mirror of https://github.com/celery/kombu.git
117 lines
3.8 KiB
ReStructuredText
117 lines
3.8 KiB
ReStructuredText
.. _guide-simple:
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==================
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Simple Interface
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==================
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.. contents::
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:local:
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:mod:`kombu.simple` is a simple interface to AMQP queueing.
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It is only slightly different from the :class:`~Queue.Queue` class in the
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Python Standard Library, which makes it excellent for users with basic
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messaging needs.
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Instead of defining exchanges and queues, the simple classes only requires
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two arguments, a connection channel and a name. The name is used as the
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queue, exchange and routing key. If the need arises, you can specify
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a :class:`~kombu.Queue` as the name argument instead.
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In addition, the :class:`~kombu.Connection` comes with
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shortcuts to create simple queues using the current connection:
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.. code-block:: pycon
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>>> queue = connection.SimpleQueue('myqueue')
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>>> # ... do something with queue
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>>> queue.close()
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This is equivalent to:
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.. code-block:: pycon
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>>> from kombu.simple import SimpleBuffer
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>>> channel = connection.channel()
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>>> queue = SimpleBuffer(channel, 'mybuffer')
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>>> # ... do something with queue
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>>> channel.close()
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>>> queue.close()
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.. _simple-send-receive:
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Sending and receiving messages
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==============================
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The simple interface defines two classes; :class:`~kombu.simple.SimpleQueue`,
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and :class:`~kombu.simple.SimpleBuffer`. The former is used for persistent
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messages, and the latter is used for transient, buffer-like queues.
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They both have the same interface, so you can use them interchangeably.
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Here is an example using the :class:`~kombu.simple.SimpleQueue` class
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to produce and consume logging messages:
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.. code-block:: python
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import socket
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import datetime
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from time import time
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from kombu import Connection
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class Logger:
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def __init__(self, connection, queue_name='log_queue',
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serializer='json', compression=None):
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self.queue = connection.SimpleQueue(queue_name)
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self.serializer = serializer
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self.compression = compression
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def log(self, message, level='INFO', context={}):
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self.queue.put({'message': message,
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'level': level,
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'context': context,
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'hostname': socket.gethostname(),
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'timestamp': time()},
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serializer=self.serializer,
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compression=self.compression)
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def process(self, callback, n=1, timeout=1):
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for i in xrange(n):
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log_message = self.queue.get(block=True, timeout=1)
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entry = log_message.payload # deserialized data.
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callback(entry)
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log_message.ack() # remove message from queue
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def close(self):
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self.queue.close()
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if __name__ == '__main__':
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from contextlib import closing
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with Connection('amqp://guest:guest@localhost:5672//') as conn:
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with closing(Logger(conn)) as logger:
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# Send message
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logger.log('Error happened while encoding video',
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level='ERROR',
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context={'filename': 'cutekitten.mpg'})
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# Consume and process message
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# This is the callback called when a log message is
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# received.
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def dump_entry(entry):
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date = datetime.datetime.fromtimestamp(entry['timestamp'])
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print('[%s %s %s] %s %r' % (date,
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entry['hostname'],
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entry['level'],
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entry['message'],
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entry['context']))
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# Process a single message using the callback above.
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logger.process(dump_entry, n=1)
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