Add new rtorrent sensor (#17421)

* New rtorrent sensor

* Fix lint issue

* Fix another lint issue

* Fix pylint issue

* how many python linters do you guys use

* Cleanup code

* python linting

* newline

.coveragerc

@@ -757,6 +757,7 @@ omit =
     homeassistant/components/sensor/radarr.py
     homeassistant/components/sensor/rainbird.py
     homeassistant/components/sensor/ripple.py
+    homeassistant/components/sensor/rtorrent.py
     homeassistant/components/sensor/scrape.py
     homeassistant/components/sensor/sense.py
     homeassistant/components/sensor/sensehat.py

homeassistant/components/sensor/rtorrent.py

@@ -0,0 +1,127 @@
+"""Support for monitoring the rtorrent BitTorrent client API."""
+import logging
+import xmlrpc.client
+
+import voluptuous as vol
+
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.const import (
+    CONF_URL, CONF_NAME,
+    CONF_MONITORED_VARIABLES, STATE_IDLE)
+from homeassistant.helpers.entity import Entity
+import homeassistant.helpers.config_validation as cv
+from homeassistant.exceptions import PlatformNotReady
+
+_LOGGER = logging.getLogger(__name__)
+
+SENSOR_TYPE_CURRENT_STATUS = 'current_status'
+SENSOR_TYPE_DOWNLOAD_SPEED = 'download_speed'
+SENSOR_TYPE_UPLOAD_SPEED = 'upload_speed'
+
+DEFAULT_NAME = 'rtorrent'
+SENSOR_TYPES = {
+    SENSOR_TYPE_CURRENT_STATUS: ['Status', None],
+    SENSOR_TYPE_DOWNLOAD_SPEED: ['Down Speed', 'kB/s'],
+    SENSOR_TYPE_UPLOAD_SPEED: ['Up Speed', 'kB/s'],
+}
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Required(CONF_URL): cv.url,
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_MONITORED_VARIABLES, default=[]): vol.All(
+        cv.ensure_list, [vol.In(SENSOR_TYPES)]),
+})
+
+
+def setup_platform(hass, config, add_entities, discovery_info=None):
+    """Set up the rtorrent sensors."""
+    url = config[CONF_URL]
+    name = config[CONF_NAME]
+
+    try:
+        rtorrent = xmlrpc.client.ServerProxy(url)
+    except (xmlrpc.client.ProtocolError, ConnectionRefusedError):
+        _LOGGER.error("Connection to rtorrent daemon failed")
+        raise PlatformNotReady
+    dev = []
+    for variable in config[CONF_MONITORED_VARIABLES]:
+        dev.append(RTorrentSensor(variable, rtorrent, name))
+
+    add_entities(dev)
+
+
+def format_speed(speed):
+    """Return a bytes/s measurement as a human readable string."""
+    kb_spd = float(speed) / 1024
+    return round(kb_spd, 2 if kb_spd < 0.1 else 1)
+
+
+class RTorrentSensor(Entity):
+    """Representation of an rtorrent sensor."""
+
+    def __init__(self, sensor_type, rtorrent_client, client_name):
+        """Initialize the sensor."""
+        self._name = SENSOR_TYPES[sensor_type][0]
+        self.client = rtorrent_client
+        self.type = sensor_type
+        self.client_name = client_name
+        self._state = None
+        self._unit_of_measurement = SENSOR_TYPES[sensor_type][1]
+        self.data = None
+        self._available = False
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return '{} {}'.format(self.client_name, self._name)
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state
+
+    @property
+    def available(self):
+        """Return true if device is available."""
+        return self._available
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit of measurement of this entity, if any."""
+        return self._unit_of_measurement
+
+    def update(self):
+        """Get the latest data from rtorrent and updates the state."""
+        multicall = xmlrpc.client.MultiCall(self.client)
+        multicall.throttle.global_up.rate()
+        multicall.throttle.global_down.rate()
+
+        try:
+            self.data = multicall()
+            self._available = True
+        except (xmlrpc.client.ProtocolError, ConnectionRefusedError):
+            _LOGGER.error("Connection to rtorrent lost")
+            self._available = False
+            return
+
+        upload = self.data[0]
+        download = self.data[1]
+
+        if self.type == SENSOR_TYPE_CURRENT_STATUS:
+            if self.data:
+                if upload > 0 and download > 0:
+                    self._state = 'Up/Down'
+                elif upload > 0 and download == 0:
+                    self._state = 'Seeding'
+                elif upload == 0 and download > 0:
+                    self._state = 'Downloading'
+                else:
+                    self._state = STATE_IDLE
+            else:
+                self._state = None
+
+        if self.data:
+            if self.type == SENSOR_TYPE_DOWNLOAD_SPEED:
+                self._state = format_speed(download)
+            elif self.type == SENSOR_TYPE_UPLOAD_SPEED:
+                self._state = format_speed(upload)