introduce a spec driven cli-main

shadow-cljs.edn

@@ -3,7 +3,7 @@
  :dependencies [[orchestra "2018.12.06-2"]]
  :builds       {:dev {:target       :node-library
                       :output-to    "target/node-lib.js"
-                      :exports   {:infra mastodon-bot.core/-main}
+                      :exports   {:infra mastodon-bot.core/main}
                       :repl-pprint  true}
                 :test {:target    :node-test
                        :output-to "target/node-tests.js"
@@ -11,5 +11,5 @@
                        :autorun   true}
                 :app {:target    :node-script
                       :output-to "target/mastodon-bot.js"
-                      :main      mastodon-bot.core/-main
+                      :main      mastodon-bot.core/main
                       :compiler-options {:optimizations :simple}}}}

src/main/mastodon_bot/core.cljs

@@ -1,16 +1,14 @@
-#!/usr/bin/env lumo
-
 (ns mastodon-bot.core
   (:require
    [clojure.spec.alpha :as s]
    [clojure.spec.test.alpha :as st]
+   [clojure.string :as cs]
    [orchestra.core :refer-macros [defn-spec]]
    [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]
-   [cljs.core :refer [*command-line-args*]]))
+   [mastodon-bot.tumblr-api :as tumblr]))
 
 (s/def ::mastodon masto/mastodon-auth?)
 (s/def ::twitter twitter/twitter-auth?)
@@ -20,6 +18,12 @@
 (def config? 
   (s/keys :req-un [::auth ::transform]))
 
+(s/def ::options (s/* #{"-h"}))
+(s/def ::config-location (s/? (s/and string?
+                                     #(not (cs/starts-with? % "-")))))
+(s/def ::args (s/cat :options ::options 
+                     :config-location ::config-location))
+
 (defn-spec mastodon-auth ::mastodon
   [config config?]
   (get-in config [:auth :mastodon]))
@@ -36,10 +40,9 @@
   [config config?]
   (:transform config))
 
-(def config (infra/load-config))
-
-(defn -main []
-  (let [mastodon-auth (mastodon-auth config)]
+(defn -main [{:keys [options config-location] :as args}]
+  (let [config (infra/load-config config-location)
+        mastodon-auth (mastodon-auth config)]
     (masto/get-mastodon-timeline
      mastodon-auth
      (fn [timeline]
@@ -77,7 +80,13 @@
                  ))))
 )))))
 
-(set! *main-cli-fn* -main)
+(defn main [& args]
+  (let [parsed-args (s/conform ::args args)]
+    (if (= ::s/invalid parsed-args)
+      (do (s/explain ::args args)
+          (infra/exit-with-error "Bad commandline arguments"))
+      (-main parsed-args))))
+
 (st/instrument 'mastodon-auth)
 (st/instrument 'twitter-auth)
 (st/instrument 'transform)

src/main/mastodon_bot/infra.cljs

@@ -10,13 +10,16 @@
   (js/console.error error)
   (js/process.exit 1))
 
-(defn find-config []
-  (let [config (or (first *command-line-args*)
+(defn find-config [config-location]
+  (let [config (or config-location
                    (-> js/process .-env .-MASTODON_BOT_CONFIG)
                    "config.edn")]
     (if (fs/existsSync config)
       config
       (exit-with-error (str "failed to read config: " config)))))
 
-(defn load-config []
-  (-> (find-config) (fs/readFileSync #js {:encoding "UTF-8"}) edn/read-string))
+(defn load-config [config-location]
+  (-> config-location
+      (find-config)
+      (fs/readFileSync #js {:encoding "UTF-8"})
+      edn/read-string))