nuxlli / env_config

Configure elixir app with env variables at run time

EnvConfig

Handles fetching values from config with support for runtime ENV loading.

All credit goes to bitwalker, this module is copied from this gist.

Usage

Fetches a value from the config, or from the environment if {:system, "VAR"} is provided.

An optional default value can be provided if desired.

In your config/config.exs:

# maybe you start your app with FOO_KEY=abcd
config :foo_app, :some_setting, {:system, "FOO_KEY"}

In your application:

EnvConfig.get(:foo_app, :some_setting) # => "abcd"

Example

iex> Application.put_env(:myapp, :test_var, {:system, "MY_ENVVAR"})
iex> System.put_env("MY_ENVVAR", "my_value")
...> #{__MODULE__}.get(:myapp, :test_var)
"my_value"

iex> Application.put_env(:myapp, :test_var, {:system, :charlist, "MY_CHARLIST"})
...> #{__MODULE__}.get(:myapp, :test_var)
nil
iex> System.put_env("MY_CHARLIST", "charlist_value")
...> #{__MODULE__}.get(:myapp, :test_var)
'charlist_value'

iex> Application.put_env(:myapp, :test_var, {:system, :boolean, "MY_BOOLEAN"})
...> System.put_env("MY_BOOLEAN", "off")
...> #{__MODULE__}.get(:myapp, :test_var)
false
iex> System.put_env("MY_BOOLEAN", "true")
...> #{__MODULE__}.get(:myapp, :test_var)
true

iex> Application.put_env(:myapp, :test_var2, 1)
...> 1 = #{__MODULE__}.get(:myapp, :test_var2)
1

iex> :default = #{__MODULE__}.get(:myapp, :missing_var, :default)
:default

Installation

If available in Hex, the package can be installed as:

1. Add env_config to your list of dependencies in mix.exs:

def deps do
  [{:env_config, "~> 0.1.0"}]
end

2. Ensure env_config is started before your application:

def application do
  [applications: [:env_config]]
end