From 65b31ca55191ba212cb4b5f4d8308789a287ba92 Mon Sep 17 00:00:00 2001
From: Michael Murphy <36900417+murphymj25@users.noreply.github.com>
Date: Wed, 17 Apr 2019 10:48:03 -0500
Subject: [PATCH] Fix Memory Leak in WatchBackend - fixes #595

---
 main.go            | 20 ++++++++++----------
 route/parse_new.go | 25 ++++++++++++++-----------
 route/table.go     |  3 +--
 3 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/main.go b/main.go
index d2481c982..a751626a7 100644
--- a/main.go
+++ b/main.go
@@ -432,6 +432,7 @@ func watchBackend(cfg *config.Config, first chan bool) {
 		svccfg   string
 		mancfg   string
 		customBE string
+		next     bytes.Buffer
 
 		once sync.Once
 	)
@@ -454,19 +455,21 @@ func watchBackend(cfg *config.Config, first chan bool) {
 		man := registry.Default.WatchManual()
 
 		for {
+
 			select {
 			case svccfg = <-svc:
 			case mancfg = <-man:
 			}
-
 			// manual config overrides service config
 			// order matters
-			next := svccfg + "\n" + mancfg
-			if next == last {
+			next.Reset()
+			next.WriteString(svccfg)
+			next.WriteString("\n")
+			next.WriteString(mancfg)
+			if next.String() == last {
 				continue
 			}
-
-			aliases, err := route.ParseAliases(next)
+			aliases, err := route.ParseAliases(next.String())
 			if err != nil {
 				log.Printf("[WARN]: %s", err)
 			}
@@ -478,14 +481,11 @@ func watchBackend(cfg *config.Config, first chan bool) {
 				continue
 			}
 			route.SetTable(t)
-			logRoutes(t, last, next, cfg.Log.RoutesFormat)
-			last = next
-
+			logRoutes(t, last, next.String(), cfg.Log.RoutesFormat)
+			last = next.String()
 			once.Do(func() { close(first) })
 		}
-
 	}
-
 }
 
 func watchNoRouteHTML(cfg *config.Config) {
diff --git a/route/parse_new.go b/route/parse_new.go
index 1ea9d5486..095343968 100644
--- a/route/parse_new.go
+++ b/route/parse_new.go
@@ -1,6 +1,8 @@
 package route
 
 import (
+	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
 	"regexp"
@@ -65,25 +67,26 @@ route weight service host/path weight w tags "tag1,tag2"
 // The commands are parsed in order and order matters.
 // Deleting a route that has not been created yet yields
 // a different result than the other way around.
-func Parse(in string) (defs []*RouteDef, err error) {
+func Parse(in bytes.Buffer) (defs []*RouteDef, err error) {
 	var def *RouteDef
-	for i, s := range strings.Split(in, "\n") {
+	scanner := bufio.NewScanner(&in)
+	for scanner.Scan() {
 		def, err = nil, nil
-		s = strings.TrimSpace(s)
+		result := strings.TrimSpace(scanner.Text())
 		switch {
-		case reComment.MatchString(s) || reBlankLine.MatchString(s):
+		case reComment.MatchString(result) || reBlankLine.MatchString(result):
 			continue
-		case reRouteAdd.MatchString(s):
-			def, err = parseRouteAdd(s)
-		case reRouteDel.MatchString(s):
-			def, err = parseRouteDel(s)
-		case reRouteWeight.MatchString(s):
-			def, err = parseRouteWeight(s)
+		case reRouteAdd.MatchString(result):
+			def, err = parseRouteAdd(result)
+		case reRouteDel.MatchString(result):
+			def, err = parseRouteDel(result)
+		case reRouteWeight.MatchString(result):
+			def, err = parseRouteWeight(result)
 		default:
 			err = errors.New("syntax error: 'route' expected")
 		}
 		if err != nil {
-			return nil, fmt.Errorf("line %d: %s", i+1, err)
+			return nil, fmt.Errorf("line %d: %s", err)
 		}
 		defs = append(defs, def)
 	}
diff --git a/route/table.go b/route/table.go
index 13c874289..ee0ce9d9c 100644
--- a/route/table.go
+++ b/route/table.go
@@ -108,8 +108,7 @@ func hostpath(prefix string) (host string, path string) {
 	return p[0], "/" + p[1]
 }
 
-func NewTable(s string) (t Table, err error) {
-
+func NewTable(s bytes.Buffer) (t Table, err error) {
 	defs, err := Parse(s)
 	if err != nil {
 		return nil, err