TattdCodeMonkey / mon_handler

Elixir GenServer used to monitor a GenEvent event handler

MonHandler - Monitored Event Handler

This is a minimal GenServer module that is used to monitor an event handler.

To use simply call add_mon_handler or start_link with the GenEvent event manager, event handler and args for your event handler. Optionally you can also pass arguments for the MonHandler GenServer.

MonHanlder will handle messages from the event manager if the event handler terminates. For normal terminations MonHandler will stop. For terminations due to errors MonHandler will re-add the event handler to the event manager.

Use Cases

Basic:

iex(x)> {:ok, manager} = GenEvent.start_link
{:ok, #PID<X.Y.Z>}
iex(x)> {:ok, mon_han} = MonHandler.start_link(manager, YourEventHandler, event_handler_args, gen_server_args)
{:ok, #PID<X.Y.Z>}
iex(x)> GenEvent.notify(manager, {:your_event, "some data"})
:ok
iex(x)> MonHandler.remove_handler(mon_han)
:ok  

Starting with a supervisor

mon_handler_config = MonHandler.get_config(manager, YourEventHandler, event_handler_args)
supervise([worker(MonHandler, [mon_handler_config, []])], [strategy: :one_for_one])

If you want to use MonHandler for multiple handlers within a single app you will need to give each an id when adding them to the supervisor.

supervise(
  [
    worker(
      MonHandler,
      [
        MonHandler.get_config(:manager_one, YourEventHandler, []),
        []
      ],
      [id: :first_handler]
    ),
    worker(
      MonHandler,
      [
        MonHandler.get_config(:manager_two, YourSecondEventHandler, []),
        []
      ],
      [id: :second_handler]
    )
  ],
  [strategy: :one_for_one]
)