bones.conf

A Clojure library designed to read configuration files and provide a component to inject into a component system-map.

Usage

Recommended implementation

(ns your.ns
  (require [bones.conf :as conf]
           [com.stuartsierra.component :as component]))

(def sys (atom {}))

(swap! sys assoc :conf (conf/map->Conf {:conf-files ["test.edn"]}))
(swap! sys assoc :xyz (component/using (map->XYZ {}) [:conf]))

;; conf will be started and assoc'd to xyz before its `start` function is executed

(swap! sys component/update-system [:xyz :conf] component/start)

;; reload conf files
(swap! sys update :conf component/start)

Special keys

Any key can be a configuration variable but these are treated special.

:conf-files required A list of file paths that can be absolute or relative. The files will get read and parsed according to the file extension. Only .edn is supported out of the box but see below for others. Environment variables will be substituted in these strings, e.g.: if APP_ENV=development, "conf/$APP_ENV.edn" -> "conf/development.edn"

:sticky-keys optional Sometimes you want to keep the configuration values around when you set them in code and reload the component. The sticky-keys will not get lost unless they also exist in a file.

:mappy-keys silly Just in case you want to use the same value for multiple keys. The second one is the real value, the first is the "symlink".

Alternative implementation:

(defn system []
  (atom (component/system-map
         :conf (conf/map->Conf :conf-files ["config.edn" "/etc/sysconfig/app.properties"]
                               :port 3000 ;; override-able via conf-files
                               :sticky-keys [:port] ;; and reloadable
                               :mappy-keys [[:zookeeper-addr :zookeeper/address]]) ;;same value
         :http (component/using
                (map->HTTP {}) ;; uses (:port conf) in start
                [:conf]))

Adding a file type

(require '[clj-yaml.core :as yaml])

(defmethod bones.conf/parse "yml" [file-path]
  (yaml/parse-string (slurp file-path)))

(require '[clojurewerkz.propertied.properties :as p])

(defmethod bones.conf/parse "properties" [file-path]
  (-> file-path
      (io/file)
      (p/load-from)
      (p/properties->map true))))

Development and Testing

start repl with lein with-profile +test repl and evaluate testing forms in test/conf_test.clj

command line tests via lein test

License

Copyright © 2016 Chris Thompson

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.