homecore-recorder

SQLite state-history recorder for HOMECORE with Home Assistant-compatible schema and optional ruvector semantic search (P2).

P1 release: SQLite database with Home Assistant-compatible schema for persistent state history. P2 (feature-gated): ruvector HNSW semantic index for natural-language queries ("show me all kitchen devices that were warm at 3 PM").

What this crate does

homecore-recorder persists HOMECORE state changes to SQLite and optionally indexes them for semantic search. It provides:

• Listener pattern — subscribes to homecore event bus and captures all StateChanged events
• SQLite schema — mirrors HA's recorder database schema (v48) for 1:1 compatibility
• Dual-write architecture — writes state snapshots to states table and attributes to state_attributes table (same as HA)
• Deduplication — avoids recording redundant state writes when state hasn't actually changed
• SemanticIndex trait — abstraction for plugging in ruvector embeddings (P2)
• NullSemanticIndex — no-op implementation used when ruvector feature is off

Data persists in .homecore/home.db (by default; configurable). Queries work via standard SQLx, so any tool that reads SQLite can access the history.

Features

• Home Assistant schema compatibility — migrate from HA's recorder.db without schema changes
• Event recording — all state changes captured with last_changed timestamp and old/new state
• Attribute persistence — JSON attributes for entities stored in separate table (HA pattern)
• Automatic deduplication — skip writes when state hasn't changed (detect via hash)
• Recorder runs table — track purge cycles and migration events (HA recorder_runs equivalent)
• Startup restoration — deterministic newest row per entity, bounded at 100,000 rows, with malformed rows isolated as typed warnings
• Semantic search (P2, --features ruvector) — embed state attributes + query by meaning
• HNSW index (P2) — k-NN search for "all warm rooms" via ruvector
• No data export overhead — SQLite is queryable directly; no proprietary format

Capabilities

Comparison to Home Assistant

Performance

• State write latency — p50 < 2 ms (SQLite WAL append); p99 < 15 ms (disk fsync)
• Query latency — < 1 ms for indexed entity_id lookups; < 50 ms for range scans (full table)
• Semantic search (P2) — < 10 ms for k-NN on 1 million state records (ruvector HNSW)
• Memory overhead — ~10 MB per million recorded states (SQLite index overhead)
• Disk space — ~2-4 KB per state record (entity_id + attributes + timestamps)
• No per-crate benchmarks yet — a follow-up issue tracks baseline measurements

Run cargo bench -p homecore-recorder --features ruvector for criterion benchmarks.

Usage

Recording state changes (P1):

use homecore_recorder::{Recorder, RecorderListener};
use homecore::HomeCore;

#[tokio::main]
async fn main() {
    let homecore = HomeCore::new();
    
    // Create the recorder (writes to .homecore/home.db)
    let recorder = Recorder::new(".homecore/home.db").await.expect("init recorder");

    // Create and spawn a listener
    let listener = RecorderListener::new(recorder.clone());
    let mut rx = homecore.event_bus().subscribe_system();
    
    tokio::spawn(async move {
        while let Ok(event) = rx.recv().await {
            if let Err(e) = listener.on_state_changed(&event).await {
                eprintln!("Recorder error: {}", e);
            }
        }
    });

    // State changes now persist to SQLite
}

Querying history directly (standard SQLite):

-- All light.kitchen state changes in the last hour
SELECT state, attributes, last_changed 
FROM states 
WHERE entity_id = 'light.kitchen' 
  AND last_changed > datetime('now', '-1 hour')
ORDER BY last_changed DESC;

-- Average brightness by hour
SELECT 
  strftime('%Y-%m-%d %H:00:00', last_changed) AS hour,
  JSON_EXTRACT(attributes, '$.brightness') AS brightness
FROM states 
WHERE entity_id = 'light.kitchen'
GROUP BY hour;

Semantic search (P2, with --features ruvector):

// (P2, not yet implemented)
// let index = SemanticIndex::new(recorder.clone()).await?;
// let results = index.search("find all warm rooms at 3pm", 5).await?;
// results.iter().for_each(|r| println!("{:?}", r));

Relation to other HOMECORE crates

homecore-recorder (state history + semantic search)
├─ homecore (state machine; listens to event bus)
├─ homecore-api (exposes recorder data via REST query endpoint, P3)
├─ homecore-automation (can trigger on historical state conditions, P3)
├─ homecore-server (starts the listener on init)
└─ ruvector-core (semantic index, P2, optional feature)

References

• ADR-132: HOMECORE Recorder — History + Semantic Search
• ADR-126: HOMECORE Home Assistant Port (master)
• Home Assistant Recorder Integration
• README — wifi-densepose