Imagine a large Elixir application—dozens of processes potentially running across a number of nodes. You’d really want a standard way to keep track of significant events as it runs. Enter the Elixir logger.
The default mix.exs starts the logger for your application.
def application do
applications: [ :logger, :httpoison, :jsx ]
The logger supports four levels of message—in increasing order of severity they are debug, info, warn, and error. You select the level of logging in two ways.
First, you can determine at compile time the minimum level of logging to include. Logging below this level is not even compiled into your code. The compile-time level is set in the config/config.exs ...