https://github.com/devth/dec

:cyclone: Deep Environmental Configuration
https://github.com/devth/dec

clojure configuration minimalist twelve-factor

Last synced: 3 months ago
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:cyclone: Deep Environmental Configuration

• Host: GitHub
• URL: https://github.com/devth/dec
• Owner: devth
• License: epl-1.0
• Created: 2016-02-14T05:21:43.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2018-09-28T16:11:14.000Z (over 6 years ago)
• Last Synced: 2024-10-03T05:10:23.626Z (4 months ago)
• Topics: clojure, configuration, minimalist, twelve-factor
• Language: Clojure
• Homepage: https://devth.com/2018/dec-deep-environmental-config
• Size: 289 KB
• Stars: 9
• Watchers: 3
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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  Deep Environmental Configuration



# dec

[![Build Status](https://travis-ci.org/devth/dec.svg?branch=master)](https://travis-ci.org/devth/dec)

[![Clojars Project](https://img.shields.io/clojars/v/dec.svg)](https://clojars.org/dec)

[![codecov](https://codecov.io/gh/devth/dec/branch/master/graph/badge.svg)](https://codecov.io/gh/devth/dec)

dec builds arbitrarily nested data structures from simple KV strings.

- Tiny codebase; tiny name

- Functionally pure

- Composable

- Zero runtime dependencies

- 100% test coverage with unit tests & [test.check](https://github.com/clojure/test.check)

- Fully linted against [eastwood](https://github.com/jonase/eastwood) &

  [kibit](https://github.com/jonase/kibit)

- Up-to-date [Change Log](CHANGELOG.md)

## Rationale

Env vars are constrained to simple key value pairs, yet they are ubiquitous.

Docker config and [12 Factor Config](http://12factor.net/config) in particular

rely on this traditional mechanism. But modern apps often require more complex

data structures, to wit: maps and lists.

## Usage

dec exposes two primary functions: `explode` and `enflat`. They are inverses of

eachother, such that `identity == (comp explode enflat)`, i.e.:

```clojure

(let [nested {:foo {:bar [:baz :qux]}}]

  (= nested (explode (enflat nested))))

;;=> true

```

Assume our env looks like:

```shell

export DEC_HOSTS_0=a.host.com

export DEC_HOSTS_1=b.host.com

export DEC_LEVEL=debug

```

Then we we obtain some env vars via

[environ](https://github.com/weavejester/environ), as one does,

filter by a known prefix, and `explode` the results:

```clojure

(require

  '[environ.core :refer [env]]

  '[dec :refer [explode]])

(explode (into {} (filter (fn [[k v]] (.startsWith (name k) "dec")) env)))

{:dec {:hosts ["a.host.com" "b.host.com"], :level "debug"}}

```

A little simpler, without the `env`:

```clojure

(explode

  {:dec-level "debug"

   :dec-hosts-0 "a.host.com"

   :dec-hosts-1 "b.host.com"})

{:dec {:hosts ["a.host.com" "b.host.com"], :level "debug"}}

````

Environ is not required, nor is it a dependency of dec; I'm using it as an

example of a common way to obtain environmental configuration.

### Custom delimiter

dec optionally takes a delimiter parameter:

```clojure

(explode {:dec.hosts.0 "a.host.com"

          :dec.hosts.1 "b.host.com"

          :dec.level "debug"}

          {:delimiter "."})

{:dec {:hosts ["a.host.com" "b.host.com"], :level "debug"}}

```

## Run tests

```

lein test

```

## Calculate code coverage

```

lein cloverage

```

## Run linters

```

lein kibit

lein eastwood

```

## License

Copyright © 2016 Trevor C. Hartman

Distributed under the Eclipse Public License either version 1.0 or any later

version.