kvdb: add loggableKeyName method

Safely logs the bucket key name as hex if it includes special
characters.

Co-authored-by: Oliver Gugger <gugger@gmail.com>

kvdb/bolt_compact.go

@@ -8,6 +8,7 @@
 package kvdb
 
 import (
+	"encoding/hex"
 	"fmt"
 	"os"
 	"path"
@@ -228,6 +229,30 @@ func (cmd *compacter) walk(db *bbolt.DB, walkFn walkFunc) error {
 	})
 }
 
+// LoggableKeyName returns a printable name of the given key.
+func LoggableKeyName(key []byte) string {
+	strKey := string(key)
+	if hasSpecialChars(strKey) {
+		return hex.EncodeToString(key)
+	}
+
+	return strKey
+}
+
+// hasSpecialChars returns true if any of the characters in the given string
+// cannot be printed.
+func hasSpecialChars(s string) bool {
+	for _, b := range s {
+		if !(b >= 'a' && b <= 'z') && !(b >= 'A' && b <= 'Z') &&
+			!(b >= '0' && b <= '9') && b != '-' && b != '_' {
+
+			return true
+		}
+	}
+
+	return false
+}
+
 // walkBucket recursively walks through a bucket.
 func (cmd *compacter) walkBucket(b *bbolt.Bucket, keyPath [][]byte, k, v []byte,
 	seq uint64, fn walkFunc) error {