Add `utils/deep-merge`

src/taoensso/timbre.clj

@@ -32,7 +32,8 @@
 
       Other keys include: :instant, :timestamp, :hostname, :ns, :error?
 
-    See source code for examples."}
+    See source code for examples and `utils/deep-merge` for a convenient way
+    to reconfigure appenders."}
   (atom {:current-level :debug
 
          ;;; Control log filtering by namespace patterns (e.g. ["my-app.*"]).

src/taoensso/timbre/utils.clj

@@ -14,4 +14,24 @@
           @d-result
           (let [d-result (delay (apply f args))]
             (swap! cache assoc args {:time-cached now :d-result d-result})
-            @d-result))))))
+            @d-result))))))
+
+(defn deep-merge-with ; From clojure.contrib.map-utils
+  "Like `merge-with` but merges maps recursively, applying the given fn
+  only when there's a non-map at a particular level.
+
+  (deepmerge-with + {:a {:b {:c 1 :d {:x 1 :y 2}} :e 3} :f 4}
+                    {:a {:b {:c 2 :d {:z 9} :z 3} :e 100}})
+  => {:a {:b {:z 3, :c 3, :d {:z 9, :x 1, :y 2}}, :e 103}, :f 4}"
+  [f & maps]
+  (apply
+   (fn m [& maps]
+     (if (every? map? maps)
+       (apply merge-with m maps)
+       (apply f maps)))
+   maps))
+
+(defn deep-merge
+  "Partial of `deep-merge-with`."
+  [& maps]
+  (apply deep-merge-with (fn [x y] y) maps))