Retry transient native HTTP range failures

src/lerobot/datasets/episode_video_streaming.py

@@ -106,10 +106,27 @@ class NativeHTTPRangeFetcher:
     _GLOBAL_SIZES: dict[tuple[str, str], int] = {}
     _GLOBAL_LOCK = threading.Lock()
 
-    def __init__(self, data_root: str | Path, *, max_connections: int = 32, timeout: float = 60.0):
+    _RETRYABLE_EXCEPTIONS = (
+        httpx.ConnectError,
+        httpx.ConnectTimeout,
+        httpx.ReadError,
+        httpx.ReadTimeout,
+        httpx.RemoteProtocolError,
+        httpx.PoolTimeout,
+    )
+
+    def __init__(
+        self,
+        data_root: str | Path,
+        *,
+        max_connections: int = 32,
+        timeout: float = 60.0,
+        max_retries: int = 4,
+    ):
         self.data_root = str(data_root).rstrip("/")
         if not self.data_root.startswith("hf://"):
             raise ValueError("NativeHTTPRangeFetcher only supports hf:// roots")
+        self.max_retries = max_retries
         self.api = HfApi()
         self.fs: HfFileSystem | None = None
         self._bucket_id: str | None = None
@@ -133,6 +150,20 @@ class NativeHTTPRangeFetcher:
         self._sizes: dict[str, int] = {}
         self._lock = threading.Lock()
 
+    def _request(self, method: str, url: str, **kwargs) -> httpx.Response:
+        last_exc: Exception | None = None
+        for attempt in range(self.max_retries + 1):
+            try:
+                return self.client.request(method, url, **kwargs)
+            except self._RETRYABLE_EXCEPTIONS as exc:
+                last_exc = exc
+                if attempt >= self.max_retries:
+                    break
+                time.sleep(min(0.5 * 2**attempt, 5.0))
+        if last_exc is None:
+            raise RuntimeError("HTTP request failed without an exception")
+        raise last_exc
+
     def _cache_key(self, relative_path: str) -> tuple[str, str]:
         return self.data_root, relative_path
 
@@ -192,7 +223,7 @@ class NativeHTTPRangeFetcher:
                 return resolved
 
         source = self._source_url(relative_path)
-        response = self.client.head(source, headers=self.api._build_hf_headers(), follow_redirects=False)
+        response = self._request("HEAD", source, headers=self.api._build_hf_headers(), follow_redirects=False)
         try:
             hf_raise_for_status(response)
             location = response.headers.get("Location")
@@ -224,8 +255,8 @@ class NativeHTTPRangeFetcher:
 
         resolved = self._resolve_url(relative_path)
         source = self._source_url(relative_path)
-        response = self.client.head(
+        response = self._request(
-            resolved, headers=self._headers_for(resolved, source), follow_redirects=True
+            "HEAD", resolved, headers=self._headers_for(resolved, source), follow_redirects=True
         )
         try:
             hf_raise_for_status(response)
@@ -243,13 +274,13 @@ class NativeHTTPRangeFetcher:
         source = self._source_url(relative_path)
         headers = self._headers_for(resolved, source)
         headers["Range"] = f"bytes={offset}-{offset + length - 1}"
-        response = self.client.get(resolved, headers=headers)
+        response = self._request("GET", resolved, headers=headers)
         if response.status_code == 403:
             response.close()
             resolved = self._resolve_url(relative_path, refresh=True)
             headers = self._headers_for(resolved, source)
             headers["Range"] = f"bytes={offset}-{offset + length - 1}"
-            response = self.client.get(resolved, headers=headers)
+            response = self._request("GET", resolved, headers=headers)
         try:
             hf_raise_for_status(response)
             return response.content