improve error messages

shadow-cljs.edn

@@ -1,6 +1,7 @@
 {:source-paths ["src/main"
                 "src/test"]
- :dependencies [[orchestra "2018.12.06-2"]]
+ :dependencies [[orchestra "2019.02.06-1"]
+                [expound "0.8.4"]]
  :builds       {:dev {:target       :node-library
                       :output-to    "target/node-lib.js"
                       :exports   {:infra mastodon-bot.core/main}

src/main/mastodon_bot/core.cljs

@@ -4,12 +4,15 @@
    [clojure.spec.test.alpha :as st]
    [clojure.string :as cs]
    [orchestra.core :refer-macros [defn-spec]]
+   [expound.alpha :as expound]
    [mastodon-bot.infra :as infra]
    [mastodon-bot.transform :as transform]
    [mastodon-bot.mastodon-api :as masto]
    [mastodon-bot.twitter-api :as twitter]
    [mastodon-bot.tumblr-api :as tumblr]))
 
+(set! s/*explain-out* expound/printer)
+
 (s/def ::mastodon masto/mastodon-auth?)
 (s/def ::twitter twitter/twitter-auth?)
 (s/def ::tumblr tumblr/tumblr-auth?)
@@ -40,9 +43,9 @@
   [config config?]
   (:transform config))
 
-(defn transform! [config-location]
+(defn-spec transform! any?
-  (let [config (infra/load-config config-location)
+  [config config?]
-        mastodon-auth (mastodon-auth config)]
+  (let [mastodon-auth (mastodon-auth config)]  
     (masto/get-mastodon-timeline
      mastodon-auth
      (fn [timeline]
@@ -80,15 +83,8 @@
                  ))))
 )))))
 
-(defn main [& args]
+(def usage
-  (let [parsed-args (s/conform ::args args)]
+  "usage:
-    (if (= ::s/invalid parsed-args)
-      (do (s/explain ::args args)
-          (infra/exit-with-error "Bad commandline arguments"))
-      (let [{:keys [options config-location]} parsed-args]
-        (cond
-          (some #(= "-h" %) options)
-          (print "usage:
                   
   node target/mastodon-bot.js [-h] /path/to/config.edn 
   
@@ -96,8 +92,22 @@
   
   npm start [-h] /path/to/config.edn
   ")
+
+(defn main [& args]
+  (let [parsed-args (s/conform ::args args)]
+    (if (= ::s/invalid parsed-args)
+      (do (s/explain ::args args)
+          (infra/exit-with-error (str "Bad commandline arguments\n" usage)))
+      (let [{:keys [options config-location]} parsed-args]
+        (cond
+          (some #(= "-h" %) options)
+          (print usage)
           :default
-          (transform! config-location))))))
+          (let [config (infra/load-config config-location)]
+            (when (not (s/valid? config? config))
+              (s/explain config? config)
+              (infra/exit-with-error "Bad configuration"))
+            (transform! config)))))))
 
 (st/instrument 'mastodon-auth)
 (st/instrument 'twitter-auth)