Expect metric only as a generic argument in logical meter formulas

shsms · shsms · commit 49fb95a12896 · 2026-04-01T13:54:58.000+02:00
And no-longer as a function parameter.

Signed-off-by: Sahas Subramanian &lt;sahas.subramanian@proton.me&gt;
diff --git a/examples/logical_meter.rs b/examples/logical_meter.rs
@@ -25,14 +25,14 @@ async fn main() -> Result<(), Error> {
     )
     .await?;
 
-    let formula_grid = logical_meter.grid(metric::AcPowerActive)?;
-    let formula_pv = logical_meter.pv(None, metric::AcPowerActive)?;
-    let formula_consumer = logical_meter.consumer(metric::AcPowerActive)?;
+    let formula_grid = logical_meter.grid::<metric::AcPowerActive>()?;
+    let formula_pv = logical_meter.pv::<metric::AcPowerActive>(None)?;
+    let formula_consumer = logical_meter.consumer::<metric::AcPowerActive>()?;
 
     // Create a formula that calculates `grid_power - pv_power + consumer_power + 100kW`.
-    let formula = logical_meter.grid(metric::AcPowerActive)?
-        - logical_meter.pv(None, metric::AcPowerActive)?
-        + logical_meter.consumer(metric::AcPowerActive)?
+    let formula = logical_meter.grid::<metric::AcPowerActive>()?
+        - logical_meter.pv::<metric::AcPowerActive>(None)?
+        + logical_meter.consumer::<metric::AcPowerActive>()?
         + Power::from_kilowatts(100.0);
 
     let mut rx = formula.subscribe().await?;
@@ -68,10 +68,10 @@ async fn main() -> Result<(), Error> {
 
     // Create a formula that calculates the grid voltage as:
     // COALESCE(grid_voltage, AVG(grid_voltage_p1, grid_voltage_p2, grid_voltage_p3) * SQRT(3))
-    let formula_grid_voltage = logical_meter.grid(metric::AcVoltage)?.coalesce(
-        logical_meter.grid(metric::AcVoltagePhase1N)?.avg(vec![
-            logical_meter.grid(metric::AcVoltagePhase2N)?,
-            logical_meter.grid(metric::AcVoltagePhase3N)?,
+    let formula_grid_voltage = logical_meter.grid::<metric::AcVoltage>()?.coalesce(
+        logical_meter.grid::<metric::AcVoltagePhase1N>()?.avg(vec![
+            logical_meter.grid::<metric::AcVoltagePhase2N>()?,
+            logical_meter.grid::<metric::AcVoltagePhase3N>()?,
         ])? * 3.0_f32.sqrt(),
     )?;
 
@@ -95,18 +95,21 @@ async fn main() -> Result<(), Error> {
     drop(consumer_rx);
 
     let mut p1 = logical_meter
-        .grid(metric::AcVoltagePhase1N)?
+        .grid::<metric::AcVoltagePhase1N>()?
         .subscribe()
         .await?;
     let mut p2 = logical_meter
-        .grid(metric::AcVoltagePhase2N)?
+        .grid::<metric::AcVoltagePhase2N>()?
         .subscribe()
         .await?;
     let mut p3 = logical_meter
-        .grid(metric::AcVoltagePhase3N)?
+        .grid::<metric::AcVoltagePhase3N>()?
+        .subscribe()
+        .await?;
+    let mut three_phase = logical_meter
+        .grid::<metric::AcVoltage>()?
         .subscribe()
         .await?;
-    let mut three_phase = logical_meter.grid(metric::AcVoltage)?.subscribe().await?;
 
     loop {
         let sample = grid_voltage_rx.recv().await.unwrap();
diff --git a/src/logical_meter/formula.rs b/src/logical_meter/formula.rs
@@ -3,6 +3,8 @@
 
 //! Formula module for the logical meter.
 
+use std::marker::PhantomData;
+
 use async_trait::async_trait;
 pub(crate) mod aggregation_formula;
 mod async_formula;
@@ -37,20 +39,19 @@ pub trait FormulaSubscriber: std::fmt::Display + Sync + Send {
 /// Parameters for creating a logical meter formula.
 pub(super) struct FormulaParams<F: GraphFormulaConnector, M: Metric> {
     pub(super) formula: F::GraphFormulaType,
-    pub(super) metric: M,
     pub(super) instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,
+    phantom: PhantomData<M>,
 }
 
 impl<F: GraphFormulaConnector, M: Metric> FormulaParams<F, M> {
     pub(super) fn new(
         formula: F::GraphFormulaType,
-        metric: M,
         instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,
     ) -> Self {
         Self {
             formula,
-            metric,
             instructions_tx,
+            phantom: PhantomData,
         }
     }
 }
diff --git a/src/logical_meter/formula/aggregation_formula.rs b/src/logical_meter/formula/aggregation_formula.rs
@@ -3,6 +3,8 @@
 
 //! An formula that supports aggregation operations.
 
+use std::marker::PhantomData;
+
 use super::{FormulaParams, FormulaSubscriber, GraphFormulaConnector};
 use crate::{
     Error, Sample, logical_meter::logical_meter_actor, metric::Metric, quantity::Quantity,
@@ -13,8 +15,8 @@ use tokio::sync::{broadcast, mpsc, oneshot};
 #[derive(Clone)]
 pub struct AggregationFormula<M: Metric> {
     formula: frequenz_microgrid_component_graph::AggregationFormula,
-    metric: M,
     instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,
+    phantom: PhantomData<M>,
 }
 
 impl<M: Metric> std::fmt::Display for AggregationFormula<M> {
@@ -56,8 +58,8 @@ impl<M: Metric> From<FormulaParams<AggregationFormula<M>, M>> for AggregationFor
     fn from(params: FormulaParams<AggregationFormula<M>, M>) -> Self {
         Self {
             formula: params.formula,
-            metric: params.metric,
             instructions_tx: params.instructions_tx,
+            phantom: PhantomData,
         }
     }
 }
@@ -66,8 +68,8 @@ impl<M: Metric> From<AggregationFormula<M>> for FormulaParams<AggregationFormula
     fn from(formula: AggregationFormula<M>) -> Self {
         FormulaParams {
             formula: formula.formula,
-            metric: formula.metric,
             instructions_tx: formula.instructions_tx,
+            phantom: PhantomData,
         }
     }
 }
diff --git a/src/logical_meter/formula/coalesce_formula.rs b/src/logical_meter/formula/coalesce_formula.rs
@@ -3,6 +3,8 @@
 
 //! An coalesce formula.
 
+use std::marker::PhantomData;
+
 use super::{FormulaParams, FormulaSubscriber, GraphFormulaConnector};
 use crate::{
     Error, Sample, logical_meter::logical_meter_actor, metric::Metric, quantity::Quantity,
@@ -13,8 +15,8 @@ use tokio::sync::{broadcast, mpsc, oneshot};
 #[derive(Clone)]
 pub struct CoalesceFormula<M: Metric> {
     formula: frequenz_microgrid_component_graph::CoalesceFormula,
-    metric: M,
     instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,
+    phantom: PhantomData<M>,
 }
 
 impl<M: Metric> std::fmt::Display for CoalesceFormula<M> {
@@ -56,8 +58,8 @@ impl<M: Metric> From<FormulaParams<CoalesceFormula<M>, M>> for CoalesceFormula<M
     fn from(params: FormulaParams<CoalesceFormula<M>, M>) -> Self {
         Self {
             formula: params.formula,
-            metric: params.metric,
             instructions_tx: params.instructions_tx,
+            phantom: PhantomData,
         }
     }
 }
@@ -66,7 +68,7 @@ impl<M: Metric> From<CoalesceFormula<M>> for FormulaParams<CoalesceFormula<M>, M
     fn from(formula: CoalesceFormula<M>) -> Self {
         FormulaParams {
             formula: formula.formula,
-            metric: formula.metric,
+            phantom: formula.phantom,
             instructions_tx: formula.instructions_tx,
         }
     }
diff --git a/src/logical_meter/formula/graph_formula_provider.rs b/src/logical_meter/formula/graph_formula_provider.rs
@@ -22,7 +22,6 @@ macro_rules! graph_formula_provider {
 
         fn $fnname(
             _graph: &ComponentGraph<ElectricalComponent, ElectricalComponentConnection>,
-            metric: Self::MetricType,
             _instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,
             $($idsparam: Option<BTreeSet<u64>>,)?
             $($idparam: u64,)?
@@ -31,7 +30,7 @@ macro_rules! graph_formula_provider {
                 format!(
                     "The component graph does not support {} formula generation for {}.",
                     stringify!($fnname),
-                    metric.str_name()
+                    Self::MetricType::str_name()
                 )
             ));
         }
@@ -70,7 +69,6 @@ macro_rules! impl_graph_formula_provider {
 
         fn $fnname(
             graph: &ComponentGraph<ElectricalComponent, ElectricalComponentConnection>,
-            metric: Self::MetricType,
             instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,
             $($idsparam: Option<BTreeSet<u64>>,)?
             $($idparam: u64,)?
@@ -80,7 +78,7 @@ macro_rules! impl_graph_formula_provider {
                     format!("Could not get {} formula: {e}", stringify!($fnname))
                 )
             })?;
-            Ok(FormulaParams::new(formula, metric, instructions_tx).into())
+            Ok(FormulaParams::new(formula, instructions_tx).into())
         }
 
     )+};
diff --git a/src/logical_meter/logical_meter_handle.rs b/src/logical_meter/logical_meter_handle.rs
diff --git a/src/metric.rs b/src/metric.rs

Original file line number	Diff line number	Diff line change
`@@ -3,6 +3,8 @@`
`3`	`3`
`4`	`4`	`//! An formula that supports aggregation operations.`
`5`	`5`
	`6`	`+use std::marker::PhantomData;`
	`7`	`+`
`6`	`8`	`use super::{FormulaParams, FormulaSubscriber, GraphFormulaConnector};`
`7`	`9`	`use crate::{`
`8`	`10`	`Error, Sample, logical_meter::logical_meter_actor, metric::Metric, quantity::Quantity,`
`@@ -13,8 +15,8 @@ use tokio::sync::{broadcast, mpsc, oneshot};`
`13`	`15`	`#[derive(Clone)]`
`14`	`16`	`pub struct AggregationFormula<M: Metric> {`
`15`	`17`	`formula: frequenz_microgrid_component_graph::AggregationFormula,`
`16`		`- metric: M,`
`17`	`18`	`instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,`
	`19`	`+ phantom: PhantomData<M>,`
`18`	`20`	`}`
`19`	`21`
`20`	`22`	`impl<M: Metric> std::fmt::Display for AggregationFormula<M> {`
`@@ -56,8 +58,8 @@ impl<M: Metric> From<FormulaParams<AggregationFormula<M>, M>> for AggregationFor`
`56`	`58`	`fn from(params: FormulaParams<AggregationFormula<M>, M>) -> Self {`
`57`	`59`	`Self {`
`58`	`60`	`formula: params.formula,`
`59`		`- metric: params.metric,`
`60`	`61`	`instructions_tx: params.instructions_tx,`
	`62`	`+ phantom: PhantomData,`
`61`	`63`	`}`
`62`	`64`	`}`
`63`	`65`	`}`
`@@ -66,8 +68,8 @@ impl<M: Metric> From<AggregationFormula<M>> for FormulaParams<AggregationFormula`
`66`	`68`	`fn from(formula: AggregationFormula<M>) -> Self {`
`67`	`69`	`FormulaParams {`
`68`	`70`	`formula: formula.formula,`
`69`		`- metric: formula.metric,`
`70`	`71`	`instructions_tx: formula.instructions_tx,`
	`72`	`+ phantom: PhantomData,`
`71`	`73`	`}`
`72`	`74`	`}`
`73`	`75`	`}`
Original file line number	Diff line number	Diff line change
`@@ -3,6 +3,8 @@`
`3`	`3`
`4`	`4`	`//! An coalesce formula.`
`5`	`5`
	`6`	`+use std::marker::PhantomData;`
	`7`	`+`
`6`	`8`	`use super::{FormulaParams, FormulaSubscriber, GraphFormulaConnector};`
`7`	`9`	`use crate::{`
`8`	`10`	`Error, Sample, logical_meter::logical_meter_actor, metric::Metric, quantity::Quantity,`
`@@ -13,8 +15,8 @@ use tokio::sync::{broadcast, mpsc, oneshot};`
`13`	`15`	`#[derive(Clone)]`
`14`	`16`	`pub struct CoalesceFormula<M: Metric> {`
`15`	`17`	`formula: frequenz_microgrid_component_graph::CoalesceFormula,`
`16`		`- metric: M,`
`17`	`18`	`instructions_tx: mpsc::Sender<logical_meter_actor::Instruction>,`
	`19`	`+ phantom: PhantomData<M>,`
`18`	`20`	`}`
`19`	`21`
`20`	`22`	`impl<M: Metric> std::fmt::Display for CoalesceFormula<M> {`
`@@ -56,8 +58,8 @@ impl<M: Metric> From<FormulaParams<CoalesceFormula<M>, M>> for CoalesceFormula<M`
`56`	`58`	`fn from(params: FormulaParams<CoalesceFormula<M>, M>) -> Self {`
`57`	`59`	`Self {`
`58`	`60`	`formula: params.formula,`
`59`		`- metric: params.metric,`
`60`	`61`	`instructions_tx: params.instructions_tx,`
	`62`	`+ phantom: PhantomData,`
`61`	`63`	`}`
`62`	`64`	`}`
`63`	`65`	`}`
`@@ -66,7 +68,7 @@ impl<M: Metric> From<CoalesceFormula<M>> for FormulaParams<CoalesceFormula<M>, M`
`66`	`68`	`fn from(formula: CoalesceFormula<M>) -> Self {`
`67`	`69`	`FormulaParams {`
`68`	`70`	`formula: formula.formula,`
`69`		`- metric: formula.metric,`
	`71`	`+ phantom: formula.phantom,`
`70`	`72`	`instructions_tx: formula.instructions_tx,`
`71`	`73`	`}`
`72`	`74`	`}`