If a client were in the middle of an object GET request and then disconnected, the proxy would wait a while (default 60s) and then time out the connection. As part of the teardown for this, the proxy would attempt to close the connection to the object server, then drain any associated buffers. However, this didn't work particularly well, resulting in the proxy reading the entire remainder of the object for no gain. Now, the proxy closes the connection hard, by calling .close() on the underlying socket._socket object. This is different from calling .close() on a socket._socketobject object, which is what you get back from socket.socket() and similar methods. Calling .close() on a socket._socketobject simply decrements a reference counter on the socket._socket, which has been observed in the past to result in socket leaks when something holds onto a reference. However, calling .close() on a socket._socket actually closes the socket regardless of who else has a reference to it. I had to delete a test assertion that said the object server never got SIGPIPE after a GET w/X-Newest. Well, you get a SIGPIPE when you write to a closed socket, and now the proxy is actually closing the sockets early, so now you *do* get a SIGPIPE. closes-bug: 1174660 Note that this will cause a regression on bug 1037337; unfortunately, the cure is worse than the disease, so out it goes. Change-Id: I9c7a2e7fdb8b4232e53ea96f86b50e8d34c27221
Swift
A distributed object storage system designed to scale from a single machine to thousands of servers. Swift is optimized for multi-tenancy and high concurrency. Swift is ideal for backups, web and mobile content, and any other unstructured data that can grow without bound.
Swift provides a simple, REST-based API fully documented at http://doc.openstack.org/.
Swift was originally developed as the basis for Rackspace's Cloud Files and was open-sourced in 2010 as part of the OpenStack project. It has since grown to include contributions from many companies and has spawned a thriving ecosystem of 3rd party tools. Swift's contributors are listed in the AUTHORS file.
Docs
To build documentation install sphinx (pip install sphinx), run
python setup.py build_sphinx, and then browse to /doc/build/html/index.html.
These docs are auto-generated after every commit and available online at
http://docs.openstack.org/developer/swift/.
For Developers
The best place to get started is the "SAIO - Swift All In One". This document will walk you through setting up a development cluster of Swift in a VM. The SAIO environment is ideal for running small-scale tests against swift and trying out new features and bug fixes.
You can run unit tests with .unittests and functional tests with
.functests.
Code Organization
- bin/: Executable scripts that are the processes run by the deployer
- doc/: Documentation
- etc/: Sample config files
- swift/: Core code
- account/: account server
- common/: code shared by different modules
- middleware/: "standard", officially-supported middleware
- ring/: code implementing Swift's ring
- container/: container server
- obj/: object server
- proxy/: proxy server
- test/: Unit and functional tests
Data Flow
Swift is a WSGI application and uses eventlet's WSGI server. After the
processes are running, the entry point for new requests is the Application
class in swift/proxy/server.py. From there, a controller is chosen, and the
request is processed. The proxy may choose to forward the request to a back-
end server. For example, the entry point for requests to the object server is
the ObjectController class in swift/obj/server.py.
For Deployers
Deployer docs are also available at http://docs.openstack.org/developer/swift/. A good starting point is at http://docs.openstack.org/developer/swift/deployment_guide.html
You can run functional tests against a swift cluster with .functests. These
functional tests require /etc/swift/test.conf to run. A sample config file
can be found in this source tree in test/sample.conf.
For Client Apps
For client applications, official Python language bindings are provided at http://github.com/openstack/python-swiftclient.
Complete API documentation at http://docs.openstack.org/api/openstack-object-storage/1.0/content/
For more information come hang out in #openstack-swift on freenode.
Thanks,
The Swift Development Team