Hotfix for the issue where we cannot download the snapshot of a blob …

…in chunks. (#282)

ChangeLog.md

@@ -2,6 +2,11 @@
 
 > See [BreakingChanges](BreakingChanges.md) for a detailed list of API breaks.
 
+## Version 0.34.1:
+
+### Blob:
+- Fixed a bug where downloading the snapshot of a blob will fail in some cases.
+
 ## Version 0.34.0:
 
 ### All:

azure/storage/blob/_download_chunking.py

@@ -20,7 +20,7 @@
 )
 from .._error import _ERROR_NO_SINGLE_THREAD_CHUNKING
 
-def _download_blob_chunks(blob_service, container_name, blob_name,
+def _download_blob_chunks(blob_service, container_name, blob_name, snapshot,
                           download_size, block_size, progress, start_range, end_range, 
                           stream, max_connections, progress_callback, validate_content, 
                           lease_id, if_modified_since, if_unmodified_since, if_match, 
@@ -32,6 +32,7 @@ def _download_blob_chunks(blob_service, container_name, blob_name,
         blob_service,
         container_name,
         blob_name,
+        snapshot,
         download_size,
         block_size,
         progress,
@@ -54,13 +55,14 @@ def _download_blob_chunks(blob_service, container_name, blob_name,
     result = list(executor.map(downloader.process_chunk, downloader.get_chunk_offsets()))
 
 class _BlobChunkDownloader(object):
-    def __init__(self, blob_service, container_name, blob_name, download_size,
+    def __init__(self, blob_service, container_name, blob_name, snapshot, download_size,
                  chunk_size, progress, start_range, end_range, stream, 
                  progress_callback, validate_content, lease_id, if_modified_since, 
                  if_unmodified_since, if_match, if_none_match, timeout, operation_context):
         self.blob_service = blob_service
         self.container_name = container_name
         self.blob_name = blob_name
+        self.snapshot = snapshot
         self.chunk_size = chunk_size
 
         self.download_size = download_size
@@ -117,6 +119,7 @@ def _download_chunk(self, chunk_start, chunk_end):
         response = self.blob_service._get_blob(
             self.container_name,
             self.blob_name,
+            snapshot=self.snapshot,
             start_range=chunk_start,
             end_range=chunk_end - 1,
             validate_content=self.validate_content,

azure/storage/blob/baseblobservice.py

@@ -1985,6 +1985,7 @@ def get_blob_to_stream(
                 self,
                 container_name,
                 blob_name,
+                snapshot,
                 download_size,
                 self.MAX_CHUNK_GET_SIZE,
                 first_get_size,

tests/test_get_blob.py

@@ -147,6 +147,21 @@ def test_get_blob_to_bytes(self):
         # Assert
         self.assertEqual(self.byte_data, blob.content)
 
+    def test_get_blob_to_bytes_snapshot(self):
+        # parallel tests introduce random order of requests, can only run live
+        if TestMode.need_recording_file(self.test_mode):
+            return
+
+        # Arrange
+        snapshot = self.bs.snapshot_blob(self.container_name, self.byte_blob)
+        self.bs.create_blob_from_bytes(self.container_name, self.byte_blob, self.byte_data) # Modify the blob so the Etag no longer matches
+
+        # Act
+        blob = self.bs.get_blob_to_bytes(self.container_name, self.byte_blob, snapshot.snapshot)
+
+        # Assert
+        self.assertEqual(self.byte_data, blob.content)
+
     def test_get_blob_to_bytes_with_progress(self):
         # parallel tests introduce random order of requests, can only run live
         if TestMode.need_recording_file(self.test_mode):