Add -dump flag to help troubleshooting

main.go

@@ -18,6 +18,7 @@ import (
 var Flags struct {
 	ConfigFile string
 	LogFile    string
+	DumpFile   string
 	Verbose    bool
 }
 
@@ -164,6 +165,7 @@ func Rewrite(t *trie.Trie) {
 func init() {
 	flag.StringVar(&Flags.ConfigFile, "c", "", "Path to rewrite config file")
 	flag.StringVar(&Flags.LogFile, "l", "", "Path to log file")
+	flag.StringVar(&Flags.DumpFile, "dump", "", "Path to dump file")
 	flag.BoolVar(&Flags.Verbose, "v", false, "Verbose logging")
 }
 
@@ -196,6 +198,16 @@ func LoadRewrites() *trie.Trie {
 	elapsed := time.Since(start)
 	L.Printf("Loaded %d unique rewrites in %s", t.Count(), elapsed)
 
+	if Flags.DumpFile != "" {
+		file, err := os.OpenFile(Flags.DumpFile, os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			L.Fatal(err)
+		}
+		defer file.Close()
+
+		t.Dump(file)
+	}
+
 	return t
 }
 

trie/trie.go

@@ -1,5 +1,10 @@
 package trie
 
+import (
+	"fmt"
+	"io"
+)
+
 func commonPrefixLength(s1 string, s2 string) int {
 	var i, l int
 
@@ -39,6 +44,21 @@ func (t *Trie) Count() int {
 	return r
 }
 
+func (t *Trie) dump(prefix string, w io.Writer) {
+	for chunk, subTrie := range t.children {
+		newPrefix := prefix + chunk
+		if subTrie.value != nil {
+			line := fmt.Sprintf("%s %s\n", newPrefix, subTrie.value)
+			w.Write([]byte(line))
+		}
+		subTrie.dump(newPrefix, w)
+	}
+}
+
+func (t *Trie) Dump(w io.Writer) {
+	t.dump("", w)
+}
+
 func (t *Trie) Put(key string, value interface{}) {
 	currentKey := key
 	currentTrie := t