Defines a Transfer Plugin.

A Transfer plugin receives data from Collectors. It uses the Collector’s label in order to differenciate from multiple Collectors.

POAAgent app reads the Transfers configuration from the config.exs file when bootstrap and will create a process per each one of them. That configuration is referenced by :transfers key.

config :poa_agent,
   :transfers,
   [
     {name, module, args}
   ]

for example

config :poa_agent,
   :transfers,
   [
     {:my_transfer, POAAgent.Plugins.Transfers.MyTransfer, [ws_key: "mykey", other_stuff: "hello"]}
   ]

name, module and args must be defined in the configuration file.

• name: Name for the new created process. Must be unique
• module: Module which implements the Transfer behaviour
• args: Initial args which will be passed to the init_transfer/1 function

Implementing A Transfer Plugin

In order to implement your Transfer Plugin you must implement 3 functions.

• init_transfer/1: Called only once when the process starts
• data_received/4: This function is called every time a Collector sends metrics to the Transfer
• handle_message/1: This is called when the transfer process receives an Erlang message
• terminate/1: Called just before stopping the process

This is a simple example of custom Transfer Plugin

defmodule POAAgent.Plugins.Transfers.MyTransfer do
  use POAAgent.Plugins.Transfer

  def init_transfer(args) do
    {:ok, :no_state}
  end

  def data_received(label, metric_type, data, state) do
    IO.puts "Received data from the collector referenced by label"
    {:ok, :no_state}
  end

  def handle_message(_message, state) do
    {:ok, state}
  end

  def terminate(_state) do
    :ok
  end

end