juxt.modular/co-dependency

Releases and Dependency Information

[juxt.modular/co-dependency "0.2.0"]

Usage

Add co-dependency to your project dependencies

(defproject your-project "your-version"
   ...
   :dependencies [[tangrammer/co-dependency "0.1.3"]]
   ...
   )

Add component and co-dependency to your ns:

(ns your-app-ns
  (:require [com.stuartsierra.component :as component]
            [tangrammer.component.co-dependency :as co-dependency]))

Define your system

Same as you do with stuartsierra/component lib but adding co-dependencies with co-dependency/co-using fn In this case :b depends on :a and :a co-depends on :b

(defn system-1 []
  (map->System1 {:a (-> (component-a)
                        (co-dependency/co-using [:b]))
                 :b (-> (component-b)
                        (component/using [:a]))
                 :c (-> (component-c)
                        (component/using [:a :b]))
                 :d (-> (component-d)
                        (component/using {:b :b :c :c}))
                 :e (component-e)})

Start your system

(def system-started-with-co-deps (co-dependency/start-system (system-1)))

Retrieving co-dependencies values

(def a (-> system-started-with-co-deps :a))
(def a-from-b (:a @(-> system-started-with-co-deps :a :b)))
;; checking identity equality
(assert (= a a-from-b))

Using stuartsierra reloaded workflow

If you use stuartsierra "reloaded" workflow then update original stuartsierra dev/start function by:

(defn start
  "Starts the current development system."
  []
  (alter-var-root #'system co-dependency/start-system))

Do you need more help?

Follow the test provided to learn how to use it :)

Drawbacks

In contrast with normal dependencies that you get using clojure map functions

(:dependency-key component)
;;=> dependency

when you want to retrieve a co-dependency you need to deref the co-dependency value

@(:co-dependency-key component)
;;=> co-dependency

License

Copyright © 2014 Juan Antonio Ruz (juxt.pro)

Distributed under the Eclipse Public License, the same as Clojure