Can't use declared function in Clojure - clojure

Question

how's it going?
My code can be found HERE
I've been trying to learn Clojure by following a guide, but I'm not quite sure why this piece of code isn't working.
Here's the code:
(ns calc-api.server.server
(:require [ring.adapter.jetty :as jetty]
[ring.middleware.params :as params]
[ring.util.http-response :as response]
[reitit.ring.middleware.muuntaja :as muuntaja]
[muuntaja.core :as m]
[reitit.ring.coercion :as coercion]
[reitit.ring :as ring]))
(def hello-routes
["/hello" {:get {:handler (fn [_]
(response/ok {:mesage "Hello Reitit!"}))}}])
(def app
(ring/ring-handler
(ring/router
[hello-routes]
{:data {:muuntaja m/instance
:middleware [params/wrap-params
muuntaja/format-middleware
coercion/coerce-exceptions-middleware
coercion/coerce-request-middleware
coercion/coerce-response-middleware]}})
(ring/create-default-handler)))
(defonce running-server (atom nil))
(defn start
[]
(when (nil? #running-server)
(reset! running-server (jetty/run-jetty #'app {:port 3000
:join? false})))
(println "Server running in port 3000"))
(defn stop
[]
(when-not (nil? #running-server)
(.stop #running-server)
(reset! running-server nil))
(println "Server stopped"))
When I run the REPL and swap over to the calc-api namespace and run the (start) function:
lein repl
(in-ns 'calc-api.server.server)
(start)
I was expecting the server to run and print the "server is running on port x", but here's the outcome:
Syntax error compiling at (/tmp/form-init2855747266943058886.clj:1:1).
Unable to resolve symbol: start in this context
Any ideas on why this is happening? All help is very much appreciated.
EDIT[1]
Following Alan Thompson's suggestion, here's what happened:
Copied my code and dependencies to the template's folder, running lein clean + lein run results in
{:clojure.main/message
"Syntax error compiling at (demo/core.clj:50:3).\nNo such namespace: log\n",
:clojure.main/triage
{:clojure.error/phase :compile-syntax-check,
:clojure.error/line 50,
:clojure.error/column 3,
:clojure.error/source "core.clj",
:clojure.error/path "demo/core.clj",
:clojure.error/class java.lang.RuntimeException,
:clojure.error/cause "No such namespace: log"},
:clojure.main/trace
{:via
[{:type clojure.lang.Compiler$CompilerException,
:message "Syntax error compiling at (demo/core.clj:50:3).",
:data
{:clojure.error/phase :compile-syntax-check,
:clojure.error/line 50,
:clojure.error/column 3,
:clojure.error/source "demo/core.clj"},
:at [clojure.lang.Compiler analyze "Compiler.java" 6812]}
{:type java.lang.RuntimeException,
:message "No such namespace: log",
:at [clojure.lang.Util runtimeException "Util.java" 221]}],
:trace
[[clojure.lang.Util runtimeException "Util.java" 221]
[clojure.lang.Compiler resolveIn "Compiler.java" 7388]
[clojure.lang.Compiler resolve "Compiler.java" 7362]
[clojure.lang.Compiler analyzeSymbol "Compiler.java" 7323]
[clojure.lang.Compiler analyze "Compiler.java" 6772]
[clojure.lang.Compiler analyze "Compiler.java" 6749]
[clojure.lang.Compiler$InvokeExpr parse "Compiler.java" 3824]
[clojure.lang.Compiler analyzeSeq "Compiler.java" 7113]
[clojure.lang.Compiler analyze "Compiler.java" 6793]
[clojure.lang.Compiler analyze "Compiler.java" 6749]
[clojure.lang.Compiler$BodyExpr$Parser parse "Compiler.java" 6122]
[clojure.lang.Compiler$FnMethod parse "Compiler.java" 5471]
[clojure.lang.Compiler$FnExpr parse "Compiler.java" 4033]
[clojure.lang.Compiler analyzeSeq "Compiler.java" 7109]
[clojure.lang.Compiler analyze "Compiler.java" 6793]
[clojure.lang.Compiler analyzeSeq "Compiler.java" 7099]
[clojure.lang.Compiler analyze "Compiler.java" 6793]
[clojure.lang.Compiler access$300 "Compiler.java" 38]
[clojure.lang.Compiler$DefExpr$Parser parse "Compiler.java" 596]
[clojure.lang.Compiler analyzeSeq "Compiler.java" 7111]
[clojure.lang.Compiler analyze "Compiler.java" 6793]
[clojure.lang.Compiler analyze "Compiler.java" 6749]
[clojure.lang.Compiler eval "Compiler.java" 7185]
[clojure.lang.Compiler load "Compiler.java" 7640]
[clojure.lang.RT loadResourceScript "RT.java" 381]
[clojure.lang.RT loadResourceScript "RT.java" 372]
[clojure.lang.RT load "RT.java" 459]
[clojure.lang.RT load "RT.java" 424]
[clojure.core$load$fn__6856 invoke "core.clj" 6115]
[clojure.core$load invokeStatic "core.clj" 6114]
[clojure.core$load doInvoke "core.clj" 6098]
[clojure.lang.RestFn invoke "RestFn.java" 408]
[clojure.core$load_one invokeStatic "core.clj" 5897]
[clojure.core$load_one invoke "core.clj" 5892]
[clojure.core$load_lib$fn__6796 invoke "core.clj" 5937]
[clojure.core$load_lib invokeStatic "core.clj" 5936]
[clojure.core$load_lib doInvoke "core.clj" 5917]
[clojure.lang.RestFn applyTo "RestFn.java" 142]
[clojure.core$apply invokeStatic "core.clj" 669]
[clojure.core$load_libs invokeStatic "core.clj" 5974]
[clojure.core$load_libs doInvoke "core.clj" 5958]
[clojure.lang.RestFn applyTo "RestFn.java" 137]
[clojure.core$apply invokeStatic "core.clj" 669]
[clojure.core$require invokeStatic "core.clj" 5996]
[clojure.core$require doInvoke "core.clj" 5996]
[clojure.lang.RestFn invoke "RestFn.java" 408]
[user$eval142$fn__146 invoke "form-init13165779102252361276.clj" 1]
[user$eval142 invokeStatic "form-init13165779102252361276.clj" 1]
[user$eval142 invoke "form-init13165779102252361276.clj" 1]
[clojure.lang.Compiler eval "Compiler.java" 7181]
[clojure.lang.Compiler eval "Compiler.java" 7171]
[clojure.lang.Compiler load "Compiler.java" 7640]
[clojure.lang.Compiler loadFile "Compiler.java" 7578]
[clojure.main$load_script invokeStatic "main.clj" 475]
[clojure.main$init_opt invokeStatic "main.clj" 477]
[clojure.main$init_opt invoke "main.clj" 477]
[clojure.main$initialize invokeStatic "main.clj" 508]
[clojure.main$null_opt invokeStatic "main.clj" 542]
[clojure.main$null_opt invoke "main.clj" 539]
[clojure.main$main invokeStatic "main.clj" 664]
[clojure.main$main doInvoke "main.clj" 616]
[clojure.lang.RestFn applyTo "RestFn.java" 137]
[clojure.lang.Var applyTo "Var.java" 705]
[clojure.main main "main.java" 40]],
:cause "No such namespace: log",
:phase :compile-syntax-check}}
Which I don't think has to do anything with my original code?
EDIT[2]
I've found a solution which I don't like but works for my learning purposes. I changed the core.clj file to require the server namespace and call the start function from there.
(ns calc-api.core
(:gen-class))
(require '[calc-api.server.server :as calc-api-server])
(defn -main
"I don't do a whole lot ... yet."
[& args]
(calc-api-server/start))
Which means I have to cmd+d every time I want to stop the server, but at least it works. Thanks for all the help provided.

Answer 1

Your problem is difficult to diagnose with only the repl information & error. As an expedient, I would suggest starting with a known working template project.
Do a git clone as the README describes, then lein clean; lein test to verify the install (& your java, etc) are configured correctly.
At that point, copy your code into src/clj/demo/core.clj and then try lein clean; lein run. Even if it doesn't work, you will get a much more detailed error message, including usable line numbers for any error.
Please update your question with the results of this experiment.