BlockingConnection¶

The blocking connection adapter module implements blocking semantics on top of Pika’s core AMQP driver. While most of the asynchronous expectations are removed when using the blocking connection adapter, it attempts to remain true to the asynchronous RPC nature of the AMQP protocol, supporting server sent RPC commands.

The user facing classes in the module consist of the BlockingConnection and the BlockingChannel classes.

Be sure to check out examples in Usage Examples.

class pika.adapters.blocking_connection.BlockingConnection(parameters=None, _impl_class=None)[source]¶

The BlockingConnection creates a layer on top of Pika’s asynchronous core providing methods that will block until their expected response has returned. Due to the asynchronous nature of the Basic.Deliver and Basic.Return calls from RabbitMQ to your application, you can still implement continuation-passing style asynchronous methods if you’d like to receive messages from RabbitMQ using basic_consume or if you want to be notified of a delivery failure when using basic_publish.

For more information about communicating with the blocking_connection adapter, be sure to check out the BlockingChannel class which implements the Channel based communication for the blocking_connection adapter.

To prevent recursion/reentrancy, the blocking connection and channel implementations queue asynchronously-delivered events received in nested context (e.g., while waiting for BlockingConnection.channel or BlockingChannel.queue_declare to complete), dispatching them synchronously once nesting returns to the desired context. This concerns all callbacks, such as those registered via BlockingConnection.add_timeout, BlockingConnection.add_on_connection_blocked_callback, BlockingConnection.add_on_connection_unblocked_callback, BlockingChannel.basic_consume, etc.

Blocked Connection deadlock avoidance: when RabbitMQ becomes low on resources, it emits Connection.Blocked (AMQP extension) to the client connection when client makes a resource-consuming request on that connection or its channel (e.g., Basic.Publish); subsequently, RabbitMQ suspsends processing requests from that connection until the affected resources are restored. See http://www.rabbitmq.com/connection-blocked.html. This may impact BlockingConnection and BlockingChannel operations in a way that users might not be expecting. For example, if the user dispatches BlockingChannel.basic_publish in non-publisher-confirmation mode while RabbitMQ is in this low-resource state followed by a synchronous request (e.g., BlockingConnection.channel, BlockingChannel.consume, BlockingChannel.basic_consume, etc.), the synchronous request will block indefinitely (until Connection.Unblocked) waiting for RabbitMQ to reply. If the blocked state persists for a long time, the blocking operation will appear to hang. In this state, BlockingConnection instance and its channels will not dispatch user callbacks. SOLUTION: To break this potential deadlock, applications may configure the blocked_connection_timeout connection parameter when instantiating BlockingConnection. Upon blocked connection timeout, this adapter will raise ConnectionClosed exception with first exception arg of pika.connection.InternalCloseReasons.BLOCKED_CONNECTION_TIMEOUT. See pika.connection.ConnectionParameters documentation to learn more about blocked_connection_timeout configuration.

add_callback_threadsafe(callback)[source]¶

Requests a call to the given function as soon as possible in the context of this connection’s thread.

NOTE: This is the only thread-safe method in BlockingConnection. All other manipulations of BlockingConnection must be performed from the connection’s thread.

For example, a thread may request a call to the BlockingChannel.basic_ack method of a BlockingConnection that is running in a different thread via

``` connection.add_callback_threadsafe(

functools.partial(channel.basic_ack, delivery_tag=…))

```

NOTE: if you know that the requester is running on the same thread as the connection it is more efficient to use the BlockingConnection.add_timeout() method with a deadline of 0.

Parameters:	callback (method) – The callback method; must be callable

add_on_connection_blocked_callback(callback_method)[source]¶

Add a callback to be notified when RabbitMQ has sent a Connection.Blocked frame indicating that RabbitMQ is low on resources. Publishers can use this to voluntarily suspend publishing, instead of relying on back pressure throttling. The callback will be passed the Connection.Blocked method frame.

See also ConnectionParameters.blocked_connection_timeout.

Parameters:	callback_method (method) – Callback to call on Connection.Blocked, having the signature callback_method(pika.frame.Method), where the method frame’s method member is of type pika.spec.Connection.Blocked

add_on_connection_unblocked_callback(callback_method)[source]¶

Add a callback to be notified when RabbitMQ has sent a Connection.Unblocked frame letting publishers know it’s ok to start publishing again. The callback will be passed the Connection.Unblocked method frame.

Parameters:	callback_method (method) – Callback to call on Connection.Unblocked, having the signature callback_method(pika.frame.Method), where the method frame’s method member is of type pika.spec.Connection.Unblocked

add_timeout(deadline, callback_method)[source]¶

Create a single-shot timer to fire after deadline seconds. Do not confuse with Tornado’s timeout where you pass in the time you want to have your callback called. Only pass in the seconds until it’s to be called.

NOTE: the timer callbacks are dispatched only in the scope of specially-designated methods: see BlockingConnection.process_data_events and BlockingChannel.start_consuming.

Parameters:	deadline (float) – The number of seconds to wait to call callback callback_method (callable) – The callback method with the signature callback_method()
Returns:	opaque timer id

basic_nack¶

Specifies if the server supports basic.nack on the active connection.

Return type:	bool

basic_nack_supported¶

Specifies if the server supports basic.nack on the active connection.

Return type:	bool

channel(channel_number=None)[source]¶

Create a new channel with the next available channel number or pass in a channel number to use. Must be non-zero if you would like to specify but it is recommended that you let Pika manage the channel numbers.

Return type:	pika.adapters.blocking_connection.BlockingChannel

close(reply_code=200, reply_text='Normal shutdown')[source]¶

Disconnect from RabbitMQ. If there are any open channels, it will attempt to close them prior to fully disconnecting. Channels which have active consumers will attempt to send a Basic.Cancel to RabbitMQ to cleanly stop the delivery of messages prior to closing the channel.

Parameters:	reply_code (int) – The code number for the close reply_text (str) – The text reason for the close

consumer_cancel_notify¶

Specifies if the server supports consumer cancel notification on the active connection.

Return type:	bool

consumer_cancel_notify_supported¶

Specifies if the server supports consumer cancel notification on the active connection.

Return type:	bool

exchange_exchange_bindings¶

Specifies if the active connection supports exchange to exchange bindings.

Return type:	bool

exchange_exchange_bindings_supported¶

Specifies if the active connection supports exchange to exchange bindings.

Return type:	bool

is_closed¶: Returns a boolean reporting the current connection state.

is_closing¶: Returns True if connection is in the process of closing due to client-initiated close request, but closing is not yet complete.

is_open¶: Returns a boolean reporting the current connection state.

process_data_events(time_limit=0)[source]¶

Will make sure that data events are processed. Dispatches timer and channel callbacks if not called from the scope of BlockingConnection or BlockingChannel callback. Your app can block on this method.

Parameters:	time_limit (float) – suggested upper bound on processing time in seconds. The actual blocking time depends on the granularity of the underlying ioloop. Zero means return as soon as possible. None means there is no limit on processing time and the function will block until I/O produces actionable events. Defaults to 0 for backward compatibility. This parameter is NEW in pika 0.10.0.

publisher_confirms¶

Specifies if the active connection can use publisher confirmations.

Return type:	bool

publisher_confirms_supported¶

Specifies if the active connection can use publisher confirmations.

Return type:	bool

remove_timeout(timeout_id)[source]¶

Remove a timer if it’s still in the timeout stack

Parameters:	timeout_id – The opaque timer id to remove

sleep(duration)[source]¶

A safer way to sleep than calling time.sleep() directly that would keep the adapter from ignoring frames sent from the broker. The connection will “sleep” or block the number of seconds specified in duration in small intervals.

Parameters:	duration (float) – The time to sleep in seconds

class pika.adapters.blocking_connection.BlockingChannel(channel_impl, connection)[source]¶

The BlockingChannel implements blocking semantics for most things that one would use callback-passing-style for with the Channel class. In addition, the BlockingChannel class implements a generator that allows you to consume messages without using callbacks.

Example of creating a BlockingChannel:

import pika

# Create our connection object
connection = pika.BlockingConnection()

# The returned object will be a synchronous channel
channel = connection.channel()

add_on_cancel_callback(callback)[source]¶

Pass a callback function that will be called when Basic.Cancel is sent by the broker. The callback function should receive a method frame parameter.

Parameters:	callback (callable) – a callable for handling broker’s Basic.Cancel notification with the call signature: callback(method_frame) where method_frame is of type pika.frame.Method with method of type spec.Basic.Cancel

add_on_return_callback(callback)[source]¶

Pass a callback function that will be called when a published message is rejected and returned by the server via Basic.Return.

Parameters:	callback (callable) – The method to call on callback with the signature callback(channel, method, properties, body), where channel: pika.Channel method: pika.spec.Basic.Return properties: pika.spec.BasicProperties body: str, unicode, or bytes (python 3.x)

basic_ack(delivery_tag=0, multiple=False)[source]¶

Acknowledge one or more messages. When sent by the client, this method acknowledges one or more messages delivered via the Deliver or Get-Ok methods. When sent by server, this method acknowledges one or more messages published with the Publish method on a channel in confirm mode. The acknowledgement can be for a single message or a set of messages up to and including a specific message.

Parameters:

delivery-tag (int) – The server-assigned delivery tag
multiple (bool) – If set to True, the delivery tag is treated as “up to and including”, so that multiple messages can be acknowledged with a single method. If set to False, the delivery tag refers to a single message. If the multiple field is 1, and the delivery tag is zero, this indicates acknowledgement of all outstanding messages.

basic_cancel(consumer_tag)[source]¶

This method cancels a consumer. This does not affect already delivered messages, but it does mean the server will not send any more messages for that consumer. The client may receive an arbitrary number of messages in between sending the cancel method and receiving the cancel-ok reply.

NOTE: When cancelling a no_ack=False consumer, this implementation automatically Nacks and suppresses any incoming messages that have not yet been dispatched to the consumer’s callback. However, when cancelling a no_ack=True consumer, this method will return any pending messages that arrived before broker confirmed the cancellation.

Parameters: consumer_tag (str) – Identifier for the consumer; the result of passing a consumer_tag that was created on another channel is undefined (bad things will happen)

Returns:

(NEW IN pika 0.10.0) empty sequence for a no_ack=False consumer; for a no_ack=True consumer, returns a (possibly empty) sequence of pending messages that arrived before broker confirmed the cancellation (this is done instead of via consumer’s callback in order to prevent reentrancy/recursion. Each message is four-tuple: (channel, method, properties, body)

channel: BlockingChannel method: spec.Basic.Deliver properties: spec.BasicProperties body: str or unicode

basic_consume(consumer_callback, queue, no_ack=False, exclusive=False, consumer_tag=None, arguments=None)[source]¶

Sends the AMQP command Basic.Consume to the broker and binds messages for the consumer_tag to the consumer callback. If you do not pass in a consumer_tag, one will be automatically generated for you. Returns the consumer tag.

NOTE: the consumer callbacks are dispatched only in the scope of specially-designated methods: see BlockingConnection.process_data_events and BlockingChannel.start_consuming.

For more information about Basic.Consume, see: http://www.rabbitmq.com/amqp-0-9-1-reference.html#basic.consume

Parameters:	consumer_callback (callable) – The function for dispatching messages to user, having the signature: consumer_callback(channel, method, properties, body) channel: BlockingChannel method: spec.Basic.Deliver properties: spec.BasicProperties body: str or unicode queue (str or unicode) – The queue to consume from no_ack (bool) – Tell the broker to not expect a response (i.e., no ack/nack) exclusive (bool) – Don’t allow other consumers on the queue consumer_tag (str or unicode) – You may specify your own consumer tag; if left empty, a consumer tag will be generated automatically arguments (dict) – Custom key/value pair arguments for the consumer
Returns:	consumer tag
Return type:	str
Raises:	pika.exceptions.DuplicateConsumerTag – if consumer with given consumer_tag is already present.

basic_get(queue=None, no_ack=False)[source]¶

Get a single message from the AMQP broker. Returns a sequence with the method frame, message properties, and body.

Parameters:	queue (str or unicode) – Name of queue to get a message from no_ack (bool) – Tell the broker to not expect a reply
Returns:	a three-tuple; (None, None, None) if the queue was empty; otherwise (method, properties, body); NOTE: body may be None
Return type:	(None, None, None)\|(spec.Basic.GetOk, spec.BasicProperties, str or unicode or None)

basic_nack(delivery_tag=None, multiple=False, requeue=True)[source]¶

This method allows a client to reject one or more incoming messages. It can be used to interrupt and cancel large incoming messages, or return untreatable messages to their original queue.

Parameters:

delivery-tag (int) – The server-assigned delivery tag
multiple (bool) – If set to True, the delivery tag is treated as “up to and including”, so that multiple messages can be acknowledged with a single method. If set to False, the delivery tag refers to a single message. If the multiple field is 1, and the delivery tag is zero, this indicates acknowledgement of all outstanding messages.
requeue (bool) – If requeue is true, the server will attempt to requeue the message. If requeue is false or the requeue attempt fails the messages are discarded or dead-lettered.

basic_publish(exchange, routing_key, body, properties=None, mandatory=False, immediate=False)[source]¶

Publish to the channel with the given exchange, routing key and body. Returns a boolean value indicating the success of the operation.

This is the legacy BlockingChannel method for publishing. See also BlockingChannel.publish that provides more information about failures.

For more information on basic_publish and what the parameters do, see:

http://www.rabbitmq.com/amqp-0-9-1-reference.html#basic.publish

NOTE: mandatory and immediate may be enabled even without delivery: confirmation, but in the absence of delivery confirmation the synchronous implementation has no way to know how long to wait for the Basic.Return or lack thereof.

Parameters:	exchange (str or unicode) – The exchange to publish to routing_key (str or unicode) – The routing key to bind on body (str or unicode) – The message body; empty string if no body properties (pika.spec.BasicProperties) – message properties mandatory (bool) – The mandatory flag immediate (bool) – The immediate flag
Returns:	True if delivery confirmation is not enabled (NEW in pika 0.10.0); otherwise returns False if the message could not be delivered (Basic.nack and/or Basic.Return) and True if the message was delivered (Basic.ack and no Basic.Return)

basic_qos(prefetch_size=0, prefetch_count=0, all_channels=False)[source]¶

Specify quality of service. This method requests a specific quality of service. The QoS can be specified for the current channel or for all channels on the connection. The client can request that messages be sent in advance so that when the client finishes processing a message, the following message is already held locally, rather than needing to be sent down the channel. Prefetching gives a performance improvement.

Parameters:

prefetch_size (int) – This field specifies the prefetch window size. The server will send a message in advance if it is equal to or smaller in size than the available prefetch size (and also falls into other prefetch limits). May be set to zero, meaning “no specific limit”, although other prefetch limits may still apply. The prefetch-size is ignored if the no-ack option is set in the consumer.
prefetch_count (int) – Specifies a prefetch window in terms of whole messages. This field may be used in combination with the prefetch-size field; a message will only be sent in advance if both prefetch windows (and those at the channel and connection level) allow it. The prefetch-count is ignored if the no-ack option is set in the consumer.
all_channels (bool) – Should the QoS apply to all channels

basic_recover(requeue=False)[source]¶

This method asks the server to redeliver all unacknowledged messages on a specified channel. Zero or more messages may be redelivered. This method replaces the asynchronous Recover.

Parameters:	requeue (bool) – If False, the message will be redelivered to the original recipient. If True, the server will attempt to requeue the message, potentially then delivering it to an alternative subscriber.

basic_reject(delivery_tag=None, requeue=True)[source]¶

Reject an incoming message. This method allows a client to reject a message. It can be used to interrupt and cancel large incoming messages, or return untreatable messages to their original queue.

Parameters:	delivery-tag (int) – The server-assigned delivery tag requeue (bool) – If requeue is true, the server will attempt to requeue the message. If requeue is false or the requeue attempt fails the messages are discarded or dead-lettered.

cancel()[source]¶

Cancel the queue consumer created by BlockingChannel.consume, rejecting all pending ackable messages.

NOTE: If you’re looking to cancel a consumer issued with BlockingChannel.basic_consume then you should call BlockingChannel.basic_cancel.

Return int:	The number of messages requeued by Basic.Nack. NEW in 0.10.0: returns 0

channel_number¶: Channel number

close(reply_code=0, reply_text='Normal shutdown')[source]¶

Will invoke a clean shutdown of the channel with the AMQP Broker.

Parameters:	reply_code (int) – The reply code to close the channel with reply_text (str) – The reply text to close the channel with

confirm_delivery()[source]¶

Turn on RabbitMQ-proprietary Confirm mode in the channel.

For more information see:: http://www.rabbitmq.com/extensions.html#confirms

connection¶: The channel’s BlockingConnection instance

consume(queue, no_ack=False, exclusive=False, arguments=None, inactivity_timeout=None)[source]¶

Blocking consumption of a queue instead of via a callback. This method is a generator that yields each message as a tuple of method, properties, and body. The active generator iterator terminates when the consumer is cancelled by client via BlockingChannel.cancel() or by broker.

Example:

for method, properties, body in channel.consume(‘queue’):

print body channel.basic_ack(method.delivery_tag)

You should call BlockingChannel.cancel() when you escape out of the generator loop.

If you don’t cancel this consumer, then next call on the same channel to consume() with the exact same (queue, no_ack, exclusive) parameters will resume the existing consumer generator; however, calling with different parameters will result in an exception.

Parameters:	queue (str or unicode) – The queue name to consume no_ack (bool) – Tell the broker to not expect a ack/nack response exclusive (bool) – Don’t allow other consumers on the queue arguments (dict) – Custom key/value pair arguments for the consumer inactivity_timeout (float) – if a number is given (in seconds), will cause the method to yield (None, None, None) after the given period of inactivity; this permits for pseudo-regular maintenance activities to be carried out by the user while waiting for messages to arrive. If None is given (default), then the method blocks until the next event arrives. NOTE that timing granularity is limited by the timer resolution of the underlying implementation. NEW in pika 0.10.0.
Yields:	tuple(spec.Basic.Deliver, spec.BasicProperties, str or unicode)
Raises:	ValueError – if consumer-creation parameters don’t match those of the existing queue consumer generator, if any. NEW in pika 0.10.0

exchange_bind(destination=None, source=None, routing_key='', arguments=None)[source]¶

Bind an exchange to another exchange.

Parameters:	destination (str or unicode) – The destination exchange to bind source (str or unicode) – The source exchange to bind to routing_key (str or unicode) – The routing key to bind on arguments (dict) – Custom key/value pair arguments for the binding
Returns:	Method frame from the Exchange.Bind-ok response
Return type:	pika.frame.Method having method attribute of type spec.Exchange.BindOk

exchange_declare(exchange=None, exchange_type='direct', passive=False, durable=False, auto_delete=False, internal=False, arguments=None)[source]¶

This method creates an exchange if it does not already exist, and if the exchange exists, verifies that it is of the correct and expected class.

If passive set, the server will reply with Declare-Ok if the exchange already exists with the same name, and raise an error if not and if the exchange does not already exist, the server MUST raise a channel exception with reply code 404 (not found).

Parameters:	exchange (str or unicode) – The exchange name consists of a non-empty sequence of these characters: letters, digits, hyphen, underscore, period, or colon. exchange_type (str) – The exchange type to use passive (bool) – Perform a declare or just check to see if it exists durable (bool) – Survive a reboot of RabbitMQ auto_delete (bool) – Remove when no more queues are bound to it internal (bool) – Can only be published to by other exchanges arguments (dict) – Custom key/value pair arguments for the exchange
Returns:	Method frame from the Exchange.Declare-ok response
Return type:	pika.frame.Method having method attribute of type spec.Exchange.DeclareOk

exchange_delete(exchange=None, if_unused=False)[source]¶

Delete the exchange.

Parameters:	exchange (str or unicode) – The exchange name if_unused (bool) – only delete if the exchange is unused
Returns:	Method frame from the Exchange.Delete-ok response
Return type:	pika.frame.Method having method attribute of type spec.Exchange.DeleteOk

exchange_unbind(destination=None, source=None, routing_key='', arguments=None)[source]¶

Unbind an exchange from another exchange.

Parameters:	destination (str or unicode) – The destination exchange to unbind source (str or unicode) – The source exchange to unbind from routing_key (str or unicode) – The routing key to unbind arguments (dict) – Custom key/value pair arguments for the binding
Returns:	Method frame from the Exchange.Unbind-ok response
Return type:	pika.frame.Method having method attribute of type spec.Exchange.UnbindOk

flow(active)[source]¶

Turn Channel flow control off and on.

NOTE: RabbitMQ doesn’t support active=False; per https://www.rabbitmq.com/specification.html: “active=false is not supported by the server. Limiting prefetch with basic.qos provides much better control”

For more information, please reference:

http://www.rabbitmq.com/amqp-0-9-1-reference.html#channel.flow

Parameters:	active (bool) – Turn flow on (True) or off (False)
Returns:	True if broker will start or continue sending; False if not
Return type:	bool

get_waiting_message_count()[source]¶

Returns the number of messages that may be retrieved from the current queue consumer generator via BlockingChannel.consume without blocking. NEW in pika 0.10.0

Return type:	int

is_closed¶

Returns True if the channel is closed.

Return type:	bool

is_closing¶

Returns True if client-initiated closing of the channel is in progress.

Return type:	bool

is_open¶

Returns True if the channel is open.

Return type:	bool

publish(exchange, routing_key, body, properties=None, mandatory=False, immediate=False)[source]¶

Publish to the channel with the given exchange, routing key, and body. Unlike the legacy BlockingChannel.basic_publish, this method provides more information about failures via exceptions.

For more information on basic_publish and what the parameters do, see:

http://www.rabbitmq.com/amqp-0-9-1-reference.html#basic.publish

NOTE: mandatory and immediate may be enabled even without delivery: confirmation, but in the absence of delivery confirmation the synchronous implementation has no way to know how long to wait for the Basic.Return.

Parameters:	exchange (str or unicode) – The exchange to publish to routing_key (str or unicode) – The routing key to bind on body (str or unicode) – The message body; empty string if no body properties (pika.spec.BasicProperties) – message properties mandatory (bool) – The mandatory flag immediate (bool) – The immediate flag
Raises:	UnroutableError – raised when a message published in publisher-acknowledgments mode (see BlockingChannel.confirm_delivery) is returned via Basic.Return followed by Basic.Ack. NackError – raised when a message published in publisher-acknowledgements mode is Nack’ed by the broker. See BlockingChannel.confirm_delivery.

queue_bind(queue, exchange, routing_key=None, arguments=None)[source]¶

Bind the queue to the specified exchange

Parameters:	queue (str or unicode) – The queue to bind to the exchange exchange (str or unicode) – The source exchange to bind to routing_key (str or unicode) – The routing key to bind on arguments (dict) – Custom key/value pair arguments for the binding
Returns:	Method frame from the Queue.Bind-ok response
Return type:	pika.frame.Method having method attribute of type spec.Queue.BindOk

queue_declare(queue='', passive=False, durable=False, exclusive=False, auto_delete=False, arguments=None)[source]¶

Declare queue, create if needed. This method creates or checks a queue. When creating a new queue the client can specify various properties that control the durability of the queue and its contents, and the level of sharing for the queue.

Leave the queue name empty for a auto-named queue in RabbitMQ

Parameters:	queue (str or unicode; if empty string, the broker will create a unique queue name;) – The queue name passive (bool) – Only check to see if the queue exists and raise ChannelClosed if it doesn’t; durable (bool) – Survive reboots of the broker exclusive (bool) – Only allow access by the current connection auto_delete (bool) – Delete after consumer cancels or disconnects arguments (dict) – Custom key/value arguments for the queue
Returns:	Method frame from the Queue.Declare-ok response
Return type:	pika.frame.Method having method attribute of type spec.Queue.DeclareOk

queue_delete(queue='', if_unused=False, if_empty=False)[source]¶

Delete a queue from the broker.

Parameters:	queue (str or unicode) – The queue to delete if_unused (bool) – only delete if it’s unused if_empty (bool) – only delete if the queue is empty
Returns:	Method frame from the Queue.Delete-ok response
Return type:	pika.frame.Method having method attribute of type spec.Queue.DeleteOk

queue_purge(queue='')[source]¶

Purge all of the messages from the specified queue

Parameters:	queue (str or unicode) – The queue to purge
Returns:	Method frame from the Queue.Purge-ok response
Return type:	pika.frame.Method having method attribute of type spec.Queue.PurgeOk

queue_unbind(queue='', exchange=None, routing_key=None, arguments=None)[source]¶

Unbind a queue from an exchange.

Parameters:	queue (str or unicode) – The queue to unbind from the exchange exchange (str or unicode) – The source exchange to bind from routing_key (str or unicode) – The routing key to unbind arguments (dict) – Custom key/value pair arguments for the binding
Returns:	Method frame from the Queue.Unbind-ok response
Return type:	pika.frame.Method having method attribute of type spec.Queue.UnbindOk

start_consuming()[source]¶

Processes I/O events and dispatches timers and basic_consume callbacks until all consumers are cancelled.

NOTE: this blocking function may not be called from the scope of a pika callback, because dispatching basic_consume callbacks from this context would constitute recursion.

Raises:	pika.exceptions.RecursionError – if called from the scope of a BlockingConnection or BlockingChannel callback

stop_consuming(consumer_tag=None)[source]¶

Cancels all consumers, signalling the start_consuming loop to exit.

NOTE: pending non-ackable messages will be lost; pending ackable messages will be rejected.

tx_commit()[source]¶

Commit a transaction.

Returns:	Method frame from the Tx.Commit-ok response
Return type:	pika.frame.Method having method attribute of type spec.Tx.CommitOk

tx_rollback()[source]¶

Rollback a transaction.

Returns:	Method frame from the Tx.Commit-ok response
Return type:	pika.frame.Method having method attribute of type spec.Tx.CommitOk

tx_select()[source]¶

Select standard transaction mode. This method sets the channel to use standard transactions. The client must use this method at least once on a channel before using the Commit or Rollback methods.

Returns:	Method frame from the Tx.Select-ok response
Return type:	pika.frame.Method having method attribute of type spec.Tx.SelectOk