From 1e9b3ed35463b64446495dd5d85147fd20edde10 Mon Sep 17 00:00:00 2001
From: Holger Cremer <HolgerCremer@gmail.com>
Date: Tue, 12 Jun 2018 17:36:28 +0200
Subject: [PATCH] adds missing watch do file ;)

---
 mqtt/watchDog.go | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 mqtt/watchDog.go

diff --git a/mqtt/watchDog.go b/mqtt/watchDog.go
new file mode 100644
index 0000000..a62f2cd
--- /dev/null
+++ b/mqtt/watchDog.go
@@ -0,0 +1,60 @@
+package mqtt
+
+import (
+	"time"
+	"github.com/sirupsen/logrus"
+	"os"
+)
+
+type watchDog struct {
+	timeout time.Duration
+	ping    chan struct{}
+	stop    chan struct{}
+}
+
+var wdLogger = logrus.WithField("where", "watchDog")
+
+// NewWatchDog creates a new watch dog
+// timeout - after this amount of time without a ping, the program will be killed and returns 3
+func NewWatchDog(timeout time.Duration) *watchDog {
+	wd := watchDog{
+		timeout: timeout,
+		ping:    make(chan struct{}),
+		stop:    make(chan struct{}),
+	}
+
+	go wd.loop()
+
+	return &wd
+}
+
+// Ping updates the watch dog timeout
+func (wd *watchDog) Ping() {
+	wd.ping <- struct{}{}
+}
+
+func (wd *watchDog) Stop() {
+	wdLogger.Println("Stopping watch dog")
+	wd.stop <- struct{}{}
+}
+
+func (wd *watchDog) loop() {
+	timer := time.NewTicker(60 * time.Second)
+	lastKeepAlive := time.Now()
+
+	for {
+		select {
+		case <-timer.C:
+			if time.Since(lastKeepAlive) > wd.timeout {
+				wdLogger.Errorf("Last keep alive (%s) is older than allowed timeout (%s). Exit!",
+					lastKeepAlive, wd.timeout)
+				os.Exit(3)
+			}
+		case <-wd.ping:
+			lastKeepAlive = time.Now()
+		case <-wd.stop:
+			timer.Stop()
+			return
+		}
+	}
+}