104 lines
2.6 KiB
ReStructuredText
104 lines
2.6 KiB
ReStructuredText
.. _guide-consumers:
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===========
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Consumers
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===========
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.. _consumer-basics:
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Basics
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======
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The :class:`Consumer` takes a connection (or channel) and a list of queues to
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consume from. Several consumers can be mixed to consume from different
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channels, as they all bind to the same connection, and ``drain_events`` will
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drain events from all channels on that connection.
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.. note::
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Kombu since 3.0 will only accept json/binary or text messages by default,
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to allow deserialization of other formats you have to specify them
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in the ``accept`` argument::
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Consumer(conn, accept=['json', 'pickle', 'msgpack', 'yaml'])
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Draining events from a single consumer:
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.. code-block:: python
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with Consumer(connection, queues, accept=['json']):
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connection.drain_events(timeout=1)
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Draining events from several consumers:
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.. code-block:: python
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from kombu.utils import nested
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with connection.channel(), connection.channel() as (channel1, channel2):
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with nested(Consumer(channel1, queues1, accept=['json']),
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Consumer(channel2, queues2, accept=['json'])):
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connection.drain_events(timeout=1)
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Or using :class:`~kombu.mixins.ConsumerMixin`:
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.. code-block:: python
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from kombu.mixins import ConsumerMixin
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class C(ConsumerMixin):
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def __init__(self, connection):
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self.connection = connection
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def get_consumers(self, Consumer, channel):
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return [
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Consumer(queues, callbacks=[self.on_message], accept=['json']),
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]
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def on_message(self, body, message):
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print("RECEIVED MESSAGE: %r" % (body, ))
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message.ack()
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C(connection).run()
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and with multiple channels again:
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.. code-block:: python
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from kombu import Consumer
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from kombu.mixins import ConsumerMixin
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class C(ConsumerMixin):
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channel2 = None
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def __init__(self, connection):
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self.connection = connection
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def get_consumers(self, _, default_channel):
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self.channel2 = default_channel.connection.channel()
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return [Consumer(default_channel, queues1,
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callbacks=[self.on_message],
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accept=['json']),
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Consumer(self.channel2, queues2,
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callbacks=[self.on_special_message],
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accept=['json'])]
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def on_consumer_end(self, connection, default_channel):
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if self.channel2:
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self.channel2.close()
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C(connection).run()
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Reference
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=========
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.. autoclass:: kombu.Consumer
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:noindex:
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:members:
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