Restarter

The "let it fail" philosophy enabled by Erlang supervision trees is powerful. Sometimes, though, Supervisor restart strategies are not enough; something that relies on an external service may fail consistently for an extended period of time, overwhelming the max_restarts and propagating the error up the supervision tree. In some cases you may not want such an error to take down your entire application.

The Restarter allows you to set a retry interval; the child will be restarted for indefinitely, every configurable amount of time.

Installation

1. Add restarter to your list of dependencies in mix.exs:

def deps do
[{:restarter, "~> 0.1.0"}]
end

1. Ensure restarter is deployed with your application:

def application do
[applications: [:restarter]]
end

Usage

To try out in iex, given:

defmodule MyGenServer do
  use GenServer

  def start_link arg do
    GenServer.start_link(__MODULE__, arg, [name: :bob])
  end

  def init(arg) do
    IO.inspect {:starting, arg}
    {:ok, []}
  end
end

In iex -S mix

{:ok, pid} = Restarter.start_link({MyGenServer, :start_link, [:sue]}, 10000, [name: :restarter])
Process.whereis(:bob) # It's been started

Process.whereis(:bob) |> Process.exit(:kill)

Process.whereis(:bob) # nil

# Wait 10 seconds


Process.whereis(:bob) # It's been re-started

Obviously, you would be starting all this in a supervision tree, with the Restarter as a worker.