System.fetch_env-exclamation-mark

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Link to this function

fetch_env!(varname)

View Source (since 1.9.0)

Specs

fetch_env!(String.t()) :: String.t()

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

Same as get_env/1 but raises instead of returning nil when the variable is not set.

Examples

iex> System.fetch_env!("PORT")
"4000"

iex> System.fetch_env!("NOT_SET")
** (ArgumentError) could not fetch environment variable "NOT_SET" because it is not set