metosin/maailma

Name: maailma

Owner: Metosin

Description: Opinionated environment variables library

Created: 2015-04-06 16:37:05.0

Updated: 2018-03-28 12:01:31.0

Pushed: 2018-03-28 12:02:07.0

Homepage: http://metosin.github.io/maailma/

Size: 87

Language: Clojure

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README

Maailma

API Docs.

Project statement

Unlike more general of our libraries (like compojure-api and ring-swagger) this project is primarily intended for use in Metosin's projects. Feel free to use, but don't expect full support.

• We might remove features if we think they are not useful anymore
• We will reject PRs and issues about features we wouldn't use ourselves

Features

• Represents application configuration as a single map which is read once on startup
  • Should work well with Component
• Reads configuration from multiple sources and recursively merges it
  • EDN files in classpath ? shipped with JAR, useful for default options
  • EDN files in filesystem ? created by hand or by deploy tooling
  • Environment variables
  • Java properties
  • Override parameter ? useful for overriding options for test systems
  • User selects the sources themselves
  • Extendable with functions
• EDN readers can be provided as option, which allows use with Integrant

Example

backend.system
require [maailma.core :as m]))

n system [override]
et [env (m/build-config
          (m/resource "config-defaults.edn")
          (m/env "prefix")
          (m/env-var "SERVER_PORT" [:http :port])
          (m/properties "prefix")
          (m/file "./config-local.edn")
          override)]
...))

Integrant example

Add reader options to resource and file calls:

load-namespaces
/build-config
(m/resource "config.edn" {:readers {'ig/ref ig/ref}})
(m/file "config-local.edn" {:readers {'ig/ref ig/ref}})))

(Not supported with read-config! function)

Notes

• Is it necessary to refresh configuration of running application?
  • Most fixes done to running production systems over REPL are very small fixes to integration logic
  • It's possible that some integration settings need to be changed quickly?
  • Probably not necessary. Most logic is isolated to pure functions and the can be replaced over REPL without touching components or configuration.

License

Copyright © 2015-2018 Metosin Oy.

Distributed under the Eclipse Public License, the same as Clojure.