Changes between Bunny 2.6.3 and 2.6.4 (unreleased)

Recovery Attempt Counting Strategy Changed

Previous behehavior is not unreasonable but is not what many users and even RabbitMQ team members come to expect. Therefore it can be considered a bug.

Previously a reconnection counter was preserved between successful recoveries. This made the integration test that uses server-sent connection.close possible.

With this change, the counter is reset after successful reconnection but there's an option to go back to the original behavior. We also do a hell of a lot more logging.

GitHub issue: #408

Changes between Bunny 2.6.2 and 2.6.3 (January 19th, 2016)

Retry on new Ruby 2.1+ variations of EAGAIN, EWOULDBLOCK

GitHub issue: #456

Changes between Bunny 2.6.1 and 2.6.2 (December 17th, 2016)

Do Not Modify Host Arrays

Bunny now can work with frozen host arrays.

GitHub issue: #446

Changes between Bunny 2.6.0 and 2.6.1 (October 23rd, 2016)

Bunny::ConsumerWorkPool#shutdown Terminates Early When It's Safe to Do So

Bunny::ConsumerWorkPool#shutdown(true) waited for consumer shutdown even if the pool wasn't active (there were no consumers on its channel).

GitHub issue: #438.

Changes between Bunny 2.5.0 and 2.6.0 (October 15th, 2016)

Graceful Shutdown of Consumers

Consumer work pool will now allow for a grace period before stopping pool threads so that delivery processing in progress can have a chance to finish.

GitHub issue: #437

Contributed by Stefan Sedich.

Bunny::Channel#wait_for_confirms Now Throws When Used on a Closed Channel

GitHub issue: #428

Contributed by Dimitar Dimitrov.

Race Condition Eliminated in Bunny::Channel#wait_for_confirms

GitHub issue: #424

Contributed by Dimitar Dimitrov.

More Defensive Consumer Work Pool

Bunny::ConsumerWorkPool#join and Bunny::ConsumerWorkPool#pause no longer fails with a NoMethodError on nil when executed on a work pool that doesn't have active threads (consumers).

This change is largely cosmetic and won't affect the majority of of projects in any way.

Changes between Bunny 2.4.0 and 2.5.0 (July 20th, 2016)

Exchange Bindings are Now Correctly Recovered

GitHub issue: #410

Contributed by Andrew Bruce.

Bunny::Channel#wait_for_confirms Awaits While There're Outstanding Unconfirmed Messages

GitHub issue: #424

Contributed by Dimitar Dimitrov.

Queue Recovery Respects the :no_declare Option

Queue recovery now respects the :no_declare option.

Bunny::Channel#wait_for_confirms Throws Early

Bunny::Channel#wait_for_confirms now throws an exception early when invoked on a closed channel.

GitHub issue: #428.

Contributed by Dimitar Dimitrov.

Changes between Bunny 2.3.0 and 2.4.0 (June 11th, 2016)

This release includes minor breaking API changes.

Unconfirmed Delivery Tag Set Reset on Network Recovery

Channels will now reset their unconfirmed delivery tag set after recovery.

GitHub issue: #406

Contributed by Bill Ruddock.

Support (Quoted) IPv6 Addresses in Address Lists

GitHub issue: #383.

Contributed by Jeremy Heiler.

Transport#read_fully Doesn't Try to Recover

Since transport is replaced by a recovering connection anyway, and this produces confusing errors up the stack.

GitHub issue: #359

Contributed by Donal McBreen.

Client-Provided Session :properties Merged with Defaults

Client-Provided Session :properties will now be merged with defaults instead of replacing them. This makes it much more convenient to override a single key.

More Predictable RABBITMQ_URL Handling

This is a breaking API change.

RABBITMQ_URL no longer will be used if any other connection options are provided. This makes it possible to use RABBITMQ_URL for some connections and options for others in a single OS process.

GitHub issue: #403

Contributed by Jimmy Petersen.

Changes between Bunny 2.2.0 and 2.3.0 (Feb 26th, 2016)

Thread#abort_on_exception Setting for Consumer Work Pool Threads

Bunny::Session#create_channel now supports a 3rd argument that, when set to true, makes consumer work pool threads to have Thread#abort_on_exception set on them.

GH issue: #382

Contributed by Seamus Abshere.

Explicit Transport Closure on Recovery

Bunny now will explicitly close previosly used transport before starting connection recovery.

GitHub issue: #377.

Contributed by bkanhoopla.

No TLS Socket Double-init

Makes sure that TLS sockets are not double-initialized.

GH issue: #345.

Contributed by Carl Hörberg.

Lazily Evaluated Debug Log Strings

GH issue: #375

Contributed by Omer Katz.

Changes between Bunny 2.1.0 and 2.2.0 (Sep 6th, 2015)

Add :addresses to connect options

Before this the connection options only allowed multiple hosts, an address is a combination of a host and a port. This makes it possible to specify different hosts with different ports.

Contributed by Bart van Zon (Tele2).

Recover from connection.close by default

Bunny will now try to reconnect also when server sent connection.close is received, e.g. when a server is restarting (but also when the connection is force closed by the server). This is in-line with how many other clients behave. The old default was recover_from_connection_close: false.

Contributed by Carl Hörberg (CloudAMQP).

Changes between Bunny 2.0.0 and 2.1.0

Bunny 2.1.0 has an important breaking change. It is highly advised that 2.1.0 is not mixed with earlier versions of Bunny in case your applications include integers in message headers.

Integer Value Serialisation in Headers

Integer values in headers are now serialised as signed 64-bit integers. Previously they were serialised as 32-bit unsigned integers, causing both underflows and overflows: incorrect values were observed by consumers.

It is highly advised that 2.1.0 is not mixed with earlier versions of Bunny in case your applications include integers in message headers.

If that's not the case, Bunny 2.1 will integeroperate with any earlier version starting with 0.9.0 just fine. Popular clients in other languages (e.g. Java and .NET) will interoperate with Bunny 2.1.0 without issues.

Explicit Ruby 2.0 Requirement

Bunny now requires Ruby 2.0 in the gemspec.

Contributed by Carl Hörberg.

JRuby Fix

Bunny runs again on JRuby. Note that JRuby users are strongly advised to use March Hare instead.

Contributed by Teodor Pripoae.

Changes between Bunny 1.7.0 and 2.0.0

Bunny 2.0 doesn't have any breaking API changes but drops Ruby 1.8 and 1.9 (both EOL'ed) support, hence the version.

Minimum Required Ruby Version is 2.0

Bunny 2.0 requires Ruby 2.0 or later.

Non-Blocking Writes

Bunny now uses non-blocking socket writes, uses a reduced number of writes for message publishing (frames are batched into a single write), and handles TCP back pressure from RabbitMQ better.

Contributed by Irina Bednova and Michael Klishin.

Reduced Timeout Use

Bunny::ContinuationQueue#poll no longer relies on Ruby's Timeout which has numerous issues, including starting a new "interruptor" thread per operation, which is far from efficient.

Contributed by Joe Eli McIlvain and Carl Hörberg.

Capped Number of Connection Recovery Attempts

:recovery_attempts is a new option that limits the number of connection recovery attempts performed by Bunny. nil means "no limit".

Contributed by Irina Bednova.

Bunny::Channel#basic_ack and Related Methods Improvements

Bunny::Channel#basic_ack, Bunny::Channel#basic_nack, and Bunny::Channel#basic_reject now adjust delivery tags between connection recoveries, as well as have a default value for the second argument.

Contributed by Wayne Conrad.

Logger Output Remains Consistent

Setting the @logger.progname attribute changes the output of the logger. This is not expected behaviour when the client provides a custom logger. Behaviour remains unchainged when the internally initialized logger is used.

Contributed by Justin Carter.

prefetch_count is Limited to 65535

Since basic.qos's prefetch_count field is of type short in the protocol, Bunny must enforce its maximum allowed value to 2^16 - 1 to avoid confusing issues due to overflow.

Per-Consumer and Per-Channel Prefetch

Recent RabbitMQ versions support basic.qos global flag, controlling whether prefetch applies per-consumer or per-channel. Bunny Channel#prefetch now allows flag to be set as optional parameter, with the same default behaviour as before (per-consumer).

Contributed by tiredpixel.

Changes between Bunny 1.6.0 and 1.7.0

TLS Peer Verification Enabled by Default

When using TLS, peer verification is now enabled by default. It is still possible to disable verification, e.g. for convenient development locally.

Peer verification is a means of protection against man-in-the-middle attacks and is highly recommended in production settings. However, it can be an inconvenience during local development. We believe it's time to have the default to be more secure.

Contributed by Michael Klishin (Pivotal) and Andre Foeken (Nedap).

Higher Default Connection Timeout

Default connection timeout has been increased to 25 seconds. The older default of 5 seconds wasn't sufficient in some edge cases with DNS resolution (e.g. when primary DNS server is down).

The value can be overriden at connection time.

Contributed by Yury Batenko.

Socket Read Timeout No Longer Set to 0 With Disabled Heartbeats

GH issue: #267.

JRuby Writes Fixes

On JRuby, Bunny reverts back to using plain old write(2) for writes. The CRuby implementation on JRuby suffers from I/O incompatibilities. Until JRuby

Bunny users who run on JRuby are highly recommended to switch to March Hare, which has nearly identical API and is significantly more efficient.

Bunny::Session#with_channel Synchornisation Improvements

Bunny::Session#with_channel is now fully synchronised and won't run into COMMAND_INVALID errors when used from multiple threads that share a connection.

Changes between Bunny 1.5.0 and 1.6.0

TLSv1 by Default

TLS connections now prefer TLSv1 (or later, if available) due to the recently discovered POODLE attack on SSLv3.

Contributed by Michael Klishin (Pivotal) and Justin Powers (

GH issues:

Socket Read and Write Timeout Improvements

Bunny now sets a read timeout on the sockets it opens, and uses timeouts as the most reliable option available on Ruby 1.9 and later.

GH issue: #254.

Contributed by Andre Foeken (Nedap).

Inline TLS Certificates Support

TLS certificate options now accept inline certificates as well as file paths.

GH issues: #255, #256.

Contributed by Will Barrett (Sqwiggle).

Changes between Bunny 1.4.0 and 1.5.0

Improved Uncaught Exception Handler

Uncaught exception handler now provides more information about the exception, including its caller (one more stack trace line).

Contributed by Carl Hörberg (CloudAMQP).

Convenience Method for Temporary (Server-named, Exclusive) Queue Declaration

Bunny::Channel#temporary_queue is a convenience method that declares a new server-named exclusive queue:

q = ch.temporary_queue

Contributed by Daniel Schierbeck (Zendesk).

Recovery Reliability Improvements

Automatic connection recovery robustness improvements. Contributed by Andre Foeken (Nedap).

Host Lists

It is now possible to pass the :hosts option to When connection to RabbitMQ (including during connection recovery), a random host will be chosen from the list.

Connection shuffling and robustness improvements.

Contributed by Andre Foeken (Nedap).

Default Channel Removed

Breaks compatibility with Bunny 0.8.x.

Bunny:Session#default_channel was removed. Please open channels explicitly now, as all the examples in the docs do.

Changes between Bunny 1.3.0 and 1.4.0

Channel#wait_for_confirms Returns Immediately If All Publishes Confirmed

Contributed by Matt Campbell.

Publisher Confirms is In Sync After Recovery

When a connection is recovered, the sequence counter resets on the broker, but not the client. To keep things in sync the client must store a confirmation offset after a recovery.

Contributed by Devin Christensen.

NoMethodError on Thread During Shutdown

During abnormal termination, Bunny::Session#close no longer tries to call the non-existent terminate_with method on its origin thread.

Changes between Bunny 1.2.0 and 1.3.0

TLS Can Be Explicitly Disabled

TLS now can be explicitly disabled even when connecting (without TLS) to the default RabbitMQ TLS/amqps port (5671):

conn = => 5671, :tls => false)

Contributed by Muhan Zou.

Single Threaded Connections Raise Shutdown Exceptions

Single threaded Bunny connections will now raise exceptions that occur during shutdown as is (instead of trying to shut down I/O loop which only threaded ones have).

Contributed by Carl Hörberg.

Synchronization Improvements for Session#close

Bunny::Session#close now better synchronizes state transitions, eliminating a few race condition scenarios with I/O reader thread.

Bunny::Exchange.default Fix

Bunny::Exchange.default no longer raises an exception.

Note that it is a legacy compatibility method. Please use Bunny::Channel#default_exchange instead.

Contributed by Justin Litchfield.

GH issue #211.

Bunny::Queue#pop_as_hash Removed

Bunny::Queue#pop_as_hash, which was added to ease migration to Bunny 0.9, was removed.

Bunny::Queue#pop Wraps Metadata

Bunny::Queue#pop now wraps basic.get-ok and message properties into Bunny::GetResponse and Bunny::MessageProperties, just like basic.consume deliveries.

GH issue: #212.

Better Synchronization for Publisher Confirms

Publisher confirms implementation now synchronizes unconfirmed set better.

Contributed by Nicolas Viennot.

Channel Allocation After Recovery

Channel id allocator is no longer reset after recovery if there are channels open. Makes it possible to open channels on a recovered connection (in addition to the channels it already had).

Changes between Bunny 1.1.0 and 1.2.0

:key Supported in Bunny::Channel#queue_bind

It is now possible to use :key (which Bunny versions prior to 0.9 used) as well as :routing_key as an argument to Bunny::Queue#bind.

System Exceptions Not Rescued by the Library

Bunny now rescues StandardError instead of Exception where it automatically does so (e.g. when dispatching deliveries to consumers).

Contributed by Alex Young.

Initial Socket Connection Timeout Again Raises Bunny::TCPConnectionFailed

Initial socket connection timeout again raises Bunny::TCPConnectionFailed on the connection origin thread.

Thread Leaks Plugged

Bunny::Session#close on connections that have experienced a network failure will correctly clean up I/O and heartbeat sender threads.

Contributed by m-o-e.

Bunny::Concurrent::ContinuationQueue#poll Rounding Fix

Bunny::Concurrent::ContinuationQueue#poll no longer floors the argument to the nearest second.

Contributed by Brian Abreu.

Routing Key Limit

Per AMQP 0-9-1 spec, routing keys cannot be longer than 255 characters. Bunny::Channel#basic_publish and Bunny::Exchange#publish now enforces this limit.

Nagle's Algorithm Disabled Correctly

Bunny now properly disables Nagle's algorithm on the sockets it opens. This likely means significantly lower latency for workloads that involve sending a lot of small messages very frequently.

Contributed by Nelson Gauthier (AirBnB).

Internal Exchanges

Exchanges now can be declared as internal:

ch = conn.create_channel
x  = ch.fanout("bunny.tests.exchanges.internal", :internal => true)

Internal exchanges cannot be published to by clients and are solely used for Exchange-to-Exchange bindings and various plugins but apps may still need to bind them. Now it is possible to do so with Bunny.

Uncaught Consumer Exceptions

Uncaught consumer exceptions are now handled by uncaught exceptions handler that can be defined per channel:

ch.on_uncaught_exception do |e, consumer|
  # ...

Changes between Bunny 1.1.0.rc1 and 1.1.0

Synchronized Session#create_channel and Session#close_channel

Full bodies of Bunny::Session#create_channel and Bunny::Session#close_channel are now synchronized, which makes sure concurrent and subsequent operations (e.g. exchange.declare) do not result in connection-level exceptions (incorrect connection state transitions).

Corrected Recovery Log Message

Bunny will now use actual recovery interval in the log.

Contributed by Chad Fowler.

Changes between Bunny 1.1.0.pre2 and 1.1.0.rc1

Full Channel State Recovery

Channel recovery now involves recovery of publisher confirms and transaction modes.

TLS Without Peer Verification

Bunny now successfully performs TLS upgrade when peer verification is disabled.

Contributed by Jordan Curzon.

Bunny::Session#with_channel Ensures the Channel is Closed

Bunny::Session#with_channel now makes sure the channel is closed even if provided block raises an exception

Contributed by Carl Hoerberg.

Channel Number = 0 is Rejected

Bunny::Session#create_channel will now reject channel number 0.

Single Threaded Mode Fixes

Single threaded mode no longer fails with

undefined method `event_loop'

Changes between Bunny 1.1.0.pre1 and 1.1.0.pre2

connection.tune.channel_max No Longer Overflows

connection.tune.channel_max could previously be configured to values greater than 2^16 - 1 (65535). This would result in a silent overflow during serialization. The issue was harmless in practice but is still a bug that can be quite confusing.

Bunny now caps max number of channels to 65535. This allows it to be forward compatible with future RabbitMQ versions that may allow limiting total # of open channels via server configuration.

amq-protocol Update

Minimum amq-protocol version is now 1.9.0 which includes bug fixes and performance improvements for channel ID allocator.

Thread Leaks Fixes

Bunny will now correctly release heartbeat sender when allocating a new one (usually happens only when connection recovers from a network failure).

Changes between Bunny 1.0.0 and 1.1.0.pre1

Versioned Delivery Tag Fix

Versioned delivery tag now ensures all the arguments it operates (original delivery tag, atomic fixnum instances, etc) are coerced to Integer before comparison.

GitHub issues: #171.

User-Provided Loggers

Bunny now can use any logger that provides the same API as Ruby standard library's Logger:

require "logger"
require "stringio"

io =
# will log to `io` =>

Default CA's Paths Are Disabled on JRuby

Bunny uses OpenSSL provided CA certificate paths. This caused problems on some platforms on JRuby (see jruby/jruby#155).

To avoid these issues, Bunny no longer uses default CA certificate paths on JRuby (there are no changes for other Rubies), so it's necessary to provide CA certificate explicitly.

Fixes CPU Burn on JRuby

Bunny now uses slightly different ways of continuously reading from the socket on CRuby and JRuby, to prevent abnormally high CPU usage on JRuby after a certain period of time (the frequency of EWOULDBLOCK being raised spiked sharply).

Changes between Bunny 1.0.0.rc2 and 1.0.0.rc3

Authentication Failure Notification Support

Bunny::AuthenticationFailureError is a new auth failure exception that subclasses Bunny::PossibleAuthenticationFailureError for backwards compatibility.

As such, Bunny::PossibleAuthenticationFailureError's error message has changed.

This extension is available in RabbitMQ 3.2+.


Bunny::Session#exchange_exists? is a new predicate that makes it easier to check if a exchange exists.

It uses a one-off channel and exchange.declare with passive set to true under the hood.


Bunny::Session#queue_exists? is a new predicate that makes it easier to check if a queue exists.

It uses a one-off channel and queue.declare with passive set to true under the hood.

Inline TLS Certificates and Keys

It is now possible to provide inline client certificate and private key (as strings) instead of filesystem paths. The options are the same:

  • :tls which, when set to true, will set SSL context up and switch to TLS port (5671)
  • :tls_cert which now can be a client certificate (public key) in PEM format
  • :tls_key which now can be a client key (private key) in PEM format
  • :tls_ca_certificates which is an array of string paths to CA certificates in PEM format

For example:

conn =                   => true,
                 :tls_cert              => ENV["TLS_CERTIFICATE"],
                 :tls_key               => ENV["TLS_PRIVATE_KEY"],
                 :tls_ca_certificates   => ["./examples/tls/cacert.pem"])

Changes between Bunny 1.0.0.rc1 and 1.0.0.rc2

Ruby 1.8.7 Compatibility Fixes

Ruby 1.8.7 compatibility fixes around timeouts.

Changes between Bunny 1.0.0.pre6 and 1.0.0.rc1

amq-protocol Update

Minimum amq-protocol version is now 1.8.0 which includes a bug fix for messages exactly 128 Kb in size.

Add timeout Bunny::ConsumerWorkPool#join

Bunny::ConsumerWorkPool#join now accepts an optional timeout argument.

Changes between Bunny 1.0.0.pre5 and 1.0.0.pre6

Respect RABBITMQ_URL value

RABBITMQ_URL env variable will now have effect even if is invoked without arguments.

Changes between Bunny 1.0.0.pre4 and 1.0.0.pre5

Ruby 1.8 Compatibility

Bunny is Ruby 1.8-compatible again and no longer references RUBY_ENGINE.


Bunny::Session.parse_uri is a new method that parses connection URIs into hashes that Bunny::Session#initialize accepts.


Default Paths for TLS/SSL CA's on All OS'es

Bunny now uses OpenSSL to detect default TLS/SSL CA's paths, extending this feature to OS'es other than Linux.

Contributed by Jingwen Owen Ou.

Changes between Bunny 1.0.0.pre3 and 1.0.0.pre4

Default Paths for TLS/SSL CA's on Linux

Bunny now will use the following TLS/SSL CA's paths on Linux by default:

  • /etc/ssl/certs/ca-certificates.crt on Ubuntu/Debian
  • /etc/ssl/certs/ca-bundle.crt on Amazon Linux
  • /etc/ssl/ca-bundle.pem on OpenSUSE
  • /etc/pki/tls/certs/ca-bundle.crt on Fedora/RHEL

and will log a warning if no CA files are available via default paths or :tls_ca_certificates.

Contributed by Carl Hörberg.

Consumers Can Be Re-Registered From Bunny::Consumer#handle_cancellation

It is now possible to re-register a consumer (and use any other synchronous methods) from Bunny::Consumer#handle_cancellation, which is now invoked in the channel's thread pool.

Bunny::Session#close Fixed for Single Threaded Connections

Bunny::Session#close with single threaded connections no longer fails with a nil pointer exception.

Changes between Bunny 1.0.0.pre2 and 1.0.0.pre3

This release has breaking API changes.

Safe[r] basic.ack, basic.nack and basic.reject implementation

Previously if a channel was recovered (reopened) by automatic connection recovery before a message was acknowledged or rejected, it would cause any operation on the channel that uses delivery tags to fail and cause the channel to be closed.

To avoid this issue, every channel keeps a counter of how many times it has been reopened and marks delivery tags with them. Using a stale tag to ack or reject a message will produce no method sent to RabbitMQ. Note that unacknowledged messages will be requeued by RabbitMQ when connection goes down anyway.

This involves an API change: Bunny::DeliveryMetadata#delivery_tag is now and instance of a class that responds to #tag and #to_i and is accepted by Bunny::Channel#ack and related methods.

Integers are still accepted by the same methods.

Changes between Bunny 1.0.0.pre1 and 1.0.0.pre2

Exclusivity Violation for Consumers Now Raises a Reasonable Exception

When a second consumer is registered for the same queue on different channels, a reasonable exception (Bunny::AccessRefused) will be raised.

Reentrant Mutex Implementation

Bunny now allows mutex impl to be configurable, uses reentrant Monitor by default.

Non-reentrant mutexes is a major PITA and may affect code that uses Bunny.

Avg. publishing throughput with Monitor drops slightly from 5.73 Khz to 5.49 Khz (about 4% decrease), which is reasonable for Bunny.

Apps that need these 4% can configure what mutex implementation is used on per-connection basis.

Eliminated Race Condition in Bunny::Session#close

Bunny::Session#close had a race condition that caused (non-deterministic) exceptions when connection transport was closed before connection reader loop was guaranteed to have stopped.

connection.close Raises Exceptions on Connection Thread

Connection-level exceptions (including when a connection is closed via management UI or rabbitmqctl) will now be raised on the connection thread so they

  • can be handled by applications
  • do not start connection recovery, which may be uncalled for

Client TLS Certificates are Optional

Bunny will no longer require client TLS certificates. Note that CA certificate list is still necessary.

If RabbitMQ TLS configuration requires peer verification, client certificate and private key are mandatory.

Changes between Bunny 0.9.0 and 1.0.0.pre1

Publishing Over Closed Connections

Publishing a message over a closed connection (during a network outage, before the connection is open) will now correctly result in an exception.

Contributed by Matt Campbell.

Reliability Improvement in Automatic Network Failure Recovery

Bunny now ensures a new connection transport (socket) is initialized before any recovery is attempted.

Reliability Improvement in Bunny::Session#create_channel

Bunny::Session#create_channel now uses two separate mutexes to avoid a (very rare) issue when the previous implementation would try to re-acquire the same mutex and fail (Ruby mutexes are non-reentrant).

Changes between Bunny 0.9.0.rc1 and 0.9.0.rc2

Channel Now Properly Restarts Consumer Pool

In a case when all consumers are cancelled, Bunny::Channel will shut down its consumer delivery thread pool.

It will also now mark the pool as not running so that it can be started again successfully if new consumers are registered later.

GH issue: #133.

Bunny::Queue#pop_waiting is Removed

A little bit of background: on MRI, the method raised ThreadErrors reliably. On JRuby, we used a different [internal] queue implementation from JDK so it wasn't an issue.

Timeout.timeout uses Thread#kill and Thread#join, both of which eventually attempt to acquire a mutex used by Queue#pop, which Bunny currently uses for continuations. The mutex is already has an owner and so a ThreadError is raised.

This is not a problem on JRuby because there we don't use Ruby's Timeout and Queue and instead rely on a JDK concurrency primitive which provides "poll with a timeout".

The issue with Thread#kill and Thread#raise has been first investigated and blogged about by Ruby implementers in 2008.

Finding a workaround will probably take a bit of time and may involve reimplementing standard library and core classes.

We don't want this issue to block Bunny 0.9 release. Neither we want to ship a broken feature. So as a result, we will drop Bunny::Queue#pop_waiting since it cannot be reliably implemented in a reasonable amount of time on MRI.

Per issue #131.

More Flexible SSLContext Configuration

Bunny will now upgrade connection to SSL in Bunny::Session#start, so it is possible to fine tune SSLContext and socket settings before that:

require "bunny"

conn =                   => true,
                 :tls_cert              => "examples/tls/client_cert.pem",
                 :tls_key               => "examples/tls/client_key.pem",
                 :tls_ca_certificates   => ["./examples/tls/cacert.pem"])

puts conn.transport.socket.inspect
puts conn.transport.tls_context.inspect

This also means that will now open the socket. Previously it was only done when Bunny::Session#start was invoked.

Changes between Bunny 0.9.0.pre13 and 0.9.0.rc1

TLS Support

Bunny 0.9 finally supports TLS. There are 3 new options takes:

  • :tls which, when set to true, will set SSL context up and switch to TLS port (5671)
  • :tls_cert which is a string path to the client certificate (public key) in PEM format
  • :tls_key which is a string path to the client key (private key) in PEM format
  • :tls_ca_certificates which is an array of string paths to CA certificates in PEM format

An example:

conn =                   => true,
                 :tls_cert              => "examples/tls/client_cert.pem",
                 :tls_key               => "examples/tls/client_key.pem",
                 :tls_ca_certificates   => ["./examples/tls/cacert.pem"])


This function was removed in v0.9.0.rc2

Bunny::Queue#pop_waiting is a new function that mimics Bunny::Queue#pop but will wait until a message is available. It uses a :timeout option and will raise an exception if the timeout is hit:

# given 1 message in the queue,
# works exactly as Bunny::Queue#get

# given no messages in the queue, will wait for up to 0.5 seconds
# for a message to become available. Raises an exception if the timeout
# is hit
q.pop_waiting(:timeout => 0.5)

This method only makes sense for collecting Request/Reply ("RPC") replies.

Bunny::InvalidCommand is now Bunny::CommandInvalid

Bunny::InvalidCommand is now Bunny::CommandInvalid (follows the exception class naming convention based on response status name).

Changes between Bunny 0.9.0.pre12 and 0.9.0.pre13

Channels Without Consumers Now Tear Down Consumer Pools

Channels without consumers left (when all consumers were cancelled) will now tear down their consumer work thread pools, thus making HotBunnies::Queue#subscribe(:block => true) calls unblock.

This is typically the desired behavior.

Consumer and Channel Available In Delivery Handlers

Delivery handlers registered via Bunny::Queue#subscribe now will have access to the consumer and channel they are associated with via the delivery_info argument:

q.subscribe do |delivery_info, properties, payload|
  delivery_info.consumer # => the consumer this delivery is for
  delivery_info.consumer # => the channel this delivery is on

This allows using Bunny::Queue#subscribe for one-off consumers much easier, including when used with the :block option.


Bunny::Exchange#wait_for_confirms is a convenience method on Bunny::Exchange that delegates to the method with the same name on exchange's channel.

Changes between Bunny 0.9.0.pre11 and 0.9.0.pre12

Ruby 1.8 Compatibility Regression Fix

Bunny::Socket no longer uses Ruby 1.9-specific constants.

Bunny::Channel#wait_for_confirms Return Value Regression Fix

Bunny::Channel#wait_for_confirms returns true or false again.

Changes between Bunny 0.9.0.pre10 and 0.9.0.pre11

Bunny::Session#create_channel Now Accepts Consumer Work Pool Size

Bunny::Session#create_channel now accepts consumer work pool size as the second argument:

# nil means channel id will be allocated by Bunny.
# 8 is the number of threads in the consumer work pool this channel will use.
ch = conn.create_channel(nil, 8)

Heartbeat Fix For Long Running Consumers

Long running consumers that don't send any data will no longer suffer from connections closed by RabbitMQ because of skipped heartbeats.

Activity tracking now takes sent frames into account.

Time-bound continuations

If a network loop exception causes "main" session thread to never receive a response, methods such as Bunny::Channel#queue will simply time out and raise Timeout::Error now, which can be handled.

It will not start automatic recovery for two reasons:

  • It will be started in the network activity loop anyway
  • It may do more damage than good

Kicking off network recovery manually is a matter of calling Bunny::Session#handle_network_failure.

The main benefit of this implementation is that it will never block the main app/session thread forever, and it is really efficient on JRuby thanks to a j.u.c. blocking queue.

Fixes #112.

Logging Support

Every Bunny connection now has a logger. By default, Bunny will use STDOUT as logging device. This is configurable using the :log_file option:

require "bunny"

conn = => :warn)

or the BUNNY_LOG_LEVEL environment variable that can take one of the following values:

  • debug (very verbose)
  • info
  • warn
  • error
  • fatal (least verbose)

Severity is set to warn by default. To disable logging completely, set the level to fatal.

To redirect logging to a file or any other object that can act as an I/O entity, pass it to the :log_file option.

Changes between Bunny 0.9.0.pre9 and 0.9.0.pre10

This release contains a breaking API change.

Concurrency Improvements On JRuby

On JRuby, Bunny now will use java.util.concurrent-backed implementations of some of the concurrency primitives. This both improves client stability (JDK concurrency primitives has been around for 9 years and have well-defined, documented semantics) and opens the door to solving some tricky failure handling problems in the future.

Explicitly Closed Sockets

Bunny now will correctly close the socket previous connection had when recovering from network issues.

Bunny::Exception Now Extends StandardError

Bunny::Exception now inherits from StandardError and not Exception.

Naked rescue like this

  # ...
rescue => e
  # ...

catches only descendents of StandardError. Most people don't know this and this is a very counter-intuitive practice, but apparently there is code out there that can't be changed that depends on this behavior.

This is a breaking API change.

Changes between Bunny 0.9.0.pre8 and 0.9.0.pre9

Bunny::Session#start Now Returns a Session

Bunny::Session#start now returns a session instead of the default channel (which wasn't intentional, default channel is a backwards-compatibility implementation detail).

Bunny::Session#start also no longer leaves dead threads behind if called multiple times on the same connection.

More Reliable Heartbeat Sender

Heartbeat sender no longer slips into an infinite loop if it encounters an exception. Instead, it will just stop (and presumably re-started when the network error recovery kicks in or the app reconnects manually).

Network Recovery After Delay

Network reconnection now kicks in after a delay to avoid aggressive reconnections in situations when we don't want to endlessly reconnect (e.g. when the connection was closed via the Management UI).

The :network_recovery_interval option passed to Bunny::Session#initialize and controls the interval. Default is 5 seconds.

Default Heartbeat Value Is Now Server-Defined

Bunny will now use heartbeat value provided by RabbitMQ by default.

Changes between Bunny 0.9.0.pre7 and 0.9.0.pre8

Stability Improvements

Several stability improvements in the network layer, connection error handling, and concurrency hazards.

Automatic Connection Recovery Can Be Disabled

Automatic connection recovery now can be disabled by passing the :automatically_recover => false option to Bunny#initialize).

When the recovery is disabled, network I/O-related exceptions will cause an exception to be raised in thee thread the connection was started on.

No Timeout Control For Publishing

Bunny::Exchange#publish and Bunny::Channel#basic_publish no longer perform timeout control (using the timeout module) which roughly increases throughput for flood publishing by 350%.

Apps that need delivery guarantees should use publisher confirms.

Changes between Bunny 0.9.0.pre6 and 0.9.0.pre7


Bunny::Channel#on_error is a new method that lets you define handlers for channel errors that are caused by methods that have no responses in the protocol (basic.ack, basic.reject, and basic.nack).

This is rarely necessary but helps make sure no error goes unnoticed.


channel.on_error |ch, channel_close|
  puts channel_close.inspect

Fixed Framing of Larger Messages With Unicode Characters

Larger (over 128K) messages with non-ASCII characters are now always encoded correctly with amq-protocol 1.2.0.

Efficiency Improvements

Publishing of large messages is now done more efficiently.

Contributed by Greg Brockman.

API Reference

Bunny API reference is now up online.

Bunny::Channel#basic_publish Support For :persistent

Bunny::Channel#basic_publish now supports both :delivery_mode and :persistent options.


Bunny::Channel#nacked_set is a counter-part to Bunny::Channel#unacked_set that contains basic.nack-ed (rejected) delivery tags.

Single-threaded Network Activity Mode

Passing :threaded => false to now will use the same thread for publisher confirmations (may be useful for retry logic implementation).

Contributed by Greg Brockman.

Changes between Bunny 0.9.0.pre5 and 0.9.0.pre6

Automatic Network Failure Recovery

Automatic Network Failure Recovery is a new Bunny feature that was earlier impemented and vetted out in amqp gem. What it does is, when a network activity loop detects an issue, it will try to periodically recover [first TCP, then] AMQP 0.9.1 connection, reopen all channels, recover all exchanges, queues, bindings and consumers on those channels (to be clear: this only includes entities and consumers added via Bunny).

Publishers and consumers will continue operating shortly after the network connection recovers.

Learn more in the Error Handling and Recovery documentation guide.

Confirms Listeners

Bunny now supports listeners (callbacks) on

ch.confirm_select do |delivery_tag, multiple, nack|
  # handle confirms (e.g. perform retries) here

Contributed by Greg Brockman.

Publisher Confirms Improvements

Publisher confirms implementation now uses non-strict equality (<=) for cases when multiple messages are confirmed by RabbitMQ at once.

Bunny::Channel#unconfirmed_set is now part of the public API that lets developers access unconfirmed delivery tags to perform retries and such.

Contributed by Greg Brockman.

Publisher Confirms Concurrency Fix

Bunny::Channel#wait_for_confirms will now correctly block the calling thread until all pending confirms are received.

Changes between Bunny 0.9.0.pre4 and 0.9.0.pre5

Channel Errors Reset

Channel error information is now properly reset when a channel is (re)opened.

GH issue: #83.

Bunny::Consumer#initial Default Change

the default value of Bunny::Consumer noack argument changed from false to true for consistency.

Bunny::Session#prefetch Removed

Global prefetch is not implemented in RabbitMQ, so Bunny::Session#prefetch is gone from the API.

Queue Redeclaration Bug Fix

Fixed a problem when a queue was not declared after being deleted and redeclared

GH issue: #80

Channel Cache Invalidation

Channel queue and exchange caches are now properly invalidated when queues and exchanges are deleted.

Changes between Bunny 0.9.0.pre3 and 0.9.0.pre4

Heartbeats Support Fixes

Heartbeats are now correctly sent at safe intervals (half of the configured interval). In addition, setting :heartbeat => 0 (or nil) will disable heartbeats, just like in Bunny 0.8 and amqp gem.

Default :heartbeat value is now 600 (seconds), the same as RabbitMQ 3.0 default.

Eliminate Race Conditions When Registering Consumers

Fixes a potential race condition between basic.consume-ok handler and delivery handler when a consumer is registered for a queue that has messages in it.

GH issue: #78.

Support for Alternative Authentication Mechanisms

Bunny now supports two authentication mechanisms and can be extended to support more. The supported methods are "PLAIN" (username and password) and "EXTERNAL" (typically uses TLS, UNIX sockets or another mechanism that does not rely on username/challenge pairs).

To use the "EXTERNAL" method, pass :auth_mechanism => "EXTERNAL" to

# uses the EXTERNAL authentication mechanism
conn = => "EXTERNAL")


A new high-level API method: Bunny::Consumer#cancel, can be used to cancel a consumer. Bunny::Queue#subscribe will now return consumer instances when the :block option is passed in as false.

Bunny::Exchange#delete Behavior Change

Bunny::Exchange#delete will no longer delete pre-declared exchanges that cannot be declared by Bunny (amq.* and the default exchange).


Bunny::DeliveryInfo#redelivered? is a new method that is an alias to Bunny::DeliveryInfo#redelivered but follows the Ruby community convention about predicate method names.

Corrected Bunny::DeliveryInfo#delivery_tag Name

Bunny::DeliveryInfo#delivery_tag had a typo which is now fixed.

Changes between Bunny 0.9.0.pre2 and 0.9.0.pre3

Client Capabilities

Bunny now correctly lists RabbitMQ extensions it currently supports in client capabilities:

  • basic.nack
  • exchange-to-exchange bindings
  • consumer cancellation notifications
  • publisher confirms

Publisher Confirms Support

Lightweight Publisher Confirms is a RabbitMQ feature that lets publishers keep track of message routing without adding noticeable throughput degradation as it is the case with AMQP 0.9.1 transactions.

Bunny 0.9.0.pre3 supports publisher confirms. Publisher confirms are enabled per channel, using the Bunny::Channel#confirm_select method. Bunny::Channel#wait_for_confirms is a method that blocks current thread until the client gets confirmations for all unconfirmed published messages:

ch = connection.create_channel

ch.using_publisher_confirmations? # => true

q  = ch.queue("", :exclusive => true)
x  = ch.default_exchange

5000.times do
  x.publish("xyzzy", :routing_key =>

ch.next_publish_seq_no.should == 5001
ch.wait_for_confirms # waits until all 5000 published messages are acknowledged by RabbitMQ

Consumers as Objects

It is now possible to register a consumer as an object instead of a block. Consumers that are class instances support cancellation notifications (e.g. when a queue they're registered with is deleted).

To support this, Bunny introduces two new methods: Bunny::Channel#basic_consume_with and Bunny::Queue#subscribe_with, that operate on consumer objects. Objects are supposed to respond to three selectors:

  • :handle_delivery with 3 arguments
  • :handle_cancellation with 1 argument
  • :consumer_tag= with 1 argument

An example:

class ExampleConsumer < Bunny::Consumer
  def cancelled?

  def handle_cancellation(_)
    @cancelled = true

# "high-level" API
ch1 = connection.create_channel
q1  = ch1.queue("", :auto_delete => true)

consumer =, q)

# "low-level" API
ch2 = connection.create_channel
q1  = ch2.queue("", :auto_delete => true)

consumer =, q)

RABBITMQ_URL ENV variable support

If RABBITMQ_URL environment variable is set, Bunny will assume it contains a valid amqp URI string and will use it. This is convenient with some PaaS technologies such as Heroku.

Changes between Bunny 0.9.0.pre1 and 0.9.0.pre2

Change Bunny::Queue#pop default for :ack to false

It makes more sense for beginners that way.

Bunny::Queue#subscribe now support the new :block option

Bunny::Queue#subscribe support the new :block option (a boolean).

It controls whether the current thread will be blocked by Bunny::Queue#subscribe.

Bunny::Exchange#publish now supports :key again

Bunny::Exchange#publish now supports :key as an alias for :routing_key.

Bunny::Session#queue et al.

Bunny::Session#queue, Bunny::Session#direct, Bunny::Session#fanout, Bunny::Session#topic, and Bunny::Session#headers were added to simplify migration. They all delegate to their respective Bunny::Channel methods on the default channel every connection has.

Bunny::Channel#exchange, Bunny::Session#exchange

Bunny::Channel#exchange and Bunny::Session#exchange were added to simplify migration:

b =

# uses default connection channel
x ="", :topic)

Bunny::Queue#subscribe now properly takes 3 arguments

q.subscribe(:exclusive => false, :ack => false) do |delivery_info, properties, payload|
  # ...

Changes between Bunny 0.8.x and 0.9.0.pre1

New convenience functions: Bunny::Channel#fanout, Bunny::Channel#topic

Bunny::Channel#fanout, Bunny::Channel#topic, Bunny::Channel#direct, Bunny::Channel#headers, andBunny::Channel#default_exchange are new convenience methods to instantiate exchanges:

conn =

ch = conn.create_channel
x  = ch.fanout("", :durable => true)

Bunny::Queue#pop and consumer handlers (Bunny::Queue#subscribe) signatures have changed

Bunny < 0.9.x example:

h = queue.pop

puts h[:delivery_info], h[:header], h[:payload]

Bunny >= 0.9.x example:

delivery_info, properties, payload = queue.pop

The improve is both in that Ruby has positional destructuring, e.g.

delivery_info, _, content = q.pop

but not hash destructuring, like, say, Clojure does.

In addition we return nil for content when it should be nil (basic.get-empty) and unify these arguments betwee

  • Bunny::Queue#pop

  • Consumer (Bunny::Queue#subscribe, etc) handlers

  • Returned message handlers

The unification moment was the driving factor.

Bunny::Client#write now raises Bunny::ConnectionError

Bunny::Client#write now raises Bunny::ConnectionError instead of Bunny::ServerDownError when network I/O operations fail.

Bunny::Client.create_channel now uses a bitset-based allocator

Instead of reusing channel instances, Bunny::Client.create_channel now opens new channels and uses bitset-based allocator to keep track of used channel ids. This avoids situations when channels are reused or shared without developer's explicit intent but also work well for long running applications that aggressively open and release channels.

This is also how amqp gem and RabbitMQ Java client manage channel ids.

Bunny::ServerDownError is now Bunny::TCPConnectionFailed

Bunny::ServerDownError is now an alias for Bunny::TCPConnectionFailed