also retry index download on exists-in-archive, change locking

Author: syphar

src/storage/mod.rs

@@ -383,19 +383,29 @@ impl AsyncStorage {
         latest_build_id: Option<BuildId>,
         path: &str,
     ) -> Result<bool> {
-        match self
-            .find_in_archive_index(archive_path, latest_build_id, path)
-            .await
-        {
-            Ok(file_info) => Ok(file_info.is_some()),
-            Err(err) => {
-                if err.downcast_ref::<PathNotFoundError>().is_some() {
-                    Ok(false)
-                } else {
-                    Err(err)
+        for attempt in 0..2 {
+            match self
+                .find_in_archive_index(archive_path, latest_build_id, path)
+                .await
+            {
+                Ok(file_info) => return Ok(file_info.is_some()),
+                Err(err) if err.downcast_ref::<PathNotFoundError>().is_some() => {
+                    return Ok(false);
+                }
+                Err(err) if attempt == 0 => {
+                    warn!(
+                        ?err,
+                        "error fetching range from archive, purging local index cache and retrying once"
+                    );
+                    self.purge_archive_index_cache(archive_path, latest_build_id)
+                        .await?;
+
+                    continue;
                 }
+                Err(err) => return Err(err),
             }
         }
+        unreachable!("exists_in_archive retry loop exited unexpectedly");
     }
 
     /// get, decompress and materialize an object from store
@@ -557,54 +567,24 @@ impl AsyncStorage {
         }
 
         let lock = self.local_index_cache_lock(&local_index_path);
+        let write_guard = lock.lock().await;
 
-        // At this point we know the index is missing or broken.
-        // Try to become the "downloader" without queueing as a writer.
-        if let Ok(write_guard) = lock.try_lock() {
-            // Double-check: maybe someone fixed it between our first failure and now.
-            if let Ok(res) = archive_index::find_in_file(&local_index_path, path_in_archive).await {
-                return Ok(res);
-            }
-
-            let remote_index_path = format!("{archive_path}.{ARCHIVE_INDEX_FILE_EXTENSION}");
-
-            // We are the repairer: download fresh index into place.
-            self.download_archive_index(&local_index_path, &remote_index_path)
-                .await?;
-
-            // Write lock is dropped here (end of scope), so others can proceed.
-            drop(write_guard);
-
-            // Final attempt: if this still fails, bubble the error.
-            return archive_index::find_in_file(local_index_path, path_in_archive).await;
+        // Double-check: maybe someone fixed it between our first failure and now.
+        if let Ok(res) = archive_index::find_in_file(&local_index_path, path_in_archive).await {
+            return Ok(res);
         }
 
-        // Someone else is already downloading/repairing. Don't queue on write(); just wait
-        // a bit and poll the fast path until it becomes readable or we give up.
-        const STEP_MS: u64 = 10;
-        const ATTEMPTS: u64 = 50; // = 500ms total wait
-        const TOTAL_WAIT_MS: u64 = STEP_MS * ATTEMPTS;
+        let remote_index_path = format!("{archive_path}.{ARCHIVE_INDEX_FILE_EXTENSION}");
 
-        let mut last_err = None;
-
-        for _ in 0..ATTEMPTS {
-            sleep(Duration::from_millis(STEP_MS)).await;
+        // We are the repairer: download fresh index into place.
+        self.download_archive_index(&local_index_path, &remote_index_path)
+            .await?;
 
-            match archive_index::find_in_file(local_index_path.clone(), path_in_archive).await {
-                Ok(res) => return Ok(res),
-                Err(err) => {
-                    // keep waiting; repair may still be in progress
-                    last_err = Some(err);
-                }
-            }
-        }
+        // Write lock is dropped here (end of scope), so others can proceed.
+        drop(write_guard);
 
-        // Still not usable after waiting: return the last error we saw.
-        Err(last_err
-            .unwrap_or_else(|| anyhow!("archive index unavailable after repair wait"))
-            .context(format!(
-                "no archive index after waiting for {TOTAL_WAIT_MS}ms"
-            )))
+        // Final attempt: if this still fails, bubble the error.
+        return archive_index::find_in_file(local_index_path, path_in_archive).await;
     }
 
     #[instrument]