Make storage upload/download have no chunk size by default.

Fixes #546.

Author: dhermes

gcloud/storage/blob.py

@@ -51,17 +51,19 @@ class Blob(_PropertyMixin):
     :param bucket: The bucket to which this blob belongs. Required, unless the
                    implicit default bucket has been set.
 
+    :type chunk_size: integer
+    :param chunk_size: The size of a chunk of data whenever iterating (1 MB).
+                       This must be a multiple of 256 KB per the API
+                       specification.
+
     :type properties: dict
     :param properties: All the other data provided by Cloud Storage.
     """
 
-    CHUNK_SIZE = 1024 * 1024  # 1 MB.
-    """The size of a chunk of data whenever iterating (1 MB).
-
-    This must be a multiple of 256 KB per the API specification.
-    """
+    _CHUNK_SIZE_MULTIPLE = 256
+    """Number that must divide the chunk size (in KB)."""
 
-    def __init__(self, name, bucket=None):
+    def __init__(self, name, bucket=None, chunk_size=None):
         if bucket is None:
             bucket = _implicit_environ.get_default_bucket()
 
@@ -70,9 +72,35 @@ def __init__(self, name, bucket=None):
 
         super(Blob, self).__init__(name=name)
 
+        self._chunk_size = None  # Needs to be defined in __init__.
+        self.chunk_size = chunk_size  # Check that setter accepts value.
         self.bucket = bucket
         self._acl = ObjectACL(self)
 
+    @property
+    def chunk_size(self):
+        """Get the blob's default chunk size.
+
+        :rtype: integer or ``NoneType``
+        :returns: The current blob's chunk size, if it is set.
+        """
+        return self._chunk_size
+
+    @chunk_size.setter
+    def chunk_size(self, value):
+        """Set the blob's default chunk size.
+
+        :type value: integer or ``NoneType``
+        :param value: The current blob's chunk size, if it is set.
+
+        :raises: :class:`ValueError` if ``value`` is not ``None`` and is not a
+                 multiple of 256 KB.
+        """
+        if value is not None and value % self._CHUNK_SIZE_MULTIPLE != 0:
+            raise ValueError('Chunk size must be a multiple of %d.' % (
+                self._CHUNK_SIZE_MULTIPLE,))
+        self._chunk_size = value
+
     @staticmethod
     def path_helper(bucket_path, blob_name):
         """Relative URL path for a blob.
@@ -226,8 +254,10 @@ def download_to_file(self, file_obj):
 
         # Use apitools 'Download' facility.
         download = transfer.Download.FromStream(file_obj, auto_transfer=False)
-        download.chunksize = self.CHUNK_SIZE
-        headers = {'Range': 'bytes=0-%d' % (self.CHUNK_SIZE - 1)}
+        headers = {}
+        if self.chunk_size is not None:
+            download.chunksize = self.chunk_size
+            headers['Range'] = 'bytes=0-%d' % (self.chunk_size - 1,)
         request = http_wrapper.Request(download_url, 'GET', headers)
 
         download.InitializeDownload(request, self.connection.http)
@@ -319,7 +349,7 @@ def upload_from_file(self, file_obj, rewind=False, size=None,
 
         upload = transfer.Upload(file_obj, content_type, total_bytes,
                                  auto_transfer=False,
-                                 chunksize=self.CHUNK_SIZE)
+                                 chunksize=self.chunk_size)
 
         url_builder = _UrlBuilder(bucket_name=self.bucket.name,
                                   object_name=self.name)

gcloud/storage/test_blob.py

@@ -69,6 +69,41 @@ def test_ctor_explicit(self):
         self.assertFalse(blob._acl.loaded)
         self.assertTrue(blob._acl.blob is blob)
 
+    def test_chunk_size_ctor(self):
+        from gcloud.storage.blob import Blob
+        BLOB_NAME = 'blob-name'
+        BUCKET = object()
+        chunk_size = 10 * Blob._CHUNK_SIZE_MULTIPLE
+        blob = self._makeOne(BLOB_NAME, bucket=BUCKET, chunk_size=chunk_size)
+        self.assertEqual(blob._chunk_size, chunk_size)
+
+    def test_chunk_size_getter(self):
+        BLOB_NAME = 'blob-name'
+        BUCKET = object()
+        blob = self._makeOne(BLOB_NAME, bucket=BUCKET)
+        self.assertEqual(blob.chunk_size, None)
+        VALUE = object()
+        blob._chunk_size = VALUE
+        self.assertTrue(blob.chunk_size is VALUE)
+
+    def test_chunk_size_setter(self):
+        BLOB_NAME = 'blob-name'
+        BUCKET = object()
+        blob = self._makeOne(BLOB_NAME, bucket=BUCKET)
+        self.assertEqual(blob._chunk_size, None)
+        blob._CHUNK_SIZE_MULTIPLE = 10
+        blob.chunk_size = 20
+        self.assertEqual(blob._chunk_size, 20)
+
+    def test_chunk_size_setter_bad_value(self):
+        BLOB_NAME = 'blob-name'
+        BUCKET = object()
+        blob = self._makeOne(BLOB_NAME, bucket=BUCKET)
+        self.assertEqual(blob._chunk_size, None)
+        blob._CHUNK_SIZE_MULTIPLE = 10
+        with self.assertRaises(ValueError):
+            blob.chunk_size = 11
+
     def test_acl_property(self):
         from gcloud.storage.acl import ObjectACL
         FAKE_BUCKET = _Bucket(None)
@@ -242,7 +277,7 @@ def test_delete(self):
         blob.delete()
         self.assertFalse(blob.exists())
 
-    def test_download_to_file(self):
+    def _download_to_file_helper(self, chunk_size=None):
         from six.moves.http_client import OK
         from six.moves.http_client import PARTIAL_CONTENT
         from io import BytesIO
@@ -259,11 +294,19 @@ def test_download_to_file(self):
         MEDIA_LINK = 'http://example.com/media/'
         properties = {'mediaLink': MEDIA_LINK}
         blob = self._makeOne(BLOB_NAME, bucket=bucket, properties=properties)
-        blob.CHUNK_SIZE = 3
+        if chunk_size is not None:
+            blob._CHUNK_SIZE_MULTIPLE = 1
+            blob.chunk_size = chunk_size
         fh = BytesIO()
         blob.download_to_file(fh)
         self.assertEqual(fh.getvalue(), b'abcdef')
 
+    def test_download_to_file_default(self):
+        self._download_to_file_helper()
+
+    def test_download_to_file_with_chunk_size(self):
+        self._download_to_file_helper(chunk_size=3)
+
     def test_download_to_filename(self):
         import os
         import time
@@ -284,7 +327,8 @@ def test_download_to_filename(self):
         properties = {'mediaLink': MEDIA_LINK,
                       'updated': '2014-12-06T13:13:50.690Z'}
         blob = self._makeOne(BLOB_NAME, bucket=bucket, properties=properties)
-        blob.CHUNK_SIZE = 3
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 3
         with NamedTemporaryFile() as f:
             blob.download_to_filename(f.name)
             f.flush()
@@ -311,7 +355,8 @@ def test_download_as_string(self):
         MEDIA_LINK = 'http://example.com/media/'
         properties = {'mediaLink': MEDIA_LINK}
         blob = self._makeOne(BLOB_NAME, bucket=bucket, properties=properties)
-        blob.CHUNK_SIZE = 3
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 3
         fetched = blob.download_as_string()
         self.assertEqual(fetched, b'abcdef')
 
@@ -330,7 +375,8 @@ def _upload_from_file_simple_test_helper(self, properties=None,
         )
         bucket = _Bucket(connection)
         blob = self._makeOne(BLOB_NAME, bucket=bucket, properties=properties)
-        blob.CHUNK_SIZE = 5
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 5
         with NamedTemporaryFile() as fh:
             fh.write(DATA)
             fh.flush()
@@ -398,7 +444,8 @@ def test_upload_from_file_resumable(self):
         )
         bucket = _Bucket(connection)
         blob = self._makeOne(BLOB_NAME, bucket=bucket)
-        blob.CHUNK_SIZE = 5
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 5
         # Set the threshhold low enough that we force a resumable uploada.
         with _Monkey(transfer, _RESUMABLE_UPLOAD_THRESHOLD=5):
             with NamedTemporaryFile() as fh:
@@ -455,7 +502,8 @@ def test_upload_from_file_w_slash_in_name(self):
         )
         bucket = _Bucket(connection)
         blob = self._makeOne(BLOB_NAME, bucket=bucket)
-        blob.CHUNK_SIZE = 5
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 5
         with NamedTemporaryFile() as fh:
             fh.write(DATA)
             fh.flush()
@@ -502,7 +550,8 @@ def _upload_from_filename_test_helper(self, properties=None,
         bucket = _Bucket(connection)
         blob = self._makeOne(BLOB_NAME, bucket=bucket,
                              properties=properties)
-        blob.CHUNK_SIZE = 5
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 5
         with NamedTemporaryFile(suffix='.jpeg') as fh:
             fh.write(DATA)
             fh.flush()
@@ -565,7 +614,8 @@ def test_upload_from_string_w_bytes(self):
         )
         bucket = _Bucket(connection)
         blob = self._makeOne(BLOB_NAME, bucket=bucket)
-        blob.CHUNK_SIZE = 5
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 5
         blob.upload_from_string(DATA)
         rq = connection.http._requested
         self.assertEqual(len(rq), 1)
@@ -603,7 +653,8 @@ def test_upload_from_string_w_text(self):
         )
         bucket = _Bucket(connection)
         blob = self._makeOne(BLOB_NAME, bucket=bucket)
-        blob.CHUNK_SIZE = 5
+        blob._CHUNK_SIZE_MULTIPLE = 1
+        blob.chunk_size = 5
         blob.upload_from_string(DATA)
         rq = connection.http._requested
         self.assertEqual(len(rq), 1)