127658bbee
Instead of just returning a generator for the data, return a tuple of (size, generator). This removes the need to call blob_size in get_blob, and leaves it up to the backend to decide how best to actually get that information. As a result: * The swift backend just needs to do a GET, rather than a HEAD then a GET. Either way, you should still get a Content-Length. * Now neither backend has a race wherein a backing blob may get deleted between the call to blob_size and stream_blob; previously, we could erroneously tell the client the blob exists but is empty. While we're refactoring, add constants for (and increase) the chunk-read size, and include Content-Length headers for GET and HEAD responses. Note that there's a bit of nuance to the return-check now: if the generator is None, the blob could not be found; if the size is None, the blob's size could not be determined -- possibly because we got a chunk-encoded response from swift. In practice, though, expect either both to be None, or neither. Change-Id: Ib85cffe17d2d57cc499d863f1b07cfad8ecd401a
139 lines
3.7 KiB
Python
139 lines
3.7 KiB
Python
# Copyright 2019 Red Hat, Inc.
|
|
#
|
|
# This module is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation, either version 3 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This software is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this software. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
from abc import ABCMeta, abstractmethod
|
|
|
|
|
|
class ObjectInfo:
|
|
def __init__(self, path, name, ctime, isdir):
|
|
self.path = path
|
|
self.name = name
|
|
self.ctime = ctime
|
|
self.isdir = isdir
|
|
|
|
|
|
class StorageDriver(metaclass=ABCMeta):
|
|
"""Base class for storage drivers.
|
|
|
|
Storage drivers should implement all of the methods in this class.
|
|
This is a low-level API with no knowledge of the intended use as
|
|
an image registry. This makes it easy to add backend drivers
|
|
since the storage abstraction layer is designed to deal with the
|
|
lowest common denominator.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def __init__(self, conf):
|
|
"""Initialize a driver.
|
|
|
|
:arg dict conf: The 'storage' section from the config file.
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def list_objects(self, path):
|
|
"""List objects at path.
|
|
|
|
Returns a list of objects rooted at `path`, one level deep.
|
|
|
|
:arg str path: The object path.
|
|
|
|
:returns: A list of ObjectInfo objects, one for each object.
|
|
:rtype: ObjectInfo
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def get_object_size(self, path):
|
|
"""Return the size of object at path.
|
|
|
|
:arg str path: The object path.
|
|
|
|
:returns: The size of the object in bytes.
|
|
:rtype: int
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def put_object(self, path, data):
|
|
"""Store an object.
|
|
|
|
Store the contents of `data` at `path`. The `data` parameter
|
|
may be a bytearray or a generator which produces bytearrays.
|
|
|
|
:arg str path: The object path.
|
|
:arg bytearray data: The data to store.
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def get_object(self, path):
|
|
"""Retrieve an object.
|
|
|
|
Return the contents of the object at `path`.
|
|
|
|
:arg str path: The object path.
|
|
|
|
:returns: The contents of the object.
|
|
:rtype: bytearray
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def stream_object(self, path):
|
|
"""Retrieve an object, streaming.
|
|
|
|
Return a generator with the content of the object at `path`.
|
|
|
|
:arg str path: The object path.
|
|
|
|
:returns: The size and contents of the object.
|
|
:rtype: tuple of (int or None, generator-of-bytearray or None)
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def delete_object(self, path):
|
|
"""Delete an object.
|
|
|
|
Delete the object stored at `path`.
|
|
|
|
:arg str path: The object path.
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def move_object(self, src_path, dst_path):
|
|
"""Move an object.
|
|
|
|
Move the object from `src_path` to `dst_path`.
|
|
|
|
:arg str src_path: The original path.
|
|
:arg str dst_path: The new path.
|
|
"""
|
|
pass
|
|
|
|
@abstractmethod
|
|
def cat_objects(self, path, chunks):
|
|
"""Concatenate objects.
|
|
|
|
Concatenate one or more objects to create a new object.
|
|
The original objects are deleted.
|
|
|
|
:arg str path: The new path.
|
|
:arg list chunks: A list of paths of objects to concatenate.
|
|
"""
|
|
pass
|