Add support for Sensor state class (#1835)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/sensor/__init__.py

@@ -22,6 +22,7 @@ from esphome.const import (
     CONF_ON_VALUE_RANGE,
     CONF_SEND_EVERY,
     CONF_SEND_FIRST_AT,
+    CONF_STATE_CLASS,
     CONF_TO,
     CONF_TRIGGER_ID,
     CONF_UNIT_OF_MEASUREMENT,
@@ -46,6 +47,7 @@ from esphome.const import (
     DEVICE_CLASS_PRESSURE,
     DEVICE_CLASS_TIMESTAMP,
     DEVICE_CLASS_VOLTAGE,
+    STATE_CLASS_NONE,
 )
 from esphome.core import CORE, coroutine_with_priority
 from esphome.util import Registry
@@ -69,6 +71,14 @@ DEVICE_CLASSES = [
     DEVICE_CLASS_VOLTAGE,
 ]
 
+sensor_ns = cg.esphome_ns.namespace("sensor")
+StateClasses = sensor_ns.enum("StateClass")
+STATE_CLASSES = {
+    "": StateClasses.STATE_CLASS_NONE,
+    "measurement": StateClasses.STATE_CLASS_MEASUREMENT,
+}
+validate_state_class = cv.enum(STATE_CLASSES, lower=True, space="_")
+
 IS_PLATFORM_COMPONENT = True
 
 
@@ -157,6 +167,7 @@ SENSOR_SCHEMA = cv.MQTT_COMPONENT_SCHEMA.extend(
         cv.Optional(CONF_ICON): icon,
         cv.Optional(CONF_ACCURACY_DECIMALS): accuracy_decimals,
         cv.Optional(CONF_DEVICE_CLASS): device_class,
+        cv.Optional(CONF_STATE_CLASS): validate_state_class,
         cv.Optional(CONF_FORCE_UPDATE, default=False): cv.boolean,
         cv.Optional(CONF_EXPIRE_AFTER): cv.All(
             cv.requires_component("mqtt"),
@@ -190,6 +201,7 @@ def sensor_schema(
     icon_: str,
     accuracy_decimals_: int,
     device_class_: Optional[str] = DEVICE_CLASS_EMPTY,
+    state_class_: Optional[str] = STATE_CLASS_NONE,
 ) -> cv.Schema:
     schema = SENSOR_SCHEMA
     if unit_of_measurement_ != UNIT_EMPTY:
@@ -214,6 +226,10 @@ def sensor_schema(
         schema = schema.extend(
             {cv.Optional(CONF_DEVICE_CLASS, default=device_class_): device_class}
         )
+    if state_class_ != STATE_CLASS_NONE:
+        schema = schema.extend(
+            {cv.Optional(CONF_STATE_CLASS, default=state_class_): validate_state_class}
+        )
     return schema
 
 
@@ -455,6 +471,8 @@ async def setup_sensor_core_(var, config):
         cg.add(var.set_internal(config[CONF_INTERNAL]))
     if CONF_DEVICE_CLASS in config:
         cg.add(var.set_device_class(config[CONF_DEVICE_CLASS]))
+    if CONF_STATE_CLASS in config:
+        cg.add(var.set_state_class(config[CONF_STATE_CLASS]))
     if CONF_UNIT_OF_MEASUREMENT in config:
         cg.add(var.set_unit_of_measurement(config[CONF_UNIT_OF_MEASUREMENT]))
     if CONF_ICON in config:

esphome/components/sensor/sensor.cpp

@@ -6,6 +6,16 @@ namespace sensor {
 
 static const char *TAG = "sensor";
 
+const char *state_class_to_string(StateClass state_class) {
+  switch (state_class) {
+    case STATE_CLASS_MEASUREMENT:
+      return "measurement";
+    case STATE_CLASS_NONE:
+    default:
+      return "";
+  }
+}
+
 void Sensor::publish_state(float state) {
   this->raw_state = state;
   this->raw_callback_.call(state);
@@ -47,6 +57,14 @@ std::string Sensor::get_device_class() {
   return this->device_class();
 }
 std::string Sensor::device_class() { return ""; }
+void Sensor::set_state_class(StateClass state_class) { this->state_class = state_class; }
+void Sensor::set_state_class(const std::string &state_class) {
+  if (str_equals_case_insensitive(state_class, "measurement")) {
+    this->state_class = STATE_CLASS_MEASUREMENT;
+  } else {
+    ESP_LOGW(TAG, "'%s' - Unrecognized state class %s", this->get_name().c_str(), state_class.c_str());
+  }
+}
 std::string Sensor::get_unit_of_measurement() {
   if (this->unit_of_measurement_.has_value())
     return *this->unit_of_measurement_;

esphome/components/sensor/sensor.h

@@ -13,6 +13,7 @@ namespace sensor {
     if (!obj->get_device_class().empty()) { \
       ESP_LOGCONFIG(TAG, "%s  Device Class: '%s'", prefix, obj->get_device_class().c_str()); \
     } \
+    ESP_LOGCONFIG(TAG, "%s  State Class: '%s'", prefix, state_class_to_string(obj->state_class)); \
     ESP_LOGCONFIG(TAG, "%s  Unit of Measurement: '%s'", prefix, obj->get_unit_of_measurement().c_str()); \
     ESP_LOGCONFIG(TAG, "%s  Accuracy Decimals: %d", prefix, obj->get_accuracy_decimals()); \
     if (!obj->get_icon().empty()) { \
@@ -26,6 +27,16 @@ namespace sensor {
     } \
   }
 
+/**
+ * Sensor state classes
+ */
+enum StateClass : uint8_t {
+  STATE_CLASS_NONE = 0,
+  STATE_CLASS_MEASUREMENT = 1,
+};
+
+const char *state_class_to_string(StateClass state_class);
+
 /** Base-class for all sensors.
  *
  * A sensor has unit of measurement and can use publish_state to send out a new value with the specified accuracy.
@@ -139,6 +150,13 @@ class Sensor : public Nameable {
   /// Return whether this sensor has gotten a full state (that passed through all filters) yet.
   bool has_state() const;
 
+  // The state class of this sensor state
+  StateClass state_class{STATE_CLASS_NONE};
+
+  /// Manually set the Home Assistant state class (see sensor::state_class)
+  void set_state_class(StateClass state_class);
+  void set_state_class(const std::string &state_class);
+
   /** Override this to set the Home Assistant device class for this sensor.
    *
    * Return "" to disable this feature.