Merge pull request #2584 from activeloopai/fy_azure_fix

[AL-2411] Fix Azure download of empty blobs

deeplake/core/storage/azure.py

@@ -142,6 +142,9 @@ def get_bytes(
         )
         if not blob_client.exists():
             raise KeyError(path)
+        # Azure raises an error when trying to download an empty blob
+        if blob_client.get_blob_properties().size == 0:
+            return b""
         byts = blob_client.download_blob(offset=offset, length=length).readall()
         return byts
 
@@ -342,6 +345,9 @@ def get_presigned_url(self, path: str, full: bool = False) -> str:
 
     def get_object_from_full_url(self, url: str) -> bytes:
         blob_client, _ = self.get_clients_from_full_path(url)
+        # Azure raises an error when trying to download an empty blob
+        if blob_client.get_blob_properties().size == 0:
+            return b""
         return blob_client.download_blob().readall()
 
     def _check_update_creds(self, force=False):

deeplake/core/storage/tests/test_storage_provider.py

@@ -220,3 +220,12 @@ def test_azure_storage_clear(azure_storage):
     azure_storage.clear()
 
     assert len(azure_storage) == 0
+
+
+def test_azure_empty_blob(azure_storage):
+    azure_storage["empty_blob"] = b""
+    assert azure_storage["empty_blob"] == b""
+    assert (
+        azure_storage.get_object_from_full_url(f"{azure_storage.root}/empty_blob")
+        == b""
+    )