File sensor (#7569)

* Add File sensor

* Use None and return

* Remove I/O

* Use less memory

* No traceback if file is empty

homeassistant/components/sensor/file.py

@@ -0,0 +1,98 @@
+"""
+Support for sensor value(s) stored in local files.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.file/
+"""
+import os
+import asyncio
+import logging
+
+import voluptuous as vol
+
+import homeassistant.helpers.config_validation as cv
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.const import (
+    CONF_VALUE_TEMPLATE, CONF_NAME, CONF_UNIT_OF_MEASUREMENT)
+from homeassistant.helpers.entity import Entity
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_FILE_PATH = 'file_path'
+
+DEFAULT_NAME = 'File'
+
+ICON = 'mdi:file'
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Required(CONF_FILE_PATH): cv.string,
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
+    vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
+})
+
+
+@asyncio.coroutine
+def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
+    """Set up the file sensor."""
+    file_path = config.get(CONF_FILE_PATH)
+    name = config.get(CONF_NAME)
+    unit = config.get(CONF_UNIT_OF_MEASUREMENT)
+    value_template = config.get(CONF_VALUE_TEMPLATE)
+
+    if value_template is not None:
+        value_template.hass = hass
+
+    async_add_devices(
+        [FileSensor(name, file_path, unit, value_template)], True)
+
+
+class FileSensor(Entity):
+    """Implementation of a file sensor."""
+
+    def __init__(self, name, file_path, unit_of_measurement, value_template):
+        """Initialize the file sensor."""
+        self._name = name
+        self._file_path = file_path
+        self._unit_of_measurement = unit_of_measurement
+        self._val_tpl = value_template
+        self._state = None
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit the value is expressed in."""
+        return self._unit_of_measurement
+
+    @property
+    def icon(self):
+        """Return the icon to use in the frontend, if any."""
+        return ICON
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state
+
+    def update(self):
+        """Get the latest entry from a file and updates the state."""
+        try:
+            with open(self._file_path, 'r', encoding='utf-8') as file_data:
+                for line in file_data:
+                    data = line
+                data = data.strip()
+        except (IndexError, FileNotFoundError, IsADirectoryError,
+                UnboundLocalError):
+            _LOGGER.warning("File or data not present at the moment: %s",
+                            os.path.basename(self._file_path))
+            return
+
+        if self._val_tpl is not None:
+            self._state = self._val_tpl.async_render_with_possible_json_value(
+                data, None)
+        else:
+            self._state = data

tests/components/sensor/test_file.py

@@ -0,0 +1,91 @@
+"""The tests for local file sensor platform."""
+import unittest
+from unittest.mock import Mock, patch
+
+# Using third party package because of a bug reading binary data in Python 3.4
+# https://bugs.python.org/issue23004
+from mock_open import MockOpen
+
+from homeassistant.setup import setup_component
+from homeassistant.const import STATE_UNKNOWN
+
+from tests.common import get_test_home_assistant
+
+
+class TestFileSensor(unittest.TestCase):
+    """Test the File sensor."""
+
+    def setup_method(self, method):
+        """Set up things to be run when tests are started."""
+        self.hass = get_test_home_assistant()
+
+    def teardown_method(self, method):
+        """Stop everything that was started."""
+        self.hass.stop()
+
+    @patch('os.path.isfile', Mock(return_value=True))
+    @patch('os.access', Mock(return_value=True))
+    def test_file_value(self):
+        """Test the File sensor."""
+        config = {
+            'sensor': {
+                'platform': 'file',
+                'name': 'file1',
+                'file_path': 'mock.file1',
+            }
+        }
+
+        m_open = MockOpen(read_data='43\n45\n21')
+        with patch('homeassistant.components.sensor.file.open', m_open,
+                   create=True):
+            assert setup_component(self.hass, 'sensor', config)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('sensor.file1')
+        self.assertEqual(state.state, '21')
+
+    @patch('os.path.isfile', Mock(return_value=True))
+    @patch('os.access', Mock(return_value=True))
+    def test_file_value_template(self):
+        """Test the File sensor with JSON entries."""
+        config = {
+            'sensor': {
+                'platform': 'file',
+                'name': 'file2',
+                'file_path': 'mock.file2',
+                'value_template': '{{ value_json.temperature }}',
+            }
+        }
+
+        data = '{"temperature": 29, "humidity": 31}\n' \
+               '{"temperature": 26, "humidity": 36}'
+
+        m_open = MockOpen(read_data=data)
+        with patch('homeassistant.components.sensor.file.open', m_open,
+                   create=True):
+            assert setup_component(self.hass, 'sensor', config)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('sensor.file2')
+        self.assertEqual(state.state, '26')
+
+    @patch('os.path.isfile', Mock(return_value=True))
+    @patch('os.access', Mock(return_value=True))
+    def test_file_empty(self):
+        """Test the File sensor with an empty file."""
+        config = {
+            'sensor': {
+                'platform': 'file',
+                'name': 'file3',
+                'file_path': 'mock.file',
+            }
+        }
+
+        m_open = MockOpen(read_data='')
+        with patch('homeassistant.components.sensor.file.open', m_open,
+                   create=True):
+            assert setup_component(self.hass, 'sensor', config)
+            self.hass.block_till_done()
+
+        state = self.hass.states.get('sensor.file3')
+        self.assertEqual(state.state, STATE_UNKNOWN)