From 6cbe28a9cd4d68487c754107a30ac53df507faa8 Mon Sep 17 00:00:00 2001
From: Anders Melchiorsen <amelchio@nogoto.net>
Date: Sun, 16 Apr 2017 04:00:01 +0200
Subject: [PATCH] Send stderr of ping tracker to devnull (#7096)

When pinging an inaccessible device, OS errors like

    ping: sendto: No route to host

can occur. For a ping tracker this is not an error but rather a normal
situation. Thus, it makes sense to hide the error.
---
 homeassistant/components/device_tracker/ping.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/homeassistant/components/device_tracker/ping.py b/homeassistant/components/device_tracker/ping.py
index 7c217b7aabb..ee9a4d19d37 100644
--- a/homeassistant/components/device_tracker/ping.py
+++ b/homeassistant/components/device_tracker/ping.py
@@ -45,7 +45,9 @@ class Host(object):
 
     def ping(self):
         """Send an ICMP echo request and return True if success."""
-        pinger = subprocess.Popen(self._ping_cmd, stdout=subprocess.PIPE)
+        pinger = subprocess.Popen(self._ping_cmd,
+                                  stdout=subprocess.PIPE,
+                                  stderr=subprocess.DEVNULL)
         try:
             pinger.communicate()
             return pinger.returncode == 0