samples: storage_download_byte_range (#674)

* samples: storage_download_byte_range

* added spacing

* updated readme

* fixed test

Author: shaffeeullah

storage/samples/snippets/snippets_test.py

@@ -37,6 +37,7 @@
 import storage_delete_file_archived_generation
 import storage_disable_bucket_lifecycle_management
 import storage_disable_versioning
+import storage_download_byte_range
 import storage_download_file
 import storage_download_into_memory
 import storage_download_public_file
@@ -211,6 +212,14 @@ def test_upload_blob_with_kms(test_bucket):
         assert kms_blob.kms_key_name.startswith(KMS_KEY)
 
 
+def test_download_byte_range(test_blob):
+    with tempfile.NamedTemporaryFile() as dest_file:
+        storage_download_byte_range.download_byte_range(
+            test_blob.bucket.name, test_blob.name, 0, 4, dest_file.name
+        )
+        assert dest_file.read() == b'Hello'
+
+
 def test_download_blob(test_blob):
     with tempfile.NamedTemporaryFile() as dest_file:
         storage_download_file.download_blob(

storage/samples/snippets/storage_download_byte_range.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+
+# [START storage_download_byte_range]
+from google.cloud import storage
+
+
+def download_byte_range(
+    bucket_name, source_blob_name, start_byte, end_byte, destination_file_name
+):
+    """Downloads a blob from the bucket."""
+    # The ID of your GCS bucket
+    # bucket_name = "your-bucket-name"
+
+    # The ID of your GCS object
+    # source_blob_name = "storage-object-name"
+
+    # The starting byte at which to begin the download
+    # start_byte = 0
+
+    # The ending byte at which to end the download
+    # end_byte = 20
+
+    # The path to which the file should be downloaded
+    # destination_file_name = "local/path/to/file"
+
+    storage_client = storage.Client()
+
+    bucket = storage_client.bucket(bucket_name)
+
+    # Construct a client side representation of a blob.
+    # Note `Bucket.blob` differs from `Bucket.get_blob` as it doesn't retrieve
+    # any content from Google Cloud Storage. As we don't need additional data,
+    # using `Bucket.blob` is preferred here.
+    blob = bucket.blob(source_blob_name)
+    blob.download_to_filename(destination_file_name, start=start_byte, end=end_byte)
+
+    print(
+        "Downloaded bytes {} to {} of object {} from bucket {} to local file {}.".format(
+            start_byte, end_byte, source_blob_name, bucket_name, destination_file_name
+        )
+    )
+
+
+# [END storage_download_byte_range]
+
+if __name__ == "__main__":
+    download_byte_range(
+        bucket_name=sys.argv[1],
+        source_blob_name=sys.argv[2],
+        start_byte=sys.argv[3],
+        end_byte=sys.argv[4],
+        destination_file_name=sys.argv[5],
+    )