phoenixframework/ex_conf

Simple Elixir Configuration Management

ExConf

Simple Elixir Configuration Management

Deprecated

ExConf has been replaced by Mix Configuration. See the Phoenix README for new configuration instructions.

Features

• Configuration definitions are evaluated at runtime, but merged/defaulted at compile time, allowing runtime dependent lookups. (i.e. System.get_env)
• Configuration modules can extend other configurations for overrides and defaults
• Evironment based lookup for settings based on provided env_var

Simple Example

defmodule MyApp.Config do
  use ExConf.Config

  config :router, ssl: true,
                  domain: "example.dev",
                  port: System.get_env("PORT")

  config :session, secret: "secret"
end

iex> MyApp.Config.router[:domain]
"example.dev"


defmodule MyApp.OtherConfig do
  use MyApp.Config

  config :session, secret: "123password"
end

iex> MyApp.OtherConfig.session[:secret]
"123password"
iex> MyApp.OtherConfig.router[:ssl]
true

Environment Based Configuration

First, establish a base configuration module that uses ExConf.Config and provide an env_var option for System.get_env lookup at runtime of the current application environment.

defmodule MyApp.Config do
  use ExConf.Config, env_var: "MIX_ENV"

  config :router, ssl: true
  config :twitter, api_token: System.get_env("API_TOKEN")
end

Next, define "submodules" for each environment you need overrides or additional settings for. The base config module will look for a "submodule" whos name is the value of :env_var fetched from System.get_env in capitalized form. This allows environment specific lookup at runtime via the env/0 function on the base module. If the environment specific config module does not exist, it falls back to the base module.

Here's what a Dev enviroment config module would look like for System.get_env("MIX_ENV") == "dev":

defmodule MyApp.Config.Dev do
  use MyApp.Config

  config :router, ssl: false
  config :twitter, api_token: "ABC"
end

iex> System.get_env("MIX_ENV")
"dev"

iex> MyApp.Config.env
MyApp.Config.Dev

iex> MyApp.Config.env.router[:ssl]
false