



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# File 'lib/march_hare/channel.rb', line 121

def initialize(session, delegate)
  @connection = session
  @delegate   = delegate

  @exchanges      = JavaConcurrent::ConcurrentHashMap.new
  @queues         = JavaConcurrent::ConcurrentHashMap.new
  # we keep track of consumers in part to gracefully shut down their
  # executors when the channel is closed. This frees library users
  # from having to worry about this. MK.
  @consumers      = JavaConcurrent::ConcurrentHashMap.new
  @shutdown_hooks = Array.new
  @confirm_hooks  = Array.new
  @recoveries_counter = JavaConcurrent::AtomicInteger.new(0)

  on_shutdown do |ch, cause|
    ch.gracefully_shut_down_consumers
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(selector, *args) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 877

def method_missing(selector, *args)
  @delegate.__send__(selector, *args)
end

Instance Attribute Details

#consumers ⇒ Array<MarchHare::Consumer> (readonly)

Returns Consumers on this channel.

Returns:

  • (Array<MarchHare::Consumer>) —

    Consumers on this channel



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# File 'lib/march_hare/channel.rb', line 118

def consumers
  @consumers
end

#recoveries_counter ⇒ Object (readonly)

Returns the value of attribute recoveries_counter.



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# File 'lib/march_hare/channel.rb', line 290

def recoveries_counter
  @recoveries_counter
end

Instance Method Details

#ack(delivery_tag, multiple = false) ⇒ Object Also known as: acknowledge

Acknowledges a message. Acknowledged messages are completely removed from the queue.

Parameters:

  • delivery_tag (Integer) —

    Delivery tag to acknowledge

  • multiple (Boolean) (defaults to: false) —

    (false) Should all unacknowledged messages up to this be acknowledged as well?

See Also:



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# File 'lib/march_hare/channel.rb', line 665

def ack(delivery_tag, multiple = false)
  guarding_against_stale_delivery_tags(delivery_tag) do
    basic_ack(delivery_tag.to_i, multiple)
  end
end

#automatically_recover(session, java_connection) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 189

def automatically_recover(session, java_connection)
  jch = java_connection.create_channel(id)

  self.revive_with(jch)
  self.recover_shutdown_hooks

  self.recover_prefetch_setting
  self.recover_confirm_mode
  self.recover_confirm_hooks
  self.recover_tx_mode
  self.recover_exchanges
  # # this includes bindings recovery
  self.recover_queues
  self.recover_consumers
  self.increment_recoveries_counter
end

#basic_ack(delivery_tag, multiple) ⇒ NilClass

Acknowledges one or more messages (deliveries).

Parameters:

  • delivery_tag (Integer) —

    Delivery tag obtained from delivery info

  • multiple (Boolean) —

    Should all deliveries up to this one be acknowledged?

Returns:

  • (NilClass) —

    nil

See Also:



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# File 'lib/march_hare/channel.rb', line 751

def basic_ack(delivery_tag, multiple)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_ack(delivery_tag.to_i, multiple)
  end
end

#basic_consume(queue, auto_ack, consumer_tag = nil, consumer) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 617

def basic_consume(queue, auto_ack, consumer_tag = nil, consumer)
  consumer.auto_ack = auto_ack
  tag = converting_rjc_exceptions_to_ruby do
    if consumer_tag
      @delegate.basic_consume(queue, auto_ack, consumer_tag, consumer)
    else
      @delegate.basic_consume(queue, auto_ack, consumer)
    end
  end
  self.register_consumer(tag, consumer)

  tag
end

#basic_get(queue, auto_ack) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 611

def basic_get(queue, auto_ack)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_get(queue, auto_ack)
  end
end

#basic_nack(delivery_tag, multiple = false, requeue = false) ⇒ NilClass

Rejects or requeues messages just like #basic_reject but can do so with multiple messages at once.

Parameters:

  • delivery_tag (Integer) —

    Delivery tag obtained from delivery info

  • requeue (Boolean) (defaults to: false) —

    Should the message be requeued?

  • multiple (Boolean) (defaults to: false) —

    Should all deliveries up to this one be rejected/requeued?

Returns:

  • (NilClass) —

    nil

See Also:



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# File 'lib/march_hare/channel.rb', line 767

def basic_nack(delivery_tag, multiple = false, requeue = false)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_nack(delivery_tag.to_i, multiple, requeue)
  end
end

#basic_publish(exchange, routing_key, mandatory, properties, body) ⇒ MarchHare::Channel

Publishes a message using basic.publish AMQP 0.9.1 method.

Parameters:

  • exchange (String) —

    Exchange to publish to

  • routing_key (String) —

    Routing key

  • body (String) —

    Message payload. It will never be modified by MarchHare or RabbitMQ in any way.

  • properties (Hash) —

    Message properties

  • opts (Hash) —

    a customizable set of options

Options Hash (properties):

  • :persistent (Boolean) —

    Should the message be persisted to disk?

  • :timestamp (Integer) —

    A timestamp associated with this message

  • :expiration (Integer) —

    Expiration time after which the message will be deleted

  • :type (String) —

    Message type, e.g. what type of event or command this message represents. Can be any string

  • :reply_to (String) —

    Queue name other apps should send the response to

  • :content_type (String) —

    Message content type (e.g. application/json)

  • :content_encoding (String) —

    Message content encoding (e.g. gzip)

  • :correlation_id (String) —

    Message correlated to this one, e.g. what request this message is a reply for

  • :priority (Integer) —

    Message priority, 0 to 9. Not used by RabbitMQ, only applications

  • :message_id (String) —

    Any message identifier

  • :user_id (String) —

    Optional user ID. Verified by RabbitMQ against the actual connection username

  • :app_id (String) —

    Optional application ID

Returns:



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# File 'lib/march_hare/channel.rb', line 605

def basic_publish(exchange, routing_key, mandatory, properties, body)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_publish(exchange, routing_key, mandatory, false, BasicPropertiesBuilder.build_properties_from(properties || Hash.new), body)
  end
end

#basic_qos(prefetch_count) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 631

def basic_qos(prefetch_count)
  r = converting_rjc_exceptions_to_ruby do
    @delegate.basic_qos(prefetch_count)
  end
  @prefetch_count = prefetch_count

  r
end

#basic_recover(requeue = true) ⇒ Object

Redeliver unacknowledged messages

Parameters:

  • requeue (Boolean) (defaults to: true) —

    Should messages be requeued?

Returns:

  • RabbitMQ response



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# File 'lib/march_hare/channel.rb', line 777

def basic_recover(requeue = true)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_recover(requeue)
  end
end

#basic_recover_async(requeue = true) ⇒ Object

Redeliver unacknowledged messages

Parameters:

  • requeue (Boolean) (defaults to: true) —

    Should messages be requeued?

Returns:

  • RabbitMQ response



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# File 'lib/march_hare/channel.rb', line 787

def basic_recover_async(requeue = true)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_recover_async(requeue)
  end
end

#basic_reject(delivery_tag, requeue) ⇒ NilClass

Rejects or requeues a message.

Examples:

Requeue a message

conn  = MarchHare.new
conn.start

ch    = conn.create_channel
q.subscribe do |delivery_info, properties, payload|
  # requeue the message
  ch.basic_reject(delivery_info.delivery_tag, true)
end

Reject a message

conn  = MarchHare.new
conn.start

ch    = conn.create_channel
q.subscribe do |delivery_info, properties, payload|
  # requeue the message
  ch.basic_reject(delivery_info.delivery_tag, false)
end

Requeue a message fetched via basic.get

conn  = MarchHare.new
conn.start

ch    = conn.create_channel
# we assume the queue exists and has messages
delivery_info, properties, payload = ch.basic_get("bunny.examples.queue3", :ack => true)
ch.basic_reject(delivery_info.delivery_tag, true)

Parameters:

  • delivery_tag (Integer) —

    Delivery tag obtained from delivery info

  • requeue (Boolean) —

    Should the message be requeued?

Returns:

  • (NilClass) —

    nil

See Also:



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# File 'lib/march_hare/channel.rb', line 738

def basic_reject(delivery_tag, requeue)
  converting_rjc_exceptions_to_ruby do
    @delegate.basic_reject(delivery_tag.to_i, requeue)
  end
end

#channel_number ⇒ Integer Also known as: id, number

Returns Channel id.

Returns:

  • (Integer) —

    Channel id



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# File 'lib/march_hare/channel.rb', line 148

def channel_number
  @delegate.channel_number
end

#close(code = 200, reason = "Goodbye") ⇒ Object

Closes the channel.

Closed channels can no longer be used. Closed channel id is returned back to the pool of available ids and may be used by a different channel opened later.



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# File 'lib/march_hare/channel.rb', line 164

def close(code = 200, reason = "Goodbye")
  v = @delegate.close(code, reason)

  @consumers.each do |tag, consumer|
    consumer.gracefully_shut_down
  end

  @connection.unregister_channel(self)

  v
end

#confirm_select ⇒ NilClass

Enables publisher confirms on the channel.

Returns:

  • (NilClass) —

    nil

See Also:



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# File 'lib/march_hare/channel.rb', line 800

def confirm_select
  converting_rjc_exceptions_to_ruby do
    @confirm_mode = true
    @delegate.confirm_select
  end
end

#converting_rjc_exceptions_to_ruby(&block) ⇒ Object

Executes a block, catching Java exceptions RabbitMQ Java client throws and transforms them to Ruby exceptions that are then re-raised.



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# File 'lib/march_hare/channel.rb', line 976

def converting_rjc_exceptions_to_ruby(&block)
  begin
    block.call
  rescue Exception, java.lang.Throwable => e
    Exceptions.convert_and_reraise(e)
  end
end

#default_exchange ⇒ Object

Provides access to the default exchange

See Also:



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# File 'lib/march_hare/channel.rb', line 402

def default_exchange
  @default_exchange ||= self.exchange("", :durable => true, :auto_delete => false, :type => "direct")
end

#deregister_exchange(exchange) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 946

def deregister_exchange(exchange)
  @exchanges.delete(exchange.name)
end

#deregister_queue(queue) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 926

def deregister_queue(queue)
  @queues.delete(queue.name)
end

#deregister_queue_named(name) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 931

def deregister_queue_named(name)
  @queues.delete(name)
end

#direct(name, opts = {}) ⇒ MarchHare::Exchange

Declares a direct exchange or looks it up in the cache of previously declared exchanges.

Parameters:

  • name (String) —

    Exchange name

  • opts (Hash) (defaults to: {}) —

    Exchange parameters

Options Hash (opts):

  • :durable (Boolean) — default: false —

    Should the exchange be durable?

  • :auto_delete (Boolean) — default: false —

    Should the exchange be automatically deleted when no longer in use?

  • :arguments (Hash) — default: {} —

    Optional exchange arguments (used by RabbitMQ extensions)

Returns:

See Also:



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# File 'lib/march_hare/channel.rb', line 350

def direct(name, opts = {})
  dx = Exchange.new(self, name, opts.merge(:type => "direct")).tap do |x|
    x.declare!
  end

  self.register_exchange(dx)
end

#exchange(name, options = {}) ⇒ MarchHare::Exchange

Declares a headers exchange or looks it up in the cache of previously declared exchanges.

Parameters:

  • name (String) —

    Exchange name

  • opts (Hash) —

    Exchange parameters

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :type (String, Symbol) — default: :direct —

    Exchange type, e.g. :fanout or “x-consistent-hash”

  • :durable (Boolean) — default: false —

    Should the exchange be durable?

  • :auto_delete (Boolean) — default: false —

    Should the exchange be automatically deleted when no longer in use?

  • :arguments (Hash) — default: {} —

    Optional exchange arguments

Returns:

See Also:



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# File 'lib/march_hare/channel.rb', line 308

def exchange(name, options={})
  dx = Exchange.new(self, name, options).tap do |x|
    x.declare!
  end

  self.register_exchange(dx)
end

#exchange_bind(destination, source, routing_key, arguments = nil) ⇒ Object

Binds an exchange to another exchange using exchange.bind method (RabbitMQ extension)

Parameters:

  • desitnation (String) —

    Destination exchange name

  • source (String) —

    Source exchange name

  • routing_key (String) —

    Routing key used for binding

  • arguments (Hash) (defaults to: nil) —

    (nil) Optional arguments

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 434

def exchange_bind(destination, source, routing_key, arguments = nil)
  converting_rjc_exceptions_to_ruby do
    @delegate.exchange_bind(destination, source, routing_key, arguments)
  end
end

#exchange_declare(name, type, durable = false, auto_delete = false, internal = false, arguments = nil) ⇒ Object

Declares a echange using echange.declare AMQP 0.9.1 method.

Parameters:

  • name (String) —

    Exchange name

  • durable (Boolean) (defaults to: false) —

    (false) Should information about this echange be persisted to disk so that it can survive broker restarts? Typically set to true for long-lived exchanges.

  • auto_delete (Boolean) (defaults to: false) —

    (false) Should this echange be deleted when it is no longer used?

  • passive (Boolean) —

    (false) If true, exchange will be checked for existence. If it does not exist, NotFound will be raised.

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 417

def exchange_declare(name, type, durable = false, auto_delete = false, internal = false, arguments = nil)
  converting_rjc_exceptions_to_ruby do
    @delegate.exchange_declare(name, type, durable, auto_delete, internal, arguments)
  end
end

#exchange_unbind(destination, source, routing_key, arguments = nil) ⇒ Object

Unbinds an exchange from another exchange using exchange.unbind method (RabbitMQ extension)

Parameters:

  • destination (String) —

    Destination exchange name

  • source (String) —

    Source exchange name

  • routing_key (String) —

    Routing key used for binding

  • arguments (Hash) (defaults to: nil) —

    ({}) Optional arguments

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 451

def exchange_unbind(destination, source, routing_key, arguments = nil)
  converting_rjc_exceptions_to_ruby do
    @delegate.exchange_unbind(destination, source, routing_key, arguments)
  end
end

#fanout(name, opts = {}) ⇒ MarchHare::Exchange

Declares a fanout exchange or looks it up in the cache of previously declared exchanges.

Parameters:

  • name (String) —

    Exchange name

  • opts (Hash) (defaults to: {}) —

    Exchange parameters

Options Hash (opts):

  • :durable (Boolean) — default: false —

    Should the exchange be durable?

  • :auto_delete (Boolean) — default: false —

    Should the exchange be automatically deleted when no longer in use?

  • :arguments (Hash) — default: {} —

    Optional exchange arguments (used by RabbitMQ extensions)

Returns:

See Also:



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# File 'lib/march_hare/channel.rb', line 329

def fanout(name, opts = {})
  dx = Exchange.new(self, name, opts.merge(:type => "fanout")).tap do |x|
    x.declare!
  end

  self.register_exchange(dx)
end

#find_queue(name) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 941

def find_queue(name)
  @queues[name]
end

#gracefully_shut_down_consumers ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 966

def gracefully_shut_down_consumers
  @consumers.each do |tag, consumer|
    consumer.gracefully_shut_down
  end
end

#guarding_against_stale_delivery_tags(tag, &block) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 985

def guarding_against_stale_delivery_tags(tag, &block)
  case tag
  # if a fixnum was passed, execute unconditionally. MK.
  when Fixnum then
    block.call
    # versioned delivery tags should be checked to avoid
    # sending out stale (invalid) tags after channel was reopened
    # during network failure recovery. MK.
  when VersionedDeliveryTag then
    if !tag.stale?(@recoveries_counter.get)
      block.call
    end
  end
end

#headers(name, opts = {}) ⇒ MarchHare::Exchange

Declares a headers exchange or looks it up in the cache of previously declared exchanges.

Parameters:

  • name (String) —

    Exchange name

  • opts (Hash) (defaults to: {}) —

    Exchange parameters

Options Hash (opts):

  • :durable (Boolean) — default: false —

    Should the exchange be durable?

  • :auto_delete (Boolean) — default: false —

    Should the exchange be automatically deleted when no longer in use?

  • :arguments (Hash) — default: {} —

    Optional exchange arguments

Returns:

See Also:



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# File 'lib/march_hare/channel.rb', line 392

def headers(name, opts = {})
  dx = Exchange.new(self, name, opts.merge(:type => "headers")).tap do |x|
    x.declare!
  end

  self.register_exchange(dx)
end

#increment_recoveries_counter ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 286

def increment_recoveries_counter
  @recoveries_counter.increment_and_get
end

#nack(delivery_tag, multiple = false, requeue = false) ⇒ Object

Rejects a message. A rejected message can be requeued or dropped by RabbitMQ. This method is similar to #reject but supports rejecting multiple messages at once, and is usually preferred.

Parameters:

  • delivery_tag (Integer) —

    Delivery tag to reject

  • multiple (Boolean) (defaults to: false) —

    (false) Should all unacknowledged messages up to this be rejected as well?

  • requeue (Boolean) (defaults to: false) —

    (false) Should this message be requeued instead of dropping it?

See Also:



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# File 'lib/march_hare/channel.rb', line 695

def nack(delivery_tag, multiple = false, requeue = false)
  guarding_against_stale_delivery_tags(delivery_tag) do
    basic_nack(delivery_tag.to_i, multiple, requeue)
  end
end

#next_publisher_seq_no ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 831

def next_publisher_seq_no
  @delegate.next_publisher_seq_no
end

#on_confirm(&block) ⇒ Object

Defines a publisher confirm handler

See Also:



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# File 'lib/march_hare/channel.rb', line 871

def on_confirm(&block)
  ch = BlockConfirmListener.from(block)
  self.add_confirm_listener(ch)
  @confirm_hooks << ch
end

#on_return(&block) ⇒ Object

Defines a returned message handler.

See Also:



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# File 'lib/march_hare/channel.rb', line 865

def on_return(&block)
  self.add_return_listener(BlockReturnListener.from(block))
end

#on_shutdown(&block) ⇒ Object

Defines a shutdown event callback. Shutdown events are broadcasted when a channel is closed, either explicitly or forcefully, or due to a network/peer failure.



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# File 'lib/march_hare/channel.rb', line 179

def on_shutdown(&block)
  sh = ShutdownListener.new(self, &block)

  @shutdown_hooks << sh
  @delegate.add_shutdown_listener(sh)

  sh
end

#open? ⇒ Boolean

Returns true if the channel is open.

Returns:

  • (Boolean) —

    true if the channel is open



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# File 'lib/march_hare/channel.rb', line 155

def open?
  @delegate.open?
end

#prefetch ⇒ Integer

Returns Active basic.qos prefetch setting.

Returns:

  • (Integer) —

    Active basic.qos prefetch setting.



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# File 'lib/march_hare/channel.rb', line 655

def prefetch
  @prefetch_count || 0
end

#prefetch=(n) ⇒ Object

Sets how many messages will be given to consumers on this channel before they have to acknowledge or reject one of the previously consumed messages

Parameters:

  • prefetch_count (Integer) —

    Prefetch (QoS setting) for this channel

See Also:



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# File 'lib/march_hare/channel.rb', line 650

def prefetch=(n)
  basic_qos(n)
end

#qos(options = {}) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 640

def qos(options={})
  basic_qos(options.fetch(:prefetch_count, 0))
end

#queue(name, options = {}) ⇒ MarchHare::Queue

Declares a queue or looks it up in the per-channel cache.

Parameters:

  • name (String) —

    Queue name. Pass an empty string to declare a server-named queue (make RabbitMQ generate a unique name).

  • options (Hash) (defaults to: {}) —

    Queue properties and other options

Options Hash (options):

  • :durable (Boolean) — default: false —

    Should this queue be durable?

  • :auto-delete (Boolean) — default: false —

    Should this queue be automatically deleted when the last consumer disconnects?

  • :exclusive (Boolean) — default: false —

    Should this queue be exclusive (only can be used by this connection, removed when the connection is closed)?

  • :arguments (Boolean) — default: {} —

    Additional optional arguments (typically used by RabbitMQ extensions and plugins)

Returns:

See Also:



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# File 'lib/march_hare/channel.rb', line 475

def queue(name, options={})
  dq = Queue.new(self, name, options).tap do |q|
    q.declare!
  end

  self.register_queue(dq)
end

#queue_bind(queue, exchange, routing_key, arguments = nil) ⇒ Object

Binds a queue to an exchange using queue.bind AMQP 0.9.1 method

Parameters:

  • name (String) —

    Queue name

  • exchange (String) —

    Exchange name

  • routing_key (String) —

    Routing key used for binding

  • arguments (Hash) (defaults to: nil) —

    (nil) Optional arguments

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 542

def queue_bind(queue, exchange, routing_key, arguments = nil)
  converting_rjc_exceptions_to_ruby do
    @delegate.queue_bind(queue, exchange, routing_key, arguments)
  end
end

#queue_declare(name, durable, exclusive, auto_delete, arguments = {}) ⇒ Object

Declares a queue using queue.declare AMQP 0.9.1 method.

Parameters:

  • name (String) —

    Queue name

  • durable (Boolean) —

    (false) Should information about this queue be persisted to disk so that it can survive broker restarts? Typically set to true for long-lived queues.

  • auto_delete (Boolean) —

    (false) Should this queue be deleted when the last consumer is cancelled?

  • exclusive (Boolean) —

    (false) Should only this connection be able to use this queue? If true, the queue will be automatically deleted when this connection is closed

  • passive (Boolean) —

    (false) If true, queue will be checked for existence. If it does not exist, NotFound will be raised.

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 498

def queue_declare(name, durable, exclusive, auto_delete, arguments = {})
  converting_rjc_exceptions_to_ruby do
    @delegate.queue_declare(name, durable, exclusive, auto_delete, arguments)
  end
end

#queue_declare_passive(name) ⇒ Object

Checks if a queue exists using queue.declare AMQP 0.9.1 method. If it does not, a channel exception will be raised.

Parameters:

  • name (String) —

    Queue name

See Also:



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# File 'lib/march_hare/channel.rb', line 510

def queue_declare_passive(name)
  converting_rjc_exceptions_to_ruby do
    @delegate.queue_declare_passive(name)
  end
end

#queue_delete(name, if_empty = false, if_unused = false) ⇒ Object

Deletes a queue using queue.delete AMQP 0.9.1 method

Parameters:

  • name (String) —

    Queue name

  • if_empty (Boolean) (defaults to: false) —

    (false) Should this queue be deleted only if it has no messages?

  • if_unused (Boolean) (defaults to: false) —

    (false) Should this queue be deleted only if it has no consumers?

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 525

def queue_delete(name, if_empty = false, if_unused = false)
  converting_rjc_exceptions_to_ruby do
    @delegate.queue_delete(name, if_empty, if_unused)
  end
end

#queue_purge(name) ⇒ Object

Purges a queue (removes all messages from it) using queue.purge AMQP 0.9.1 method.

Parameters:

  • name (String) —

    Queue name

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 571

def queue_purge(name)
  converting_rjc_exceptions_to_ruby do
    @delegate.queue_purge(name)
  end
end

#queue_unbind(queue, exchange, routing_key, arguments = nil) ⇒ Object

Unbinds a queue from an exchange using queue.unbind AMQP 0.9.1 method

Parameters:

  • name (String) —

    Queue name

  • exchange (String) —

    Exchange name

  • routing_key (String) —

    Routing key used for binding

  • arguments (Hash) (defaults to: nil) —

    ({}) Optional arguments

Returns:

  • RabbitMQ response

See Also:



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# File 'lib/march_hare/channel.rb', line 559

def queue_unbind(queue, exchange, routing_key, arguments = nil)
  converting_rjc_exceptions_to_ruby do
    @delegate.queue_unbind(queue, exchange, routing_key, arguments)
  end
end

#recover_confirm_hooks ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 219

def recover_confirm_hooks
  @confirm_hooks.each do |ch|
    @delegate.add_confirm_listener(ch)
  end
end

#recover_confirm_mode ⇒ Object

Recovers publisher confirms mode. Used by the Automatic Network Failure Recovery feature.



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# File 'lib/march_hare/channel.rb', line 234

def recover_confirm_mode
  confirm_select if @confirm_mode
end

#recover_consumers ⇒ Object

Recovers consumers. Used by the Automatic Network Failure Recovery feature.



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# File 'lib/march_hare/channel.rb', line 273

def recover_consumers
  @consumers.values.each do |c|
    begin
      self.unregister_consumer(c.consumer_tag)
      c.recover_from_network_failure
    rescue Exception => e
      # TODO: logger
      $stderr.puts "Caught exception when recovering consumer #{c.consumer_tag}"
    end
  end
end

#recover_exchanges ⇒ Object

Recovers exchanges. Used by the Automatic Network Failure Recovery feature.



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# File 'lib/march_hare/channel.rb', line 247

def recover_exchanges
  @exchanges.values.each do |x|
    begin
      x.recover_from_network_failure
    rescue Exception => e
      # TODO: logger
      $stderr.puts "Caught exception when recovering exchange #{x.name}"
    end
  end
end

#recover_prefetch_setting ⇒ Object

Recovers basic.qos setting. Used by the Automatic Network Failure Recovery feature.



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# File 'lib/march_hare/channel.rb', line 228

def recover_prefetch_setting
  basic_qos(@prefetch_count) if @prefetch_count
end

#recover_queues ⇒ Object

Recovers queues and bindings. Used by the Automatic Network Failure Recovery feature.



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# File 'lib/march_hare/channel.rb', line 260

def recover_queues
  @queues.values.each do |q|
    begin
      q.recover_from_network_failure
    rescue Exception => e
      # TODO: logger
      $stderr.puts "Caught exception when recovering queue #{q.name}"
    end
  end
end

#recover_shutdown_hooks ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 212

def recover_shutdown_hooks
  @shutdown_hooks.each do |sh|
    @delegate.add_shutdown_listener(sh)
  end
end

#recover_tx_mode ⇒ Object

Recovers transaction mode. Used by the Automatic Network Failure Recovery feature.



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# File 'lib/march_hare/channel.rb', line 240

def recover_tx_mode
  tx_select if @tx_mode
end

#register_consumer(consumer_tag, consumer) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 956

def register_consumer(consumer_tag, consumer)
  @consumers[consumer_tag] = consumer
end

#register_exchange(exchange) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 951

def register_exchange(exchange)
  @exchanges[exchange.name] = exchange
end

#register_queue(queue) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 936

def register_queue(queue)
  @queues[queue.name] = queue
end

#reject(delivery_tag, requeue = false) ⇒ Object

Rejects a message. A rejected message can be requeued or dropped by RabbitMQ.

Parameters:

  • delivery_tag (Integer) —

    Delivery tag to reject

  • requeue (Boolean) (defaults to: false) —

    Should this message be requeued instead of dropping it?

See Also:



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# File 'lib/march_hare/channel.rb', line 680

def reject(delivery_tag, requeue = false)
  guarding_against_stale_delivery_tags(delivery_tag) do
    basic_reject(delivery_tag.to_i, requeue)
  end
end

#revive_with(java_ch) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 207

def revive_with(java_ch)
  @delegate = java_ch
end

#session ⇒ MarchHare::Session Also known as: client, connection

Returns Connection this channel is on.

Returns:



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# File 'lib/march_hare/channel.rb', line 141

def session
  @connection
end

#topic(name, opts = {}) ⇒ MarchHare::Exchange

Declares a topic exchange or looks it up in the cache of previously declared exchanges.

Parameters:

  • name (String) —

    Exchange name

  • opts (Hash) (defaults to: {}) —

    Exchange parameters

Options Hash (opts):

  • :durable (Boolean) — default: false —

    Should the exchange be durable?

  • :auto_delete (Boolean) — default: false —

    Should the exchange be automatically deleted when no longer in use?

  • :arguments (Hash) — default: {} —

    Optional exchange arguments (used by RabbitMQ extensions)

Returns:

See Also:



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# File 'lib/march_hare/channel.rb', line 371

def topic(name, opts = {})
  dx = Exchange.new(self, name, opts.merge(:type => "topic")).tap do |x|
    x.declare!
  end

  self.register_exchange(dx)
end

#tx_commit ⇒ Object

Commits a transaction



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# File 'lib/march_hare/channel.rb', line 850

def tx_commit
  converting_rjc_exceptions_to_ruby do
    @delegate.tx_commit
  end
end

#tx_rollback ⇒ Object

Rolls back a transaction



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# File 'lib/march_hare/channel.rb', line 857

def tx_rollback
  converting_rjc_exceptions_to_ruby do
    @delegate.tx_rollback
  end
end

#tx_select ⇒ Object

Enables transactions on the channel



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# File 'lib/march_hare/channel.rb', line 836

def tx_select
  converting_rjc_exceptions_to_ruby do
    @tx_mode = true
    @delegate.tx_select
  end
end

#unregister_consumer(consumer_tag) ⇒ Object 



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# File 'lib/march_hare/channel.rb', line 961

def unregister_consumer(consumer_tag)
  @consumers.delete(consumer_tag)
end

#using_publisher_confirms? ⇒ Boolean Also known as: uses_publisher_confirms?

Returns true if publisher confirms are enabled for this channel.

Returns:

  • (Boolean) —

    true if publisher confirms are enabled for this channel



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# File 'lib/march_hare/channel.rb', line 808

def using_publisher_confirms?
  !!@confirm_mode
end

#using_tx? ⇒ Boolean Also known as: uses_tx?

Returns true if transactions are enabled for this channel.

Returns:

  • (Boolean) —

    true if transactions are enabled for this channel



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# File 'lib/march_hare/channel.rb', line 844

def using_tx?
  !!@tx_mode
end

#wait_for_confirms(timeout = nil) ⇒ Boolean

Waits until all outstanding publisher confirms arrive.

Takes an optional timeout in milliseconds. Will raise an exception in timeout has occured.

Parameters:

  • timeout (Integer) (defaults to: nil) —

    Timeout in milliseconds

Returns:

  • (Boolean) —

    true if all confirms were positive, false if some were negative



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# File 'lib/march_hare/channel.rb', line 821

def wait_for_confirms(timeout = nil)
  if timeout
    converting_rjc_exceptions_to_ruby do
      @delegate.wait_for_confirms(timeout)
    end
  else
    @delegate.wait_for_confirms
  end
end