initial commit

.gitignore

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+.DS_Store
+/target
+/classes
+/checkouts
+/out
+pom.xml
+pom.xml.asc
+*.jar
+*.class
+/.lein-*
+/.nrepl-port
+/*.project
+/*.classpath
+/.settings/
+*.iml
+*.ipr
+*.iws
+.idea

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2016 Gered King
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# config
+
+Simple Clojure library for managing application configuration stored in
+an external file in EDN format.
+
+## Leiningen
+
+```clj
+[gered/config "0.1"]
+```
+
+## Usage
+
+FIXME
+
+## License
+
+Copyright © 2016 Gered King
+
+Distributed under the the MIT License. See LICENSE for more details.

project.clj

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+(defproject gered/config "0.1"
+  :description  "Management of application configuration stored in an external EDN file."
+  :url          "https://github.com/gered/config"
+  :license      {:name "MIT License"
+                 :url  "http://opensource.org/licenses/MIT"}
+
+  :dependencies [[org.clojure/tools.logging "0.3.1"]]
+
+  :profiles     {:provided
+                 {:dependencies [[org.clojure/clojure "1.8.0"]]}})

src/config/core.clj

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+(ns config.core
+  (:refer-clojure :exclude [load get])
+  (:require
+    [clojure.java.io :as io]
+    [clojure.edn :as edn]
+    [clojure.tools.logging :as log]))
+
+(def default-options
+  {
+   ; whether to log a warning whenever config.core/get is called to access config values
+   ; which are undefined in the configuration
+   :log-undefined?   true
+
+   ; whether to throw an exception whenever config.core/get is called to access config values
+   ; which are undefined in the configuration
+   :throw-undefined? false
+   })
+
+(defn load-edn-config
+  [f]
+  (edn/read-string (slurp f)))
+
+(defn load
+  "Loads and returns an EDN configuration stored in a file. If the file is not
+   specified tries to load from 'config.edn' in the current directory.
+
+   For supported options, see config.core/default-options."
+  {:arglists '([]
+               [options]
+               [f]
+               [f options])}
+  [& args]
+  (let [[f options] (if (map? (first args))
+                      [nil (first args)]
+                      args)]
+    {:options (merge default-options options)
+     :config  (load-edn-config (or f "config.edn"))}))
+
+(defn get
+  "Returns a value from a loaded configuration under the path ks. May log a warning
+   or throw an exception if the value is undefined in the configuration depending on
+   the options specified when the configuration was loaded."
+  [config & ks]
+  (let [options (:options config)
+        value   (get-in (:config config) ks ::undefined)]
+    (if (= ::undefined value)
+      (do
+        (if (:log-undefined? options) (log/warn "Read of undefined configuration value" ks))
+        (if (:throw-undefined? options) (throw (ex-info (str "Read of undefined configuration value " ks) {:ks ks :config (:config config)}))))
+      value)))