GenServer pg_dump

pg_dump.ex

defmodule MyApp.PgDump do
  use GenServer
  require Logger

  @backup_config Application.get_env(:myapp, :db_backup_config)
  def start_link do
    GenServer.start_link(__MODULE__, [], name: :pg_dump)
  end

  defp schedule_database_backup() do
    Process.send_after(self(), :database_backup, 1000 * 60 * @backup_config[:interval]) #6 hours
  end
  def init(state) do
    schedule_database_backup()
    {:ok, state}
  end

  def handle_info(:database_backup, state) do

    db_config = Application.get_env(:myapp, MyApp.Repo)

    file_name = "#{@backup_config[:path]}/#{db_config[:database]}_#{Timex.now |> Timex.to_unix}"
    command = "pg_dump -d #{db_config[:database]} | gzip -9 > #{file_name}.sql.gz" |> String.to_charlist
    :os.cmd(command)

    {:ok, files} = File.ls(@backup_config[:path])
    file_length = length(files)

    if file_length > @backup_config[:max_storage] do
      files
      |> Enum.slice(0, file_length - @backup_config[:max_storage])
      |> Enum.each(fn(file) ->
        File.rm!("#{@backup_config[:path]}/#{file}")
      end)
    end

    schedule_database_backup()
    {:noreply, state}
  end
end