wabbit

v0.4.0

wabbit v0.4.0 Wabbit.Basic View Source

Functions to publish, consume and acknowledge messages.

Link to this section Summary

Functions

ack(channel, delivery_tag, options \\ [])

Acknowledges one or more messages

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

Registers a queue consumer process

nack(channel, delivery_tag, options \\ [])

Negative acknowledge of one or more messages

publish(channel, payload, options \\ [])

Publishes a message to an Exchange

qos(channel, options \\ [])

Sets the message prefetch count or size (in bytes)

reject(channel, delivery_tag, options \\ [])

Rejects (and, optionally, requeues) a message

Link to this section Functions

Link to this function ack(channel, delivery_tag, options \\ []) View Source

Acknowledges one or more messages.

If multiple is set to true, all messages up to the one specified by delivery_tag are considered acknowledged by the server.

Link to this function consume(channel, queue, options \\ []) View Source

Registers a queue consumer process.

The pid of the process can be set using the subscriber argument and defaults to the calling process.

The consumer process will receive the following messages:

  • {:basic_deliver, payload, meta} - This is sent for each message consumed, where payload contains the message content and meta contains all the metadata set when sending with Basic.publish or additional info set by the broker

  • {:basic_consume_ok, %{consumer_tag: consumer_tag}} - Sent when the consumer process is registered with Basic.consume. The caller receives the same information as the return of Basic.consume

  • {:basic_cancel, %{consumer_tag: consumer_tag, no_wait: no_wait}} - Sent by the broker when the consumer is unexpectedly cancelled (such as after a queue deletion)

  • {:basic_cancel_ok, %{consumer_tag: consumer_tag}} - Sent to the consumer process after a call to Basic.cancel

Options

  • :consumer_tag - Identifier for the consumer, valid within the current channel
  • :no_local - If the no-local field is set the server will not send messages to the connection that published them
  • :no_ack - If this field is set the server does not expect acknowledgements for messages
  • :exclusive - Request exclusive consumer access, meaning only this consumer can access the queue
  • :no_wait - If set, the server will not respond to the method
  • :arguments - A set of arguments for the consume
Link to this function nack(channel, delivery_tag, options \\ []) View Source

Negative acknowledge of one or more messages.

If :multiple is set to true, all messages up to the one specified by delivery_tag are considered as not acknowledged by the server.

If :requeue is set to true, the message will be returned to the queue and redelivered to the next available consumer. This is a RabbitMQ specific extension to AMQP 0.9.1. It is equivalent to reject, but allows rejecting multiple messages using the multiple option.

Link to this function publish(channel, payload, options \\ []) View Source

Publishes a message to an Exchange.

This method publishes a message to a specific exchange. The message will be routed to queues as defined by the exchange configuration and distributed to any subscribers.

The parameter :exchange specifies the name of the exchange to publish to. If set to empty string, it publishes to the default exchange.

The :routing_key parameter specifies the routing key for the message.

The :payload parameter specifies the message content as a binary.

In addition to the previous parameters, the following options can be used:

Options

  • :mandatory - If set, returns an error if the broker can’t route the message to a queue (default false)
  • :immediate - If set, returns an error if the broker can’t deliver te message to a consumer immediately (default false)
  • :content_type - MIME Content type
  • :content_encoding - MIME Content encoding
  • :headers - Message headers. Can be used with headers Exchanges
  • :persistent - If set, uses persistent delivery mode. Messages marked as persistent that are delivered to durable queues will be logged to disk
  • :correlation_id - application correlation identifier
  • :priority - message priority, ranging from 0 to 9
  • :reply_to - name of the reply queue
  • :expiration - how long the message is valid (in milliseconds)
  • :message_id - message identifier
  • :timestamp - timestamp associated with this message (epoch time)
  • :type - message type as a string
  • :user_id - creating user ID. RabbitMQ will validate this against the active connection user
  • :app_id - publishing application ID

Examples 

iex> Wabbit.Basic.publish channel, "Hello World!", exchange: "my_exchange", routing_key: "my_routing_key", persistent: true
:ok
Link to this function qos(channel, options \\ []) View Source

Sets the message prefetch count or size (in bytes).

If :global is set to true this applies to the entire Connection, otherwise it applies only to the specified Channel.

Options

  • :prefetch_size - Number of messages to be sent in advance
  • :prefetch_count - Specifies a prefetch window in terms of whole messages
  • :global - QoS settings scope
Link to this function reject(channel, delivery_tag, options \\ []) View Source

Rejects (and, optionally, requeues) a message.