|
|
@@ -0,0 +1,79 @@
|
|
|
+===============
|
|
|
+ Routing Tasks
|
|
|
+===============
|
|
|
+
|
|
|
+**NOTE** This document refers to functionality only available in brokers
|
|
|
+using AMQP. Other brokers may implement some functionality, see their
|
|
|
+respective documenation for more information, or contact the `mailinglist`_.
|
|
|
+
|
|
|
+.. _`mailinglist`: http://groups.google.com/group/celery-users
|
|
|
+
|
|
|
+AMQP Primer
|
|
|
+===========
|
|
|
+
|
|
|
+Exchanges, queues and routing keys.
|
|
|
+-----------------------------------
|
|
|
+TODO Mindblowing one-line simple explanation here. TODO
|
|
|
+
|
|
|
+Exchange type
|
|
|
+-------------
|
|
|
+
|
|
|
+The exchange type defines how the messages are routed through the exchange.
|
|
|
+The exchanges defined in the standard is ``direct``, ``topic``, ``fanout`` and
|
|
|
+``headers``. Also non-standard exchange types available as plugins to RabbitMQ, like
|
|
|
+the last value cache plug-in.
|
|
|
+
|
|
|
+
|
|
|
+Consumers and Producers
|
|
|
+-----------------------
|
|
|
+TODO
|
|
|
+
|
|
|
+Related API commands
|
|
|
+-------------------------
|
|
|
+
|
|
|
+* exchange.declare(exchange_name, type, passive, durable, auto_delete, internal)
|
|
|
+
|
|
|
+Declares an exchange by name.
|
|
|
+
|
|
|
+ * ``passive`` means the exchange won't be created, but you can use this to
|
|
|
+ check if the exchange already exists.
|
|
|
+
|
|
|
+ * Durable exchanges are persistent. I.e. they survive a broker restart.
|
|
|
+
|
|
|
+ * ``auto_delete`` means the queue will be deleted by the broker when there
|
|
|
+ are no more queues using it.
|
|
|
+
|
|
|
+* queue.declare(queue_name, passive, durable, exclusive, auto_delete)
|
|
|
+
|
|
|
+Declares a queue by name.
|
|
|
+
|
|
|
+ * exclusive queues can only be consumed from by the current connection.
|
|
|
+ implies ``auto_delete``.
|
|
|
+
|
|
|
+* queue.bind(queue_name, exchange_name, routing_key)
|
|
|
+
|
|
|
+Binds a queue to an exchange with a routing key.
|
|
|
+Unbound queues will not receive messages, so this is necessary.
|
|
|
+
|
|
|
+* queue.delete(name, if_unused, if_empty)
|
|
|
+
|
|
|
+Deletes a queue and its binding.
|
|
|
+
|
|
|
+* exchange.delete(name, if_unused)
|
|
|
+
|
|
|
+Deletes an exchange.
|
|
|
+
|
|
|
+**NOTE**: Declaring does not necessarily mean "create". When you declare you
|
|
|
+*assert* that the entity exists and it is operable. There is no rule as to
|
|
|
+whom should initially create the exchange/queue/binding, whether consumer
|
|
|
+or producer. Usually the first one to need it will create it.
|
|
|
+
|
|
|
+
|
|
|
+Hands-on with the API
|
|
|
+---------------------
|
|
|
+
|
|
|
+Celery comes with a tool called ``camqadm`` (short for celery AMQP admin).
|
|
|
+It's used for simple admnistration tasks like deleting queues/exchanges,
|
|
|
+purging queues and creating queue entities. In short it's for simple command
|
|
|
+line access to the AMQP API.
|
|
|
+
|
Ask Solem