Tweaks to config file handling.

If --config config.yaml wasn't specified, don't error out if
config.yaml doesn't exist.

src/main/lemondronor/circlebot.cljs

@@ -483,6 +483,9 @@
 (defn build-config [config cli-config secrets]
   (util/deep-merge default-config config cli-config secrets))
 
+
+(def default-config-path "config.yaml")
+
 (defn main [& args]
   (-> commander
       (.option "--lat <lat>" "Latitude of the circle of region of interest" parse-number)
@@ -493,11 +496,17 @@
       (.option "--basestation-sqb <path>" "Path to a basestation.sqb database file")
       (.option "--tweeting" "Enables tweeting")
       (.option "--no-tweeting" "Do not tweet")
-      (.option "--config <path>" "Path to the configuration yaml file" "config.yaml")
+      (.option "--config <path>" "Path to the configuration yaml file")
       (.option "--secrets <path>" "Path to the secrets yaml file" "secrets.yaml")
       (.parse (.-argv js/process)))
   (let [start-time (current-time)]
-    (p/let [base-config (util/read-config (.-config commander))
+    ;; If --config-path is specified, definitely try to read that
+    ;; file. Otherwise, only read config.yaml if it exists.
+    (p/let [base-config (if-let [config-path (.-config commander)]
+                          (util/read-config config-path)
+                          (if (fs/existsSync default-config-path)
+                            (util/read-config default-config-path)
+                            {}))
             cli-config (build-config-from-commander commander)
             secrets (util/read-config (.-secrets commander))
             config (build-config base-config cli-config secrets)
@@ -524,3 +533,10 @@
                      (/ (- end-time start-time) 1000)
                      (count new-db)
                      (count potential-circles)))))))
+
+
+;; (.on js/process "unhandledRejection"
+;;      (fn [reason promise]
+;;        (log-error "Error: %s" (.-message reason))
+;;        (println (.-stack reason))
+;;        (.exit js/process 1)))

src/main/lemondronor/circlebot/util.cljs

@@ -29,10 +29,13 @@
 
 (defn read-config [path]
   (log-verbose "Reading config file %s" path)
+  (p/try
     (p/let [data (read-file path {:encoding "utf-8"})]
       (let [config (-> (yaml/safeLoad data)
                        (js->clj :keywordize-keys true))]
-      (or config {}))))
+        (or config {})))
+    (p/catch :default e
+      (throw (str "Error reading config file '" path "': " e)))))
 
 
 ;; Fetches a URL. Returns a promise that resolves to the body of the