Fix tokio blocking deadlock in search indexing by offloading add_document to spawn_blocking

server/src/search.rs

@@ -1,12 +1,12 @@
 use crate::models::{Adr, Entity, Snippet, Task};
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex};
 use tantivy::schema::*;
 use tantivy::{Index, IndexReader, IndexWriter, ReloadPolicy, doc};
 
 pub struct MemoryIndex {
     index: Index,
     reader: IndexReader,
-    writer: Mutex<IndexWriter>,
+    writer: Arc<Mutex<IndexWriter>>,
 
     // Schema fields
     pub id_field: Field,
@@ -40,7 +40,7 @@ impl MemoryIndex {
         Ok(Self {
             index,
             reader,
-            writer: Mutex::new(writer),
+            writer: Arc::new(Mutex::new(writer)),
             id_field,
             title_field,
             body_field,
@@ -49,28 +49,36 @@ impl MemoryIndex {
         })
     }
 
-    pub fn index_entity(&self, e: &Entity) -> tantivy::Result<()> {
-        let writer = self.writer.lock().unwrap();
-        writer.add_document(doc!(
+    pub fn index_entity(&self, e: &Entity) -> tokio::task::JoinHandle<tantivy::Result<()>> {
+        let writer = Arc::clone(&self.writer);
+        let doc = doc!(
             self.id_field => e.name.clone(),
             self.title_field => e.name.clone(),
             self.body_field => e.observations.join(" "),
             self.type_field => "entity",
             self.namespace_field => e.namespace.clone()
-        ))?;
-        Ok(())
+        );
+        tokio::task::spawn_blocking(move || {
+            let writer = writer.lock().unwrap();
+            writer.add_document(doc)?;
+            Ok(())
+        })
     }
 
-    pub fn index_task(&self, t: &Task) -> tantivy::Result<()> {
-        let writer = self.writer.lock().unwrap();
-        writer.add_document(doc!(
+    pub fn index_task(&self, t: &Task) -> tokio::task::JoinHandle<tantivy::Result<()>> {
+        let writer = Arc::clone(&self.writer);
+        let doc = doc!(
             self.id_field => t.id.clone(),
             self.title_field => t.title.clone(),
             self.body_field => t.description.clone(),
             self.type_field => "task",
             self.namespace_field => "global"
-        ))?;
-        Ok(())
+        );
+        tokio::task::spawn_blocking(move || {
+            let writer = writer.lock().unwrap();
+            writer.add_document(doc)?;
+            Ok(())
+        })
     }
 
     pub fn commit(&self) -> tantivy::Result<()> {
@@ -133,28 +141,36 @@ impl MemoryIndex {
         Ok(results)
     }
 
-    pub fn index_snippet(&self, s: &Snippet) -> tantivy::Result<()> {
-        let writer = self.writer.lock().unwrap();
-        writer.add_document(doc!(
+    pub fn index_snippet(&self, s: &Snippet) -> tokio::task::JoinHandle<tantivy::Result<()>> {
+        let writer = Arc::clone(&self.writer);
+        let doc = doc!(
             self.id_field => s.name.clone(),
             self.title_field => s.name.clone(),
             self.body_field => format!("{} {}", s.language, s.description),
             self.type_field => "snippet",
             self.namespace_field => "global"
-        ))?;
-        Ok(())
+        );
+        tokio::task::spawn_blocking(move || {
+            let writer = writer.lock().unwrap();
+            writer.add_document(doc)?;
+            Ok(())
+        })
     }
 
-    pub fn index_adr(&self, a: &Adr) -> tantivy::Result<()> {
-        let writer = self.writer.lock().unwrap();
-        writer.add_document(doc!(
+    pub fn index_adr(&self, a: &Adr) -> tokio::task::JoinHandle<tantivy::Result<()>> {
+        let writer = Arc::clone(&self.writer);
+        let doc = doc!(
             self.id_field => a.id.clone(),
             self.title_field => a.title.clone(),
             self.body_field => format!("{} {} {}", a.context, a.decision, a.consequence),
             self.type_field => "adr",
             self.namespace_field => "global"
-        ))?;
-        Ok(())
+        );
+        tokio::task::spawn_blocking(move || {
+            let writer = writer.lock().unwrap();
+            writer.add_document(doc)?;
+            Ok(())
+        })
     }
 }
 
@@ -163,8 +179,8 @@ mod tests {
     use super::*;
     use tempfile::TempDir;
 
-    #[test]
-    fn test_search_index_and_retrieve() {
+    #[tokio::test]
+    async fn test_search_index_and_retrieve() {
         let temp_dir = TempDir::new().unwrap();
         let index = MemoryIndex::new(temp_dir.path()).unwrap();
 
@@ -175,7 +191,7 @@ mod tests {
             namespace: "global".to_string(),
             git_branch: None,
         };
-        index.index_entity(&entity).unwrap();
+        index.index_entity(&entity).await.unwrap();
 
         let task = Task {
             id: "task-1".to_string(),
@@ -189,7 +205,7 @@ mod tests {
             dependencies: vec![],
             parent_id: None,
         };
-        index.index_task(&task).unwrap();
+        index.index_task(&task).await.unwrap();
 
         let snippet = Snippet {
             name: "test_snippet".to_string(),
@@ -198,7 +214,7 @@ mod tests {
             description: "A test snippet".to_string(),
             updated_at: 0,
         };
-        index.index_snippet(&snippet).unwrap();
+        index.index_snippet(&snippet).await.unwrap();
 
         let adr = Adr {
             id: "adr-1".to_string(),
@@ -208,7 +224,7 @@ mod tests {
             consequence: "Test consequence".to_string(),
             timestamp: 0,
         };
-        index.index_adr(&adr).unwrap();
+        index.index_adr(&adr).await.unwrap();
 
         index.commit().unwrap();
         index.reader.reload().unwrap();