don't make the user specify sensor IDs in config

While working on #6354, it turned out that having to manually assign
these was really easy to mess up when you want to simulate a lot of
sensors, and there wasn't an easy way to get "real" ID values from an
inventory of a real life SP, so the config writer has to assign them
sequentially anyway. #6354 ended up using `component_details`
rather than `read_sensor`, so being able to assign sensor IDs identical
to those from Hubris turned out to not be that important, since (IIUC)
the only way to get the `SensorId`s is to look at the Hubris archive,
while *component* IDs can be discovered dynamically from the inventory
APIs.

sp-sim/examples/config.toml

@@ -31,7 +31,7 @@ description = "FAKE Southwest temperature sensor"
 capabilities = 2
 presence = "Present"
 sensors = [
-    { name = "Southwest", kind = "Temperature", sensor_id = 0, last_data.value = 41.7890625, last_data.timestamp = 1234 },
+    { name = "Southwest", kind = "Temperature", last_data.value = 41.7890625, last_data.timestamp = 1234 },
 ]
 
 [[simulated_sps.gimlet]]
@@ -56,7 +56,7 @@ description = "FAKE Southwest temperature sensor"
 capabilities = 2
 presence = "Present"
 sensors = [
-    { name = "Southwest", kind = "Temperature", sensor_id = 0, last_data.value = 41.7890625, last_data.timestamp = 1234 },
+    { name = "Southwest", kind = "Temperature", last_data.value = 41.7890625, last_data.timestamp = 1234 },
 ]
 
 

sp-sim/src/sensors.rs

@@ -21,8 +21,7 @@ use std::collections::HashMap;
 
 pub(crate) struct Sensors {
     by_component: HashMap<SpComponent, Vec<u32>>,
-
-    sensors: HashMap<u32, Sensor>,
+    sensors: Vec<Sensor>,
 }
 
 #[derive(Debug)]
@@ -35,7 +34,6 @@ struct Sensor {
 pub struct SensorDef {
     pub name: String,
     pub kind: MeasurementKind,
-    pub sensor_id: u32,
 }
 
 // TODO(eliza): note that currently, we just hardcode these in
@@ -104,7 +102,7 @@ impl Sensors {
     pub(crate) fn from_component_configs<'a>(
         cfgs: impl IntoIterator<Item = &'a SpComponentConfig>,
     ) -> Self {
-        let mut sensors = HashMap::new();
+        let mut sensors = Vec::new();
         let mut by_component = HashMap::new();
         for cfg in cfgs {
             if cfg.sensors.is_empty() {
@@ -122,19 +120,11 @@ impl Sensors {
 
             let mut ids = Vec::with_capacity(cfg.sensors.len());
             for sensor in &cfg.sensors {
-                let sensor_id = sensor.def.sensor_id;
-                let prev = sensors.insert(
-                    sensor_id,
-                    Sensor {
-                        def: sensor.def.clone(),
-                        state: sensor.state.clone(),
-                    },
-                );
-                assert!(
-                    prev.is_none(),
-                    "invalid config: sensor ID {sensor_id} already exists!\n
-                     previous sensor: {prev:#?}\nnew sensor: {sensor:#?}"
-                );
+                let sensor_id = sensors.len() as u32;
+                sensors.push(Sensor {
+                    def: sensor.def.clone(),
+                    state: sensor.state.clone(),
+                });
                 ids.push(sensor_id)
             }
 
@@ -150,8 +140,8 @@ impl Sensors {
         component: &SpComponent,
         index: BoundsChecked,
     ) -> Option<&'sensors Sensor> {
-        let id = self.by_component.get(component)?.get(index.0 as usize)?;
-        self.sensors.get(id)
+        let &id = self.by_component.get(component)?.get(index.0 as usize)?;
+        self.sensors.get(id as usize)
     }
 
     pub(crate) fn num_component_details(
@@ -201,7 +191,8 @@ impl Sensors {
         &self,
         SensorRequest { id, kind }: SensorRequest,
     ) -> Result<SensorResponse, SensorError> {
-        let sensor = self.sensors.get(&id).ok_or(SensorError::InvalidSensor)?;
+        let sensor =
+            self.sensors.get(id as usize).ok_or(SensorError::InvalidSensor)?;
         match kind {
             SensorRequestKind::LastReading => {
                 Ok(SensorResponse::LastReading(sensor.state.last_reading()))