More changes for registry-v2 in python.

Implement the minimal changes to the local filesystem storage driver and feed them through the distributed storage driver.
Create a digest package which contains digest_tools and checksums.
Fix the tests to use the new v1 endpoint locations.
Fix repository.delete_instance to properly filter the generated queries to avoid most subquery deletes, but still generate them when not explicitly filtered.

storage/local.py

@@ -3,10 +3,13 @@ import shutil
 import hashlib
 import io
 
-from storage.basestorage import BaseStorage
+from uuid import uuid4
+
+from storage.basestorage import BaseStorageV2
+from digest import digest_tools
 
 
-class LocalStorage(BaseStorage):
+class LocalStorage(BaseStorageV2):
 
   def __init__(self, storage_path):
     self._root_path = storage_path
@@ -46,15 +49,26 @@ class LocalStorage(BaseStorage):
   def stream_write(self, path, fp, content_type=None, content_encoding=None):
     # Size is mandatory
     path = self._init_path(path, create=True)
-    with open(path, mode='wb') as f:
-      while True:
-        try:
-          buf = fp.read(self.buffer_size)
-          if not buf:
-            break
-          f.write(buf)
-        except IOError:
+    with open(path, mode='wb') as out_fp:
+      self._stream_write_to_fp(fp, out_fp)
+
+  def _stream_write_to_fp(self, in_fp, out_fp, num_bytes=-1):
+    """ Copy the specified number of bytes from the input file stream to the output stream. If
+        num_bytes < 0 copy until the stream ends.
+    """
+    bytes_copied = 0
+    bytes_remaining = num_bytes
+    while bytes_remaining > 0 or num_bytes < 0:
+      try:
+        buf = in_fp.read(self.buffer_size)
+        if not buf:
           break
+        out_fp.write(buf)
+        bytes_copied += len(buf)
+      except IOError:
+        break
+
+    return bytes_copied
 
   def list_directory(self, path=None):
     path = self._init_path(path)
@@ -92,3 +106,36 @@ class LocalStorage(BaseStorage):
           break
         sha_hash.update(buf)
     return sha_hash.hexdigest()[:7]
+
+
+  def _rel_upload_path(self, uuid):
+    return 'uploads/{0}'.format(uuid)
+
+
+  def initiate_chunked_upload(self):
+    new_uuid = str(uuid4())
+
+    # Just create an empty file at the path
+    with open(self._init_path(self._rel_upload_path(new_uuid), create=True), 'w'):
+      pass
+
+    return new_uuid
+
+  def stream_upload_chunk(self, uuid, offset, length, in_fp):
+    with open(self._init_path(self._rel_upload_path(uuid)), 'r+b') as upload_storage:
+      upload_storage.seek(offset)
+      return self._stream_write_to_fp(in_fp, upload_storage, length)
+
+  def complete_chunked_upload(self, uuid, final_path, digest_to_verify):
+    content_path = self._rel_upload_path(uuid)
+    content_digest = digest_tools.sha256_digest_from_generator(self.stream_read(content_path))
+
+    if not digest_tools.digests_equal(content_digest, digest_to_verify):
+      msg = 'Given: {0} Computed: {1}'.format(digest_to_verify, content_digest)
+      raise digest_tools.InvalidDigestException(msg)
+
+    final_path = self._init_path(final_path, create=True)
+    shutil.move(self._init_path(content_path), final_path)
+
+
+