Elixir MOM v0.5.3 MOM

Message Oriented Middleware

Implements basic MOM to allow Message passing between the users. It is used mainly as Request-Reply (RPC).

Example of use:

iex> alias MOM.{Channel, Tap, Message}
iex> {:ok, ch} = Channel.Broadcast.start_link
iex> Tap.tap(ch,"tap test")
iex> {:ok, ag} = Agent.start_link(fn -> nil end ) # a singleton with value nil, will be updated
iex> sub_id = Channel.subscribe(ch, fn _ -> Agent.update(ag, fn _ -> :updated end) end)
iex> Agent.get(ag, &(&1))
nil
iex> Channel.send(ch, %Message{})
iex> :timer.sleep(100) # Bad, I know, but send is asynchronous.
iex> Agent.get(ag, &(&1))
:updated
iex> Agent.update(ag, fn _ -> nil end)
iex> Channel.unsubscribe(ch, sub_id) # unsubscribe, should not update
iex> Channel.send(ch, %Message{})
iex> Agent.get(ag, &(&1))
nil

Summary

Functions

Called when an application is started

Functions

start(type, args)

Called when an application is started.

This function is called when an application is started using Application.start/2 (and functions on top of that, such as Application.ensure_started/2). This function should start the top-level process of the application (which should be the top supervisor of the application’s supervision tree if the application follows the OTP design principles around supervision).

start_type defines how the application is started:

  • :normal - used if the startup is a normal startup or if the application is distributed and is started on the current node because of a failover from another node and the application specification key :start_phases is :undefined.
  • {:takeover, node} - used if the application is distributed and is started on the current node because of a failover on the node node.
  • {:failover, node} - used if the application is distributed and is started on the current node because of a failover on node node, and the application specification key :start_phases is not :undefined.

start_args are the arguments passed to the application in the :mod specification key (e.g., mod: {MyApp, [:my_args]}).

This function should either return {:ok, pid} or {:ok, pid, state} if startup is successful. pid should be the PID of the top supervisor. state can be an arbitrary term, and if omitted will default to []; if the application is later stopped, state is passed to the stop/1 callback (see the documentation for the c:stop/1 callback for more information).

use Application provides no default implementation for the start/2 callback.

Callback implementation for Application.start/2.