Prevent ping integration from blocking startup (#38504)

.coveragerc

@@ -636,6 +636,7 @@ omit =
     homeassistant/components/picotts/tts.py
     homeassistant/components/piglow/light.py
     homeassistant/components/pilight/*
+    homeassistant/components/ping/const.py
     homeassistant/components/ping/binary_sensor.py
     homeassistant/components/ping/device_tracker.py
     homeassistant/components/pioneer/media_player.py

homeassistant/components/ping/binary_sensor.py

@@ -10,9 +10,13 @@ import voluptuous as vol
 from homeassistant.components.binary_sensor import PLATFORM_SCHEMA, BinarySensorEntity
 from homeassistant.const import CONF_HOST, CONF_NAME
 import homeassistant.helpers.config_validation as cv
+from homeassistant.util.process import kill_subprocess
+
+from .const import PING_TIMEOUT
 
 _LOGGER = logging.getLogger(__name__)
 
+
 ATTR_ROUND_TRIP_TIME_AVG = "round_trip_time_avg"
 ATTR_ROUND_TRIP_TIME_MAX = "round_trip_time_max"
 ATTR_ROUND_TRIP_TIME_MDEV = "round_trip_time_mdev"
@@ -20,12 +24,14 @@ ATTR_ROUND_TRIP_TIME_MIN = "round_trip_time_min"
 
 CONF_PING_COUNT = "count"
 
-DEFAULT_NAME = "Ping Binary sensor"
+DEFAULT_NAME = "Ping"
 DEFAULT_PING_COUNT = 5
 DEFAULT_DEVICE_CLASS = "connectivity"
 
 SCAN_INTERVAL = timedelta(minutes=5)
 
+PARALLEL_UPDATES = 0
+
 PING_MATCHER = re.compile(
     r"(?P<min>\d+.\d+)\/(?P<avg>\d+.\d+)\/(?P<max>\d+.\d+)\/(?P<mdev>\d+.\d+)"
 )
@@ -39,17 +45,19 @@ WIN32_PING_MATCHER = re.compile(r"(?P<min>\d+)ms.+(?P<max>\d+)ms.+(?P<avg>\d+)ms
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
     {
         vol.Required(CONF_HOST): cv.string,
-        vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
-        vol.Optional(CONF_PING_COUNT, default=DEFAULT_PING_COUNT): cv.positive_int,
+        vol.Optional(CONF_NAME): cv.string,
+        vol.Optional(CONF_PING_COUNT, default=DEFAULT_PING_COUNT): vol.Range(
+            min=1, max=100
+        ),
     }
 )
 
 
 def setup_platform(hass, config, add_entities, discovery_info=None):
     """Set up the Ping Binary sensor."""
-    name = config.get(CONF_NAME)
-    host = config.get(CONF_HOST)
-    count = config.get(CONF_PING_COUNT)
+    host = config[CONF_HOST]
+    count = config[CONF_PING_COUNT]
+    name = config.get(CONF_NAME, f"{DEFAULT_NAME} {host}")
 
     add_entities([PingBinarySensor(name, PingData(host, count))], True)
 
@@ -129,7 +137,7 @@ class PingData:
             self._ping_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE
         )
         try:
-            out = pinger.communicate()
+            out = pinger.communicate(timeout=self._count + PING_TIMEOUT)
             _LOGGER.debug("Output is %s", str(out))
             if sys.platform == "win32":
                 match = WIN32_PING_MATCHER.search(str(out).split("\n")[-1])
@@ -142,6 +150,9 @@ class PingData:
             match = PING_MATCHER.search(str(out).split("\n")[-1])
             rtt_min, rtt_avg, rtt_max, rtt_mdev = match.groups()
             return {"min": rtt_min, "avg": rtt_avg, "max": rtt_max, "mdev": rtt_mdev}
+        except subprocess.TimeoutExpired:
+            kill_subprocess(pinger)
+            return False
         except (subprocess.CalledProcessError, AttributeError):
             return False
 

homeassistant/components/ping/const.py

@@ -0,0 +1,3 @@
+"""Tracks devices by sending a ICMP echo request (ping)."""
+
+PING_TIMEOUT = 3

homeassistant/components/ping/device_tracker.py

@@ -14,9 +14,13 @@ from homeassistant.components.device_tracker.const import (
     SOURCE_TYPE_ROUTER,
 )
 import homeassistant.helpers.config_validation as cv
+from homeassistant.util.process import kill_subprocess
+
+from .const import PING_TIMEOUT
 
 _LOGGER = logging.getLogger(__name__)
 
+PARALLEL_UPDATES = 0
 CONF_PING_COUNT = "count"
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
@@ -47,8 +51,12 @@ class Host:
             self._ping_cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL
         )
         try:
-            pinger.communicate()
+            pinger.communicate(timeout=1 + PING_TIMEOUT)
             return pinger.returncode == 0
+        except subprocess.TimeoutExpired:
+            kill_subprocess(pinger)
+            return False
+
         except subprocess.CalledProcessError:
             return False
 

homeassistant/util/process.py

@@ -0,0 +1,12 @@
+"""Util to handle processes."""
+
+import subprocess
+
+
+def kill_subprocess(process: subprocess.Popen) -> None:
+    """Force kill a subprocess and wait for it to exit."""
+    process.kill()
+    process.communicate()
+    process.wait()
+
+    del process

tests/util/test_process.py

@@ -0,0 +1,26 @@
+"""Test process util."""
+
+import os
+import subprocess
+
+import pytest
+
+from homeassistant.util import process
+
+
+async def test_kill_process():
+    """Test killing a process."""
+    sleeper = subprocess.Popen(
+        "sleep 1000",
+        shell=True,  # nosec # shell by design
+        stdout=subprocess.DEVNULL,
+        stderr=subprocess.DEVNULL,
+    )
+    pid = sleeper.pid
+
+    assert os.kill(pid, 0) is None
+
+    process.kill_subprocess(sleeper)
+
+    with pytest.raises(OSError):
+        os.kill(pid, 0)