fix(rustdb-indexes): persist created indexes and restore them on server startup

rust/crates/rustdb-commands/src/handlers/index_handler.rs

@@ -101,7 +101,15 @@ async fn handle_create_indexes(
             expire_after_seconds,
         };
 
-        // Create the index.
+        let options_for_persist = IndexOptions {
+            name: options.name.clone(),
+            unique: options.unique,
+            sparse: options.sparse,
+            expire_after_seconds: options.expire_after_seconds,
+        };
+        let key_for_persist = key.clone();
+
+        // Create the index in-memory.
         let mut engine = ctx
             .indexes
             .entry(ns_key.clone())
@@ -110,6 +118,22 @@ async fn handle_create_indexes(
         match engine.create_index(key, options) {
             Ok(index_name) => {
                 debug!(index_name = %index_name, "Created index");
+
+                // Persist index spec to disk.
+                let mut spec = doc! { "key": key_for_persist };
+                if options_for_persist.unique {
+                    spec.insert("unique", true);
+                }
+                if options_for_persist.sparse {
+                    spec.insert("sparse", true);
+                }
+                if let Some(ttl) = options_for_persist.expire_after_seconds {
+                    spec.insert("expireAfterSeconds", ttl as i64);
+                }
+                if let Err(e) = ctx.storage.save_index(db, coll, &index_name, spec).await {
+                    tracing::warn!(index = %index_name, error = %e, "failed to persist index spec");
+                }
+
                 created_count += 1;
             }
             Err(e) => {
@@ -180,9 +204,21 @@ async fn handle_drop_indexes(
     match index_spec {
         Some(Bson::String(name)) if name == "*" => {
             // Drop all indexes except _id_.
+            // Collect names to drop from storage first.
+            let names_to_drop: Vec<String> = if let Some(engine) = ctx.indexes.get(&ns_key) {
+                engine.list_indexes().iter()
+                    .filter(|info| info.name != "_id_")
+                    .map(|info| info.name.clone())
+                    .collect()
+            } else {
+                Vec::new()
+            };
             if let Some(mut engine) = ctx.indexes.get_mut(&ns_key) {
                 engine.drop_all_indexes();
             }
+            for idx_name in &names_to_drop {
+                let _ = ctx.storage.drop_index(db, coll, idx_name).await;
+            }
         }
         Some(Bson::String(name)) => {
             // Drop by name.
@@ -196,6 +232,7 @@ async fn handle_drop_indexes(
                     name
                 )));
             }
+            let _ = ctx.storage.drop_index(db, coll, name).await;
         }
         Some(Bson::Document(key_spec)) => {
             // Drop by key spec: find the index with matching key.
@@ -210,6 +247,7 @@ async fn handle_drop_indexes(
                     engine.drop_index(&name).map_err(|e| {
                         CommandError::IndexError(e.to_string())
                     })?;
+                    let _ = ctx.storage.drop_index(db, coll, &name).await;
                 } else {
                     return Err(CommandError::IndexError(
                         "index not found with specified key".into(),