From 35d8d0d8d886664c630f8e17128927e9f11d4f07 Mon Sep 17 00:00:00 2001
From: Peter Stuifzand <peter@stuifzand.eu>
Date: Mon, 10 Dec 2018 19:33:32 +0100
Subject: [PATCH] Add mutexes around saving the files

---
 cmd/hubserver/main.go | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/cmd/hubserver/main.go b/cmd/hubserver/main.go
index ca14a29..7e23cd2 100644
--- a/cmd/hubserver/main.go
+++ b/cmd/hubserver/main.go
@@ -13,6 +13,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -43,8 +44,11 @@ type Stat struct {
 }
 
 type subscriptionHandler struct {
+	LockSubs    sync.Mutex
 	Subscribers map[string][]Subscriber
-	Stats       map[string]Stat
+
+	LockStats sync.Mutex
+	Stats     map[string]Stat
 }
 
 func (handler *subscriptionHandler) handlePublish(w http.ResponseWriter, r *http.Request) error {
@@ -147,6 +151,7 @@ func (handler *subscriptionHandler) handleUnsubscription(w http.ResponseWriter,
 
 func (handler *subscriptionHandler) handleSubscription(w http.ResponseWriter, r *http.Request) error {
 	log.Printf("subscription request received: %s %#v\n", r.URL.String(), r.Form)
+
 	callback := r.Form.Get("hub.callback")
 	topic := r.Form.Get("hub.topic")
 	secret := r.Form.Get("hub.secret")
@@ -319,6 +324,9 @@ func (handler *subscriptionHandler) loadStats() error {
 }
 
 func (handler *subscriptionHandler) loadSubscriptions() error {
+	handler.LockStats.Lock()
+	defer handler.LockStats.Unlock()
+
 	file, err := os.Open("./subscription.json")
 	if err != nil {
 		if os.IsExist(err) {
@@ -343,6 +351,8 @@ func (handler *subscriptionHandler) load() error {
 }
 
 func (handler *subscriptionHandler) saveStats() error {
+	handler.LockStats.Lock()
+	defer handler.LockStats.Unlock()
 	file, err := os.Create("./stats.json")
 	if err != nil {
 		return err
@@ -355,6 +365,9 @@ func (handler *subscriptionHandler) saveStats() error {
 }
 
 func (handler *subscriptionHandler) saveSubscriptions() error {
+	handler.LockSubs.Lock()
+	defer handler.LockSubs.Unlock()
+
 	file, err := os.Create("./subscription.json")
 	if err != nil {
 		return err