[sensor] Extend timeout filter with option to return last value received (#10115)

esphome/components/sensor/__init__.py

@@ -596,7 +596,7 @@ async def throttle_filter_to_code(config, filter_id):
     return cg.new_Pvariable(filter_id, config)
 
 
-TIMEOUT_WITH_PRIORITY_SCHEMA = cv.maybe_simple_value(
+THROTTLE_WITH_PRIORITY_SCHEMA = cv.maybe_simple_value(
     {
         cv.Required(CONF_TIMEOUT): cv.positive_time_period_milliseconds,
         cv.Optional(CONF_VALUE, default="nan"): cv.Any(
@@ -610,7 +610,7 @@ TIMEOUT_WITH_PRIORITY_SCHEMA = cv.maybe_simple_value(
 @FILTER_REGISTRY.register(
     "throttle_with_priority",
     ThrottleWithPriorityFilter,
-    TIMEOUT_WITH_PRIORITY_SCHEMA,
+    THROTTLE_WITH_PRIORITY_SCHEMA,
 )
 async def throttle_with_priority_filter_to_code(config, filter_id):
     if not isinstance(config[CONF_VALUE], list):
@@ -631,7 +631,9 @@ async def heartbeat_filter_to_code(config, filter_id):
 TIMEOUT_SCHEMA = cv.maybe_simple_value(
     {
         cv.Required(CONF_TIMEOUT): cv.positive_time_period_milliseconds,
-        cv.Optional(CONF_VALUE, default="nan"): cv.templatable(cv.float_),
+        cv.Optional(CONF_VALUE, default="nan"): cv.Any(
+            "last", cv.templatable(cv.float_)
+        ),
     },
     key=CONF_TIMEOUT,
 )
@@ -639,8 +641,11 @@ TIMEOUT_SCHEMA = cv.maybe_simple_value(
 
 @FILTER_REGISTRY.register("timeout", TimeoutFilter, TIMEOUT_SCHEMA)
 async def timeout_filter_to_code(config, filter_id):
-    template_ = await cg.templatable(config[CONF_VALUE], [], float)
-    var = cg.new_Pvariable(filter_id, config[CONF_TIMEOUT], template_)
+    if config[CONF_VALUE] == "last":
+        var = cg.new_Pvariable(filter_id, config[CONF_TIMEOUT])
+    else:
+        template_ = await cg.templatable(config[CONF_VALUE], [], float)
+        var = cg.new_Pvariable(filter_id, config[CONF_TIMEOUT], template_)
     await cg.register_component(var, {})
     return var
 

esphome/components/sensor/filter.cpp

@@ -417,12 +417,17 @@ void OrFilter::initialize(Sensor *parent, Filter *next) {
 
 // TimeoutFilter
 optional<float> TimeoutFilter::new_value(float value) {
-  this->set_timeout("timeout", this->time_period_, [this]() { this->output(this->value_.value()); });
+  if (this->value_.has_value()) {
+    this->set_timeout("timeout", this->time_period_, [this]() { this->output(this->value_.value().value()); });
+  } else {
+    this->set_timeout("timeout", this->time_period_, [this, value]() { this->output(value); });
+  }
   return value;
 }
 
-TimeoutFilter::TimeoutFilter(uint32_t time_period, TemplatableValue<float> new_value)
-    : time_period_(time_period), value_(std::move(new_value)) {}
+TimeoutFilter::TimeoutFilter(uint32_t time_period) : time_period_(time_period) {}
+TimeoutFilter::TimeoutFilter(uint32_t time_period, const TemplatableValue<float> &new_value)
+    : time_period_(time_period), value_(new_value) {}
 float TimeoutFilter::get_setup_priority() const { return setup_priority::HARDWARE; }
 
 // DebounceFilter

esphome/components/sensor/filter.h

@@ -330,7 +330,8 @@ class ThrottleWithPriorityFilter : public Filter {
 
 class TimeoutFilter : public Filter, public Component {
  public:
-  explicit TimeoutFilter(uint32_t time_period, TemplatableValue<float> new_value);
+  explicit TimeoutFilter(uint32_t time_period);
+  explicit TimeoutFilter(uint32_t time_period, const TemplatableValue<float> &new_value);
 
   optional<float> new_value(float value) override;
 
@@ -338,7 +339,7 @@ class TimeoutFilter : public Filter, public Component {
 
  protected:
   uint32_t time_period_;
-  TemplatableValue<float> value_;
+  optional<TemplatableValue<float>> value_;
 };
 
 class DebounceFilter : public Filter, public Component {

tests/components/template/common.yaml

@@ -153,6 +153,9 @@ sensor:
       - timeout:
           timeout: 1h
           value: 20.0
+      - timeout:
+          timeout: 1min
+          value: last
       - timeout:
           timeout: 1d
       - to_ntc_resistance: