fix(mqtt): one HA device per node — closes #898

After the #872 MQTT wiring, the JSON->VitalsSnapshot bridge hard-coded a
single node_id (the MQTT client id) and the publisher used one
OwnedDiscoveryBuilder, so every physical node collapsed into a single
Home-Assistant device (identifiers:["wifi_densepose_wifi-densepose-1"]),
contradicting the one-device-per-node docs.

- Bridge (main.rs): emit one VitalsSnapshot per node in the sensing
  update's nodes[] (each carries its own node_id + RSSI; shared aggregate
  presence/vitals), falling back to a single aggregate snapshot when
  there is no per-node data (wifi/simulate sources).
- Publisher (publisher.rs): add OwnedDiscoveryBuilder::for_node(), and
  publish discovery + availability lazily on first sight of each node_id,
  routing state to per-node topics. Heartbeat/refresh/offline-LWT iterate
  all known nodes. Result: N distinct HA devices, one per node.

3 new unit tests (distinct nodes -> distinct wifi_densepose_<node>
identifiers); full MQTT suite 71 passed, example builds.

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Fixed
+- **MQTT multi-node deployments now create one Home-Assistant device per node — closes #898.** After the #872 MQTT wiring landed, the JSON→`VitalsSnapshot` bridge hard-coded a single `node_id` (the MQTT client id) and the publisher used a single `OwnedDiscoveryBuilder`, so every physical node collapsed into one device (`identifiers:["wifi_densepose_wifi-densepose-1"]`), contradicting the "one device per node" docs. The bridge now emits one snapshot per node in the sensing update's `nodes[]` (each with its own `node_id` + RSSI, falling back to a single aggregate snapshot for wifi/simulate sources), and the publisher derives a per-node builder (`OwnedDiscoveryBuilder::for_node`) that publishes discovery + availability lazily on first sight of each `node_id` and routes state to per-node topics — yielding N distinct HA devices with per-node availability/LWT. Unit-tested (distinct nodes → distinct `wifi_densepose_<node>` identifiers); 71 MQTT tests pass.
 - **Person count no longer pinned to 1 — addresses #803.** The aggregate occupancy reported by the sensing server was derived from `smoothed_person_score`, an EMA-smoothed *activity* score (amplitude variance / motion / spectral energy). That score saturates near a single occupant — one moving person maxes it out — so it cannot discriminate occupancy *count* and stayed clamped at 1 across S3/C6 and the Python/Docker/Rust servers. Meanwhile the count-aware per-node estimates the ESP32 paths already compute (firmware `n_persons`, and the DynamicMinCut `corr_persons`) were stashed in `NodeState::prev_person_count` and then **discarded** by the aggregator (same dead-wiring class as #872). The aggregator now takes `max(activity_count, node_max)` via a unit-tested `aggregate_person_count` helper, so a node positively estimating 2–3 occupants is surfaced instead of overwritten. The fix can only ever *raise* the count when a node reports more people, so the single-occupant case is provably never inflated (regression-guarded by test). **Second half:** the pure-CSI per-node path itself clamped its own estimate — the DynamicMinCut occupancy (`estimate_persons_from_correlation`, 0–3) was mapped to a score via `corr_persons / 3.0`, putting 2 people at 0.667, *just under* the 0.70 up-threshold of `score_to_person_count`, so the per-node count never climbed past 1 (so `node_max` was also stuck at 1 for CSI-only nodes). Replaced it with a threshold-aligned `corr_persons_to_score` mapping (1→0.40, 2→0.74, 3→0.96) whose steady state round-trips back to the same count through the EMA + hysteresis, while still gating transient noise. A convergence test replays the exact EMA loop to prove min-cut=2 now reports 2 (and documents that the old `/3.0` mapping reported 1). Full multi-person accuracy still depends on the underlying estimator quality; this removes the two server-side clamps that masked it. 586 sensing-server tests pass.
 - **MQTT publisher now actually runs (`--mqtt`) — closes #872.** The `--mqtt*` flags were defined only in `cli::Args` (dead code, referenced nowhere) while the binary parses a *separate* `main::Args` with no mqtt fields, and `main.rs` never started the `mqtt::` publisher — so MQTT/Home-Assistant integration was completely unwired (`--mqtt` errored as an unexpected argument, and even with the Docker image's `--features mqtt` build the publisher never ran). Earlier attempts chased a Docker *rebuild*; the real cause was disconnected *code*. Extracted the flags into a shared `cli::MqttArgs` (`#[command(flatten)]` into both structs), spawn the publisher on `--mqtt`, and bridge the JSON sensing broadcast into the typed `VitalsSnapshot` stream with a defensive `serde_json::Value` mapping. Verified end-to-end against `mosquitto`: 20 HA auto-discovery entities + live state (presence/person-count/…). 577 (default) / 580 (`--features mqtt`) tests pass.
 

v2/crates/wifi-densepose-sensing-server/src/main.rs

@@ -6213,24 +6213,44 @@ async fn main() {
                                 Some(_) => 1.0,
                                 None => 0.0,
                             };
-                            let snap = mqtt::state::VitalsSnapshot {
+                            let ts = (v["timestamp"].as_f64().unwrap_or(0.0) * 1000.0) as i64;
-                                node_id: node_id.clone(),
+                            let conf = cls["confidence"].as_f64().unwrap_or(0.0);
-                                timestamp_ms: (v["timestamp"].as_f64().unwrap_or(0.0) * 1000.0) as i64,
+                            let presence_score = if presence { conf.max(0.0) } else { 0.0 };
+                            let breathing = vit["breathing_rate_bpm"].as_f64();
+                            let hr = vit["heart_rate_bpm"].as_f64();
+                            // #898: emit one snapshot per physical node so each
+                            // surfaces as its own Home-Assistant device (with
+                            // its own RSSI + availability). Falls back to a
+                            // single aggregate snapshot when there is no
+                            // per-node data (e.g. wifi / simulate sources).
+                            let mk = |nid: String, rssi: Option<f64>| mqtt::state::VitalsSnapshot {
+                                node_id: nid,
+                                timestamp_ms: ts,
                                 presence,
                                 motion,
-                                presence_score: if presence {
+                                presence_score,
-                                    cls["confidence"].as_f64().unwrap_or(1.0)
+                                breathing_rate_bpm: breathing,
-                                } else {
+                                heartrate_bpm: hr,
-                                    0.0
-                                },
-                                breathing_rate_bpm: vit["breathing_rate_bpm"].as_f64(),
-                                heartrate_bpm: vit["heart_rate_bpm"].as_f64(),
                                 n_persons,
-                                rssi_dbm: v["nodes"][0]["rssi_dbm"].as_f64(),
+                                rssi_dbm: rssi,
-                                vital_confidence: cls["confidence"].as_f64().unwrap_or(0.0),
+                                vital_confidence: conf,
                                 ..Default::default()
                             };
-                            let _ = vtx.send(snap);
+                            match v["nodes"].as_array() {
+                                Some(arr) if !arr.is_empty() => {
+                                    for node in arr {
+                                        let n = node["node_id"].as_u64().unwrap_or(0);
+                                        let nid = format!("{node_id}-node{n}");
+                                        let _ = vtx.send(mk(nid, node["rssi_dbm"].as_f64()));
+                                    }
+                                }
+                                _ => {
+                                    let _ = vtx.send(mk(
+                                        node_id.clone(),
+                                        v["nodes"][0]["rssi_dbm"].as_f64(),
+                                    ));
+                                }
+                            }
                         }
                     });
                     tracing::info!("MQTT publisher started -> {host}:{port}");

v2/crates/wifi-densepose-sensing-server/src/mqtt/publisher.rs

@@ -117,6 +117,23 @@ impl OwnedDiscoveryBuilder {
             via_device: self.via_device.as_deref(),
         }
     }
+
+    /// Derive a per-node builder from this base (issue #898). Each physical
+    /// RuView node must surface as its own Home-Assistant device — the base
+    /// builder's `node_id` (the MQTT client id) is replaced with the actual
+    /// node id, giving a distinct `wifi_densepose_<node>` device identifier
+    /// and a per-node friendly name, instead of collapsing every node into a
+    /// single hard-coded device.
+    pub fn for_node(&self, node_id: &str) -> OwnedDiscoveryBuilder {
+        OwnedDiscoveryBuilder {
+            discovery_prefix: self.discovery_prefix.clone(),
+            node_id: node_id.to_string(),
+            node_friendly_name: Some(format!("RuView node {node_id}")),
+            sw_version: self.sw_version.clone(),
+            model: self.model.clone(),
+            via_device: self.via_device.clone(),
+        }
+    }
 }
 
 /// Core run loop. Pumps the broadcast channel + the MQTT event loop in
@@ -129,20 +146,19 @@ async fn run(
     let opts = build_mqtt_options(&cfg);
     let (client, mut eventloop): (AsyncClient, EventLoop) = AsyncClient::new(opts, 256);
 
-    let builder_borrowed = builder_owned.as_borrowed();
     let entities = DiscoveryBuilder::enabled_entities(
         cfg.privacy_mode,
         cfg.publish_pose,
         &[], // no_semantic — wire from cli::Args in P3.5
     );
 
-    if let Err(e) = publish_all_discovery(&client, &builder_borrowed, &entities).await {
+    // #898: one Home-Assistant device per node. Discovery + availability are
-        warn!("[mqtt] initial discovery publish failed: {e}");
+    // published lazily the first time a snapshot for a given node_id arrives;
-    }
+    // each node's builder + availability are retained here for heartbeats and
-    let avail = NodeAvailability::for_builder(&builder_borrowed, &entities);
+    // the offline LWT. (Previously a single hard-coded builder collapsed every
-    if let Err(e) = publish_availability(&client, &avail, "online").await {
+    // node into one device.)
-        warn!("[mqtt] initial availability publish failed: {e}");
+    let mut nodes: std::collections::HashMap<String, (OwnedDiscoveryBuilder, NodeAvailability)> =
-    }
+        std::collections::HashMap::new();
 
     let mut rate_limiter = RateLimiter::new();
     let mut last_heartbeat = Instant::now();
@@ -179,14 +195,20 @@ async fn run(
             // Periodic heartbeat / discovery refresh.
             _ = tokio::time::sleep(Duration::from_secs(1)) => {
                 if last_heartbeat.elapsed() >= AVAILABILITY_HEARTBEAT {
-                    if let Err(e) = publish_availability(&client, &avail, "online").await {
+                    for (_, na) in nodes.values() {
-                        warn!("[mqtt] heartbeat publish failed: {e}");
+                        if let Err(e) = publish_availability(&client, na, "online").await {
+                            warn!("[mqtt] heartbeat publish failed: {e}");
+                        }
                     }
                     last_heartbeat = Instant::now();
                 }
                 if last_refresh.elapsed() >= Duration::from_secs(cfg.refresh_secs) {
-                    if let Err(e) = publish_all_discovery(&client, &builder_borrowed, &entities).await {
+                    for (nb, _) in nodes.values() {
-                        warn!("[mqtt] discovery refresh failed: {e}");
+                        if let Err(e) =
+                            publish_all_discovery(&client, &nb.as_borrowed(), &entities).await
+                        {
+                            warn!("[mqtt] discovery refresh failed: {e}");
+                        }
                     }
                     last_refresh = Instant::now();
                 }
@@ -197,18 +219,39 @@ async fn run(
                 match recv {
                     Ok(snap) => {
                         let elapsed = start_instant.elapsed();
-                        publish_snapshot(&client, &builder_borrowed, &snap, &cfg, &mut rate_limiter, elapsed).await;
+                        // #898: on first sight of a node_id, publish that
+                        // node's discovery + availability; then route its
+                        // state to per-node topics.
+                        if !nodes.contains_key(&snap.node_id) {
+                            let nb = builder_owned.for_node(&snap.node_id);
+                            let borrowed = nb.as_borrowed();
+                            if let Err(e) =
+                                publish_all_discovery(&client, &borrowed, &entities).await
+                            {
+                                warn!("[mqtt] node {} discovery failed: {e}", snap.node_id);
+                            }
+                            let na = NodeAvailability::for_builder(&borrowed, &entities);
+                            if let Err(e) = publish_availability(&client, &na, "online").await {
+                                warn!("[mqtt] node {} availability failed: {e}", snap.node_id);
+                            }
+                            nodes.insert(snap.node_id.clone(), (nb, na));
+                        }
+                        let borrowed = nodes[&snap.node_id].0.as_borrowed();
+                        publish_snapshot(&client, &borrowed, &snap, &cfg, &mut rate_limiter, elapsed).await;
                     }
                     Err(broadcast::error::RecvError::Lagged(n)) => {
                         warn!("[mqtt] lagged behind broadcast by {n} messages — dropped");
                     }
                     Err(broadcast::error::RecvError::Closed) => {
                         info!("[mqtt] broadcast channel closed, draining");
-                        // Publish offline before exit.
+                        // Publish offline for every known node before exit.
-                        let _ = publish_availability(&client, &avail, "offline").await;
+                        for (_, na) in nodes.values() {
+                            let _ = publish_availability(&client, na, "offline").await;
+                        }
                         let _ = client.disconnect().await;
                         return;
                     }
+
                 }
             }
         }
@@ -296,3 +339,52 @@ async fn publish_state(client: &AsyncClient, m: &StateMessage) -> Result<(), Cli
     };
     client.publish(&m.topic, qos, m.retain, m.payload.clone()).await
 }
+
+#[cfg(test)]
+mod per_node_device_tests {
+    //! Issue #898 — each physical node must surface as its own Home-Assistant
+    //! device, not collapse into one hard-coded device.
+    use super::*;
+
+    fn base() -> OwnedDiscoveryBuilder {
+        OwnedDiscoveryBuilder {
+            discovery_prefix: "homeassistant".into(),
+            node_id: "wifi-densepose-1".into(),
+            node_friendly_name: Some("RuView".into()),
+            sw_version: "0.0.0".into(),
+            model: "test".into(),
+            via_device: None,
+        }
+    }
+
+    fn device_identifiers(b: &OwnedDiscoveryBuilder) -> Vec<String> {
+        b.as_borrowed().build(EntityKind::Presence).device.identifiers
+    }
+
+    #[test]
+    fn for_node_overrides_node_id_and_friendly_name() {
+        let n = base().for_node("node-A");
+        assert_eq!(n.node_id, "node-A");
+        assert_eq!(n.node_friendly_name.as_deref(), Some("RuView node node-A"));
+    }
+
+    #[test]
+    fn distinct_nodes_yield_distinct_ha_device_identifiers() {
+        let b = base();
+        let a = device_identifiers(&b.for_node("node-A"));
+        let c = device_identifiers(&b.for_node("node-B"));
+        assert_eq!(a, vec!["wifi_densepose_node-A".to_string()]);
+        assert_eq!(c, vec!["wifi_densepose_node-B".to_string()]);
+        assert_ne!(a, c, "#898: two nodes must not collapse into one device");
+    }
+
+    #[test]
+    fn single_node_keeps_a_stable_identity() {
+        // Two snapshots from the same node map to the same device.
+        let b = base();
+        assert_eq!(
+            device_identifiers(&b.for_node("node-7")),
+            device_identifiers(&b.for_node("node-7"))
+        );
+    }
+}