<div align="center">
<img src="https://user-images.githubusercontent.com/194400/151025711-574482bb-918d-499f-b7cd-32bf224403c8.png"
alt="envar rainbow logo">
A collection of functions for checking/getting/setting **environment variables** in **`Elixir`**.
<!-- Better LOGO #HelpWanted -->
[](http://codecov.io/github/dwyl/envar?branch=main)
[](https://hex.pm/packages/envar)
[](https://libraries.io/hex/envar "Zero Dependencies")
[](https://github.com/dwyl/envar/issues)
[](http://hits.dwyl.com/dwyl/envar)
</div><br />
## Why?
We needed a way of checking that environment variables were defined
and improving the developer experience when they are not.
## What?
**`envar`** is our solution to a very specific problem:
the developer experience when a required environment variable is undefined.
<br />
## How?
### Installation
Install the package
by adding `envar` to your list of dependencies in your `mix.exs` file:
```elixir
def deps do
[
{:envar, "~> 1.1.0"}
]
end
```
## Usage
Load an `.env` file
containing a line-separated list of environment variables
on your `localhost`:
```elixir
Envar.load(".env")
```
That will locate the `.env` file in your project
and set each environment variable in it.
If the `.env` _must_ exist e.g. in a `:test` context,
invoke:
```elixir
Envar.require_env_file(".env")
```
That will log an `Error` if the file does not exist (or can't be found):
```sh
09:10:54.103 [error] Required .env file does not exist at path: /Alex/awesome/project/.env
```
<br />
When you need to retrieve a specific environment variable,
use the following:
```elixir
DATABASE_URL = Envar.get("DATABASE_URL")
```
<br />
If you want to define a default/fallback value
for the environment variable when it's not set,
simply add it as the second argument:
```elixir
DATABASE_URL = Envar.get("DATABASE_URL", "postgres://uname:pass@host:5432/dbname"")
```
<br />
If you need to check that a variable is set,
use `is_set?/1`
```elixir
if Envar.is_set?("Heroku") do
# do stuff on Heroku
end
```
To check if _any_ of the variables in a `List` are set,
invoke `Envar.is_set_any?/1`:
```elixir
if Envar.is_set_any?(~w/HEROKU FLYIO/) do
# Do something on non-prod environment
end
```
Conversely, to confirm that _all_ the environment variables
in a list are set, invoke `Envar.is_set_all?/1`:
```elixir
if Envar.is_set_all?(~w/ADMIN_EMAIL AUTH_API_KEY/) do
# Do something with the required environment variables
end
```
We needed a couple more convenience functions,
so we wrote them!
If you need to read an `.env` file and get the
keys & values as a `Map`, invoke `Envar.read/1`:
```elixir
iex> Envar.read(".env")
%{
"ADMIN_EMAIL" => "alex@gmail.com",
"EVERYTHING" => "awesome!",
"SECRET" => "master plan"
}
```
If you need just the `keys`
of the list of environment variables in an `.env` file,
invoke: `Envar.keys/1`:
```elixir
iex> Envar.keys(".env")
["ADMIN_EMAIL", "EVERYTHING", "SECRET"]
```
And if you need just the `values`
of the environment variables in an `.env` file,
invoke: `Envar.values/1`:
```elixir
iex> Envar.values(".env")
["alex@gmail.com", "awesome!", "master plan"]
```
For more detail, please see docs:
https://hexdocs.pm/envar/Envar.html#functions
<br /><br />
Happy `Elixir` Coding! 🚀
<br /><br />
## Context
We created this module after doing
a search of the `Elixir` (Hex.pm)
ecosystem, <br />
see:
[dwyl/learn-environment-variables/issues/18](https://github.com/dwyl/learn-environment-variables/issues/18)
There are several modules available,
we wanted something very basic/specific to our needs. <br />
We don't expect anyone else to use this;
it's Open Source
because that's just what we do: <br />
[/manifesto.md#open-source-always](https://github.com/dwyl/start-here/blob/master/manifesto.md#open-source-always)
