# Exenv
[](https://travis-ci.org/nsweeting/exenv)
[](https://hex.pm/packages/exenv)
Exenv provides an adapter-based solution to loading environment variables from
external sources.
It currently only has support for the following adapter:
* `Exenv.Adapters.Dotenv` (load from .env files)
## Installation
This package can be installed by adding `exenv` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:exenv, "~> 0.1.1"}
]
end
```
## Documentation
Please see [HexDocs](https://hexdocs.pm/exenv/Exenv.html#content) for additional
documentation. This readme provides a brief overview, but it is recommended that
the docs are used.
## Getting Started
If all you want is to load a `.env` file on application start - then you're already
done! Out of the box, `Exenv` is configured to start itself with the `Exenv.Adapters.Dotenv`
adapter configured with sane defaults. This means autoloading on application start - with
the `.env` file required to be within your projects root directory.
## Configuration
If you need finer grained control of things, `Exenv` provides extensive config mechansims.
If you do not want `Exenv` to start on application start, simply add the following line to
you `config.exs` file.
```elixir
config :exenv, start_on_application: false
```
If you choose to do the above, you will be responsble for adding `Exenv` to your own
supervision tree.
```elixir
defmodule MySupervisor do
use Supervisor
def start_link(opts) do
Supervisor.start_link(__MODULE__, :ok, opts)
end
def init(:ok) do
children = [
{Exenv, []}
]
Supervisor.init(children, strategy: :one_for_one)
end
end
```
We can pass configuration options to `Exenv` from application config, or directly
from the `child_spec/1` callback.
```elixir
config :exenv, [
start_on_application: false,
adapters: [
{Exenv.Adapters.Dotenv, [file: "path/to/.env"]}
]
]
```
```elixir
children = [
{Exenv, [adapters: [{Exenv.Adapters.Dotenv, [file: "path/to/.env"]}]]}
]
Supervisor.init(children, strategy: :one_for_one)
```
Options passed to the `child_spec/1` callback take precedence over any application
config.
By default, all adapters will autoload their environment vars when `Exenv` starts up.
You can override this behaviour on a per-adapter basis, by simply passing the
`autoload: false` key within your adapter config.
```elixir
[
adapters: [
{Exenv.Adapters.Dotenv, [autoload: false, file: "path/to/.env"]}
]
]
```
You can then manually load all env vars from your defined adapters:
```elixir
Exenv.load()
```
