enki v0.2.0 Enki

Enki is a simple queue that provides Mnesia persistence across nodes and ttf (time-to-flight) capability.

Time-to-flight means that, when dequeuing a message, if the dequeue is not ack'd within a given period of time, the message is automatically added back to the queue. This ensures that no messages are lost.

Queues must be created by calling Enki.init and passing a list of model module names. Each model must be created as

defmodule MyApp.MyModel do
  use Enki.Message,
    attributes: [:attr1, :attr2, :attr3]
end

This replaces the need to use defstruct, as it ensures the correct Enki meta is used.

Examples

Enki.init([MyModel])
Enki.enq(%MyModel{a: 1, b: 2})
%MyModel{enki_id: id, a: 1, b: 2}} = Enki.deq(MyModel)
:ok = Enki.ack(id)

Link to this section Summary

Functions

ack(id)

Acknowledges a dequeued message.

delete(queue, id)

Deletes a message by id.

delete_all(queue)

Delete all messages in the queue.

deq(queue, ttf \\ nil)

Dequeues a message from the queue.

enq(message)

Adds a message to the queue.

get(queue, id)

Retrieves a message by id without dequeuing.

init(types)

Initialises the Queues.

start(type, args)

Enki application start method.

Link to this section Functions

ack(id)

Acknowledges a dequeued message.

If the message is in-flight, it will not be re-added to the queue after the alotted ttf.

Parameters

name	description
`id`	The `id` of the message to acknowledge (required).

delete(queue, id)

Deletes a message by id.

Directly deletes a message in the queue.

Parameters

name	description
`queue`	The module type (atom) of the message to delete (required).
`id`	The `id` of the message to delete (required).

delete_all(queue)

Delete all messages in the queue.

Any in-flight messages are cancelled, so messages are not added back to the queue.

Parameters

name	description
`queue`	The module type (atom) of the messages to delete (required).

deq(queue, ttf \\ nil)

Dequeues a message from the queue.

Returns the message in a Message model as its payload parameter. The message is typically the oldest in the queue.

Parameters

name	description
`queue`	The module type (atom) of the message to dequeue (required).
`ttf`	The time-to-flight for the message. If provided, verrides the message in the config (optional).

enq(message)

enq(Enki.Message.t()) :: Enki.Message.t()

Adds a message to the queue.

Returns a Message instance containing the enki_id of the message on the queue and the message itself as a payload.

Parameters

name	description
`message`	The model instance to queue (required).

get(queue, id)

Retrieves a message by id without dequeuing.

Recalling a message directly does NOT put it in flight.

Parameters

name	description
`queue`	The module type (atom) of the message to retrieve (required).
`id`	The `id` of the message to retrieve (required).

init(types)

init([atom()]) :: :ok | no_return()

Initialises the Queues.

Example:

Enki.init([MyModel, MyOtherModel])

Parameters

name	description
`types`	A list of model instances to use as queue types (required).

start(type, args)

Enki application start method.

Gets called automatically when included in your mix applications list.