chore: upgrade various dependencies and lockfile

Cargo.toml

@@ -5,6 +5,7 @@ members = [
     "emitter-and-signal",
     "entrypoint",
     "home-assistant",
+    "persisted",
     "protocol",
     "python-utils",
 ]
@@ -14,17 +15,22 @@ resolver = "2"
 license = "Unlicense"
 
 [workspace.dependencies]
-backon = "1.5"
-chrono = "0.4.40"
-chrono-tz = "0.10.1"
-deranged = "0.4"
-derive_more = "2.0.1"
-ext-trait = "2.0.0"
+backon = "1.6"
+bytes = "1.11"
+chrono = "0.4.42"
+chrono-tz = "0.10.4"
+deranged = "0.5"
+derive_more = "2.1.0"
+ext-trait = "2.0.1"
+mitsein = "0.8"
 palette = "0.7"
-pyo3 = "0.24.0"
-pyo3-async-runtimes = "0.24.0"
-serde = "1.0.219"
-snafu = "0.8.5"
-strum = "0.27.1"
-tokio = "1.32.0"
-tracing = "0.1.37"
+pyo3 = "0.27"
+pyo3-async-runtimes = "0.27"
+serde = "1.0.228"
+snafu = "0.8.9"
+strum = "0.27.2"
+tokio = "1.48.0"
+tracing = "0.1.43"
+typed-builder = "0.22"
+typed-builder-macro = "0.22"
+url = "2.5"

entrypoint/Cargo.toml

@@ -21,8 +21,9 @@ clap = { version = "4", features = ["derive", "env"] }
 deranged = { workspace = true, features = ["serde"] }
 driver-kasa = { path = "../driver/kasa" }
 emitter-and-signal = { path = "../emitter-and-signal" }
-home-assistant = { path = "../home-assistant" }
+home-assistant = { path = "../home-assistant", features = ["tracing"] }
 im = { version = "15.1.0", features = ["rayon"] }
+persisted = { path = "../persisted" }
 protocol = { path = "../protocol" }
 pyo3 = { workspace = true, features = [
     "auto-initialize",

entrypoint/src/lib.rs

@@ -1,14 +1,16 @@
-use std::{path::PathBuf, str::FromStr, time::Duration};
+use std::{num::NonZeroUsize, path::PathBuf, str::FromStr, time::Duration};
 
 use clap::Parser;
 use driver_kasa::connection::LB130USHandle;
 use home_assistant::{
-    home_assistant::HomeAssistant, light::HomeAssistantLight, object_id::ObjectId,
+    event::context::context::Context, home_assistant::HomeAssistant, light::HomeAssistantLight,
+    notify::service::mobile_app::StandardNotification, object_id::ObjectId,
 };
+use persisted::{persisted, Config, Keyspace, Partition, PartitionCreateOptions};
 use protocol::light::{IsOff, IsOn};
 use pyo3::prelude::*;
 use shadow_rs::shadow;
-use tokio::time::interval;
+use tokio::{task::spawn_blocking, time::interval};
 use tracing::{level_filters::LevelFilter, Level};
 use tracing_appender::rolling::{self, RollingFileAppender};
 use tracing_subscriber::{
@@ -100,28 +102,49 @@ async fn real_main(
     //     object_id: ObjectId::from_str("jacob_s_lamp_side").unwrap(),
     // };
 
-    let ip = [10, 0, 3, 71];
-    let port = 9999;
+    // let ip = [10, 0, 3, 71];
+    // let port = 9999;
 
-    let some_light = LB130USHandle::new(
-        (ip, port).into(),
-        Duration::from_secs(10),
-        (64).try_into().unwrap(),
-    );
+    // let some_light = LB130USHandle::new(
+    //     (ip, port).into(),
+    //     Duration::from_secs(10),
+    //     (64).try_into().unwrap(),
+    // );
 
-    let mut interval = interval(Duration::from_secs(20));
-    interval.tick().await;
+    let mut int = interval(Duration::from_secs(170));
+    let mut value = 0;
+
+    tokio::time::sleep(Duration::from_secs(15)).await;
+
+    let services = Python::attach(|py| home_assistant.services(py)).unwrap();
     loop {
-        interval.tick().await;
+        int.tick().await;
 
-        tracing::info!("about to call get_sysinfo");
-        let sysinfo_res = some_light.get_sysinfo().await;
-        tracing::info!(?sysinfo_res, "got sys info");
+        tracing::debug!(?value);
+        // let service_result: Result<Py<PyAny>, _> = services
+        //     .call_service(
+        //         StandardNotification::builder()
+        //             .object_id(ObjectId("galaxy_s21_ultra_1".parse().unwrap()))
+        //             .message(format!("The counter is now {value:?}").parse().unwrap())
+        //             .title("New value of the counter".into())
+        //             .build(),
+        //         Option::<Context<()>>::None,
+        //         Option::<()>::None,
+        //         false,
+        //     )
+        //     .await;
+        // tracing::debug!(?service_result);
 
-        let is_on = some_light.is_on().await;
-        tracing::info!(?is_on);
-        let is_off = some_light.is_off().await;
-        tracing::info!(?is_off);
+        value += 1;
+
+        // tracing::info!("about to call get_sysinfo");
+        // let sysinfo_res = some_light.get_sysinfo().await;
+        // tracing::info!(?sysinfo_res, "got sys info");
+
+        // let is_on = some_light.is_on().await;
+        // tracing::info!(?is_on);
+        // let is_off = some_light.is_off().await;
+        // tracing::info!(?is_off);
 
         // let is_on = lamp.is_on().await;
         // tracing::info!(?is_on);
@@ -131,13 +154,98 @@ async fn real_main(
         // let something = lamp.turn_on().await;
         // tracing::info!(?something);
     }
+
+    if let Some(persistence_directory) = persistence_directory {
+        let config = Config::new(persistence_directory);
+        let keyspace = Keyspace::open(config).unwrap(); // TODO: just debugging and experiencing it
+        let partition_name = "trying_this_out_partition";
+        let create_options = PartitionCreateOptions::default();
+        let partition =
+            spawn_blocking(move || keyspace.open_partition(partition_name, create_options))
+                .await
+                .unwrap()
+                // TODO: just debugging and experiencing it
+                .unwrap();
+
+        let identifier = "0a7wmg09awgmagw97nawg7awg90a8wgn982".into();
+        let buffer = NonZeroUsize::new(128).unwrap();
+        let (setter, signal, task) = persisted(partition, identifier, buffer).await;
+
+        let consumer = tokio::spawn({
+            let mut subscription = signal.subscribe().unwrap();
+
+            let services = Python::attach(|py| home_assistant.services(py)).unwrap();
+            async move {
+                let initial = subscription.get();
+                tracing::debug!(?initial);
+
+                loop {
+                    tracing::info!("waiting for changed");
+                    subscription.changed().await.unwrap();
+
+                    let value = subscription.get();
+                    tracing::debug!(?value);
+
+                    // TODO: WIP: DEBUGGING
+                    let service_result: Result<Py<PyAny>, _> = services
+                        .call_service(
+                            StandardNotification::builder()
+                                .object_id(ObjectId("galaxy_s21_ultra_1".parse().unwrap()))
+                                .message(format!("The counter is now {value:?}").parse().unwrap())
+                                .title("New value of the counter".into())
+                                .build(),
+                            Option::<Context<()>>::None,
+                            Option::<()>::None,
+                            false,
+                        )
+                        .await;
+
+                    tracing::error!(?service_result);
+                    let service_result_introspection = Python::attach(|py| {
+                        service_result
+                            .map(|ret| ret.bind(py).get_type().name().unwrap().to_string())
+                    });
+                    tracing::error!(?service_result_introspection);
+                }
+            }
+        });
+
+        let producer = tokio::spawn({
+            let mut subscription = signal.subscribe().unwrap();
+            async move {
+                let mut int = interval(Duration::from_secs(190));
+
+                loop {
+                    int.tick().await;
+
+                    let value = subscription.get();
+                    tracing::debug!(?value);
+
+                    // let mut counter = value.unwrap_or(14u16);
+                    // tracing::info!(?counter);
+
+                    if let Ok(counter) = value {
+                        let counter: u16 = counter + 1;
+                        setter.set(counter).await.unwrap();
+                    }
+                }
+            }
+        });
+
+        producer.await.unwrap();
+        consumer.await.unwrap();
+        task.await.unwrap();
+
+        unreachable!();
+    } else {
+        panic!("please set PERSISTENCE_DIRECTORY while debugging and trying persisted out")
+    }
 }
 
 #[pyfunction]
 fn main<'py>(py: Python<'py>, home_assistant: HomeAssistant) -> PyResult<Bound<'py, PyAny>> {
     let args = Args::parse();
-
-    pyo3_async_runtimes::tokio::future_into_py::<_, ()>(py, async {
+    pyo3_async_runtimes::tokio::future_into_py::<_, ()>(py, async move {
         real_main(args, home_assistant).await;
     })
 }

entrypoint/src/tracing_to_home_assistant.rs

@@ -49,7 +49,7 @@ impl<S: Subscriber> Layer<S> for TracingToHomeAssistant {
 
         let log_data: Option<LogData<()>> = None;
 
-        Python::with_gil(|py| {
+        Python::attach(|py| {
             let Ok(hass_logger) = HassLogger::new(py, target) else {
                 return;
             };

home-assistant/Cargo.toml

@@ -19,14 +19,17 @@ derive_more = { workspace = true, features = [
     "try_into",
 ] }
 emitter-and-signal = { path = "../emitter-and-signal" }
+mitsein = { workspace = true }
 once_cell = "1.21.3"
 protocol = { path = "../protocol" }
 pyo3 = { workspace = true }
 pyo3-async-runtimes = { workspace = true, features = ["tokio-runtime"] }
 python-utils = { path = "../python-utils" }
-smol_str = "0.3.2"
 snafu = { workspace = true }
 strum = { workspace = true, features = ["derive"] }
 tokio = { workspace = true }
 tracing = { optional = true, workspace = true }
+typed-builder = { workspace = true }
 ulid = "1.2.0"
+uom = "0.37.0"
+url = { workspace = true }

home-assistant/src/entity_id.rs

@@ -1,6 +1,10 @@
 use std::{convert::Infallible, fmt::Display, str::FromStr};
 
-use pyo3::{exceptions::PyValueError, prelude::*, types::PyString};
+use pyo3::{
+    exceptions::{PyException, PyValueError},
+    prelude::*,
+    types::PyString,
+};
 use snafu::{ResultExt, Snafu};
 
 use super::{
@@ -44,21 +48,39 @@ impl Display for EntityId {
     }
 }
 
-impl From<EntityIdParsingError> for PyErr {
-    fn from(error: EntityIdParsingError) -> Self {
-        PyValueError::new_err(error.to_string())
+#[derive(Debug, Snafu)]
+pub enum ExtractEntityIdError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+
+    /// couldn't parse the string as an [`EntityId`]
+    ParseError { source: EntityIdParsingError },
+}
+
+impl From<ExtractEntityIdError> for PyErr {
+    fn from(error: ExtractEntityIdError) -> Self {
+        match &error {
+            ExtractEntityIdError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            ExtractEntityIdError::ParseError { .. } => PyValueError::new_err(error.to_string()),
+        }
     }
 }
 
-impl<'py> FromPyObject<'py> for EntityId {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract()?;
-        let entity_id = EntityId::from_str(s)?;
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py> FromPyObject<'a, 'py> for EntityId {
+    type Error = ExtractEntityIdError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract().context(ExtractStringSnafu)?;
+        let entity_id = EntityId::from_str(s).context(ParseSnafu)?;
 
         Ok(entity_id)
     }
 }
 
+// TODO: replace with a derive(DisplayToPy) (analogous to serde_with::SerializeDisplay) once I make one
 impl<'py> IntoPyObject<'py> for EntityId {
     type Target = PyString;
     type Output = Bound<'py, Self::Target>;

home-assistant/src/event/context/context.rs

@@ -28,7 +28,7 @@ impl<'py, Event: IntoPyObject<'py>> IntoPyObject<'py> for Context<Event> {
             .bind(py);
 
         let context_class = homeassistant_core.getattr("Context")?;
-        let context_class = context_class.downcast_into::<PyType>()?;
+        let context_class = context_class.cast_into::<PyType>()?;
 
         let context_instance = context_class.call1((self.user_id, self.parent_id, self.id))?;
 

home-assistant/src/event/context/id.rs

@@ -1,18 +1,35 @@
-use std::convert::Infallible;
+use std::{convert::Infallible, sync::Arc};
 
-use pyo3::{prelude::*, types::PyString};
-use smol_str::SmolStr;
+use pyo3::{exceptions::PyTypeError, prelude::*, types::PyString};
+use snafu::{ResultExt, Snafu};
 use ulid::Ulid;
 
 #[derive(Debug, Clone)]
 pub enum Id {
     Ulid(Ulid),
-    Other(SmolStr),
+    Other(Arc<str>),
 }
 
-impl<'py> FromPyObject<'py> for Id {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract::<String>()?;
+#[derive(Debug, Snafu)]
+pub enum ExtractIdError {
+    /// couldn't extract the given object as a string
+    ExtractStringError { source: PyErr },
+}
+
+impl From<ExtractIdError> for PyErr {
+    fn from(error: ExtractIdError) -> Self {
+        match &error {
+            ExtractIdError::ExtractStringError { .. } => PyTypeError::new_err(error.to_string()),
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py> FromPyObject<'a, 'py> for Id {
+    type Error = ExtractIdError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract::<&str>().context(ExtractStringSnafu)?;
 
         if let Ok(ulid) = s.parse() {
             Ok(Id::Ulid(ulid))
@@ -22,6 +39,7 @@ impl<'py> FromPyObject<'py> for Id {
     }
 }
 
+// TODO: replace with a derive(DisplayToPy) (analogous to serde_with::SerializeDisplay) once I make one
 impl<'py> IntoPyObject<'py> for Id {
     type Target = PyString;
 
@@ -32,7 +50,7 @@ impl<'py> IntoPyObject<'py> for Id {
     fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
         match self {
             Id::Ulid(ulid) => ulid.to_string().into_pyobject(py),
-            Id::Other(id) => id.as_str().into_pyobject(py),
+            Id::Other(id) => id.into_pyobject(py),
         }
     }
 }

home-assistant/src/event/event_origin.rs

@@ -1,6 +1,10 @@
 use std::str::FromStr;
 
-use pyo3::{exceptions::PyValueError, prelude::*};
+use pyo3::{
+    exceptions::{PyException, PyTypeError, PyValueError},
+    prelude::*,
+};
+use snafu::{ResultExt, Snafu};
 
 #[derive(Debug, Clone, strum::EnumString, strum::Display)]
 #[strum(serialize_all = "UPPERCASE")]
@@ -9,12 +13,41 @@ pub enum EventOrigin {
     Remote,
 }
 
-impl<'py> FromPyObject<'py> for EventOrigin {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.str()?;
-        let s = s.extract()?;
-        let event_origin =
-            EventOrigin::from_str(s).map_err(|err| PyValueError::new_err(err.to_string()))?;
+#[derive(Debug, Snafu)]
+pub enum ExtractEventOriginError {
+    /// couldn't turn the object into a string with `str` (Python function)
+    ToStrError { source: PyErr },
+
+    /// after calling `str` on the object, it's somehow not extractable as a string?!
+    NotString { source: PyErr },
+
+    /// this is not an expected value for [`EventOrigin`]
+    UnexpectedValue {
+        source: <EventOrigin as FromStr>::Err,
+    },
+}
+
+impl From<ExtractEventOriginError> for PyErr {
+    fn from(error: ExtractEventOriginError) -> Self {
+        match &error {
+            ExtractEventOriginError::ToStrError { .. } => PyException::new_err(error.to_string()),
+            ExtractEventOriginError::NotString { .. } => PyTypeError::new_err(error.to_string()),
+            ExtractEventOriginError::UnexpectedValue { .. } => {
+                PyValueError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+impl<'a, 'py> FromPyObject<'a, 'py> for EventOrigin {
+    type Error = ExtractEventOriginError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.str().context(ToStrSnafu)?;
+        // TODO: could I go straight to trying to extract an &str without calling .str() first? if so then I could
+        // TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+        let s = s.extract().context(NotStringSnafu)?;
+        let event_origin = EventOrigin::from_str(s).context(UnexpectedValueSnafu)?;
 
         Ok(event_origin)
     }

home-assistant/src/event/specific/state_changed.rs

@@ -1,21 +1,41 @@
-use pyo3::exceptions::PyValueError;
+use pyo3::exceptions::{PyTypeError, PyValueError};
 use pyo3::prelude::*;
+use snafu::{ResultExt, Snafu};
 
 use crate::{entity_id::EntityId, state_object::StateObject};
 
 #[derive(Debug, Clone)]
 pub struct Type;
 
-impl<'py> FromPyObject<'py> for Type {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract::<&str>()?;
+#[derive(Debug, Snafu)]
+pub enum ExtractTypeError {
+    /// couldn't extract this object as a string
+    ExtractStringError { source: PyErr },
+
+    /// expected a string of value "state_changed", but got {actual}
+    UnexpectedValue { actual: String },
+}
+
+impl From<ExtractTypeError> for PyErr {
+    fn from(error: ExtractTypeError) -> Self {
+        match &error {
+            ExtractTypeError::ExtractStringError { .. } => PyTypeError::new_err(error.to_string()),
+            ExtractTypeError::UnexpectedValue { .. } => PyValueError::new_err(error.to_string()),
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStrLiteral) / #[literal = "state_changed"] once I learn how to make something like that and see about serde or strum integration or inspiration
+impl<'a, 'py> FromPyObject<'a, 'py> for Type {
+    type Error = ExtractTypeError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract::<&str>().context(ExtractStringSnafu)?;
 
         if s == "state_changed" {
             Ok(Type)
         } else {
-            Err(PyValueError::new_err(format!(
-                "expected a string of value 'state_changed', but got {s}"
-            )))
+            Err(ExtractTypeError::UnexpectedValue { actual: s.into() })
         }
     }
 }

home-assistant/src/home_assistant.rs

@@ -2,17 +2,20 @@ use std::convert::Infallible;
 
 use pyo3::prelude::*;
 
-use python_utils::{detach, validate_type_by_name};
+use python_utils::{detach, validate_type_by_name, TypeByNameValidationError};
+use snafu::{ResultExt, Snafu};
 
 use super::{service_registry::ServiceRegistry, state_machine::StateMachine};
 
 #[derive(Debug)]
 pub struct HomeAssistant(Py<PyAny>);
 
-impl<'source> FromPyObject<'source> for HomeAssistant {
-    fn extract_bound(ob: &Bound<'source, PyAny>) -> PyResult<Self> {
+impl<'a, 'py> FromPyObject<'a, 'py> for HomeAssistant {
+    type Error = TypeByNameValidationError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
         // region: Validation
-        validate_type_by_name(ob, "HomeAssistant")?;
+        validate_type_by_name(&ob, "HomeAssistant")?;
         // endregion: Validation
 
         Ok(Self(detach(ob)))
@@ -29,6 +32,24 @@ impl<'py> IntoPyObject<'py> for &HomeAssistant {
     }
 }
 
+#[derive(Debug, Snafu)]
+pub enum GetStatesError {
+    /// couldn't get the `states` attribute on the Home Assistant object
+    GetStatesAttributeError { source: PyErr },
+
+    /// couldn't extract the `states` as a [`StateMachine`]
+    ExtractStateMachineError { source: TypeByNameValidationError },
+}
+
+#[derive(Debug, Snafu)]
+pub enum GetServicesError {
+    /// couldn't get the `services` attribute on the Home Assistant object
+    GetServicesAttributeError { source: PyErr },
+
+    /// couldn't extract the `states` as a [`ServiceRegistry`]
+    ExtractServiceRegistryError { source: TypeByNameValidationError },
+}
+
 impl HomeAssistant {
     /// Return the representation
     pub fn repr(&self, py: Python<'_>) -> Result<String, PyErr> {
@@ -48,13 +69,19 @@ impl HomeAssistant {
         is_stopping.extract(py)
     }
 
-    pub fn states(&self, py: Python<'_>) -> Result<StateMachine, PyErr> {
-        let states = self.0.getattr(py, "states")?;
-        states.extract(py)
+    pub fn states(&self, py: Python<'_>) -> Result<StateMachine, GetStatesError> {
+        let states = self
+            .0
+            .getattr(py, "states")
+            .context(GetStatesAttributeSnafu)?;
+        states.extract(py).context(ExtractStateMachineSnafu)
     }
 
-    pub fn services(&self, py: Python<'_>) -> Result<ServiceRegistry, PyErr> {
-        let services = self.0.getattr(py, "services")?;
-        services.extract(py)
+    pub fn services(&self, py: Python<'_>) -> Result<ServiceRegistry, GetServicesError> {
+        let services = self
+            .0
+            .getattr(py, "services")
+            .context(GetServicesAttributeSnafu)?;
+        services.extract(py).context(ExtractServiceRegistrySnafu)
     }
 }

home-assistant/src/lib.rs

@@ -1,13 +1,21 @@
+pub mod binary_sensor;
 pub mod domain;
 pub mod entity_id;
 pub mod event;
 pub mod home_assistant;
+pub mod input_boolean;
+pub mod input_number;
+pub mod input_text;
 pub mod light;
 pub mod logger;
+pub mod notify;
 pub mod object_id;
+pub mod sensor;
 pub mod service;
 pub mod service_registry;
 pub mod slug;
 pub mod state;
 pub mod state_machine;
 pub mod state_object;
+pub mod switch;
+pub mod unit_of_measurement;

home-assistant/src/light/mod.rs

@@ -3,7 +3,9 @@ use pyo3::prelude::*;
 use snafu::{ResultExt, Snafu};
 use state::LightState;
 
-use crate::state::HomeAssistantState;
+use crate::{
+    home_assistant::GetStatesError, state::HomeAssistantState, state_machine::GetStateError,
+};
 
 use super::{
     domain::Domain, entity_id::EntityId, home_assistant::HomeAssistant, object_id::ObjectId,
@@ -29,7 +31,15 @@ impl HomeAssistantLight {
 
 #[derive(Debug, Snafu)]
 pub enum GetStateObjectError {
-    PythonError { source: PyErr },
+    /// couldn't get the state machine registry
+    GetStatesError { source: GetStatesError },
+    
+    /// this state object exists in the state machine registry, but it couldn't be extracted as a light state object
+    GetStateError { source: GetStateError<
+        <StateObject<HomeAssistantState<LightState>, LightAttributes, Py<PyAny>> as FromPyObject<'static, 'static>>::Error
+    > },
+
+    /// this entity does not have a state object in the registry
     EntityMissing,
 }
 
@@ -40,12 +50,12 @@ impl HomeAssistantLight {
         StateObject<HomeAssistantState<LightState>, LightAttributes, Py<PyAny>>,
         GetStateObjectError,
     > {
-        Python::with_gil(|py| {
-            let states = self.home_assistant.states(py).context(PythonSnafu)?;
+        Python::attach(|py| {
+            let states = self.home_assistant.states(py).context(GetStatesSnafu)?;
             let entity_id = self.entity_id();
             let state_object = states
                 .get(py, entity_id)
-                .context(PythonSnafu)?
+                .context(GetStateSnafu)?
                 .ok_or(GetStateObjectError::EntityMissing)?;
 
             Ok(state_object)

home-assistant/src/light/protocol.rs

@@ -1,5 +1,7 @@
 use super::service::{turn_off::TurnOff, turn_on::TurnOn};
-use super::{state::LightState, GetStateObjectError, HomeAssistantLight};
+use super::{GetStateObjectError, HomeAssistantLight};
+use crate::home_assistant::GetServicesError;
+use crate::service_registry::CallServiceError;
 use crate::{
     event::context::context::Context,
     state::{ErrorState, HomeAssistantState, UnexpectedState},
@@ -35,21 +37,31 @@ impl GetState for HomeAssistantLight {
     }
 }
 
+#[derive(Debug, Snafu)]
+pub enum SetStateError {
+    /// couldn't get the service registry
+    GetServicesError { source: GetServicesError },
+
+    /// couldn't call the service
+    CallServiceError { source: CallServiceError },
+}
+
 impl SetState for HomeAssistantLight {
-    type Error = PyErr;
+    type Error = SetStateError;
 
     async fn set_state(&mut self, state: protocol::light::State) -> Result<(), Self::Error> {
         let context: Option<Context<()>> = None;
         let target: Option<()> = None;
 
-        let services = Python::with_gil(|py| self.home_assistant.services(py))?;
+        let services =
+            Python::attach(|py| self.home_assistant.services(py)).context(GetServicesSnafu)?;
 
         let _: IsNone = match state {
             protocol::light::State::Off => {
                 services
                     .call_service(
                         TurnOff {
-                            entity_id: self.entity_id(),
+                            object_id: self.object_id.clone(),
                         },
                         context,
                         target,
@@ -61,7 +73,7 @@ impl SetState for HomeAssistantLight {
                 services
                     .call_service(
                         TurnOn {
-                            entity_id: self.entity_id(),
+                            object_id: self.object_id.clone(),
                         },
                         context,
                         target,
@@ -69,7 +81,8 @@ impl SetState for HomeAssistantLight {
                     )
                     .await
             }
-        }?;
+        }
+        .context(CallServiceSnafu)?;
 
         Ok(())
     }

home-assistant/src/light/service/turn_off.rs

@@ -3,13 +3,12 @@ use std::str::FromStr;
 use pyo3::IntoPyObject;
 
 use crate::{
-    entity_id::EntityId,
-    service::{service_domain::ServiceDomain, service_id::ServiceId, IntoServiceCall},
+    domain::Domain, entity_id::EntityId, object_id::ObjectId, service::{IntoServiceCall, service_domain::ServiceDomain, service_id::ServiceId}
 };
 
 #[derive(Debug, Clone)]
 pub struct TurnOff {
-    pub entity_id: EntityId,
+    pub object_id: ObjectId,
 }
 
 #[derive(Debug, Clone, IntoPyObject)]
@@ -24,7 +23,8 @@ impl IntoServiceCall for TurnOff {
         let service_domain = ServiceDomain::from_str("light").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
         let service_id = ServiceId::from_str("turn_off").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
 
-        let Self { entity_id } = self;
+        let Self { object_id } = self;
+        let entity_id = EntityId(Domain::Light, object_id);
 
         let service_data = TurnOffServiceData { entity_id };
 

home-assistant/src/light/service/turn_on.rs

@@ -3,13 +3,12 @@ use std::str::FromStr;
 use pyo3::IntoPyObject;
 
 use crate::{
-    entity_id::EntityId,
-    service::{service_domain::ServiceDomain, service_id::ServiceId, IntoServiceCall},
+    domain::Domain, entity_id::EntityId, object_id::ObjectId, service::{IntoServiceCall, service_domain::ServiceDomain, service_id::ServiceId}
 };
 
 #[derive(Debug, Clone)]
 pub struct TurnOn {
-    pub entity_id: EntityId,
+    pub object_id: ObjectId,
 }
 
 #[derive(Debug, Clone, IntoPyObject)]
@@ -24,7 +23,9 @@ impl IntoServiceCall for TurnOn {
         let service_domain = ServiceDomain::from_str("light").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
         let service_id = ServiceId::from_str("turn_on").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
 
-        let Self { entity_id } = self;
+        let Self { object_id } = self;
+        let entity_id = EntityId(Domain::Light, object_id);
+
         let service_data = TurnOnServiceData { entity_id };
 
         (service_domain, service_id, service_data)

home-assistant/src/light/state.rs

@@ -1,6 +1,10 @@
 use std::str::FromStr;
 
-use pyo3::{exceptions::PyValueError, prelude::*};
+use pyo3::{
+    exceptions::{PyException, PyValueError},
+    prelude::*,
+};
+use snafu::{ResultExt, Snafu};
 use strum::EnumString;
 
 #[derive(Debug, Clone, EnumString, strum::Display)]
@@ -10,12 +14,36 @@ pub enum LightState {
     Off,
 }
 
-impl<'py> FromPyObject<'py> for LightState {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract::<String>()?;
+#[derive(Debug, Snafu)]
+pub enum ExtractLightStateError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
 
-        let state =
-            LightState::from_str(&s).map_err(|err| PyValueError::new_err(err.to_string()))?;
+    /// couldn't parse the string as a [`LightState`]
+    ParseError {
+        source: <LightState as FromStr>::Err,
+    },
+}
+
+impl From<ExtractLightStateError> for PyErr {
+    fn from(error: ExtractLightStateError) -> Self {
+        match &error {
+            ExtractLightStateError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            ExtractLightStateError::ParseError { .. } => PyValueError::new_err(error.to_string()),
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py> FromPyObject<'a, 'py> for LightState {
+    type Error = ExtractLightStateError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract::<&str>().context(ExtractStringSnafu)?;
+
+        let state = LightState::from_str(&s).context(ParseSnafu)?;
 
         Ok(state)
     }

home-assistant/src/logger.rs

@@ -1,15 +1,17 @@
 use arbitrary_value::{arbitrary::Arbitrary, map::Map};
 use once_cell::sync::OnceCell;
 use pyo3::{prelude::*, types::PyTuple};
-use python_utils::{detach, validate_type_by_name};
+use python_utils::{detach, validate_type_by_name, TypeByNameValidationError};
 
 #[derive(Debug)]
 pub struct HassLogger(Py<PyAny>);
 
-impl<'source> FromPyObject<'source> for HassLogger {
-    fn extract_bound(ob: &Bound<'source, PyAny>) -> PyResult<Self> {
+impl<'a, 'py> FromPyObject<'a, 'py> for HassLogger {
+    type Error = TypeByNameValidationError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
         // region: Validation
-        validate_type_by_name(ob, "HassLogger")?;
+        validate_type_by_name(&ob, "HassLogger")?;
         // endregion: Validation
 
         Ok(Self(detach(ob)))

home-assistant/src/notify/mod.rs

@@ -0,0 +1 @@
+pub mod service;

home-assistant/src/notify/service/mobile_app/command/mod.rs

@@ -0,0 +1,3 @@
+mod request_location_update;
+
+pub use request_location_update::RequestLocationUpdate;

home-assistant/src/notify/service/mobile_app/command/request_location_update.rs

@@ -0,0 +1,33 @@
+use std::str::FromStr;
+
+use crate::{
+    notify::service::mobile_app::SpecialMessage,
+    object_id::ObjectId,
+    service::{service_domain::ServiceDomain, service_id::ServiceId, IntoServiceCall},
+};
+
+use super::super::NotifyMobileAppServiceData;
+
+#[derive(Debug, Clone, typed_builder::TypedBuilder)]
+pub struct RequestLocationUpdate {
+    pub object_id: ObjectId,
+}
+
+impl IntoServiceCall for RequestLocationUpdate {
+    type ServiceData = NotifyMobileAppServiceData;
+
+    fn into_service_call(self) -> (ServiceDomain, ServiceId, Self::ServiceData) {
+        let RequestLocationUpdate { object_id } = self;
+
+        let service_domain = ServiceDomain::from_str("notify").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
+
+        let service_id = ServiceId::from_str(&format!("mobile_app_{object_id}")).expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
+
+        let service_data = NotifyMobileAppServiceData::builder()
+            .message(SpecialMessage::RequestLocationUpdate.to_string())
+            // .data(NotifyMobileAppServiceDataData::builder().build()) // TODO
+            .build();
+
+        (service_domain, service_id, service_data)
+    }
+}

home-assistant/src/notify/service/mobile_app/mod.rs

@@ -0,0 +1,223 @@
+use std::{convert::Infallible, str::FromStr};
+
+use pyo3::{types::PyString, Bound, IntoPyObject, Python};
+use python_utils::IntoPyObjectViaDisplay;
+use snafu::Snafu;
+use strum::EnumString;
+use url::Url;
+
+pub mod command;
+pub mod standard;
+pub mod text_to_speech;
+
+pub use command::*;
+pub use standard::StandardNotification;
+pub use text_to_speech::TextToSpeech;
+
+#[derive(Debug, Clone, derive_more::Display)]
+pub struct NonSpecialMessage(String);
+
+#[derive(Debug, Clone, EnumString, strum::Display)]
+#[strum(serialize_all = "snake_case")]
+pub enum SpecialMessage {
+    ClearBadge,
+    ClearNotification,
+    CommandActivity,
+    CommandAppLock,
+    CommandAutoScreenBrightness,
+    CommandBluetooth,
+    CommandBleTransmitter,
+    CommandBeaconMonitor,
+    CommandBroadcastIntent,
+    CommandDnd,
+    CommandFlashlight,
+    CommandHighAccuracyMode,
+    CommandLaunchApp,
+    CommandMedia,
+    CommandRingerMode,
+    CommandScreenBrightnessLevel,
+    CommandScreenOffTimeout,
+    CommandScreenOn,
+    CommandStopTts,
+    CommandPersistentConnection,
+    CommandUpdateSensors,
+    CommandVolumeLevel,
+    CommandWebivew,
+    RemoveChannel,
+    RequestLocationUpdate,
+    // #[strum(serialize = "TTS")] TODO: WIP: TESTING
+    Tts,
+    UpdateComplications,
+    UpdateWidgets,
+}
+
+/// wasn't supposed to get a specially-behaving message here, but got {got}
+#[derive(Debug, Clone, Snafu)]
+pub struct WasSpecialMessage {
+    pub got: SpecialMessage,
+}
+
+impl FromStr for NonSpecialMessage {
+    type Err = WasSpecialMessage;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match SpecialMessage::from_str(s) {
+            Ok(special_message) => Err(WasSpecialMessage {
+                got: special_message,
+            }),
+            Err(_e) => Ok(NonSpecialMessage(s.into())),
+        }
+    }
+}
+
+/// How much of a notification is visible on the lock screen
+#[derive(Debug, Clone, Default, EnumString, strum::Display)]
+#[strum(serialize_all = "snake_case")]
+pub enum Visibility {
+    /// always show all notification content
+    Public,
+    /// visibility depends on your setting in the system Settings app > Notifications;
+    /// if the option to show sensitive notifications when locked is enabled all notification content will be shown,
+    /// otherwise only basic information such as the icon and app name are visible
+    #[default]
+    Private,
+    /// always hide notification from lock screen
+    Secret,
+}
+
+// TODO: replace with a derive(DisplayToPy) (analogous to serde_with::SerializeDisplay) once I make one
+impl<'py> IntoPyObject<'py> for Visibility {
+    type Target = PyString;
+    type Output = Bound<'py, Self::Target>;
+    type Error = Infallible;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        let s = self.to_string();
+        s.into_pyobject(py)
+    }
+}
+
+#[derive(Debug, Clone, EnumString, strum::Display)]
+pub enum Behavior {
+    /// prompt for text to return with the event
+    #[strum(serialize = "textInput")]
+    TextInput,
+}
+
+// TODO: replace with a derive(DisplayToPy) (analogous to serde_with::SerializeDisplay) once I make one
+impl<'py> IntoPyObject<'py> for Behavior {
+    type Target = PyString;
+    type Output = Bound<'py, Self::Target>;
+    type Error = Infallible;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        let s = self.to_string();
+        s.into_pyobject(py)
+    }
+}
+
+#[derive(Debug, Clone, Default, EnumString, strum::Display)]
+#[strum(serialize_all = "camelCase")]
+pub enum ActivationMode {
+    /// launch the app when tapped
+    Foreground,
+    /// just fires the event
+    #[default]
+    Background,
+}
+
+// TODO: replace with a derive(DisplayToPy) (analogous to serde_with::SerializeDisplay) once I make one
+impl<'py> IntoPyObject<'py> for ActivationMode {
+    type Target = PyString;
+    type Output = Bound<'py, Self::Target>;
+    type Error = Infallible;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        let s = self.to_string();
+        s.into_pyobject(py)
+    }
+}
+
+// TODO: better typed versions like `CallNumber` or `OpenWebpage` where Action: From<CallNumber> and Action: From<OpenWebPage>
+#[derive(Debug, Clone, IntoPyObject, typed_builder::TypedBuilder)]
+#[builder(field_defaults(default, setter(strip_option(fallback_suffix = "_option"))))]
+pub struct Action {
+    // TODO: proper type
+    // TODO: I wish I could call this identifier or something instead
+    #[builder(!default, setter(!strip_option))]
+    pub action: String,
+    #[builder(!default, setter(!strip_option))]
+    pub title: String,
+
+    pub uri: Option<IntoPyObjectViaDisplay<Url>>,
+    pub behavior: Option<Behavior>,
+
+    // TODO: make this written as activationMode
+    /// (iOS only) decide whether to open the app (to the foreground) when tapped
+    /// or merely fire an event (in the background)
+    pub activation_mode: Option<ActivationMode>,
+
+    // TODO: make this written as authenticationRequired
+    /// (iOS only) require entering a passcode to use the action
+    pub authentication_required: Option<bool>,
+
+    /// (iOS only) color the action's title red, indicating a destructive action
+    pub destructive: Option<bool>,
+
+    // TODO: make this written as textInputButtonTitle
+    /// (iOS only) Title to use for text input for actions that prompt
+    pub text_input_button_title: Option<String>,
+
+    // TODO: make this written as textInputPlaceholder
+    /// (iOS only) Placeholder to use for text input for actions that prompt
+    pub text_input_placeholder: Option<String>,
+
+    // TODO: proper type
+    /// (iOS only) icon to use for the notification
+    pub icon: Option<String>,
+}
+
+#[derive(Debug, Clone, Default, EnumString, strum::Display)]
+#[strum(serialize_all = "snake_case", suffix = "_stream")]
+pub enum MediaStream {
+    Alarm,
+    Call,
+    Dtmf,
+    #[default]
+    Music,
+    Notification,
+    Ring,
+    System,
+}
+
+// TODO: replace with a derive(DisplayToPy) (analogous to serde_with::SerializeDisplay) once I make one
+impl<'py> IntoPyObject<'py> for MediaStream {
+    type Target = PyString;
+    type Output = Bound<'py, Self::Target>;
+    type Error = Infallible;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        let s = self.to_string();
+        s.into_pyobject(py)
+    }
+}
+
+#[derive(Debug, Default, Clone, IntoPyObject, typed_builder::TypedBuilder)]
+#[builder(field_defaults(default, setter(strip_option(fallback_suffix = "_option"))))]
+pub struct NotifyMobileAppServiceDataData {
+    actions: Option<Vec<Action>>,
+    media_stream: Option<MediaStream>,
+    tts_text: Option<String>,
+    visibility: Option<Visibility>,
+}
+
+#[derive(Debug, Clone, IntoPyObject, typed_builder::TypedBuilder)]
+#[builder(field_defaults(default, setter(strip_option(fallback_suffix = "_option"))))]
+pub struct NotifyMobileAppServiceData {
+    #[builder(!default, setter(!strip_option))]
+    message: String,
+
+    title: Option<String>,
+    #[builder(setter(!strip_option))]
+    data: NotifyMobileAppServiceDataData,
+}

home-assistant/src/notify/service/mobile_app/standard.rs

@@ -0,0 +1,60 @@
+use std::str::FromStr;
+
+use mitsein::vec1::Vec1;
+use pyo3::{types::PyAnyMethods, IntoPyObject, Python};
+
+use crate::{
+    object_id::ObjectId,
+    service::{service_domain::ServiceDomain, service_id::ServiceId, IntoServiceCall},
+};
+
+use super::{
+    Action, NonSpecialMessage, NotifyMobileAppServiceData, NotifyMobileAppServiceDataData,
+    Visibility,
+};
+
+#[derive(Debug, Clone, typed_builder::TypedBuilder)]
+pub struct StandardNotification {
+    pub object_id: ObjectId,
+
+    #[builder(default, setter(strip_option))]
+    pub title: Option<String>,
+    pub message: NonSpecialMessage,
+
+    #[builder(default, setter(strip_option))]
+    pub actions: Option<Vec1<Action>>,
+
+    #[builder(default, setter(strip_option))]
+    pub visibility: Option<Visibility>,
+}
+
+impl IntoServiceCall for StandardNotification {
+    type ServiceData = NotifyMobileAppServiceData;
+
+    fn into_service_call(self) -> (ServiceDomain, ServiceId, Self::ServiceData) {
+        let StandardNotification {
+            object_id,
+            title,
+            message,
+            actions,
+            visibility,
+        } = self;
+
+        let service_domain = ServiceDomain::from_str("notify").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
+
+        let service_id = ServiceId::from_str(&format!("mobile_app_{object_id}")).expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
+
+        let service_data = NotifyMobileAppServiceData::builder()
+            .title_option(title)
+            .message(message.to_string())
+            .data(
+                NotifyMobileAppServiceDataData::builder()
+                    .actions_option(actions.map(Into::into))
+                    .visibility_option(visibility)
+                    .build(),
+            )
+            .build();
+
+        (service_domain, service_id, service_data)
+    }
+}

home-assistant/src/notify/service/mobile_app/text_to_speech.rs

@@ -0,0 +1,45 @@
+use std::str::FromStr;
+
+use crate::{
+    notify::service::mobile_app::SpecialMessage,
+    object_id::ObjectId,
+    service::{service_domain::ServiceDomain, service_id::ServiceId, IntoServiceCall},
+};
+
+use super::{MediaStream, NotifyMobileAppServiceData, NotifyMobileAppServiceDataData};
+
+#[derive(Debug, Clone, typed_builder::TypedBuilder)]
+pub struct TextToSpeech {
+    pub object_id: ObjectId,
+
+    pub message: String,
+    pub media_stream: Option<MediaStream>,
+}
+
+impl IntoServiceCall for TextToSpeech {
+    type ServiceData = NotifyMobileAppServiceData;
+
+    fn into_service_call(self) -> (ServiceDomain, ServiceId, Self::ServiceData) {
+        let TextToSpeech {
+            object_id,
+            message,
+            media_stream,
+        } = self;
+
+        let service_domain = ServiceDomain::from_str("notify").expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
+
+        let service_id = ServiceId::from_str(&format!("mobile_app_{object_id}")).expect("statically written and known to be a valid slug; hoping to get compiler checks instead in the future");
+
+        let service_data = NotifyMobileAppServiceData::builder()
+            .message(SpecialMessage::Tts.to_string())
+            .data(
+                NotifyMobileAppServiceDataData::builder()
+                    .tts_text(message)
+                    .media_stream_option(media_stream)
+                    .build(),
+            )
+            .build();
+
+        (service_domain, service_id, service_data)
+    }
+}

home-assistant/src/notify/service/mod.rs

@@ -0,0 +1 @@
+pub mod mobile_app;

home-assistant/src/sensor/device_classes/mod.rs

@@ -0,0 +1 @@
+mod power;

home-assistant/src/sensor/device_classes/power.rs

@@ -0,0 +1,125 @@
+use std::{future::Future, str::FromStr, sync::Arc};
+
+use emitter_and_signal::{Signal, SignalExt};
+use pyo3::{
+    exceptions::{PyException, PyValueError},
+    prelude::*,
+};
+use python_utils::FromPyObjectViaParse;
+use snafu::{ensure, ResultExt, Snafu};
+
+use super::super::state_classes::measurement::Measurement;
+use crate::{
+    domain::Domain,
+    entity_id::EntityId,
+    home_assistant::HomeAssistant,
+    object_id::ObjectId,
+    state_object::{self, StateObject, StateObjectSignalError},
+    unit_of_measurement::power::UnitOfMeasurement,
+};
+
+#[derive(Debug)]
+struct Power;
+
+#[derive(Debug, Snafu)]
+pub enum ExtractPowerError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+
+    /// the string {actual:?} is not "power" like it's supposed to be
+    NotPower { actual: String },
+}
+
+impl From<ExtractPowerError> for PyErr {
+    fn from(error: ExtractPowerError) -> Self {
+        match &error {
+            ExtractPowerError::ExtractStringError { .. } => PyException::new_err(error.to_string()),
+            ExtractPowerError::NotPower { .. } => PyValueError::new_err(error.to_string()),
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStrLiteral) / #[literal = "state_changed"] once I learn how to make something like that and see about serde or strum integration or inspiration
+impl<'a, 'py> FromPyObject<'a, 'py> for Power {
+    type Error = ExtractPowerError;
+
+    fn extract(obj: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let string: &str = obj.extract().context(ExtractStringSnafu)?;
+
+        ensure!(
+            string == "power",
+            NotPowerSnafu {
+                actual: string.to_owned()
+            }
+        );
+
+        Ok(Self)
+    }
+}
+
+#[derive(Debug, FromPyObject)]
+#[pyo3(from_item_all)]
+pub struct PowerSensorAttributes {
+    state_class: Measurement,
+    device_class: Power,
+    unit_of_measurement: UnitOfMeasurement,
+}
+
+#[derive(Debug, Snafu)]
+pub enum CreateSignalError {
+    /// couldn't get the underlying state object signal
+    StateObjectSignalError {
+        source: state_object::CreateSignalError,
+    },
+
+    /// couldn't map the state object to a power value
+    MappedSignalError {
+        source: emitter_and_signal::signal_ext::ProducerAlreadyExited,
+    },
+}
+
+pub fn signal<'py>(
+    py: Python<'py>,
+    home_assistant: &'py HomeAssistant,
+    object_id: ObjectId,
+) -> Result<
+    (
+        Signal<Option<Arc<Result<uom::si::f64::Power, StateObjectSignalError<PyErr>>>>>,
+        impl Future<Output = Result<(), emitter_and_signal::signal::JoinError>>,
+    ),
+    CreateSignalError,
+> {
+    let entity_id = EntityId(Domain::Light, object_id);
+
+    let (signal, task1) =
+        StateObject::<FromPyObjectViaParse<f64>, PowerSensorAttributes, Py<PyAny>>::signal(
+            py,
+            home_assistant,
+            entity_id,
+        )
+        .context(StateObjectSignalSnafu)?;
+
+    let (signal, task2) = signal
+        .map(|state_object_result_option| {
+            state_object_result_option.map(|state_object_result| {
+                Arc::new(
+                    Result::as_ref(&state_object_result)
+                        .map(|state_object| {
+                            let amount = state_object.state.0;
+                            let unit_of_measurement = state_object.attributes.unit_of_measurement;
+
+                            let power = unit_of_measurement.into_uom(amount);
+
+                            power
+                        })
+                        .map_err(|e| todo!()),
+                )
+            })
+        })
+        .context(MappedSignalSnafu)?;
+
+    Ok((
+        signal,
+        async move { tokio::try_join!(task1, task2).map(|_| ()) },
+    ))
+}

home-assistant/src/sensor/mod.rs

@@ -0,0 +1,2 @@
+pub mod device_classes;
+pub mod state_classes;

home-assistant/src/sensor/state_classes/measurement.rs

@@ -0,0 +1,48 @@
+use pyo3::{
+    exceptions::{PyException, PyValueError},
+    prelude::*,
+};
+use snafu::{ensure, ResultExt, Snafu};
+
+#[derive(Debug)]
+pub struct Measurement;
+
+#[derive(Debug, Snafu)]
+pub enum ExtractMeasurementError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+
+    /// the string {actual:?} is not "measurement" like it's supposed to be
+    NotMeasurement { actual: String },
+}
+
+impl From<ExtractMeasurementError> for PyErr {
+    fn from(error: ExtractMeasurementError) -> Self {
+        match &error {
+            ExtractMeasurementError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            ExtractMeasurementError::NotMeasurement { .. } => {
+                PyValueError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStrLiteral) / #[literal = "state_changed"] once I learn how to make something like that and see about serde or strum integration or inspiration
+impl<'a, 'py> FromPyObject<'a, 'py> for Measurement {
+    type Error = ExtractMeasurementError;
+
+    fn extract(obj: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let string: &str = obj.extract().context(ExtractStringSnafu)?;
+
+        ensure!(
+            string == "measurement",
+            NotMeasurementSnafu {
+                actual: string.to_owned()
+            }
+        );
+
+        Ok(Self)
+    }
+}

home-assistant/src/sensor/state_classes/mod.rs

@@ -0,0 +1 @@
+pub mod measurement;

home-assistant/src/service_registry.rs

@@ -1,33 +1,64 @@
 use super::{event::context::context::Context, service::IntoServiceCall};
-use pyo3::prelude::*;
-use python_utils::{detach, validate_type_by_name};
+use pyo3::{
+    exceptions::{PyException, PyTypeError},
+    prelude::*,
+};
+use python_utils::{detach, validate_type_by_name, TypeByNameValidationError};
+use snafu::{ResultExt, Snafu};
 
 #[derive(Debug)]
 pub struct ServiceRegistry(Py<PyAny>);
 
-impl<'py> FromPyObject<'py> for ServiceRegistry {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
+impl<'a, 'py> FromPyObject<'a, 'py> for ServiceRegistry {
+    type Error = TypeByNameValidationError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
         // region: Validation
-        validate_type_by_name(ob, "ServiceRegistry")?;
+        validate_type_by_name(&ob, "ServiceRegistry")?;
         // endregion: Validation
 
         Ok(Self(detach(ob)))
     }
 }
 
+#[derive(Debug, Snafu)]
+pub enum CallServiceError {
+    /// couldn't successfully call `async_call` and turn it into a `Future`
+    CallIntoFutureError { source: PyErr },
+
+    /// couldn't await the `Future` from the `async_call`
+    AwaitFutureError { source: PyErr },
+
+    /// couldn't extract the service response as the requested type
+    ExtractServiceResponseError { source: PyErr },
+}
+
+impl From<CallServiceError> for PyErr {
+    fn from(error: CallServiceError) -> Self {
+        match &error {
+            CallServiceError::CallIntoFutureError { .. } => PyException::new_err(error.to_string()),
+            CallServiceError::AwaitFutureError { .. } => PyException::new_err(error.to_string()),
+            CallServiceError::ExtractServiceResponseError { .. } => {
+                PyTypeError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
 impl ServiceRegistry {
     pub async fn call_service<
+        'a,
         ServiceData: for<'py> IntoPyObject<'py>,
         Target: for<'py> IntoPyObject<'py>,
         Event: for<'py> IntoPyObject<'py>,
-        ServiceResponse: for<'py> FromPyObject<'py>,
+        ServiceResponse: 'static + for<'py> FromPyObjectOwned<'py>,
     >(
-        &self,
+        &'a self,
         service_call: impl IntoServiceCall<ServiceData = ServiceData>,
         context: Option<Context<Event>>,
         target: Option<Target>,
         return_response: bool,
-    ) -> PyResult<ServiceResponse> {
+    ) -> Result<ServiceResponse, CallServiceError> {
         let (domain, service, service_data) = service_call.into_service_call();
 
         let blocking = true;
@@ -42,13 +73,21 @@ impl ServiceRegistry {
             return_response,
         );
 
-        let future = Python::with_gil::<_, PyResult<_>>(|py| {
+        let future = Python::attach::<_, PyResult<_>>(|py| {
             let service_registry = self.0.bind(py);
             let awaitable = service_registry.call_method("async_call", args, None)?;
             pyo3_async_runtimes::tokio::into_future(awaitable)
+        })
+        .context(CallIntoFutureSnafu)?;
+
+        let service_response = future.await.context(AwaitFutureSnafu)?;
+        let service_response = Python::attach(move |py| {
+            service_response
+                .extract(py)
+                .map_err(Into::into)
+                .context(ExtractServiceResponseSnafu)
         })?;
 
-        let service_response = future.await?;
-        Python::with_gil(|py| service_response.extract(py))
+        Ok(service_response)
     }
 }

home-assistant/src/slug.rs

@@ -1,11 +1,11 @@
-use std::str::FromStr;
+use std::{str::FromStr, sync::Arc};
 
 use pyo3::{exceptions::PyValueError, PyErr};
-use smol_str::SmolStr;
 use snafu::Snafu;
 
+// TODO: derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
 #[derive(Debug, Clone, derive_more::Display)]
-pub struct Slug(SmolStr);
+pub struct Slug(Arc<str>);
 
 #[derive(Debug, Clone, Snafu)]
 #[snafu(display("expected a lowercase ASCII alphabetical character (i.e. a through z) or a digit (i.e. 0 through 9) or an underscore (i.e. _) but encountered {encountered}"))]

home-assistant/src/state.rs

@@ -1,71 +0,0 @@
-use std::{convert::Infallible, str::FromStr};
-
-use pyo3::{exceptions::PyValueError, prelude::*};
-use smol_str::SmolStr;
-use strum::EnumString;
-
-/// A state in Home Assistant that is known to represent an error of some kind:
-/// * `unavailable` (the device is likely offline or unreachable from the Home Assistant instance)
-/// * `unknown` (I don't know how to explain this one)
-#[derive(Debug, Clone, EnumString, strum::Display)]
-#[strum(serialize_all = "snake_case")]
-pub enum ErrorState {
-    Unavailable,
-    Unknown,
-}
-
-impl<'py> FromPyObject<'py> for ErrorState {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract::<String>()?;
-
-        let state =
-            ErrorState::from_str(&s).map_err(|err| PyValueError::new_err(err.to_string()))?;
-
-        Ok(state)
-    }
-}
-
-#[derive(Debug, Clone, derive_more::Display, derive_more::FromStr)]
-pub struct UnexpectedState(pub SmolStr);
-
-impl<'py> FromPyObject<'py> for UnexpectedState {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract::<String>()?;
-        let s = SmolStr::new(s);
-
-        Ok(UnexpectedState(s))
-    }
-}
-
-#[derive(Debug, Clone, derive_more::Display)]
-pub enum HomeAssistantState<State> {
-    Ok(State),
-    Err(ErrorState),
-    UnexpectedErr(UnexpectedState),
-}
-
-impl<State: FromStr> FromStr for HomeAssistantState<State> {
-    type Err = Infallible;
-
-    fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
-        if let Ok(ok) = State::from_str(s) {
-            return Ok(HomeAssistantState::Ok(ok));
-        }
-
-        if let Ok(error) = ErrorState::from_str(s) {
-            return Ok(HomeAssistantState::Err(error));
-        }
-
-        Ok(HomeAssistantState::UnexpectedErr(UnexpectedState(s.into())))
-    }
-}
-
-impl<'py, State: FromStr + FromPyObject<'py>> FromPyObject<'py> for HomeAssistantState<State> {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        let s = ob.extract::<String>()?;
-
-        let Ok(state) = s.parse();
-
-        Ok(state)
-    }
-}

home-assistant/src/state/error_state.rs

@@ -0,0 +1,55 @@
+use std::str::FromStr;
+
+use pyo3::{
+    exceptions::{PyException, PyValueError},
+    prelude::*,
+};
+use snafu::{ResultExt, Snafu};
+use strum::EnumString;
+
+/// A state in Home Assistant that is known to represent an error of some kind:
+/// * `unavailable` (the device is likely offline or unreachable from the Home Assistant instance)
+/// * `unknown` (I don't know how to explain this one)
+#[derive(Debug, Clone, EnumString, strum::Display)]
+#[strum(serialize_all = "snake_case")]
+pub enum ErrorState {
+    Unavailable,
+    Unknown,
+}
+
+#[derive(Debug, Snafu)]
+pub enum ExtractErrorStateError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+
+    /// the string had an unexpected value
+    UnexpectedValue {
+        source: <ErrorState as FromStr>::Err,
+    },
+}
+
+impl From<ExtractErrorStateError> for PyErr {
+    fn from(error: ExtractErrorStateError) -> Self {
+        match &error {
+            ExtractErrorStateError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            ExtractErrorStateError::UnexpectedValue { .. } => {
+                PyValueError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py> FromPyObject<'a, 'py> for ErrorState {
+    type Error = ExtractErrorStateError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract::<String>().context(ExtractStringSnafu)?;
+
+        let state = ErrorState::from_str(&s).context(UnexpectedValueSnafu)?;
+
+        Ok(state)
+    }
+}

home-assistant/src/state/mod.rs

@@ -0,0 +1,64 @@
+use std::{convert::Infallible, str::FromStr};
+
+use pyo3::{exceptions::PyException, prelude::*};
+use snafu::{ResultExt, Snafu};
+
+pub mod error_state;
+pub mod unexpected_state;
+
+pub use error_state::ErrorState;
+pub use unexpected_state::UnexpectedState;
+
+#[derive(Debug, Clone, derive_more::Display)]
+pub enum HomeAssistantState<State> {
+    Ok(State),
+    Err(ErrorState),
+    UnexpectedErr(UnexpectedState),
+}
+
+impl<State: FromStr> FromStr for HomeAssistantState<State> {
+    type Err = Infallible;
+
+    fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
+        if let Ok(ok) = State::from_str(s) {
+            return Ok(HomeAssistantState::Ok(ok));
+        }
+
+        if let Ok(error) = ErrorState::from_str(s) {
+            return Ok(HomeAssistantState::Err(error));
+        }
+
+        Ok(HomeAssistantState::UnexpectedErr(UnexpectedState(s.into())))
+    }
+}
+
+#[derive(Debug, Snafu)]
+pub enum ExtractHomeAssistantStateError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+}
+
+impl From<ExtractHomeAssistantStateError> for PyErr {
+    fn from(error: ExtractHomeAssistantStateError) -> Self {
+        match &error {
+            ExtractHomeAssistantStateError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py, State: FromStr + FromPyObject<'a, 'py>> FromPyObject<'a, 'py>
+    for HomeAssistantState<State>
+{
+    type Error = ExtractHomeAssistantStateError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract::<&str>().context(ExtractStringSnafu)?;
+
+        let Ok(state) = s.parse();
+
+        Ok(state)
+    }
+}

home-assistant/src/state/unexpected_state.rs

@@ -0,0 +1,35 @@
+use std::sync::Arc;
+
+use pyo3::{exceptions::PyException, prelude::*};
+use snafu::{ResultExt, Snafu};
+
+#[derive(Debug, Clone, derive_more::Display)]
+pub struct UnexpectedState(pub Arc<str>);
+
+#[derive(Debug, Snafu)]
+pub enum ExtractUnexpectedStateError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+}
+
+impl From<ExtractUnexpectedStateError> for PyErr {
+    fn from(error: ExtractUnexpectedStateError) -> Self {
+        match &error {
+            ExtractUnexpectedStateError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py> FromPyObject<'a, 'py> for UnexpectedState {
+    type Error = ExtractUnexpectedStateError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = ob.extract::<String>().context(ExtractStringSnafu)?;
+        let s = s.into();
+
+        Ok(UnexpectedState(s))
+    }
+}

home-assistant/src/state_machine.rs

@@ -1,34 +1,58 @@
+use std::sync::Arc;
+
 use super::entity_id::EntityId;
 use super::state_object::StateObject;
 use pyo3::prelude::*;
-use python_utils::{detach, validate_type_by_name};
+use python_utils::{detach, validate_type_by_name, TypeByNameValidationError};
+use snafu::{ResultExt, Snafu};
 
 #[derive(Debug)]
 pub struct StateMachine(Py<PyAny>);
 
-impl<'py> FromPyObject<'py> for StateMachine {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
+impl<'a, 'py> FromPyObject<'a, 'py> for StateMachine {
+    type Error = TypeByNameValidationError;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
         // region: Validation
-        validate_type_by_name(ob, "StateMachine")?;
+        validate_type_by_name(&ob, "StateMachine")?;
         // endregion: Validation
 
         Ok(Self(detach(ob)))
     }
 }
 
+#[derive(Debug, Clone, Snafu)]
+pub enum GetStateError<ExtractStateObjectError: 'static + snafu::Error> {
+    /// couldn't get this state object from the state machine
+    GetStateObjectError { source: Arc<PyErr> },
+
+    /// couldn't extract the state as a [`StateObject`]
+    ExtractStateObjectError { source: ExtractStateObjectError },
+}
+
 impl StateMachine {
     pub fn get<
+        'a,
         'py,
-        State: FromPyObject<'py>,
-        Attributes: FromPyObject<'py>,
-        ContextEvent: FromPyObject<'py>,
+        State: FromPyObjectOwned<'py>,
+        Attributes: FromPyObjectOwned<'py>,
+        ContextEvent: FromPyObjectOwned<'py>,
     >(
-        &self,
+        &'a self,
         py: Python<'py>,
         entity_id: EntityId,
-    ) -> PyResult<Option<StateObject<State, Attributes, ContextEvent>>> {
+    ) -> Result<
+        Option<StateObject<State, Attributes, ContextEvent>>,
+        GetStateError<
+            <Option<StateObject<State, Attributes, ContextEvent>> as FromPyObject<'a, 'py>>::Error,
+        >,
+    > {
         let args = (entity_id.to_string(),);
-        let state = self.0.call_method1(py, "get", args)?;
-        state.extract(py)
+        let state = self
+            .0
+            .call_method1(py, "get", args)
+            .map_err(Arc::new)
+            .context(GetStateObjectSnafu)?;
+        Ok(state.extract(py).context(ExtractStateObjectSnafu)?)
     }
 }

home-assistant/src/state_object.rs

@@ -2,7 +2,7 @@ use super::{
     event::{context::context::Context, specific::state_changed},
     home_assistant::HomeAssistant,
 };
-use crate::entity_id::EntityId;
+use crate::{entity_id::EntityId, home_assistant::GetStatesError, state_machine::GetStateError};
 use chrono::{DateTime, Utc};
 use emitter_and_signal::signal::Signal;
 use once_cell::sync::OnceCell;
@@ -10,6 +10,7 @@ use pyo3::{
     prelude::*,
     types::{PyCFunction, PyDict, PyTuple},
 };
+use snafu::{ResultExt, Snafu};
 use std::{future::Future, sync::Arc};
 use tokio::{select, sync::mpsc};
 
@@ -24,30 +25,68 @@ pub struct StateObject<State, Attributes, ContextEvent> {
     pub context: Context<ContextEvent>,
 }
 
+pub type ExtractStateObjectError<'a, 'py, State, Attributes, ContextEvent> =
+    <StateObject<State, Attributes, ContextEvent> as FromPyObject<'a, 'py>>::Error;
+
+#[derive(Debug, Snafu)]
+pub enum CreateSignalError {
+    /// couldn't get the state machine from the Home Assistant object
+    GetStatesError { source: GetStatesError },
+}
+
+#[derive(Debug, Clone, Snafu)]
+pub enum StateObjectSignalError<ExtractStateObjectError: 'static + snafu::Error> {
+    /// couldn't get the state object directly from the state machine
+    GetFromStateMachine {
+        source: GetStateError<ExtractStateObjectError>,
+    },
+
+    /// couldn't get the state object from the new state event
+    GetFromNewStateEvent { source: Arc<PyErr> },
+}
+
 impl<
-        State: Send + Sync + 'static + for<'py> FromPyObject<'py>,
-        Attributes: Send + Sync + 'static + for<'py> FromPyObject<'py>,
-        ContextEvent: Send + Sync + 'static + for<'py> FromPyObject<'py>,
+        State: Send + Sync + 'static + for<'a, 'py> FromPyObject<'a, 'py>,
+        Attributes: Send + Sync + 'static + for<'a, 'py> FromPyObject<'a, 'py>,
+        ContextEvent: Send + Sync + 'static + for<'a, 'py> FromPyObject<'a, 'py>,
     > StateObject<State, Attributes, ContextEvent>
 {
-    pub fn store(
-        py: Python<'_>,
-        home_assistant: &HomeAssistant,
+    pub fn signal<'a, 'py>(
+        py: Python<'py>,
+        home_assistant: &'py HomeAssistant,
         entity_id: EntityId,
-    ) -> PyResult<(
-        Signal<Option<Arc<Self>>>,
+    ) -> Result<
+        (
+            Signal<
+                Option<
+                    Arc<
+                        Result<
+                            Self,
+                            StateObjectSignalError<<Self as FromPyObject<'a, 'py>>::Error>,
+                        >,
+                    >,
+                >,
+            >,
             impl Future<Output = Result<(), emitter_and_signal::signal::JoinError>>,
-    )> {
-        let state_machine = home_assistant.states(py)?;
-        let current = state_machine.get(py, entity_id.clone())?;
+        ),
+        CreateSignalError,
+    > {
+        let state_machine = home_assistant.states(py).context(GetStatesSnafu)?;
+        let current = state_machine
+            .get(py, entity_id.clone())
+            .context(GetFromStateMachineSnafu)
+            .transpose();
 
-        let py_home_assistant = home_assistant.into_pyobject(py)?.unbind();
+        let Ok(py_home_assistant) = home_assistant.into_pyobject(py);
+        let py_home_assistant = py_home_assistant.unbind();
 
-        let (store, task) = Signal::new(current.map(Arc::new), |mut publisher_stream| async move {
+        let (signal, task) = Signal::new(
+            current.map(Arc::new),
+            |mut publisher_stream| async move {
                 while let Some(publisher) = publisher_stream.wait().await {
                     let (new_state_sender, mut new_state_receiver) = mpsc::channel(8);
 
-                let untrack = Python::with_gil::<_, PyResult<_>>(|py| {
+                    let untrack = Python::attach::<_, PyResult<_>>(|py| {
                         static EVENT_MODULE: OnceCell<Py<PyModule>> = OnceCell::new();
 
                         let event_module = EVENT_MODULE
@@ -65,7 +104,7 @@ impl<
                                 #[cfg(feature = "tracing")]
                                 tracing::debug!("calling the closure");
 
-                                if let Ok((event,)) = args.extract::<(
+                                let new_state_res = args.extract::<(
                                     state_changed::Event<
                                         State,
                                         Attributes,
@@ -75,13 +114,9 @@ impl<
                                         ContextEvent,
                                         Py<PyAny>,
                                     >,
-                                )>() {
-                                    let new_state = event.data.new_state;
+                                )>().map(|event| event.0.data.new_state).map_err(Arc::new).context(GetFromNewStateEventSnafu);
 
-                                    #[cfg(feature = "tracing")]
-                                    tracing::debug!("sending a new state"); // TODO: remove
-                                    new_state_sender.try_send(new_state).unwrap();
-                                }
+                                new_state_sender.try_send(new_state_res).unwrap();
                             };
                             let callback = PyCFunction::new_closure(py, None, None, callback)?;
                             let args = (
@@ -91,44 +126,35 @@ impl<
                             );
                             event_module.call_method1("async_track_state_change_event", args)?
                         };
-                    #[cfg(feature = "tracing")]
-                    tracing::debug!(?untrack, "as any");
-
-                    let is_callable = untrack.is_callable();
-                    #[cfg(feature = "tracing")]
-                    tracing::debug!(?is_callable);
-
-                    // let untrack = untrack.downcast_into::<PyFunction>()?;
-                    // tracing::debug!(?untrack, "as downcast");
 
                         let untrack = untrack.unbind();
-                    #[cfg(feature = "tracing")]
-                    tracing::debug!(?untrack, "as unbound");
 
                         Ok(untrack)
                     });
 
                     if let Ok(untrack) = untrack {
                         #[cfg(feature = "tracing")]
-                    tracing::debug!("untrack is ok, going to wait for the next relevant event...");
+                        tracing::debug!(
+                            "untrack is ok, going to wait for the next relevant event..."
+                        );
                         loop {
                             select! {
                                 biased;
                                 _ = publisher.all_unsubscribed() => {
                                     #[cfg(feature = "tracing")]
                                     tracing::debug!("calling untrack");
-                                let res = Python::with_gil(|py| untrack.call0(py));
+                                    let res = Python::attach(|py| untrack.call0(py));
 
                                     #[cfg(feature = "tracing")]
                                     tracing::debug!(?res);
                                     break;
                                 }
-                            new_state = new_state_receiver.recv() => {
-                                match new_state {
-                                    Some(new_state) => {
+                                new_state_res_option = new_state_receiver.recv() => {
+                                    match new_state_res_option {
+                                        Some(new_state_res) => {
                                             #[cfg(feature = "tracing")]
                                             tracing::debug!("publishing new state");
-                                        publisher.publish(new_state.map(Arc::new))
+                                            publisher.publish(new_state_res.transpose().map(Arc::new));
                                         },
                                         None => {
                                             #[cfg(feature = "tracing")]
@@ -144,8 +170,9 @@ impl<
                         tracing::debug!("untrack is err");
                     }
                 }
-        });
+            },
+        );
 
-        Ok((store, task))
+        Ok((signal, task))
     }
 }

home-assistant/src/switch/mod.rs

@@ -0,0 +1 @@
+

home-assistant/src/unit_of_measurement/mod.rs

@@ -0,0 +1 @@
+pub mod power;

home-assistant/src/unit_of_measurement/power.rs

@@ -0,0 +1,102 @@
+use std::str::FromStr;
+
+use pyo3::{
+    exceptions::{PyException, PyValueError},
+    prelude::*,
+};
+use snafu::{ResultExt, Snafu};
+use strum::EnumString;
+use uom::{
+    si::{
+        energy::btu,
+        power::{gigawatt, kilowatt, megawatt, milliwatt, terawatt, watt},
+        quantities::{Energy, Power, Time},
+        time::hour,
+        Units, SI,
+    },
+    Conversion,
+};
+
+/// Power units
+#[derive(Debug, Clone, Copy, EnumString, strum::Display)]
+#[strum(serialize_all = "snake_case")]
+pub enum UnitOfMeasurement {
+    #[strum(serialize = "mW")]
+    MilliWatt,
+    #[strum(serialize = "W")]
+    Watt,
+    #[strum(serialize = "kW")]
+    KiloWatt,
+    #[strum(serialize = "MW")]
+    MegaWatt,
+    #[strum(serialize = "GW")]
+    GigaWatt,
+    #[strum(serialize = "TW")]
+    TeraWatt,
+    #[strum(serialize = "BTU/h")]
+    BtuPerhour,
+}
+
+#[derive(Debug, Snafu)]
+pub enum ExtractUnitOfMeasurementError {
+    /// couldn't extract the object as a string
+    ExtractStringError { source: PyErr },
+
+    /// couldn't parse the string as a [`UnitOfMeasurement`]
+    ParseError {
+        source: <UnitOfMeasurement as FromStr>::Err,
+    },
+}
+
+impl From<ExtractUnitOfMeasurementError> for PyErr {
+    fn from(error: ExtractUnitOfMeasurementError) -> Self {
+        match &error {
+            ExtractUnitOfMeasurementError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            ExtractUnitOfMeasurementError::ParseError { .. } => {
+                PyValueError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+// TODO: replace with a derive(PyFromStr) (analogous to serde_with::DeserializeFromStr) once I make one
+impl<'a, 'py> FromPyObject<'a, 'py> for UnitOfMeasurement {
+    type Error = ExtractUnitOfMeasurementError;
+
+    fn extract(obj: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = obj.extract().context(ExtractStringSnafu)?;
+        let unit_of_measurement = UnitOfMeasurement::from_str(s).context(ParseSnafu)?;
+
+        Ok(unit_of_measurement)
+    }
+}
+
+impl UnitOfMeasurement {
+    pub fn into_uom<V>(&self, amount: V) -> Power<V>
+    where
+        V: uom::num::Num + uom::Conversion<V, T = V>,
+        milliwatt: Conversion<V, T = V>,
+        watt: Conversion<V, T = V>,
+        kilowatt: Conversion<V, T = V>,
+        megawatt: Conversion<V, T = V>,
+        gigawatt: Conversion<V, T = V>,
+        terawatt: Conversion<V, T = V>,
+        btu: Conversion<V, T = V>,
+        hour: Conversion<V, T = V>,
+        SI<V>: Units<V>,
+    {
+        match self {
+            UnitOfMeasurement::MilliWatt => Power::new::<milliwatt>(amount),
+            UnitOfMeasurement::Watt => Power::new::<watt>(amount),
+            UnitOfMeasurement::KiloWatt => Power::new::<kilowatt>(amount),
+            UnitOfMeasurement::MegaWatt => Power::new::<megawatt>(amount),
+            UnitOfMeasurement::GigaWatt => Power::new::<gigawatt>(amount),
+            UnitOfMeasurement::TeraWatt => Power::new::<terawatt>(amount),
+            UnitOfMeasurement::BtuPerhour => {
+                Energy::new::<btu>(amount) / Time::new::<hour>(V::one())
+            }
+        }
+    }
+}

persisted/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "persisted"
+version = "0.1.0"
+edition = "2021"
+license.workspace = true
+
+[dependencies]
+bytes = { workspace = true }
+emitter-and-signal = { path = "../emitter-and-signal" }
+fjall = "2.11"
+postcard = { version = "1.1", features = ["use-std"] }
+serde = { workspace = true }
+snafu = { workspace = true }
+tokio = { workspace = true, features = ["rt", "sync"] }

persisted/src/lib.rs

@@ -0,0 +1,111 @@
+pub use bytes::Bytes;
+use emitter_and_signal::signal::{JoinError, Signal};
+pub use fjall::{Config, Keyspace, Partition, PartitionCreateOptions};
+use serde::{Deserialize, Serialize};
+use snafu::{OptionExt, ResultExt, Snafu};
+use std::{fmt::Debug, future::Future, num::NonZeroUsize, ops::Deref, sync::Arc};
+use tokio::{
+    select,
+    sync::{mpsc, oneshot},
+    task::spawn_blocking,
+};
+
+#[derive(Debug, Clone, Snafu)]
+pub enum PersistedError {
+    Missing,
+    CreationError {
+        // Wrapped in [`Arc`] to make this [`Clone`]
+        source: Arc<fjall::Error>,
+    },
+    DeserializationError {
+        source: postcard::Error,
+    },
+}
+
+pub async fn persisted<T: Debug + Send + Sync + 'static + Serialize + for<'a> Deserialize<'a>>(
+    partition: Partition,
+    identifier: Bytes,
+    buffer: NonZeroUsize,
+) -> (
+    Setter<T>,
+    Signal<Result<T, PersistedError>>,
+    impl Future<Output = Result<(), JoinError>>,
+) {
+    let initial = spawn_blocking({
+        let partition = partition.clone();
+        let identifier = identifier.clone();
+        move || partition.get(identifier.deref())
+    })
+    .await
+    .unwrap()
+    .map_err(Arc::new)
+    .context(CreationSnafu)
+    .and_then(|op| op.context(MissingSnafu))
+    .and_then(|slice| postcard::from_bytes(&slice).context(DeserializationSnafu));
+
+    let (set_tx, mut set_rx) = mpsc::channel(buffer.get());
+    let setter = Setter { sender: set_tx };
+
+    let (signal, task) = Signal::new(initial, move |mut publisher_stream| async move {
+        while let Some(publisher) = publisher_stream.wait().await {
+            loop {
+                select! {
+                    biased;
+                    _ = publisher.all_unsubscribed() => {
+                        break;
+                    }
+                    new_value_opt = set_rx.recv() => {
+                        let Some((new_value, callback)) = new_value_opt else { return };
+                        let serialized_res = postcard::to_stdvec(&new_value).context(SerializationSnafu);
+                        // Stand-in for Option::async_and_then
+                        let persisted_res = match serialized_res {
+                            Ok(serialized) => spawn_blocking({
+                                let partition = partition.clone();
+                                let identifier = identifier.clone();
+                                move || partition.insert(identifier.deref(), serialized)
+                            }).await.unwrap().context(SavingSnafu),
+                            Err(error) => Err(error),
+                        };
+
+                        if persisted_res.is_ok() {
+                            publisher.publish(Ok(new_value));
+                        }
+
+                        let _ = callback.send(persisted_res);
+                    }
+                }
+            }
+        }
+    });
+
+    (setter, signal, task)
+}
+
+#[derive(Debug, Clone)]
+pub struct Setter<T: 'static> {
+    sender: mpsc::Sender<(T, oneshot::Sender<Result<(), SetError<T>>>)>,
+}
+
+// TODO: add doc comments functioning as error Display
+#[derive(Debug, Snafu)]
+pub enum SetError<T: 'static> {
+    Closed { source: mpsc::error::SendError<T> },
+    NoFeedback { source: oneshot::error::RecvError },
+    SerializationError { source: postcard::Error },
+    SavingError { source: fjall::Error },
+}
+
+impl<T: Debug> Setter<T> {
+    pub async fn set(&self, value: T) -> Result<(), SetError<T>> {
+        let (callback_tx, callback_rx) = oneshot::channel();
+
+        self.sender
+            .send((value, callback_tx))
+            .await
+            .map_err(|send_error| mpsc::error::SendError(send_error.0 .0))
+            .context(ClosedSnafu)?;
+
+        let set_res = callback_rx.await.context(NoFeedbackSnafu)?;
+        set_res
+    }
+}

python-utils/Cargo.toml

@@ -5,4 +5,6 @@ edition = "2021"
 license = { workspace = true }
 
 [dependencies]
+derive_more = { workspace = true }
 pyo3 = { workspace = true }
+snafu = { workspace = true }

python-utils/src/lib.rs

@@ -1,45 +1,150 @@
-use std::convert::Infallible;
+use std::{convert::Infallible, fmt::Display, str::FromStr, sync::Arc};
 
-use pyo3::{exceptions::PyTypeError, prelude::*, types::PyNone};
+use pyo3::{
+    exceptions::{PyException, PyTypeError, PyValueError},
+    prelude::*,
+    types::PyString,
+};
+use snafu::{ResultExt, Snafu};
 
-#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub struct IsNone;
-
-impl<'py> FromPyObject<'py> for IsNone {
-    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
-        ob.downcast::<PyNone>()?;
-        Ok(IsNone)
-    }
-}
-
-impl<'py> IntoPyObject<'py> for IsNone {
-    type Target = PyNone;
-
-    type Output = Borrowed<'py, 'py, Self::Target>;
-
-    type Error = Infallible;
-
-    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
-        Ok(PyNone::get(py))
-    }
-}
+pub mod none;
+pub use none::IsNone;
 
 /// Create a GIL-independent reference
-pub fn detach<T>(bound: &Bound<T>) -> Py<T> {
-    let py = bound.py();
-    bound.as_unbound().clone_ref(py)
+pub fn detach<T>(borrowed: Borrowed<'_, '_, T>) -> Py<T> {
+    let py = borrowed.py();
+    borrowed.as_unbound().clone_ref(py)
+}
+/// Create a GIL-independent reference
+pub fn detach_bound<T>(bound: &Bound<T>) -> Py<T> {
+    detach(bound.as_borrowed())
 }
 
-pub fn validate_type_by_name(bound: &Bound<PyAny>, expected_type_name: &str) -> PyResult<()> {
+#[derive(Debug, Snafu)]
+pub enum TypeByNameValidationError {
+    /// error getting the type name of this object
+    GetTypeNameError { source: PyErr },
+    /// error extracting the (successfully retrieved) type name as an [`&str`]
+    ExtractTypeNameError { source: PyErr },
+
+    /// error getting the fully qualified type name of this object
+    GetFullyQualifiedTypeNameError { source: PyErr },
+    /// error extracting the (successfully retrieved) fully qualified type name as an [`&str`]
+    ExtractFullyQualifiedTypeNameError { source: PyErr },
+
+    /// expected an instance of {expected} but got an instance of {actual}
+    UnexpectedType { expected: String, actual: String },
+}
+
+impl From<TypeByNameValidationError> for PyErr {
+    fn from(error: TypeByNameValidationError) -> Self {
+        match &error {
+            TypeByNameValidationError::GetTypeNameError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            TypeByNameValidationError::ExtractTypeNameError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            TypeByNameValidationError::GetFullyQualifiedTypeNameError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            TypeByNameValidationError::ExtractFullyQualifiedTypeNameError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            TypeByNameValidationError::UnexpectedType { .. } => {
+                PyTypeError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+pub fn validate_type_by_name(
+    bound: &Bound<PyAny>,
+    expected_type_name: &str,
+) -> Result<(), TypeByNameValidationError> {
     let py_type = bound.get_type();
-    let type_name = py_type.name()?;
-    let type_name = type_name.to_str()?;
+    let type_name = py_type.name().context(GetTypeNameSnafu)?;
+    let type_name = type_name.to_str().context(ExtractTypeNameSnafu)?;
 
     if type_name != expected_type_name {
-        let fully_qualified_type_name = py_type.fully_qualified_name()?;
-        let fully_qualified_type_name = fully_qualified_type_name.to_str()?;
-        return Err(PyTypeError::new_err(format!("expected an instance of {expected_type_name} but got an instance of {fully_qualified_type_name}")));
+        let fully_qualified_type_name = py_type
+            .fully_qualified_name()
+            .context(GetFullyQualifiedTypeNameSnafu)?;
+        let fully_qualified_type_name = fully_qualified_type_name
+            .to_str()
+            .context(ExtractFullyQualifiedTypeNameSnafu)?;
+        return Err(TypeByNameValidationError::UnexpectedType {
+            expected: expected_type_name.to_owned(),
+            actual: fully_qualified_type_name.to_owned(),
+        });
     }
 
     return Ok(());
 }
+
+#[derive(Debug, Clone, derive_more::Display)]
+pub struct IntoPyObjectViaDisplay<T>(pub T);
+
+impl<'py, T> IntoPyObject<'py> for IntoPyObjectViaDisplay<T>
+where
+    T: Display,
+{
+    type Target = PyString;
+    type Output = Bound<'py, Self::Target>;
+    type Error = Infallible;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        let s = self.to_string();
+        s.into_pyobject(py)
+    }
+}
+
+#[derive(Debug, Clone, derive_more::FromStr)]
+pub struct FromPyObjectViaParse<T>(pub T);
+
+#[derive(Debug, Clone, Snafu)]
+pub enum ExtractPyObjectViaParseError<ParseError>
+where
+    ParseError: 'static + snafu::Error,
+{
+    /// couldn't extract the object as a string
+    ExtractStringError { source: Arc<PyErr> },
+
+    /// couldn't parse the string as an instance of this Rust type
+    ParseError { source: ParseError },
+}
+
+impl<E> From<ExtractPyObjectViaParseError<E>> for PyErr
+where
+    E: 'static + snafu::Error,
+{
+    fn from(error: ExtractPyObjectViaParseError<E>) -> Self {
+        match &error {
+            ExtractPyObjectViaParseError::ExtractStringError { .. } => {
+                PyException::new_err(error.to_string())
+            }
+            ExtractPyObjectViaParseError::ParseError { .. } => {
+                PyValueError::new_err(error.to_string())
+            }
+        }
+    }
+}
+
+impl<'a, 'py, T> FromPyObject<'a, 'py> for FromPyObjectViaParse<T>
+where
+    T: FromStr,
+    <T as FromStr>::Err: 'static + snafu::Error,
+    PyErr: From<ExtractPyObjectViaParseError<<T as FromStr>::Err>>,
+{
+    type Error = ExtractPyObjectViaParseError<<T as FromStr>::Err>;
+
+    fn extract(obj: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        let s = obj
+            .extract::<&str>()
+            .map_err(Arc::new)
+            .context(ExtractStringSnafu)?;
+        let t = T::from_str(s).context(ParseSnafu)?;
+
+        Ok(FromPyObjectViaParse(t))
+    }
+}

python-utils/src/none.rs

@@ -0,0 +1,27 @@
+use std::convert::Infallible;
+
+use pyo3::{types::PyNone, Borrowed, FromPyObject, IntoPyObject, PyAny, PyErr, Python};
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub struct IsNone;
+
+impl<'a, 'py> FromPyObject<'a, 'py> for IsNone {
+    type Error = PyErr;
+
+    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> Result<Self, Self::Error> {
+        ob.cast::<PyNone>()?;
+        Ok(IsNone)
+    }
+}
+
+impl<'py> IntoPyObject<'py> for IsNone {
+    type Target = PyNone;
+
+    type Output = Borrowed<'py, 'py, Self::Target>;
+
+    type Error = Infallible;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        Ok(PyNone::get(py))
+    }
+}