component-jimfs.clj

(defrecord JimFSFactory []
  component/Lifecycle
  (start [t] (Jimfs/newFileSystem (Configuration/unix))))

(extend-protocol component/Lifecycle
  Jimfs
  (stop [t] (.close t)))

(defrecord PathFactory [fs]
  component/Lifecycle
  (start [t]
    (doto (.getPath fs "some-file" (make-array String 0))
      (Files/createFile (make-array FileAttribute 0)))))

(-> (component/system-map
     :fs (->JimFSFactory)
     :path (map->PathFactory {}))
    (component/system-using
     {:path [:fs]})
    (component/start)
    (doto (-> :path
              (Files/exists (make-array LinkOption 0))
              prn))
    (component/stop))