AMQP.Queue (amqp v3.0.0) View Source

Functions to operate on Queues.

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Functions

Binds a Queue to an Exchange.

Returns a number of active consumers on the queue.

Declares a queue. The optional queue parameter is used to set the name. If set to an empty string (default), the server will assign a name.

Deletes a Queue by name.

Returns true if queue is empty (has no messages ready), false otherwise.

Returns the number of messages that are ready for delivery (e.g. not pending acknowledgements) in the queue.

Discards all messages in the Queue.

Returns the message count and consumer count for the given queue. Uses declare/3 with the :passive option set.

Convenience to consume messages from a Queue.

Unbinds a Queue from an Exchange.

Stops the consumer identified by consumer_tag from consuming.

Link to this section Functions

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bind(channel, queue, exchange, options \\ [])

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Specs

Binds a Queue to an Exchange.

Options

  • :routing_key - The routing key used to bind the queue to the exchange (default "")

  • :nowait - If true, the binding is not synchronous (default false)

  • :arguments - A list of arguments to pass when binding (of type AMQP.arguments/0). See the README for more information (default [])

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consumer_count(channel, queue)

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Specs

consumer_count(AMQP.Channel.t(), AMQP.Basic.queue()) :: integer() | no_return()

Returns a number of active consumers on the queue.

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declare(channel, queue \\ "", options \\ [])

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Specs

declare(AMQP.Channel.t(), AMQP.Basic.queue(), keyword()) ::
  {:ok,
   %{
     queue: AMQP.Basic.queue(),
     message_count: integer(),
     consumer_count: integer()
   }}
  | :ok
  | AMQP.Basic.error()

Declares a queue. The optional queue parameter is used to set the name. If set to an empty string (default), the server will assign a name.

Besides the queue name, the following options can be used:

Options

  • :durable - If set, keeps the Queue between restarts of the broker (default false)

  • :auto_delete - If set, deletes the Queue once all subscribers disconnect (default to false)

  • :exclusive - If set, only one subscriber can consume from the Queue (default false)

  • :passive - If set, raises an error unless the queue already exists (default false)

  • :nowait - If set, the declare operation is asynchronous (default false)

  • :arguments - A list of arguments to pass when declaring (of type AMQP.arguments/0). See the README for more information (default [])

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delete(channel, queue, options \\ [])

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Specs

delete(AMQP.Channel.t(), AMQP.Basic.queue(), keyword()) ::
  {:ok, map()} | :ok | AMQP.Basic.error()

Deletes a Queue by name.

Options

  • :if_unused - If set, the server will only delete the queue if it has no consumers. If the queue has consumers, it's not deleted and an error is returned

  • :if_empty - If set, the server will only delete the queue if it has no messages

  • :nowait - If set, the delete operation is asynchronous

Specs

Returns true if queue is empty (has no messages ready), false otherwise.

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message_count(channel, queue)

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Specs

message_count(AMQP.Channel.t(), AMQP.Basic.queue()) :: integer() | no_return()

Returns the number of messages that are ready for delivery (e.g. not pending acknowledgements) in the queue.

Specs

purge(AMQP.Channel.t(), AMQP.Basic.queue()) :: {:ok, map()} | AMQP.Basic.error()

Discards all messages in the Queue.

Specs

status(AMQP.Channel.t(), AMQP.Basic.queue()) ::
  {:ok, map()} | AMQP.Basic.error()

Returns the message count and consumer count for the given queue. Uses declare/3 with the :passive option set.

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subscribe(channel, queue, fun, options \\ [])

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Specs

subscribe(
  AMQP.Channel.t(),
  AMQP.Basic.queue(),
  (String.t(), map() -> any()),
  keyword()
) :: {:ok, String.t()} | AMQP.Basic.error()

Convenience to consume messages from a Queue.

The handler function must have arity 2 and will receive as arguments a binary with the message payload and a Map with the message properties.

The consumed message will be acknowledged after executing the handler function.

If an exception is raised by the handler function, the message is rejected.

This convenience function will spawn a process and register it using AMQP.Basic.consume/4.

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unbind(channel, queue, exchange, options \\ [])

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Specs

Unbinds a Queue from an Exchange.

Options

  • :routing_key - The routing queue for removing the binding (default "")

  • :arguments - A list of arguments to pass when unbinding (of type AMQP.arguments/0). See the README for more information (defaults [])

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unsubscribe(channel, consumer_tag)

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Specs

Stops the consumer identified by consumer_tag from consuming.

Internally just calls AMQP.Basic.cancel/2.