System.fetch_env

You're seeing just the function fetch_env, go back to System module for more information.

fetch_env(varname)

(since 1.9.0)

Specs

fetch_env(String.t()) :: {:ok, String.t()} | :error

Returns the value of the given environment variable or :error if not found.

If the environment variable varname is set, then {:ok, value} is returned where value is a string. If varname is not set, :error is returned.

Examples

iex> System.fetch_env("PORT")
{:ok, "4000"}

iex> System.fetch_env("NOT_SET")
:error