Linter demands unreachable exception. OK, fine

pangeo_forge_recipes/transforms.py

@@ -161,9 +161,9 @@ class TransferFilesWithConcurrency(beam.DoFn):
     secrets: Optional[Dict] = None
     open_kwargs: Optional[Dict] = None
     fsspec_sync_patch: bool = False
-    max_retries: int
-    initial_backoff: float
-    backoff_factor: float
+    max_retries: int = 5
+    initial_backoff: float = 1.0
+    backoff_factor: float = 2.0
 
     def process(self, indexed_urls):
         with ThreadPoolExecutor(max_workers=self.max_concurrency) as executor:
@@ -184,18 +184,24 @@ def transfer_file(self, index: int, url: str) -> Tuple[int, str]:
         while retries <= self.max_retries:
             try:
                 open_kwargs = self.open_kwargs or {}
-                self.transfer_target.cache_file(url, self.secrets, self.fsspec_sync_patch, **open_kwargs)
+                self.transfer_target.cache_file(
+                    url, self.secrets, self.fsspec_sync_patch, **open_kwargs
+                )
                 return (index, self.transfer_target._full_path(url))
             except Exception as e:
                 if retries == self.max_retries:
                     logger.error(f"Max retries reached for {url}: {e}")
                     raise e
                 else:
-                    backoff_time = self.initial_backoff * (self.backoff_factor ** retries)
-                    logger.warning(f"Error transferring file {url}: {e}. Retrying in {backoff_time} seconds...")
+                    backoff_time = self.initial_backoff * (self.backoff_factor**retries)
+                    logger.warning(
+                        f"Error transferring file {url}: {e}. Retrying in {backoff_time} seconds..."
+                    )
                     time.sleep(backoff_time)
                     retries += 1
 
+        raise RuntimeError(f"Failed to transfer file {url} after {self.max_retries} attempts.")
+
 
 @dataclass
 class CheckpointFileTransfer(beam.PTransform):
@@ -255,7 +261,7 @@ def expand(self, pcoll):
                     fsspec_sync_patch=self.fsspec_sync_patch,
                     max_retries=self.max_retries,
                     initial_backoff=self.initial_backoff,
-                    backoff_factor=self.backoff_factor
+                    backoff_factor=self.backoff_factor,
                 )
             )
         )