nREPL with default NS

repl.clj

(ns com.nda.myproduct
  (:require
    [clojure.tools.nrepl.server :as server]
    [clojure.tools.nrepl.middleware :as middleware]
    [clojure.tools.nrepl.middleware.session :as session]))

; util funcs
;...


; repl

(defonce
  nrepl-server
  (do
    (defn- wrap-init-vars
      [init-ns]
      (with-local-vars
        [wrap-init-vars'
         (fn [h]
           ;; this needs to be a var, since it's in the nREPL session
           (with-local-vars [init-ns-sentinel nil]
             (fn [{:keys [session] :as msg}]
               (when-not (@session init-ns-sentinel)
                 (swap! session assoc
                        init-ns-sentinel true
                        (var *ns*) (try (require init-ns)
                                        (create-ns init-ns)
                                        (catch Throwable t
                                          (.printStackTrace t)
                                          (create-ns 'user)))))
               (h msg))))]
        (doto wrap-init-vars'
          ;; set-descriptor! currently nREPL only accepts a var
          (middleware/set-descriptor!
            {:requires #{#'session/session}
             :expects  #{"eval"}})
          (alter-var-root (constantly @wrap-init-vars')))))

    (defn start-server
      [{:keys [init-ns] :as opts}]
      (let [init-ns-mw [(wrap-init-vars init-ns)]
            middleware (concat init-ns-mw server/default-middlewares)
            handler (apply server/default-handler middleware)
            opts (assoc opts :handler handler)]
        (apply server/start-server (mapcat identity opts))))


    (start-server {:init-ns 'com.nda.myproduct
                   :port    16872})))