sensor.py

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"""Support for sensor value(s) stored in local files."""
 
from __future__ import annotations
 
import logging
import os
 
from file_read_backwards import FileReadBackwards
 
from homeassistant.components.sensor import SensorEntity
from homeassistant.config_entries import ConfigEntry
from homeassistant.const import (
    CONF_FILE_PATH,
    CONF_NAME,
    CONF_UNIT_OF_MEASUREMENT,
    CONF_VALUE_TEMPLATE,
)
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.template import Template
 
from .const import DEFAULT_NAME, FILE_ICON
 
_LOGGER = logging.getLogger(__name__)
 
 
async def async_setup_entry(
    hass: HomeAssistant,
    entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up the file sensor."""
    config = dict(entry.data)
    options = dict(entry.options)
    file_path: str = config[CONF_FILE_PATH]
    unique_id: str = entry.entry_id
    name: str = config.get(CONF_NAME, DEFAULT_NAME)
    unit: str | None = options.get(CONF_UNIT_OF_MEASUREMENT)
    value_template: Template | None = None
 
    if CONF_VALUE_TEMPLATE in options:
        value_template = Template(options[CONF_VALUE_TEMPLATE], hass)
 
    async_add_entities(
        [FileSensor(unique_id, name, file_path, unit, value_template)], True
    )
 
 
class FileSensor(SensorEntity):
    """Implementation of a file sensor."""
 
    _attr_icon = FILE_ICON
 
    def __init__(
        self,
        unique_id: str,
        name: str,
        file_path: str,
        unit_of_measurement: str | None,
        value_template: Template | None,
    ) -> None:
        """Initialize the file sensor."""
        self._attr_name_attr_name = name
        self._file_path_file_path = file_path
        self._attr_native_unit_of_measurement_attr_native_unit_of_measurement = unit_of_measurement
        self._val_tpl_val_tpl = value_template
        self._attr_unique_id_attr_unique_id = unique_id
 
    def update(self) -> None:
        """Get the latest entry from a file and updates the state."""
        try:
            with FileReadBackwards(self._file_path_file_path, encoding="utf-8") as file_data:
                for line in file_data:
                    data = line
                    break
                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_file_path),
            )
            return
 
        if self._val_tpl_val_tpl is not None:
            self._attr_native_value_attr_native_value = (
                self._val_tpl_val_tpl.async_render_with_possible_json_value(data, None)
            )
        else:
            self._attr_native_value_attr_native_value = data