Add MQTT select (#52120)

* Add MQTT select

* Fix value_template support

* Lint

homeassistant/components/mqtt/select.py

@@ -0,0 +1,171 @@
+"""Configure select in a device through MQTT topic."""
+import functools
+import logging
+
+import voluptuous as vol
+
+from homeassistant.components import select
+from homeassistant.components.select import SelectEntity
+from homeassistant.const import CONF_NAME, CONF_OPTIMISTIC, CONF_VALUE_TEMPLATE
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.helpers import config_validation as cv
+from homeassistant.helpers.reload import async_setup_reload_service
+from homeassistant.helpers.restore_state import RestoreEntity
+from homeassistant.helpers.typing import ConfigType
+
+from . import (
+    CONF_COMMAND_TOPIC,
+    CONF_QOS,
+    CONF_STATE_TOPIC,
+    DOMAIN,
+    PLATFORMS,
+    subscription,
+)
+from .. import mqtt
+from .const import CONF_RETAIN
+from .debug_info import log_messages
+from .mixins import MQTT_ENTITY_COMMON_SCHEMA, MqttEntity, async_setup_entry_helper
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_OPTIONS = "options"
+
+DEFAULT_NAME = "MQTT Select"
+DEFAULT_OPTIMISTIC = False
+
+
+def validate_config(config):
+    """Validate that the configuration is valid, throws if it isn't."""
+    if len(config[CONF_OPTIONS]) < 2:
+        raise vol.Invalid(f"'{CONF_OPTIONS}' must include at least 2 options")
+
+    return config
+
+
+PLATFORM_SCHEMA = vol.All(
+    mqtt.MQTT_RW_PLATFORM_SCHEMA.extend(
+        {
+            vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+            vol.Optional(CONF_OPTIMISTIC, default=DEFAULT_OPTIMISTIC): cv.boolean,
+            vol.Required(CONF_OPTIONS): cv.ensure_list,
+            vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
+        },
+    ).extend(MQTT_ENTITY_COMMON_SCHEMA.schema),
+    validate_config,
+)
+
+
+async def async_setup_platform(
+    hass: HomeAssistant, config: ConfigType, async_add_entities, discovery_info=None
+):
+    """Set up MQTT select through configuration.yaml."""
+    await async_setup_reload_service(hass, DOMAIN, PLATFORMS)
+    await _async_setup_entity(hass, async_add_entities, config)
+
+
+async def async_setup_entry(hass, config_entry, async_add_entities):
+    """Set up MQTT select dynamically through MQTT discovery."""
+    setup = functools.partial(
+        _async_setup_entity, hass, async_add_entities, config_entry=config_entry
+    )
+    await async_setup_entry_helper(hass, select.DOMAIN, setup, PLATFORM_SCHEMA)
+
+
+async def _async_setup_entity(
+    hass, async_add_entities, config, config_entry=None, discovery_data=None
+):
+    """Set up the MQTT select."""
+    async_add_entities([MqttSelect(hass, config, config_entry, discovery_data)])
+
+
+class MqttSelect(MqttEntity, SelectEntity, RestoreEntity):
+    """representation of an MQTT select."""
+
+    def __init__(self, hass, config, config_entry, discovery_data):
+        """Initialize the MQTT select."""
+        self._config = config
+        self._optimistic = False
+        self._sub_state = None
+
+        self._attr_current_option = None
+
+        SelectEntity.__init__(self)
+        MqttEntity.__init__(self, hass, config, config_entry, discovery_data)
+
+    @staticmethod
+    def config_schema():
+        """Return the config schema."""
+        return PLATFORM_SCHEMA
+
+    def _setup_from_config(self, config):
+        """(Re)Setup the entity."""
+        self._optimistic = config[CONF_OPTIMISTIC]
+        self._attr_options = config[CONF_OPTIONS]
+
+        value_template = self._config.get(CONF_VALUE_TEMPLATE)
+        if value_template is not None:
+            value_template.hass = self.hass
+
+    async def _subscribe_topics(self):
+        """(Re)Subscribe to topics."""
+
+        @callback
+        @log_messages(self.hass, self.entity_id)
+        def message_received(msg):
+            """Handle new MQTT messages."""
+            payload = msg.payload
+            value_template = self._config.get(CONF_VALUE_TEMPLATE)
+            if value_template is not None:
+                payload = value_template.async_render_with_possible_json_value(payload)
+
+            if payload not in self.options:
+                _LOGGER.error(
+                    "Invalid option for %s: '%s' (valid options: %s)",
+                    self.entity_id,
+                    payload,
+                    self.options,
+                )
+                return
+
+            self._attr_current_option = payload
+            self.async_write_ha_state()
+
+        if self._config.get(CONF_STATE_TOPIC) is None:
+            # Force into optimistic mode.
+            self._optimistic = True
+        else:
+            self._sub_state = await subscription.async_subscribe_topics(
+                self.hass,
+                self._sub_state,
+                {
+                    "state_topic": {
+                        "topic": self._config.get(CONF_STATE_TOPIC),
+                        "msg_callback": message_received,
+                        "qos": self._config[CONF_QOS],
+                    }
+                },
+            )
+
+        if self._optimistic:
+            last_state = await self.async_get_last_state()
+            if last_state:
+                self._attr_current_option = last_state.state
+
+    async def async_select_option(self, option: str) -> None:
+        """Update the current value."""
+        if self._optimistic:
+            self._attr_current_option = option
+            self.async_write_ha_state()
+
+        mqtt.async_publish(
+            self.hass,
+            self._config[CONF_COMMAND_TOPIC],
+            option,
+            self._config[CONF_QOS],
+            self._config[CONF_RETAIN],
+        )
+
+    @property
+    def assumed_state(self):
+        """Return true if we do optimistic updates."""
+        return self._optimistic