feat(console): persist Host KV in libSQL

Store KV entries through Toasty with a composite service ID and key primary key, including an additive table migration for existing Console databases.

Bridge synchronous Wasmtime Host calls to async persistence with a bounded worker queue and response timeout capped by the service deadline.

Verify same-service revision sharing, cross-service isolation, deletion, exact capability reporting, and persistence after reopening Console.

crates/wasmeld-console/src/persistence.rs

@@ -1,10 +1,14 @@
 //! Toasty models and transactional libSQL snapshots for Console control data.
 //!
 //! Component bytes and WIT packages remain filesystem artifacts. This module
-//! persists only service manifests, deployments, metrics, and the bounded
-//! event history.
+//! persists service manifests, deployments, metrics, the bounded event
+//! history, and service-scoped Host KV entries.
 
-use std::path::Path;
+use std::{
+    path::Path,
+    sync::Arc,
+    time::{SystemTime, UNIX_EPOCH},
+};
 
 use toasty::Db;
 use toasty_driver_turso::Turso;
@@ -40,9 +44,19 @@ pub(crate) struct StoredDeployment {
     pub updated_at_ms: u64,
 }
 
+#[derive(Clone, Debug, toasty::Model)]
+#[key(service_id, entry_key)]
+pub(crate) struct StoredKvEntry {
+    pub service_id: String,
+    pub entry_key: String,
+    pub value: Vec<u8>,
+    pub updated_at_ms: u64,
+}
+
 /// Serialized access to the Toasty database connection.
+#[derive(Clone)]
 pub(crate) struct Persistence {
-    db: Mutex<Db>,
+    db: Arc<Mutex<Db>>,
 }
 
 impl Persistence {
@@ -53,7 +67,8 @@ impl Persistence {
             .models(toasty::models!(
                 StoredService,
                 StoredEvent,
-                StoredDeployment
+                StoredDeployment,
+                StoredKvEntry
             ))
             .build(Turso::file(path))
             .await?;
@@ -74,9 +89,24 @@ impl Persistence {
             )
             .exec(&mut db)
             .await?;
-            return Ok(Self { db: Mutex::new(db) });
+            toasty::sql::statement(
+                r#"CREATE TABLE IF NOT EXISTS "stored_kv_entries" (
+                    "service_id" TEXT NOT NULL,
+                    "entry_key" TEXT NOT NULL,
+                    "value" BLOB NOT NULL,
+                    "updated_at_ms" INTEGER NOT NULL,
+                    PRIMARY KEY ("service_id", "entry_key")
+                )"#,
+            )
+            .exec(&mut db)
+            .await?;
+            return Ok(Self {
+                db: Arc::new(Mutex::new(db)),
+            });
         }
-        Ok(Self { db: Mutex::new(db) })
+        Ok(Self {
+            db: Arc::new(Mutex::new(db)),
+        })
     }
 
     /// Loads the complete service and deployment sets plus retained events.
@@ -139,4 +169,46 @@ impl Persistence {
 
         tx.commit().await
     }
+
+    pub(crate) async fn kv_get(
+        &self,
+        service_id: &str,
+        entry_key: &str,
+    ) -> toasty::Result<Option<Vec<u8>>> {
+        let mut db = self.db.lock().await;
+        Ok(
+            StoredKvEntry::filter_by_service_id_and_entry_key(service_id, entry_key)
+                .first()
+                .exec(&mut *db)
+                .await?
+                .map(|entry| entry.value),
+        )
+    }
+
+    pub(crate) async fn kv_set(
+        &self,
+        service_id: String,
+        entry_key: String,
+        value: Vec<u8>,
+    ) -> toasty::Result<()> {
+        let mut db = self.db.lock().await;
+        StoredKvEntry::upsert_by_service_id_and_entry_key(service_id, entry_key)
+            .value(value)
+            .updated_at_ms(unix_time_ms())
+            .exec(&mut *db)
+            .await?;
+        Ok(())
+    }
+
+    pub(crate) async fn kv_delete(&self, service_id: &str, entry_key: &str) -> toasty::Result<()> {
+        let mut db = self.db.lock().await;
+        StoredKvEntry::delete_by_service_id_and_entry_key(&mut *db, service_id, entry_key).await
+    }
+}
+
+fn unix_time_ms() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|duration| u64::try_from(duration.as_millis()).unwrap_or(u64::MAX))
+        .unwrap_or_default()
 }