Allow logging function to be customized

src/duplicacy_log.go

@@ -23,6 +23,7 @@ const (
     ASSERT = 4
 )
 
+var LogFunction func(level int, logID string, message string)
 
 var printLogHeader = false
 
@@ -117,6 +118,11 @@ func logf(level int, logID string, format string, v ...interface{}) {
 
     message := fmt.Sprintf(format, v...)
 
+    if LogFunction != nil {
+        LogFunction(level, logID, message)
+        return
+    }
+
     now := time.Now()
 
     // Uncomment this line to enable unbufferred logging for tests