https://github.com/gocardless/prius

Environmentally-friendly application config
https://github.com/gocardless/prius

Last synced: about 2 months ago
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Environmentally-friendly application config

• Host: GitHub
• URL: https://github.com/gocardless/prius
• Owner: gocardless
• License: mit
• Created: 2015-01-31T18:10:19.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2024-07-12T15:28:56.000Z (3 months ago)
• Last Synced: 2024-07-29T05:34:57.270Z (2 months ago)
• Language: Ruby
• Size: 77.1 KB
• Stars: 24
• Watchers: 93
• Forks: 4
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Prius

Environmentally-friendly application config for Ruby.

[![Gem Version](https://badge.fury.io/rb/prius.svg)](http://badge.fury.io/rb/prius)

[![Build Status](https://circleci.com/gh/gocardless/prius.svg?style=svg)](https://app.circleci.com/pipelines/github/gocardless/prius)

Prius helps you guarantee that your environment variables are:

- **Present** - an exception is raised if an environment variable is missing,

  so you can hear about it as soon as your app boots.

- **Valid** - an environment variable can be coerced to a desired type

  (integer, boolean, string, or date), and an exception will be raised if the value

  doesn't match the type.

## Usage

#### Installing

```

$ gem install prius

```

#### Quick Start

```ruby

# Load a required environment variable into the Prius registry:

Prius.load(:github_token)

# Use the environment variable:

Prius.get(:github_token)

# Load an optional environment variable:

Prius.load(:might_be_here_or_not, required: false)

# Load and alias an environment variable:

Prius.load(:alias_name, env_var: "HORRENDOUS_SYSTEM_VAR_NAME")

# Load and coerce an environment variable (or raise):

Prius.load(:my_flag, type: :bool)

```

You probably want to `load` all your environment variables as your app starts,

so you catch config issues at boot time.

#### Loading Environment Variables

Environment variables need to be loaded into the Prius registry before being

used. Typically this is done in an initialiser.

```ruby

Prius.load(name, **options)

```

If an environment variable can't be loaded, Prius will raise one of:

- `MissingValueError` if the environment variable was expected to be set but couldn't be found.

- `TypeMismatchError` if the environment variable wasn't of the expected type (see below).

`Prius.load` accepts the following options:

| Param             | Default       | Description                                                                               |

|-------------------|---------------|-------------------------------------------------------------------------------------------|

| `required`        | `true`        | Flag to require the environment variable to have been set.                                |

| `type`            | `:string`     | Type to coerce the environment variable to. Allowed values are `:string`, `:int`, `:bool`, and `:date`. |

| `env_var`         | `name.upcase` | Name of the environment variable name (if different from the upcased `name`).             |

#### Reading Environment Variables

Once a variable has been loaded into the registry it can be read using:

```ruby

Prius.get(name)

```

If the environment variable hasn't been loaded, Prius will raise an `UndeclaredNameError`.

#### Test and development environments

To make running your app in test and development environments easier we

recommend using [Dotenv](https://github.com/bkeepers/dotenv) to automatically

load a file of dummy config values.

---

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