# Configex


`Configex` helps you to deal with Elixir configuration.

Here are the **reasons** why I have created this library:

Elixir is a **compiled** language and getting environment variables on compilation time is **wrong in most of times**.

On compiled language projects there's usually a CI machine(s) that compiles the code and package it. The compiled code package is usually deployed to another machine(s) to run. Very frequently CI and production machines are even on different networks. Ideally CI machines should not know ENV vars like production secrets, etc.

In addition to that if an ENV var has to change, let's say that you have a new secret due to a new service provision then you **cannot
just restart** the app, but you'll have to run CI again to **re-compile** and **re-deploy** the same code base, but with the new ENV var. This is not desirable at all in terms of maintainability of the app you are building.

## How to use `Configex`

The easiest way to use `Configex` is by calling `get_config!/3`:

defmodule MyModule do
  use Configex

  def my_config(), do: get_config!(:my_app, :my_config)

Cool, so far `get_config!/3` will do the same work as `Application.get_env/3`.

Now let's see how `Configex` can benefit us.

## The benefits of using `Configex`:

1.  💥  It raises an error if a configuration is missing and if no `default` is provided.

2.  💥  It raises an error if an ENV var is missing and if no `default` is provided.

3.  💥  It raises an error if an ENV var is used **on compilation time**.

4.  ⚙️  You can configure ENV vars like `config :my_app, my_config: {:system, "MY_ENV"}`

5.  ⚙️  You can configure ENV vars with a default value like `config :my_app, my_config: {:system, "MY_ENV", "<some default>"}`

6.  ⚙️  You can configure ENV vars recursively like `config :my_app, my_config: [port: {:system, "MY_ENV"}]`

## Configuration Example:

use Mix.Config

config :my_app,
  hardcoded: "Some hardcoded value",
  env: {:system, "MY_ENV", "some system default"}

## Usage Example:

  defmodule MyApp.MyModule do
    use Configex

    @hardcoded_conf get_config!(:my_app, :hardcoded)

    def hardcoded_conf(), do: @hardcoded_conf
    def env_conf(), do: get_config!(:my_app, :env)

## Documentation

There's much more use cases on the [hexdocs/configex documentation][hexdocs-configex].

## Installation

Check out `configex` dependency version on [][hex-pm-configex]. The package can be installed by adding `configex` to your list of dependencies in `mix.exs`:

def deps do
    {:configex, "~> 0.1.0"}

## Development

Check out the `Makefile` for useful development tasks.

<!-- Links & Images -->
[hex-pm-configex]: 'Configex on Hex'
[hexdocs-configex]: 'Configex on HexDocs'