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Features

Runtime configure from Environment
Zero custom runtime.exs coding
Explicit type conversion
Address any Application environment node
Fully automatic scan of Environment variables

Basics

Common Env prefix: je__ (can be customized)
Separator is two successive underscores __ (equals a dot .)
Think of Application Env as a single root Keyword tree

Examples

A string config

Config:

config :my_app, :a_string_value, "this is a string"

Jetenv:

export je__my_app__a_string_value__S="this is a string"

Note, the prefix je__ and the type suffix __S

A value in the tree

Config

config :my_app, :group_of_options, [
  option_bool: true,
  sub_options: [
    deeper_option_number: 14
  ]
]

Jetenv

je__my_app__group_of_options__option_bool__B=true
je__my_app__group_of_options__sub_options__deeper_option_number__I=14

A JSON value (maps/lists)

Note that as Config does not merge non-keyword nodes, nor does Jetenv.

Config

  config :my_app, :map_data,
    %{
      a: 11,
      b: 12
    }

Jetenv

je__my_app__map_data__J={"a": 11, "b": 12}

Result

iex(2)> Jetenv.load_all_env
[my_app: [map_data: %{"a" => 11, "b" => 12}]]
iex(3)> Jetenv.load_all_env |> Application.put_all_env
:ok
iex(4)> Application.get_all_env :my_app
[map_data: %{"a" => 11, "b" => 12}]

Jetenv.load_env will load config only for loaded Applications. load_all_env will load anything found with the active prefix, this will emit warnings on startup that configuration elements exist for an unloaded application (which is why it's not the default behaviour).

These two are clearly not equivalent, but Jetenv can also handle erlang terms.

Erlang Term

sh% export je__my_app__config1__map__G='#{a => 1, b => 2}.'
sh% iex -S mix
iex(1)> Jetenv.load_all_env(prefix: "je")
[my_app: [config1: [map: %{a: 1, b: 2}]]]
iex(2)> Jetenv.load_all_env(prefix: "je") |> Application.put_all_env
:ok
iex(3)> Application.get_all_env :my_app
[config1: [map: %{a: 1, b: 2}]]

Adding to a project

No forklift required
Use runtime_merge to cooperate with Config

For a new project

import Config
Jetenv.load_env()

For an existing runtime.exs:

import Config

config :my_app .....
Jetenv.load_env() |> Jetenv.runtime_merge()

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