Add sensor platform to Tailscale (#60751)

Co-authored-by: Martin Hjelmare <marhje52@gmail.com>

homeassistant/components/tailscale/sensor.py

@@ -0,0 +1,73 @@
+"""Support for Tailscale sensors."""
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from datetime import datetime
+
+from tailscale import Device as TailscaleDevice
+
+from homeassistant.components.sensor import (
+    SensorDeviceClass,
+    SensorEntity,
+    SensorEntityDescription,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+
+from . import TailscaleEntity
+from .const import DOMAIN
+
+
+@dataclass
+class TailscaleSensorEntityDescriptionMixin:
+    """Mixin for required keys."""
+
+    value_fn: Callable[[TailscaleDevice], datetime | None]
+
+
+@dataclass
+class TailscaleSensorEntityDescription(
+    SensorEntityDescription, TailscaleSensorEntityDescriptionMixin
+):
+    """Describes a Tailscale sensor entity."""
+
+
+SENSORS: tuple[TailscaleSensorEntityDescription, ...] = (
+    TailscaleSensorEntityDescription(
+        key="expires",
+        name="Expires",
+        device_class=SensorDeviceClass.TIMESTAMP,
+        value_fn=lambda device: device.expires,
+    ),
+)
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up a Tailscale sensors based on a config entry."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+    async_add_entities(
+        TailscaleSensorEntity(
+            coordinator=coordinator,
+            device=device,
+            description=description,
+        )
+        for device in coordinator.data.values()
+        for description in SENSORS
+    )
+
+
+class TailscaleSensorEntity(TailscaleEntity, SensorEntity):
+    """Defines a Tailscale sensor."""
+
+    entity_description: TailscaleSensorEntityDescription
+
+    @property
+    def native_value(self) -> datetime | None:
+        """Return the state of the sensor."""
+        return self.entity_description.value_fn(self.coordinator.data[self.device_id])