Change history¶

3.0.19¶

release-date:	2014-06-09 03:10 P.M UTC
release-by:	Ask Solem

The wheel distribution did not support Python 2.6 by failing to list the extra dependencies required.
Durable and auto_delete queues/exchanges can be be cached using maybe_declare.

3.0.18¶

release-date:	2014-06-02 06:00 P.M UTC
release-by:	Ask Solem

A typo introduced in 3.0.17 caused kombu.async.hub to crash (Issue #360).

3.0.17¶

release-date:	2014-06-02 05:00 P.M UTC
release-by:	Ask Solem

kombu[librabbitmq] now depends on librabbitmq 1.5.2.
Async: Event loop now selectively removes file descriptors for the mode it failed in, and keeps others (e.g read vs write).

Fix contributed by Roger Hu.
CouchDB: Now works without userid set.

Fix contributed by Latitia M. Haskins.
SQLAlchemy: Now supports recovery from connection errors.

Contributed by Felix Schwarz.
Redis: Restore at shutdown now works when ack emulation is disabled.
kombu.common.eventloop() accidentally swallowed socket errors.
Adds kombu.utils.url.sanitize_url()

3.0.16¶

release-date:	2014-05-06 01:00 P.M UTC
release-by:	Ask Solem

kombu[librabbitmq] now depends on librabbitmq 1.5.1.
Redis: Fixes TypeError problem in unregister (Issue #342).

Fix contributed by Tobias Schottdorf.
Tests: Some unit tests accidentally required the redis-py library.

Fix contributed by Randy Barlow.
librabbitmq: Would crash when using an older version of librabbitmq, now emits warning instead.

3.0.15¶

release-date:	2014-04-15 09:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.4.5.
RabbitMQ 3.3 changes QoS semantics (Issue #339).
See the RabbitMQ release notes here: http://www.rabbitmq.com/blog/2014/04/02/breaking-things-with-rabbitmq-3-3/

A new connection property has been added that can be used to detect whether the remote server is using this new QoS behavior:
>>> Connection('amqp://').qos_behavior_matches_spec False
so if your application depends on the old semantics you can use this to set the apply_global flag appropriately:
def update_prefetch_count(channel, new_value): channel.basic_qos( 0, new_value, not channel.connection.client.qos_behavior_matches_spec, )
Users of librabbitmq is encouraged to upgrade to librabbitmq 1.5.0.

The kombu[librabbitmq] extra has been updated to depend on this version.
Pools: Now takes transport options into account when comparing connections (Issue #333).
MongoDB: Fixes Python 3 compatibility.
Async: select: Ignore socket errors when attempting to unregister handles from the loop.
Pidbox: Can now be configured to use a serializer other than json, but specifying a serializer argument to Mailbox.

Contributed by Dmitry Malinovsky.
Message decompression now works with Python 3.

Fix contributed by Adam Gaca.

3.0.14¶

release-date:	2014-03-19 07:00 P.M UTC
release-by:	Ask Solem

MongoDB: Now endures a connection failover (Issue #123).

Fix contributed by Alex Koshelev.
MongoDB: Fixed KeyError when a replica set member is removed.

Also fixes celery#971 and celery/#898.

Fix contributed by Alex Koshelev.
MongoDB: Fixed MongoDB broadcast cursor re-initialization bug.

Fix contributed by Alex Koshelev.
Async: Fixed bug in lax semaphore implementation where in some usage patterns the limit was not honored correctly.

Fix contributed by Ionel Cristian Mărieș.
Redis: Fixed problem with fanout when using Python 3 (Issue #324).
Redis: Fixed AttributeError from attempting to close a non-existing connection (Issue #320).

3.0.13¶

release-date:	2014-03-03 04:00 P.M UTC
release-by:	Ask Solem

Redis: Fixed serious race condition that could lead to data loss.

The delivery tags were accidentally set to be an incremental number local to the channel, but the delivery tags need to be globally unique so that a message can not overwrite an older message in the backup store.

This change is not backwards incompatible and you are encouraged to update all your system using a previous version as soon as possible.
Now depends on amqp 1.4.4.
Pidbox: Now makes sure message encoding errors are handled by default, so that a custom error handler does not need to be specified.
Redis: The fanout exchange can now use AMQP patterns to route and filter messages.
This change is backwards incompatible and must be enabled with the fanout_patterns transport option:
>>> conn = kombu.Connection('redis://', transport_options={ ... 'fanout_patterns': True, ... })
When enabled the exchange will work like an amqp topic exchange if the binding key is a pattern.

This is planned to be default behavior in the future.
Redis: Fixed cycle no such attribute error.

3.0.12¶

release-date:	2014-02-09 03:50 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.4.3.
Fixes Python 3.4 logging incompatibility (Issue #311).
Redis: Now properly handles unknown pub/sub messages.

Fix contributed by Sam Stavinoha.
amqplib: Fixed bug where more bytes were requested from the socket than necessary.

Fix contributed by Ionel Cristian Mărieș.

3.0.11¶

release-date:	2014-02-03 05:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.4.2.
Now always trusts messages of type application/data and application/text or which have an unspecified content type (Issue #306).
Compression errors are now handled as decode errors and will trigger the Consumer.on_decode_error callback if specified.
New kombu.Connection.get_heartbeat_interval() method that can be used to access the negotiated heartbeat value.
kombu.common.oid_for no longer uses the MAC address of the host, but

instead uses a process-wide UUID4 as a node id.

This avoids a call to uuid.getnode() at module scope.
Hub.add: Now normalizes registered fileno.

Contributed by Ionel Cristian Mărieș.
SQS: Fixed bug where the prefetch count limit was not respected.

3.0.10¶

release-date:	2014-01-17 05:40 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.4.1.
maybe_declare now raises a “recoverable connection error” if the channel is disconnected instead of a ChannelError so that the operation can be retried.
Redis: Consumer.cancel() is now thread safe.

This fixes an issue when using gevent/eventlet and a message is handled after the consumer is cancelled resulting in a “message for queue without consumers” error.
Retry operations would not always respect the interval_start value when calculating the time to sleep for (Issue #303).

Fix contributed by Antoine Legrand.
Timer: Fixed “unhashable type” error on Python 3.
Hub: Do not attempt to unregister operations on an already closed poller instance.

3.0.9¶

release-date:	2014-01-13 05:30 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.4.0.
Redis: Basic cancel for fanout based queues now sends a corresponding UNSUBSCRIBE command to the server.

This fixes an issue with pidbox where reply messages could be received after the consumer was cancelled, giving the "message to queue without consumers" error.
MongoDB: Improved connection string and options handling (Issue #266 + Issue #120).

Contributed by Alex Koshelev.
SQS: Limit the number of messages when receiving in batch to 10.

This is a hard limit enforced by Amazon so the sqs transport must not exceeed this value.

Fix contributed by Eric Reynolds.
ConsumerMixin: consume now checks heartbeat every time the socket times out.

Contributed by Dustin J. Mitchell.
Retry Policy: A max retries of 0 did not retry forever.

Fix contributed by Antoine Legrand.
Simple: If passing a Queue object the simple utils will now take default routing key from that queue.

Contributed by Fernando Jorge Mota.
repr(producer) no longer evaluates the underlying channnel.
Redis: The map of Redis error classes are now exposed at the module level using the kombu.transport.redis.get_redis_error_classes() function.
Async: Hub.close now sets .poller to None.

3.0.8¶

release-date:	2013-12-16 05:00 P.M UTC
release-by:	Ask Solem

Serializer: loads and dumps now wraps exceptions raised into DecodeError and kombu.exceptions.EncodeError respectively.

Contributed by Ionel Cristian Maries
Redis: Would attempt to read from the wrong connection if a select/epoll/kqueue exception event happened.

Fix contributed by Michael Nelson.
Redis: Disabling ack emulation now works properly.

Fix contributed by Michael Nelson.
Redis: IOError and OSError are now treated as recoverable connection errors.
SQS: Improved performance by reading messages in bulk.

Contributed by Matt Wise.
Connection Pool: Attempting to acquire from a closed pool will now raise RuntimeError.

3.0.7¶

release-date:	2013-12-02 04:00 P.M UTC
release-by:	Ask Solem

Fixes Python 2.6 compatibility.
Redis: Fixes ‘bad file descriptor’ issue.

3.0.6¶

release-date:	2013-11-21 04:50 P.M UTC
release-by:	Ask Solem

Timer: No longer attempts to hash keyword arguments (Issue #275).
Async: Did not account for the long type for file descriptors.

Fix contributed by Fabrice Rabaute.
PyPy: kqueue support was broken.
Redis: Bad pub/sub payloads no longer crashes the consumer.
Redis: Unix socket URLs can now specify a virtual host by including it as a query parameter.
Example URL specifying a virtual host using database number 3:
```
redis+socket:///tmp/redis.sock?virtual_host=3
```
kombu.VERSION is now a named tuple.

3.0.5¶

release-date:	2013-11-15 11:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.3.3.
Redis: Fixed Python 3 compatibility problem (Issue #270).
MongoDB: Fixed problem with URL parsing when authentication used.

Fix contributed by dongweiming.
pyamqp: Fixed small issue when publishing the message and the property dictionary was set to None.

Fix contributed by Victor Garcia.
Fixed problem in repr(LaxBoundedSemaphore).

Fix contributed by Antoine Legrand.
Tests now passing on Python 3.3.

3.0.4¶

release-date:	2013-11-08 01:00 P.M UTC
release-by:	Ask Solem

common.QoS: decrement_eventually now makes sure the value does not go below 1 if a prefetch count is enabled.

3.0.3¶

release-date:	2013-11-04 03:00 P.M UTC
release-by:	Ask Solem

SQS: Properly reverted patch that caused delays between messages.

Contributed by James Saryerwinnie
select: Clear all registerd fds on poller.cloe
Eventloop: unregister if EBADF raised.

3.0.2¶

release-date:	2013-10-29 02:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp version 1.3.2.
select: Fixed problem where unregister did not properly remove the fd.

3.0.1¶

release-date:	2013-10-24 04:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp version 1.3.1.
Redis: New option fanout_keyprefix
This transport option is recommended for all users as it ensures that broadcast (fanout) messages sent is only seen by the current virtual host:
Connection('redis://', transport_options={'fanout_keyprefix': True})
However, enabling this means that you cannot send or receive messages from older Kombu versions so make sure all of your participants are upgraded and have the transport option enabled.

This will be the default behavior in Kombu 4.0.
Distribution: Removed file requirements/py25.txt.
MongoDB: Now disables auto_start_request.
MongoDB: Enables use_greenlets if eventlet/gevent used.
Pidbox: Fixes problem where expires header was None, which is a value not supported by the amq protocol.
ConsumerMixin: New consumer_context method for starting the consumer without draining events.

3.0.0¶

release-date:	2013-10-14 04:00 P.M BST
release-by:	Ask Solem

Now depends on amqp version 1.3.
No longer supports Python 2.5

The minimum Python version supported is now Python 2.6.0 for Python2, and Python 3.3 for Python3.
Dual codebase supporting both Python 2 and 3.

No longer using 2to3, making it easier to maintain support for both versions.
pickle, yaml and msgpack deserialization is now disabled by default.
This means that Kombu will by default refuse to handle any content type other than json.

Pickle is known to be a security concern as it will happily load any object that is embedded in a pickle payload, and payloads can be crafted to do almost anything you want. The default serializer in Kombu is json but it also supports a number of other serialization formats that it will evaluate if received: including pickle.

It was always assumed that users were educated about the security implications of pickle, but in hindsight we don’t think users should be expected to secure their services if we have the ability to be secure by default.

By disabling any content type that the user did not explicitly want enabled we ensure that the user must be conscious when they add pickle as a serialization format to support.

The other built-in serializers (yaml and msgpack) are also disabled even though they aren’t considered insecure [1] at this point. Instead they’re disabled so that if a security flaw is found in one of these libraries in the future, you will only be affected if you have explicitly enabled them.

To have your consumer accept formats other than json you have to explicitly add the wanted formats to a white-list of accepted content types:
>>> c = Consumer(conn, accept=['json', 'pickle', 'msgpack'])
or when using synchronous access:
>>> msg = queue.get(accept=['json', 'pickle', 'msgpack'])
The accept argument was first supported for consumers in version 2.5.10, and first supported by Queue.get in version 2.5.15 so to stay compatible with previous versions you can enable the previous behavior:
>>> from kombu import enable_insecure_serializers >>> enable_insecure_serializers()
But note that this has global effect, so be very careful should you use it.

Footnotes

[1]
The PyYAML library has a yaml.load() function with some of the same security implications as pickle, but Kombu uses the yaml.safe_load() function which is not known to be affected.
kombu.async: Experimental event loop implementation.

This code was previously in Celery but was moved here to make it easier for async transport implementations.

The API is meant to match the Tulip API which will be included in Python 3.4 as the asyncio module. It’s not a complete implementation obviously, but the goal is that it will be easy to change to it once that is possible.
Utility function kombu.common.ipublish has been removed.

Use Producer(..., retry=True) instead.
Utility function kombu.common.isend_reply has been removed

Use send_reply(..., retry=True) instead.
kombu.common.entry_to_queue and kombu.messaging.entry_to_queue has been removed.

Use Queue.from_dict(name, **options) instead.
Redis: Messages are now restored at the end of the list.

Contributed by Mark Lavin.
StdConnectionError and StdChannelError is removed

and amqp.ConnectionError and amqp.ChannelError is used instead.
Message object implementation has moved to kombu.message.Message.
Serailization: Renamed functions encode/decode to dumps() and loads().

For backward compatibility the old names are still available as aliases.
The kombu.log.anon_logger function has been removed.

Use get_logger() instead.
queue_declare now returns namedtuple with queue, message_count, and consumer_count fields.
LamportClock: Can now set lock class
kombu.utils.clock: Utilities for ordering events added.
SimpleQueue now allows you to override the exchange type used.

Contributed by Vince Gonzales.
Zookeeper transport updated to support new changes in the kazoo library.

Contributed by Mahendra M.
pyamqp/librabbitmq: Transport options are now forwarded as keyword arguments

to the underlying connection (Issue #214).
Transports may now distinguish between recoverable and irrecoverable connection and channel errors.
kombu.utils.Finalize has been removed: Use multiprocessing.util.Finalize instead.
Memory transport now supports the fanout exchange type.

Contributed by Davanum Srinivas.
Experimental new Pyro transport (kombu.transport.pyro).

Contributed by Tommie McAfee.

Experimental new SoftLayer MQ transport (kombu.transport.SLMQ).

Contributed by Kevin McDonald

Eventio: Kqueue breaks in subtle ways so select is now used instead.
SQLAlchemy transport: Can now specify table names using the queue_tablename and message_tablename transport options.

Contributed by Ryan Petrello.

Redis transport: Now supports using local UNIX sockets to communicate with the: Redis server (Issue #1283)

To connect using a UNIX socket you have to use the redis+socket URL-prefix: redis+socket:///tmp/redis.sock.

This functionality was merged from the celery-redis-unixsocket project. Contributed by Maxime Rouyrre.

ZeroMQ transport: drain_events now supports timeout.

Contributed by Jesper Thomschütz.

2.5.16¶

release-date:	2013-10-04 03:30 P.M BST
release-by:	Ask Solem

Python3: Fixed problem with dependencies not being installed.

2.5.15¶

release-date:	2013-10-04 03:30 P.M BST
release-by:	Ask Solem

Declaration cache: Now only keeps hash of declaration so that it does not keep a reference to the channel.
Declaration cache: Now respects entity.can_cache_declaration attribute.
Fixes Python 2.5 compatibility.
Fixes tests after python-msgpack changes.
Queue.get: Now supports accept argument.

2.5.14¶

release-date:	2013-08-23 05:00 P.M BST
release-by:	Ask Solem

safe_str did not work properly resulting in UnicodeDecodeError (Issue #248).

2.5.13¶

release-date:	2013-08-16 04:00 P.M BST
release-by:	Ask Solem

Now depends on amqp 1.0.13
Fixed typo in Django functional tests.
safe_str now returns Unicode in Python 2.x

Fix contributed by Germán M. Bravo.
amqp: Transport options are now merged with arguments supplied to the connection.
Tests no longer depends on distribute, which was deprecated and merged back into setuptools.

Fix contributed by Sascha Peilicke.
ConsumerMixin now also restarts on channel related errors.

Fix contributed by Corentin Ardeois.

2.5.12¶

release-date:	2013-06-28 03:30 P.M BST
release-by:	Ask Solem

Redis: Ignore errors about keys missing in the round-robin cycle.
Fixed test suite errors on Python 3.
Fixed msgpack test failures.

2.5.11¶

release-date:	2013-06-25 02:30 P.M BST
release-by:	Ask Solem

Now depends on amqp 1.0.12 (Py3 compatibility issues).
MongoDB: Removed cause of a “database name in URI is being ignored” warning.

Fix by Flavio Percoco Premoli
Adds passive option to Exchange.

Setting this flag means that the exchange will not be declared by kombu, but that it must exist already (or an exception will be raised).

Contributed by Rafal Malinowski
Connection.info() now gives the current hostname and not the list of available hostnames.

Fix contributed by John Shuping.
pyamqp: Transport options are now forwarded as kwargs to amqp.Connection.
librabbitmq: Transport options are now forwarded as kwargs to librabbitmq.Connection.
librabbitmq: Now raises NotImplementedError if SSL is enabled.

The librabbitmq library does not support ssl, but you can use stunnel or change to the pyamqp:// transport instead.

Fix contributed by Dan LaMotte.
librabbitmq: Fixed a cyclic reference at connection close.
eventio: select implementation now removes bad file descriptors.
eventio: Fixed Py3 compatibility problems.
Functional tests added for py-amqp and librabbitmq transports.
Resource.force_close_all no longer uses a mutex.
Pidbox: Now ignores IconsistencyError when sending replies, as this error simply means that the client may no longer be alive.
Adds new Connection.collect method, that can be used to clean up after connections without I/O.
queue_bind is no longer called for queues bound to the “default exchange” (Issue #209).

Contributed by Jonathan Halcrow.
The max_retries setting for retries was not respected correctly (off by one).

2.5.10¶

release-date:	2013-04-11 06:10 P.M BST
release-by:	Ask Solem

Note about upcoming changes for Kombu 3.0¶

Kombu 3 consumers will no longer accept pickle/yaml or msgpack by default, and you will have to explicitly enable untrusted deserializers either globally using kombu.enable_insecure_serializers(), or using the accept argument to Consumer.

Changes¶

New utility function to disable/enable untrusted serializers.
- kombu.disable_insecure_serializers()
- kombu.enable_insecure_serializers().
Consumer: accept can now be used to specify a whitelist of content types to accept.
If the accept whitelist is set and a message is received with a content type that is not in the whitelist then a ContentDisallowed exception is raised. Note that this error can be handled by the already existing on_decode_error callback

Examples:
Consumer(accept=['application/json']) Consumer(accept=['pickle', 'json'])
Now depends on amqp 1.0.11
pidbox: Mailbox now supports the accept argument.
Redis: More friendly error for when keys are missing.
Connection URLs: The parser did not work well when there were multiple ‘+’ tokens.

2.5.9¶

release-date:	2013-04-08 05:07 P.M BST
release-by:	Ask Solem

Pidbox: Now warns if there are multiple nodes consuming from the same pidbox.
Adds Queue.on_declared

A callback to be called when the queue is declared, with signature (name, messages, consumers).
Now uses fuzzy matching to suggest alternatives to typos in transport names.
SQS: Adds new transport option queue_prefix.

Contributed by j0hnsmith.
pyamqp: No longer overrides verify_connection.
SQS: Now specifies the driver_type and driver_name attributes.

Fix contributed by Mher Movsisyan.
Fixed bug with kombu.utils.retry_over_time when no errback specified.

2.5.8¶

release-date:	2013-03-21 04:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.0.10 which fixes a Python 3 compatibility error.
Redis: Fixed a possible race condition (Issue #171).
Redis: Ack emulation/visibility_timeout can now be disabled using a transport option.
Ack emulation adds quite a lot of overhead to ensure data is safe even in the event of an unclean shutdown. If data loss do not worry you there is now an ack_emulation transport option you can use to disable it:
Connection('redis://', transport_options={'ack_emulation': False})
SQS: Fixed boto v2.7 compatibility (Issue #207).
Exchange: Should not try to re-declare default exchange ("") (Issue #209).
SQS: Long polling is now disabled by default as it was not implemented correctly, resulting in long delays between receiving messages (Issue #202).
Fixed Python 2.6 incompatibility depending on exc.errno being available.

Fix contributed by Ephemera.

2.5.7¶

release-date:	2013-03-08 01:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.0.9
Redis: A regression in 2.5.6 caused the redis transport to ignore options set in transport_options.
Redis: New socket_timeout transport option.
Redis: InconsistencyError is now regarded as a recoverable error.
Resource pools: Will no longer attempt to release resource that was never acquired.
MongoDB: Now supports the ssl option.

Contributed by Sebastian Pawlus.

2.5.6¶

release-date:	2013-02-08 01:00 P.M UTC
release-by:	Ask Solem

Now depends on amqp 1.0.8 which works around a bug found on some Python 2.5 installations where 2**32 overflows to 0.

2.5.5¶

release-date:	2013-02-07 05:00 P.M UTC
release-by:	Ask Solem

SQS: Now supports long polling (Issue #176).

The polling interval default has been changed to 0 and a new transport option (wait_time_seconds) has been added. This parameter specifies how long to wait for a message from SQS, and defaults to 20 seconds, which is the maximum value currently allowed by Amazon SQS.

Contributed by James Saryerwinnie.

SQS: Now removes unpickleable fields before restoring messages.
Consumer.__exit__ now ignores exceptions occurring while cancelling the consumer.
Virtual: Routing keys can now consist of characters also used in regular expressions (e.g. parens) (Issue #194).
Virtual: Fixed compression header when restoring messages.

Fix contributed by Alex Koshelev.
Virtual: ack/reject/requeue now works while using basic_get.
Virtual: Message.reject is now supported by virtual transports (requeue depends on individual transport support).
Fixed typo in hack used for static analyzers.

Fix contributed by Basil Mironenko.

2.5.4¶

release-date:	2012-12-10 12:35 P.M UTC
release-by:	Ask Solem

Fixed problem with connection clone and multiple URLs (Issue #182).

Fix contributed by Dane Guempel.
zeromq: Now compatible with libzmq 3.2.x.

Fix contributed by Andrey Antukh.
Fixed Python 3 installation problem (Issue #187).

2.5.3¶

release-date:	2012-11-29 12:35 P.M UTC
release-by:	Ask Solem

Pidbox: Fixed compatibility with Python 2.6

2.5.2¶

release-date:	2012-11-29 12:35 P.M UTC
release-by:	Ask Solem

2.5.2¶

release-date:	2012-11-29 12:35 P.M UTC
release-by:	Ask Solem

[Redis] Fixed connection leak and added a new ‘max_connections’ transport option.

2.5.1¶

release-date:	2012-11-28 12:45 P.M UTC
release-by:	Ask Solem

Fixed bug where return value of Queue.as_dict could not be serialized with JSON (Issue #177).

2.5.0¶

release-date:	2012-11-27 04:00 P.M UTC
release-by:	Ask Solem

py-amqp is now the new default transport, replacing amqplib.
The new py-amqp library is a fork of amqplib started with the following goals:
Uses AMQP 0.9.1 instead of 0.8

Support for heartbeats (Issue #79 + Issue #131)

Automatically revives channels on channel errors.

Support for all RabbitMQ extensions

Consumer Cancel Notifications (Issue #131)

Publisher Confirms (Issue #131).

Exchange-to-exchange bindings: exchange_bind / exchange_unbind.

API compatible with librabbitmq so that it can be used as a pure-python replacement in environments where rabbitmq-c cannot be compiled. librabbitmq will be updated to support all the same features as py-amqp.
Support for using multiple connection URL’s for failover.
The first argument to Connection can now be a list of connection URLs:
Connection(['amqp://foo', 'amqp://bar'])
or it can be a single string argument with several URLs separated by semicolon:
Connection('amqp://foo;amqp://bar')
There is also a new keyword argument failover_strategy that defines how ensure_connection()/ ensure()/kombu.Connection.autoretry() will reconnect in the event of connection failures.

The default reconnection strategy is round-robin, which will simply cycle through the list forever, and there’s also a shuffle strategy that will select random hosts from the list. Custom strategies can also be used, in that case the argument must be a generator yielding the URL to connect to.

Example:
Connection('amqp://foo;amqp://bar')
Now supports PyDev, PyCharm, pylint and other static code analysis tools.
Queue now supports multiple bindings.
You can now have multiple bindings in the same queue by having the second argument be a list:
from kombu import binding, Queue Queue('name', [ binding(Exchange('E1'), routing_key='foo'), binding(Exchange('E1'), routing_key='bar'), binding(Exchange('E2'), routing_key='baz'), ])
To enable this, helper methods have been added:
bind_to()

unbind_from()
Contributed by Rumyana Neykova.
Custom serializers can now be registered using Setuptools entry-points.

See Creating extensions using Setuptools entry-points.
New kombu.common.QoS class used as a thread-safe way to manage changes to a consumer or channels prefetch_count.

This was previously an internal class used in Celery now moved to the kombu.common module.
Consumer now supports a on_message callback that can be used to process raw messages (not decoded).

Other callbacks specified using the callbacks argument, and the receive method will be not be called when a on message callback is present.
New utility kombu.common.ignore_errors() ignores connection and channel errors.

Must only be used for cleanup actions at shutdown or on connection loss.

Support for exchange-to-exchange bindings.

The Exchange entity gained bind_to and unbind_from methods:
e1 = Exchange('A')(connection)
e2 = Exchange('B')(connection)

e2.bind_to(e1, routing_key='rkey', arguments=None)
e2.unbind_from(e1, routing_key='rkey', arguments=None)
This is currently only supported by the pyamqp transport.

Contributed by Rumyana Neykova.

2.4.10¶

release-date:	2012-11-22 06:00 P.M UTC
release-by:	Ask Solem

The previous versions connection pool changes broke Redis support so that it would always connect to localhost (default setting) no matter what connection parameters were provided (Issue #176).

2.4.9¶

release-date:	2012-11-21 03:00 P.M UTC
release-by:	Ask Solem

Redis: Fixed race condition that could occur while trying to restore messages (Issue #171).

Fix contributed by Ollie Walsh.
Redis: Each channel is now using a specific connection pool instance, which is disconnected on connection failure.
ProducerPool: Fixed possible dead-lock in the acquire method.
ProducerPool: force_close_all no longer tries to call the non-existent Producer._close.
librabbitmq: Now implements transport.verify_connection so that connection pools will not give back connections that are no longer working.
New and better repr() for Queue and Exchange objects.
Python3: Fixed problem with running the unit test suite.
Python3: Fixed problem with JSON codec.

2.4.8¶

release-date:	2012-11-02 05:00 P.M UTC
release-by:	Ask Solem

Redis: Improved fair queue cycle implementation (Issue #166).

Contributed by Kevin McCarthy.

Redis: Unacked message restore limit is now unlimited by default.

Also, the limit can now be configured using the unacked_restore_limit transport option:

Connection('redis://', transport_options={
    'unacked_restore_limit': 100,
})

A limit of 100 means that the consumer will restore at most 100
messages at each pass.

Redis: Now uses a mutex to ensure only one consumer restores messages at a time.

The mutex expires after 5 minutes by default, but can be configured using the unacked_mutex_expire transport option.
LamportClock.adjust now returns the new clock value.
Heartbeats can now be specified in URLs.

Fix contributed by Mher Movsisyan.
Kombu can now be used with PyDev, PyCharm and other static analysis tools.
Fixes problem with msgpack on Python 3 (Issue #162).

Fix contributed by Jasper Bryant-Greene
amqplib: Fixed bug with timeouts when SSL is used in non-blocking mode.

Fix contributed by Mher Movsisyan

2.4.7¶

release-date:	2012-09-18 03:00 P.M BST
release-by:	Ask Solem

Virtual: Unknown exchanges now default to ‘direct’ when sending a message.
MongoDB: Fixed memory leak when merging keys stored in the db (Issue #159)

Fix contributed by Michael Korbakov.
MongoDB: Better index for MongoDB transport (Issue #158).

This improvement will create a new compund index for queue and _id in order to be able to use both indexed fields for getting a new message (using queue field) and sorting by _id. It’ll be necessary to manually delete the old index from the collection.

Improvement contributed by rmihael

2.4.6¶

release-date:	2012-09-12 03:00 P.M BST
release-by:	Ask Solem

Adds additional compatibility dependencies:
- Python <= 2.6:
  importlib
  
  ordereddict
- Python <= 2.5
  simplejson

2.4.5¶

release-date:	2012-08-30 03:36 P.M BST
release-by:	Ask Solem

Last version broke installtion on PyPy and Jython due to test requirements clean-up.

2.4.4¶

release-date:	2012-08-29 04:00 P.M BST
release-by:	Ask Solem

amqplib: Fixed a bug with asynchronously reading large messages.
pyamqp: Now requires amqp 0.9.3
Cleaned up test requirements.

2.4.3¶

release-date:	2012-08-25 10:30 P.M BST
release-by:	Ask Solem

Fixed problem with amqp transport alias (Issue #154).

2.4.2¶

release-date:	2012-08-24 05:00 P.M BST
release-by:	Ask Solem

Having an empty transport name broke in 2.4.1.

2.4.1¶

release-date:	2012-08-24 04:00 P.M BST
release-by:	Ask Solem

Redis: Fixed race condition that could cause the consumer to crash (Issue #151)

Often leading to the error message "could not convert string to float"
Connection retry could cause an inifite loop (Issue #145).
The amqp alias is now resolved at runtime, so that eventlet detection works even if patching was done later.

2.4.0¶

release-date:	2012-08-17 08:00 P.M BST
release-by:	Ask Solem

New experimental ZeroMQ <kombu.transport.zmq transport.

Contributed by John Watson.
Redis: Ack timed-out messages were not restored when using the eventloop.
Now uses pickle protocol 2 by default to be cross-compatible with Python 3.

The protocol can also now be changed using the PICKLE_PROTOCOL environment variable.
Adds Transport.supports_ev attribute.
Pika: Queue purge was not working properly.

Fix contributed by Steeve Morin.
Pika backend was no longer working since Kombu 2.3

Fix contributed by Steeve Morin.

2.3.2¶

release-date:	2012-08-01 06:00 P.M BST
release-by:	Ask Solem

Fixes problem with deserialization in Python 3.

2.3.1¶

release-date:	2012-08-01 04:00 P.M BST
release-by:	Ask Solem

librabbitmq: Can now handle messages that does not have a content_encoding/content_type set (Issue #149).

Fix contributed by C Anthony Risinger.
Beanstalk: Now uses localhost by default if the URL does not contain a host.

2.3.0¶

release-date:	2012-07-24 03:50 P.M BST
release-by:	Ask Solem

New pyamqp:// transport!
The new py-amqp library is a fork of amqplib started with the following goals:
Uses AMQP 0.9.1 instead of 0.8

Should support all RabbitMQ extensions

API compatible with librabbitmq so that it can be used as a pure-python replacement in environments where rabbitmq-c cannot be compiled.
If you start using use py-amqp instead of amqplib you can enjoy many advantages including:
Heartbeat support (Issue #79 + Issue #131)

Consumer Cancel Notifications (Issue #131)

Publisher Confirms
amqplib has not been updated in a long while, so maintaining our own fork ensures that we can quickly roll out new features and fixes without resorting to monkey patching.

To use the py-amqp transport you must install the amqp library:
```
$ pip install amqp
```
and change the connection URL to use the correct transport:
>>> conn = Connection('pyamqp://guest:guest@localhost//')
The pyamqp:// transport will be the default fallback transport in Kombu version 3.0, when librabbitmq is not installed, and librabbitmq will also be updated to support the same features.
Connection now supports heartbeat argument.

If enabled you must make sure to manually maintain heartbeats by calling the Connection.heartbeat_check at twice the rate of the specified heartbeat interval.

E.g. if you have Connection(heartbeat=10), then you must call Connection.heartbeat_check() every 5 seconds.

if the server has not sent heartbeats at a suitable rate then the heartbeat check method must raise an error that is listed in Connection.connection_errors.

The attribute Connection.supports_heartbeats has been added for the ability to inspect if a transport supports heartbeats or not.

Calling heartbeat_check on a transport that does not support heartbeats results in a noop operation.
SQS: Fixed bug with invalid characters in queue names.

Fix contributed by Zach Smith.
utils.reprcall: Fixed typo where kwargs argument was an empty tuple by default, and not an empty dict.

2.2.6¶

release-date:	2012-07-10 05:00 P.M BST
release-by:	Ask Solem

Adds kombu.messaging.entry_to_queue for compat with previous versions.

2.2.5¶

release-date:	2012-07-10 05:00 P.M BST
release-by:	Ask Solem

Pidbox: Now sets queue expire at 10 seconds for reply queues.
EventIO: Now ignores ValueError raised by epoll unregister.
MongoDB: Fixes Issue #142

Fix by Flavio Percoco Premoli

2.2.4¶

release-date:	2012-07-05 04:00 P.M BST
release-by:	Ask Solem

Support for msgpack-python 0.2.0 (Issue #143)

The latest msgpack version no longer supports Python 2.5, so if you’re still using that you need to depend on an earlier msgpack-python version.

Fix contributed by Sebastian Insua
maybe_declare() no longer caches entities with the auto_delete flag set.
New experimental filesystem transport.

Contributed by Bobby Beever.
Virtual Transports: Now support anonymous queues and exchanges.

2.2.3¶

release-date:	2012-06-24 05:00 P.M BST
release-by:	Ask Solem

BrokerConnection now renamed to Connection.

The name Connection has been an alias for a very long time, but now the rename is official in the documentation as well.

The Connection alias has been available since version 1.1.3, and BrokerConnection will still work and is not deprecated.
Connection.clone() now works for the sqlalchemy transport.
kombu.common.eventloop(), kombu.utils.uuid(), and kombu.utils.url.parse_url() can now be imported from the kombu module directly.
Pidbox transport callback after_reply_message_received now happens in a finally block.
Trying to use the librabbitmq:// transport will now show the right name in the ImportError if librabbitmq is not installed.

The librabbitmq falls back to the older pylibrabbitmq name for compatibility reasons and would therefore show No module named pylibrabbitmq instead of librabbitmq.

2.2.2¶

release-date:	2012-06-22 02:30 P.M BST
release-by:	Ask Solem

Now depends on anyjson 0.3.3
Json serializer: Now passes buffer objects directly, since this is supported in the latest anyjson version.
Fixes blocking epoll call if timeout was set to 0.

Fix contributed by John Watson.
setup.py now takes requirements from the requirements/ directory.
The distribution directory contrib/ is now renamed to extra/

2.2.1¶

release-date:	2012-06-21 01:00 P.M BST
release-by:	Ask Solem

SQS: Default visibility timeout is now 30 minutes.

Since we have ack emulation the visibility timeout is only in effect if the consumer is abrubtly terminated.
retry argument to Producer.publish now works properly, when the declare argument is specified.
Json serializer: didn’t handle buffer objects (Issue #135).

Fix contributed by Jens Hoffrichter.
Virtual: Now supports passive argument to exchange_declare.

Exchange & Queue can now be bound to connections (which will use the default channel):

>>> exchange = Exchange('name')
>>> bound_exchange = exchange(connection)
>>> bound_exchange.declare()

SimpleQueue & SimpleBuffer can now be bound to connections (which will use the default channel).
Connection.manager.get_bindings now works for librabbitmq and pika.

Adds new transport info attributes:

- ``Transport.driver_type``

    Type of underlying driver, e.g. "amqp", "redis", "sql".

- ``Transport.driver_name``

    Name of library used e.g. "amqplib", "redis", "pymongo".

- ``Transport.driver_version()``

    Version of underlying library.

2.2.0¶

release-date:	2012-06-07 03:10 P.M BST
release-by:	Ask Solem

Important Notes¶

The canonical source code repository has been moved to

http://github.com/celery/kombu
Pidbox: Exchanges used by pidbox are no longer auto_delete.
Auto delete has been described as a misfeature, and therefore we have disabled it.

For RabbitMQ users old exchanges used by pidbox must be removed, these are named mailbox_name.pidbox, and reply.mailbox_name.pidbox.

The following command can be used to clean up these exchanges:
```
VHOST=/ URL=amqp:// python -c'import sys,kombu;[kombu.Connection(
    sys.argv[-1]).channel().exchange_delete(x)
        for x in sys.argv[1:-1]]' \
    $(sudo rabbitmqctl -q list_exchanges -p "$VHOST" \
    | grep \.pidbox | awk '{print $1}') "$URL"
```
The VHOST variable must be set to the target RabbitMQ virtual host, and the URL must be the AMQP URL to the server.
The amqp transport alias will now use librabbitmq if installed.
py-librabbitmq is a fast AMQP client for Python using the librabbitmq C library.

It can be installed by:
```
$ pip install librabbitmq
```
It will not be used if the process is monkey patched by eventlet/gevent.

News¶

Redis: Ack emulation improvements.
Reducing the possibility of data loss.

Acks are now implemented by storing a copy of the message when the message is consumed. The copy is not removed until the consumer acknowledges or rejects it.

This means that unacknowledged messages will be redelivered either when the connection is closed, or when the visibility timeout is exceeded.
- Visibility timeout
  This is a timeout for acks, so that if the consumer does not ack the message within this time limit, the message is redelivered to another consumer.
  
  The timeout is set to one hour by default, but can be changed by configuring a transport option:
  
  >>> Connection('redis://', transport_options={ ... 'visibility_timeout': 1800, # 30 minutes ... })
NOTE: Messages that have not been acked will be redelivered if the visibility timeout is exceeded, for Celery users this means that ETA/countdown tasks that are scheduled to execute with a time that exceeds the visibility timeout will be executed twice (or more). If you plan on using long ETA/countdowns you should tweak the visibility timeout accordingly:
BROKER_TRANSPORT_OPTIONS = {'visibility_timeout': 18000} # 5 hours
Setting a long timeout means that it will take a long time for messages to be redelivered in the event of a power failure, but if so happens you could temporarily set the visibility timeout lower to flush out messages when you start up the systems again.
Experimental Apache ZooKeeper transport

More information is in the module reference: kombu.transport.zookeeper.

Contributed by Mahendra M.

Redis: Priority support.
The message’s priority field is now respected by the Redis transport by having multiple lists for each named queue. The queues are then consumed by in order of priority.

The priority field is a number in the range of 0 - 9, where 0 is the default and highest priority.

The priority range is collapsed into four steps by default, since it is unlikely that nine steps will yield more benefit than using four steps. The number of steps can be configured by setting the priority_steps transport option, which must be a list of numbers in sorted order:
>>> x = Connection('redis://', transport_options={ ... 'priority_steps': [0, 2, 4, 6, 8, 9], ... })
Priorities implemented in this way is not as reliable as priorities on the server side, which is why nickname the feature “quasi-priorities”; Using routing is still the suggested way of ensuring quality of service, as client implemented priorities fall short in a number of ways, e.g. if the worker is busy with long running tasks, has prefetched many messages, or the queues are congested.

Still, it is possible that using priorities in combination with routing can be more beneficial than using routing or priorities alone. Experimentation and monitoring should be used to prove this.

Contributed by Germán M. Bravo.
Redis: Now cycles queues so that consuming is fair.

This ensures that a very busy queue won’t block messages from other queues, and ensures that all queues have an equal chance of being consumed from.

This used to be the case before, but the behavior was accidentally changed while switching to using blocking pop.
Redis: Auto delete queues that are bound to fanout exchanges is now deleted at channel.close.
amqplib: Refactored the drain_events implementation.
Pidbox: Now uses connection.default_channel.
Pickle serialization: Can now decode buffer objects.
Exchange/Queue declarations can now be cached even if the entity is non-durable.

This is possible because the list of cached declarations are now kept with the connection, so that the entities will be redeclared if the connection is lost.
Kombu source code now only uses one-level of explicit relative imports.

Fixes¶

eventio: Now ignores ENOENT raised by epoll.register, and EEXIST from epoll.unregister.
eventio: kqueue now ignores KeyError on unregister.
Redis: Message.reject now supports the requeue argument.
Redis: Remove superfluous pipeline call.

Fix contributed by Thomas Johansson.
Redis: Now sets redelivered header for redelivered messages.
Now always makes sure references to sys.exc_info() is removed.
Virtual: The compression header is now removed before restoring messages.
More tests for the SQLAlchemy backend.

Contributed by Franck Cuny.
Url parsing did not handle MongoDB URLs properly.

Fix contributed by Flavio Percoco Premoli.
Beanstalk: Ignore default tube when reserving.

Fix contributed by Zhao Xiaohong.

Nonblocking consume support¶

librabbitmq, amqplib and redis transports can now be used non-blocking.

The interface is very manual, and only consuming messages is non-blocking so far.

The API should not be regarded as stable or final in any way. It is used by Celery which has very limited needs at this point. Hopefully we can introduce a proper callback-based API later.

Transport.eventmap

Is a map of fd -> callback(fileno, event) to register in an eventloop.
Transport.on_poll_start()

Is called before every call to poll. The poller must support register(fd, callback) and unregister(fd) methods.
Transport.on_poll_start(poller)

Called when the hub is initialized. The poller argument must support the same interface as kombu.utils.eventio.poll.
Connection.ensure_connection now takes a callback argument which is called for every loop while the connection is down.
Adds connection.drain_nowait

This is a non-blocking alternative to drain_events, but only supported by amqplib/librabbitmq.
drain_events now sets connection.more_to_read if there is more data to read.

This is to support eventloops where other things must be handled between draining events.

2.1.8¶

release-date:	2012-05-06 03:06 P.M BST
release-by:	Ask Solem

Bound Exchange/Queue’s are now pickleable.
Consumer/Producer can now be instantiated without a channel, and only later bound using .revive(channel).
ProducerPool now takes Producer argument.
fxrange() now counts forever if the stop argument is set to None. (fxrange is like xrange but for decimals).
Auto delete support for virtual transports were incomplete and could lead to problems so it was removed.
Cached declarations (maybe_declare()) are now bound to the underlying connection, so that entities are redeclared if the connection is lost.

This also means that previously uncacheable entities (e.g. non-durable) can now be cached.
compat ConsumerSet: can now specify channel.

2.1.7¶

release-date:	2012-04-27 06:00 P.M BST
release-by:	Ask Solem

compat consumerset now accepts optional channel argument.

2.1.6¶

release-date:	2012-04-23 01:30 P.M BST
release-by:	Ask Solem

SQLAlchemy transport was not working correctly after URL parser change.
maybe_declare now stores cached declarations per underlying connection instead of globally, in the rare case that data disappears from the broker after connection loss.
Django: Added South migrations.

Contributed by Joseph Crosland.

2.1.5¶

release-date:	2012-04-13 03:30 P.M BST
release-by:	Ask Solem

The url parser removed more than the first leading slash (Issue #121).
SQLAlchemy: Can now specify url using + separator
Example:
Connection('sqla+mysql://localhost/db')
Better support for anonymous queues (Issue #116).

Contributed by Michael Barrett.
Connection.as_uri now quotes url parts (Issue #117).
Beanstalk: Can now set message TTR as a message property.

Contributed by Andrii Kostenko

2.1.4¶

release-date:	2012-04-03 04:00 P.M GMT
release-by:	Ask Solem

MongoDB: URL parsing are now delegated to the pymongo library (Fixes Issue #103 and Issue #87).

Fix contributed by Flavio Percoco Premoli and James Sullivan
SQS: A bug caused SimpleDB to be used even if sdb persistence was not enabled (Issue #108).

Fix contributed by Anand Kumria.
Django: Transaction was committed in the wrong place, causing data cleanup to fail (Issue #115).

Fix contributed by Daisuke Fujiwara.
MongoDB: Now supports replica set URLs.

Contributed by Flavio Percoco Premoli.
Redis: Now raises a channel error if a queue key that is currently being consumed from disappears.

Fix contributed by Stephan Jaekel.
All transport ‘channel_errors’ lists now includes kombu.exception.StdChannelError.
All kombu exceptions now inherit from a common KombuError.

2.1.3¶

release-date:	2012-03-20 03:00 P.M GMT
release-by:	Ask Solem

Fixes Jython compatibility issues.
Fixes Python 2.5 compatibility issues.

2.1.2¶

release-date:	2012-03-01 01:00 P.M GMT
release-by:	Ask Solem

amqplib: Last version broke SSL support.

2.1.1¶

release-date:	2012-02-24 02:00 P.M GMT
release-by:	Ask Solem

Connection URLs now supports encoded characters.
Fixed a case where connection pool could not recover from connection loss.

Fix contributed by Florian Munz.
We now patch amqplib’s __del__ method to skip trying to close the socket if it is not connected, as this resulted in an annoying warning.
Compression can now be used with binary message payloads.

Fix contributed by Steeve Morin.

2.1.0¶

release-date:	2012-02-04 10:38 P.M GMT
release-by:	Ask Solem

MongoDB: Now supports fanout (broadcast) (Issue #98).

Contributed by Scott Lyons.
amqplib: Now detects broken connections by using MSG_PEEK.
pylibrabbitmq: Now supports basic_get (Issue #97).
gevent: Now always uses the select polling backend.
pika transport: Now works with pika 0.9.5 and 0.9.6dev.

The old pika transport (supporting 0.5.x) is now available as alias oldpika.

(Note terribly latency has been experienced with the new pika versions, so this is still an experimental transport).
Virtual transports: can now set polling interval via the transport options (Issue #96).
Example:
>>> Connection('sqs://', transport_options={ ... 'polling_interval': 5.0})
The default interval is transport specific, but usually 1.0s (or 5.0s for the Django database transport, which can also be set using the KOMBU_POLLING_INTERVAL setting).
Adds convenience function: kombu.common.eventloop().

2.0.0¶

release-date:	2012-01-15 06:34 P.M GMT
release-by:	Ask Solem

Important Notes¶

Python Compatibility¶

No longer supports Python 2.4.

Users of Python 2.4 can still use the 1.x series.

The 1.x series has entered bugfix-only maintenance mode, and will stay that way as long as there is demand, and a willingness to maintain it.

New Transports¶

django-kombu is now part of Kombu core.
The Django message transport uses the Django ORM to store messages.

It uses polling, with a default polling interval of 5 seconds. The polling interval can be increased or decreased by configuring the KOMBU_POLLING_INTERVAL Django setting, which is the polling interval in seconds as an int or a float. Note that shorter polling intervals can cause extreme strain on the database: if responsiveness is needed you shall consider switching to a non-polling transport.

To use it you must use transport alias "django", or as an URL:
```
django://
```
and then add kombu.transport.django to INSTALLED_APPS, and run manage.py syncdb to create the necessary database tables.

Upgrading

If you have previously used django-kombu, then the entry in INSTALLED_APPS must be changed from djkombu to kombu.transport.django:
```
INSTALLED_APPS = (…,
                  'kombu.transport.django')
```
If you have previously used django-kombu, then there is no need to recreate the tables, as the old tables will be fully compatible with the new version.
kombu-sqlalchemy is now part of Kombu core.

This change requires no code changes given that the sqlalchemy transport alias is used.

News¶

kombu.mixins.ConsumerMixin is a mixin class that lets you easily write consumer programs and threads.

See Examples and Consumers.
SQS Transport: Added support for SQS queue prefixes (Issue #84).
The queue prefix can be set using the transport option queue_name_prefix:
BrokerTransport('SQS://', transport_options={ 'queue_name_prefix': 'myapp'})
Contributed by Nitzan Miron.

Producer.publish now supports automatic retry.

Retry is enabled by the reply argument, and retry options set by the retry_policy argument:
exchange = Exchange('foo')
producer.publish(message, exchange=exchange, retry=True,
                 declare=[exchange], retry_policy={
                    'interval_start': 1.0})
See ensure() for a list of supported retry policy options.

Producer.publish now supports a declare keyword argument.

This is a list of entities (Exchange, or Queue) that should be declared before the message is published.

Fixes¶

Redis transport: Timeout was multiplied by 1000 seconds when using select for event I/O (Issue #86).

1.5.1¶

release-date:	2011-11-30 01:00 P.M GMT
release-by:	Ask Solem

Fixes issue with kombu.compat introduced in 1.5.0 (Issue #83).
Adds the ability to disable content_types in the serializer registry.
Any message with a content type that is disabled will be refused. One example would be to disable the Pickle serializer:
>>> from kombu.serialization import registry # by name >>> registry.disable('pickle') # or by mime-type. >>> registry.disable('application/x-python-serialize')

1.5.0¶

release-date:	2011-11-27 06:00 P.M GMT
release-by:	Ask Solem

kombu.pools: Fixed a bug resulting in resources not being properly released.

This was caused by the use of __hash__ to distinguish them.
Virtual transports: Dead-letter queue is now disabled by default.
The dead-letter queue was enabled by default to help application authors, but now that Kombu is stable it should be removed. There are after all many cases where messages should just be dropped when there are no queues to buffer them, and keeping them without supporting automatic cleanup is rather considered a resource leak than a feature.

If wanted the dead-letter queue can still be enabled, by using the deadletter_queue transport option:
>>> x = Connection('redis://', ... transport_options={'deadletter_queue': 'ae.undeliver'})
In addition, an UndeliverableWarning is now emitted when the dead-letter queue is enabled and a message ends up there.

Contributed by Ionel Maries Cristian.
MongoDB transport now supports Replicasets (Issue #81).

Contributed by Ivan Metzlar.
The Connection.ensure methods now accepts a max_retries value of 0.

A value of 0 now means do not retry, which is distinct from None which means retry indefinitely.

Contributed by Dan McGee.
SQS Transport: Now has a lowercase sqs alias, so that it can be used with broker URLs (Issue #82).

Fix contributed by Hong Minhee
SQS Transport: Fixes KeyError on message acknowledgements (Issue #73).

The SQS transport now uses UUID’s for delivery tags, rather than a counter.

Fix contributed by Brian Bernstein.
SQS Transport: Unicode related fixes (Issue #82).

Fix contributed by Hong Minhee.
Redis version check could crash because of improper handling of types (Issue #63).
Fixed error with Resource.force_close_all when resources were not yet properly initialized (Issue #78).

1.4.3¶

release-date:	2011-10-27 10:00 P.M BST
release-by:	Ask Solem

Fixes bug in ProducerPool where too many resources would be acquired.

1.4.2¶

release-date:	2011-10-26 05:00 P.M BST
release-by:	Ask Solem

Eventio: Polling should ignore errno.EINTR
SQS: str.encode did only start accepting kwargs after Py2.7.
simple_task_queue example didn’t run correctly (Issue #72).

Fix contributed by Stefan Eletzhofer.
Empty messages would not raise an exception not able to be handled by on_decode_error (Issue #72)

Fix contributed by Christophe Chauvet.
CouchDB: Properly authenticate if user/password set (Issue #70)

Fix contributed by Rafael Duran Castaneda
Connection.Consumer had the wrong signature.

Fix contributed by Pavel Skvazh

1.4.1¶

release-date:	2011-09-26 04:00 P.M BST
release-by:	Ask Solem

1.4.0 broke the producer pool, resulting in new connections being established for every acquire.

1.4.0¶

release-date:	2011-09-22 05:00 P.M BST
release-by:	Ask Solem

Adds module kombu.mixins.

This module contains a ConsumerMixin class that can be used to easily implement a message consumer thread that consumes messages from one or more kombu.Consumer instances.
New example: Task Queue Example

Using the ConsumerMixin, default channels and the global connection pool to demonstrate new Kombu features.
MongoDB transport did not work with MongoDB >= 2.0 (Issue #66)

Fix contributed by James Turk.
Redis-py version check did not account for beta identifiers in version string.

Fix contributed by David Ziegler.
Producer and Consumer now accepts a connection instance as the first argument.
The connections default channel will then be used.

In addition shortcut methods has been added to Connection:
>>> connection.Producer(exchange) >>> connection.Consumer(queues=..., callbacks=...)
Connection has aquired a connected attribute that can be used to check if the connection instance has established a connection.
ConnectionPool.acquire_channel now returns the connections default channel rather than establising a new channel that must be manually handled.
Added kombu.common.maybe_declare

maybe_declare(entity) declares an entity if it has not previously been declared in the same process.
kombu.compat.entry_to_queue() has been moved to kombu.common
New module kombu.clocks now contains an implementation of Lamports logical clock.

1.3.5¶

release-date:	2011-09-16 06:00 P.M BST
release-by:	Ask Solem

Python 3: AMQP_PROTOCOL_HEADER must be bytes, not str.

1.3.4¶

release-date:	2011-09-16 06:00 P.M BST
release-by:	Ask Solem

Fixes syntax error in pools.reset

1.3.3¶

release-date:	2011-09-15 02:00 P.M BST
release-by:	Ask Solem

pools.reset did not support after forker arguments.

1.3.2¶

release-date:	2011-09-10 01:00 P.M BST
release-by:	Mher Movsisyan

Broke Python 2.5 compatibility by importing parse_qsl from urlparse
Connection.default_channel is now closed when connection is revived after connection failures.
Pika: Channel now supports the connection.client attribute as required by the simple interface.
pools.set_limit now raises an exception if the limit is lower than the previous limit.
pools.set_limit no longer resets the pools.

1.3.1¶

release-date:	2011-10-07 03:00 P.M BST
release-by:	Ask Solem

Last release broke after fork for pool reinitialization.
Producer/Consumer now has a connection attribute, giving access to the Connection of the instance.
Pika: Channels now have access to the underlying Connection instance using channel.connection.client.

This was previously required by the Simple classes and is now also required by Consumer and Producer.
Connection.default_channel is now closed at object revival.
Adds kombu.clocks.LamportClock.
compat.entry_to_queue has been moved to new module kombu.common.

1.3.0¶

release-date:	2011-10-05 01:00 P.M BST
release-by:	Ask Solem

Broker connection info can be now be specified using URLs
The broker hostname can now be given as an URL instead, of the format:
```
transport://user:password@hostname:port/virtual_host
```
for example the default broker is expressed as:
>>> Connection('amqp://guest:guest@localhost:5672//')
Transport defaults to amqp, and is not required. user, password, port and virtual_host is also not mandatory and will default to the corresponding transports default.
Note

Note that the path component (virtual_host) always starts with a forward-slash. This is necessary to distinguish between the virtual host ‘’ (empty) and ‘/’, which are both acceptable virtual host names.

A virtual host of ‘/’ becomes:

amqp://guest:guest@localhost:5672//

and a virtual host of ‘’ (empty) becomes:
amqp://guest:guest@localhost:5672/
So the leading slash in the path component is always required.

Now comes with default global connection and producer pools.

The acquire a connection using the connection parameters from a Connection:
>>> from kombu import Connection, connections
>>> connection = Connection('amqp://guest:guest@localhost//')
>>> with connections[connection].acquire(block=True):
...     # do something with connection
To acquire a producer using the connection parameters from a Connection:
>>> from kombu import Connection, producers
>>> connection = Connection('amqp://guest:guest@localhost//')
>>> with producers[connection].acquire(block=True):
...     producer.publish({'hello': 'world'}, exchange='hello')
Acquiring a producer will in turn also acquire a connection from the associated pool in connections, so you the number of producers is bound the same limit as number of connections.

The default limit of 100 connections per connection instance can be changed by doing:
>>> from kombu import pools
>>> pools.set_limit(10)
The pool can also be forcefully closed by doing:
>>> from kombu import pools
>>> pool.reset()

SQS Transport: Persistence using SimpleDB is now disabled by default, after reports of unstable SimpleDB connections leading to errors.
Producer can now be used as a context manager.
Producer.__exit__ now properly calls release instead of close.

The previous behavior would lead to a memory leak when using the kombu.pools.ProducerPool
Now silences all exceptions from import ctypes to match behaviour of the standard Python uuid module, and avoid passing on MemoryError exceptions on SELinux-enabled systems (Issue #52 + Issue #53)
amqp is now an alias to the amqplib transport.
kombu.syn.detect_environment now returns ‘default’, ‘eventlet’, or ‘gevent’ depending on what monkey patches have been installed.
Serialization registry has new attribute type_to_name so it is possible to lookup serializater name by content type.
Exchange argument to Producer.publish can now be an Exchange instance.
compat.Publisher now supports the channel keyword argument.
Acking a message on some transports could lead to KeyError being raised (Issue #57).
Connection pool: Connections are no long instantiated when the pool is created, but instantiated as needed instead.
Tests now pass on PyPy.
Connection.as_uri now includes the password if the keyword argument include_password is set.
Virtual transports now comes with a default default_connection_params attribute.

1.2.1¶

release-date:	2011-07-29 12:52 P.M BST
release-by:	Ask Solem

Now depends on amqplib >= 1.0.0.
Redis: Now automatically deletes auto_delete queues at basic_cancel.
serialization.unregister added so it is possible to remove unwanted seralizers.
Fixes MemoryError while importing ctypes on SELinux (Issue #52).
Connection.autoretry is a version of ensure that works with arbitrary functions (i.e. it does not need an associated object that implements the revive method.

Example usage:
```
channel = connection.channel()
try:
    ret, channel = connection.autoretry(send_messages, channel=channel)
finally:
    channel.close()
```
ConnectionPool.acquire no longer force establishes the connection.

The connection will be established as needed.
Connection.ensure now supports an on_revive callback that is applied whenever the connection is re-established.
Consumer.consuming_from(queue) returns True if the Consumer is consuming from queue.
Consumer.cancel_by_queue did not remove the queue from queues.
compat.ConsumerSet.add_queue_from_dict now automatically declared the queue if auto_declare set.

1.2.0¶

release-date:	2011-07-15 12:00 P.M BST
release-by:	Ask Solem

Virtual: Fixes cyclic reference in Channel.close (Issue #49).
Producer.publish: Can now set additional properties using keyword arguments (Issue #48).
Adds Queue.no_ack option to control the no_ack option for individual queues.
Recent versions broke pylibrabbitmq support.
SimpleQueue and SimpleBuffer can now be used as contexts.
Test requirements specifies PyYAML==3.09 as 3.10 dropped Python 2.4 support
Now properly reports default values in Connection.info/.as_uri

1.1.6¶

release-date:	2011-06-13 04:00 P.M BST
release-by:	Ask Solem

Redis: Fixes issue introduced in 1.1.4, where a redis connection failure could leave consumer hanging forever.
SQS: Now supports fanout messaging by using SimpleDB to store routing tables.
This can be disabled by setting the supports_fanout transport option:
>>> Connection(transport='SQS', ... transport_options={'supports_fanout': False})
SQS: Now properly deletes a message when a message is acked.
SQS: Can now set the Amazon AWS region, by using the region transport option.
amqplib: Now uses localhost as default hostname instead of raising an error.

1.1.5¶

release-date:	2011-06-07 06:00 P.M BST
release-by:	Ask Solem

Fixes compatibility with redis-py 2.4.4.

1.1.4¶

release-date:	2011-06-07 04:00 P.M BST
release-by:	Ask Solem

Redis transport: Now requires redis-py version 2.4.4 or later.

New Amazon SQS transport added.

Usage:

>>> conn = Connection(transport='SQS',
...                   userid=aws_access_key_id,
...                   password=aws_secret_access_key)

The environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are also supported.

librabbitmq transport: Fixes default credentials support.
amqplib transport: Now supports login_method for SSL auth.

Connection now supports the login_method keyword argument.

Default login_method is AMQPLAIN.

1.1.3¶

release-date:	2011-04-21 04:00 P.M CEST
release-by:	Ask Solem

Redis: Consuming from multiple connections now works with Eventlet.
Redis: Can now perform channel operations while the channel is in BRPOP/LISTEN mode (Issue #35).

Also the async BRPOP now times out after 1 second, this means that cancelling consuming from a queue/starting consuming from additional queues has a latency of up to one second (BRPOP does not support subsecond timeouts).
Virtual: Allow channel objects to be closed multiple times without error.
amqplib: AttributeError has been added to the list of known connection related errors (Connection.connection_errors).
amqplib: Now converts SSLError timeout errors to socket.timeout (http://bugs.python.org/issue10272)
Ensures cyclic references are destroyed when the connection is closed.

1.1.2¶

release-date:	2011-04-06 04:00 P.M CEST
release-by:	Ask Solem

Redis: Fixes serious issue where messages could be lost.

The issue could happen if the message exceeded a certain number of kilobytes in size.

It is recommended that all users of the Redis transport should upgrade to this version, even if not currently experiencing any issues.

1.1.1¶

release-date:	2011-04-05 03:51 P.M CEST
release-by:	Ask Solem

1.1.0 started using Queue.LifoQueue which is only available in Python 2.6+ (Issue #33). We now ship with our own LifoQueue.

1.1.0¶

release-date:	2011-04-05 01:05 P.M CEST
release-by:	Ask Solem

Important Notes¶

Virtual transports: Message body is now base64 encoded by default (Issue #27).
This should solve problems sending binary data with virtual transports.

Message compatibility is handled by adding a body_encoding property, so messages sent by older versions is compatible with this release. However – If you are accessing the messages directly not using Kombu, then you have to respect the body_encoding property.

If you need to disable base64 encoding then you can do so via the transport options:
Connection(transport='...', transport_options={'body_encoding': None})
For transport authors:

You don’t have to change anything in your custom transports, as this is handled automatically by the base class.

If you want to use a different encoder you can do so by adding a key to Channel.codecs. Default encoding is specified by the Channel.body_encoding attribute.

A new codec must provide two methods: encode(data) and decode(data).
ConnectionPool/ChannelPool/Resource: Setting limit=None (or 0) now disables pool semantics, and will establish and close the resource whenever acquired or released.
ConnectionPool/ChannelPool/Resource: Is now using a LIFO queue instead of the previous FIFO behavior.

This means that the last resource released will be the one acquired next. I.e. if only a single thread is using the pool this means only a single connection will ever be used.
Connection: Cloned connections did not inherit transport_options (__copy__).
contrib/requirements is now located in the top directory of the distribution.
MongoDB: Now supports authentication using the userid and password arguments to Connection (Issue #30).
Connection: Default autentication credentials are now delegated to the individual transports.

This means that the userid and password arguments to Connection is no longer guest/guest by default.

The amqplib and pika transports will still have the default credentials.
Consumer.__exit__() did not have the correct signature (Issue #32).
Channel objects now have a channel_id attribute.
MongoDB: Version sniffing broke with development versions of

mongod (Issue #29).
New environment variable KOMBU_LOG_CONNECTION will now emit debug

log messages for connection related actions.

KOMBU_LOG_DEBUG will also enable KOMBU_LOG_CONNECTION.

1.0.7¶

release-date:	2011-03-28 05:45 P.M CEST
release-by:	Ask Solem

Now depends on anyjson 0.3.1

cjson is no longer a recommended json implementation, and anyjson will now emit a deprecation warning if used.
Please note that the Pika backend only works with version 0.5.2.

The latest version (0.9.x) drastically changed API, and it is not compatible yet.
on_decode_error is now called for exceptions in message_to_python (Issue #24).
Redis: did not respect QoS settings.
Redis: Creating a connection now ensures the connection is established.

This means Connection.ensure_connection works properly with Redis.
consumer_tag argument to Queue.consume can’t be None (Issue #21).

A None value is now automatically converted to empty string. An empty string will make the server generate a unique tag.
Connection now supports a transport_options argument.

This can be used to pass additional arguments to transports.
Pika: drain_events raised socket.timeout even if no timeout set (Issue #8).

1.0.6¶

release-date:	2011-03-22 04:00 P.M CET
release-by:	Ask Solem

The delivery_mode aliases (persistent/transient) were not automatically converted to integer, and would cause a crash if using the amqplib transport.
Redis: The redis-py InvalidData exception suddenly changed name to DataError.

The KOMBU_LOG_DEBUG environment variable can now be set to log all channel method calls.

Support for the following environment variables have been added:

KOMBU_LOG_CHANNEL will wrap channels in an object that logs every method call.

KOMBU_LOG_DEBUG both enables channel logging and configures the root logger to emit messages to standard error.

Example Usage:
$ KOMBU_LOG_DEBUG=1 python
>>> from kombu import Connection
>>> conn = Connection()
>>> channel = conn.channel()
Start from server, version: 8.0, properties:
    {u'product': 'RabbitMQ',..............  }
Open OK! known_hosts []
using channel_id: 1
Channel open
>>> channel.queue_declare('myq', passive=True)
[Kombu channel:1] queue_declare('myq', passive=True)
(u'myq', 0, 1)

1.0.5¶

release-date:	2011-03-17 04:00 P.M CET
release-by:	Ask Solem

Fixed memory leak when creating virtual channels. All virtual transports affected (redis, mongodb, memory, django, sqlalchemy, couchdb, beanstalk).
Virtual Transports: Fixed potential race condition when acking messages.

If you have been affected by this, the error would show itself as an exception raised by the OrderedDict implementation. (object no longer exists).
MongoDB transport requires the findandmodify command only available in MongoDB 1.3+, so now raises an exception if connected to an incompatible server version.
Virtual Transports: basic.cancel should not try to remove unknown consumer tag.

1.0.4¶

release-date:	2011-02-28 04:00 P.M CET
release-by:	Ask Solem

Added Transport.polling_interval

Used by django-kombu to increase the time to sleep between SELECTs when there are no messages in the queue.

Users of django-kombu should upgrade to django-kombu v0.9.2.

1.0.3¶

release-date:	2011-02-12 04:00 P.M CET
release-by:	Ask Solem

ConnectionPool: Re-connect if amqplib connection closed
Adds Queue.as_dict + Exchange.as_dict.

1.0.2¶

release-date:	2011-01-31 10:45 P.M CET
release-by:	Ask Solem

amqplib: Message properties were not set properly.
Ghettoq backend names are now automatically translated to the new names.

1.0.1¶

release-date:	2011-01-28 12:00 P.M CET
release-by:	Ask Solem

Redis: Now works with Linux (epoll)

1.0.0¶

release-date:	2011-01-27 12:00 P.M CET
release-by:	Ask Solem

Initial release

0.1.0¶

release-date:	2010-07-22 04:20 P.M CET
release-by:	Ask Solem

Initial fork of carrot

Navigation

Change history¶

3.0.19¶

3.0.18¶

3.0.17¶

3.0.16¶

3.0.15¶

3.0.14¶

3.0.13¶

3.0.12¶

3.0.11¶

3.0.10¶

3.0.9¶

3.0.8¶

3.0.7¶

3.0.6¶

3.0.5¶

3.0.4¶

3.0.3¶

3.0.2¶

3.0.1¶

3.0.0¶

2.5.16¶

2.5.15¶

2.5.14¶

2.5.13¶

2.5.12¶

2.5.11¶

2.5.10¶

Note about upcoming changes for Kombu 3.0¶

Changes¶

2.5.9¶

2.5.8¶

2.5.7¶

2.5.6¶

2.5.5¶

2.5.4¶

2.5.3¶

2.5.2¶

2.5.2¶

2.5.1¶

2.5.0¶

2.4.10¶

2.4.9¶

2.4.8¶

2.4.7¶

2.4.6¶

2.4.5¶

2.4.4¶

2.4.3¶

2.4.2¶

2.4.1¶

2.4.0¶

2.3.2¶

2.3.1¶

2.3.0¶

2.2.6¶

2.2.5¶

2.2.4¶

2.2.3¶

2.2.2¶

2.2.1¶

2.2.0¶

Important Notes¶

News¶

Fixes¶

Nonblocking consume support¶

2.1.8¶

2.1.7¶

2.1.6¶

2.1.5¶

2.1.4¶

2.1.3¶

2.1.2¶

2.1.1¶

2.1.0¶

2.0.0¶

Important Notes¶

Python Compatibility¶

New Transports¶