This shows how to use custom immutant init functions to load arbitrary files according to the environment the app is running. This uses a combination of: leiningen profiles + custom immutant init function + clojure's ability to evaluate scripts + some magical stuff with namespaces.

dev.clj

(defn handler 
    [r] ((build-routes) r))

(web/start handler
  :reload true)

(msg/start "/queue/delivery.status")

(msg/respond "/queue/delivery.status" handle-delivery-status)

(register-job #'import-job)
(register-job #'check-import)
;register-job is function not provided here
;since the intention is tho show the configuration solution

init.clj

(ns tserver.init
  (:use [clojure.tools.logging :only (info error debug)]))

(defn setup-config-ns [e]
	(binding [*ns* *ns*]
      (in-ns 'tserver.init)
      (refer-clojure)
      (use '[clojure.main :only (load-script)])
      (require '[immutant.messaging :as msg]
               '[immutant.web :as web]
               '[immutant.util :as util])))

(defn load-config 
  "Attempts to evaluate the specified env file defined by `:env` 
  in the `proficel.clj`. `:env` is a immutant custom config.
  `:env` MUST be a keyword: Ex.: :dev, :prod :office
  Uses :dev by default.
  Note: The abscence of the requrested file will prevent the server to start.
  These siles MUST be located at `src/tserver/config/%s.clj"
  [] 
  (binding [*ns* *ns*]
    (in-ns 'tserver.init)
    (let [ev (get-in (immutant.registry/get :config) [:env] :dev)
    	    config-file (format "src/tserver/config/%s.clj" (name ev))]
  	  (setup-config-ns ev)
      (info "Using config file " config-file)
  	  (load-file config-file)
  	  (immutant.registry/put :env ev))))

(defn init []
  ;;mybe do some stuff before
  (load-config)) ;;maybe do some stuff after

project.clj

(defproject tserver "0.1.0-SNAPSHOT"
  :description "A foo project"
  :url "http://foo.com/"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.4.0"]
                 [compojure "1.0.2"]
                 ;... and many other dependecies
  :jvm-opts ["-Xmx2g" "-server"]
  :immutant {:init "tserver.init/init"} ;; our custo immutant init function
  :profiles {:dev {:immutant {:context-path "/"
                              :nrepl-port 4242
                              :lein-profiles [:dev]
                              :env :dev}}}) ;:dev will identify which config file to load