Merge pull request #1877 from tursodatabase/fix-wal-pull

libsql: Fix WAL pull logic on last frame

Author: penberg

libsql/src/local/database.rs

@@ -476,10 +476,13 @@ impl Database {
 
         loop {
             match sync_ctx.pull_one_frame(generation, frame_no).await {
-                Ok(frame) => {
+                Ok(Some(frame)) => {
                     conn.wal_insert_frame(&frame)?;
                     frame_no += 1;
                 }
+                Ok(None) => {
+                    break;
+                }
                 Err(e) => {
                     tracing::debug!("pull_one_frame error: {:?}", e);
                     err.replace(e);

libsql/src/sync.rs

@@ -107,7 +107,7 @@ impl SyncContext {
     }
 
     #[tracing::instrument(skip(self))]
-    pub(crate) async fn pull_one_frame(&mut self, generation: u32, frame_no: u32) -> Result<Bytes> {
+    pub(crate) async fn pull_one_frame(&mut self, generation: u32, frame_no: u32) -> Result<Option<Bytes>> {
         let uri = format!(
             "{}/sync/{}/{}/{}",
             self.sync_url,
@@ -116,9 +116,13 @@ impl SyncContext {
             frame_no + 1
         );
         tracing::debug!("pulling frame");
-        let frame = self.pull_with_retry(uri, self.max_retries).await?;
-        self.durable_frame_num = frame_no;
-        Ok(frame)
+        match self.pull_with_retry(uri, self.max_retries).await? {
+            Some(frame) => {
+                self.durable_frame_num = frame_no;
+                Ok(Some(frame))
+            }
+            None => Ok(None),
+        }
     }
 
     #[tracing::instrument(skip(self, frame))]
@@ -232,7 +236,7 @@ impl SyncContext {
         }
     }
 
-    async fn pull_with_retry(&self, uri: String, max_retries: usize) -> Result<Bytes> {
+    async fn pull_with_retry(&self, uri: String, max_retries: usize) -> Result<Option<Bytes>> {
         let mut nr_retries = 0;
         loop {
             let mut req = http::Request::builder().method("GET").uri(uri.clone());
@@ -256,7 +260,10 @@ impl SyncContext {
                 let frame = hyper::body::to_bytes(res.into_body())
                     .await
                     .map_err(SyncError::HttpBody)?;
-                return Ok(frame);
+                return Ok(Some(frame));
+            }
+            if res.status() == StatusCode::BAD_REQUEST {
+                return Ok(None);
             }
             // If we've retried too many times or the error is not a server error,
             // return the error.