12d8a53fff
PEP 333 (WSGI) says: "If the iterable returned by the application has
a close() method, the server or gateway must call that method upon
completion of the current request[.]"
There's a bunch of places where we weren't doing that; some of them
matter more than others. Calling .close() can prevent a connection
leak in some cases. In others, it just provides a certain pedantic
smugness. Either way, we should do what WSGI requires.
Noteworthy goofs include:
* If a client is downloading a large object and disconnects halfway
through, a proxy -> obj connection may be leaked. In this case,
the WSGI iterable is a SegmentedIterable, which lacked a close()
method. Thus, when the WSGI server noticed the client disconnect,
it had no way of telling the SegmentedIterable about it, and so
the underlying iterable for the segment's data didn't get
closed.
Here, it seems likely (though unproven) that the object server
would time out and kill the connection, or that a
ChunkWriteTimeout would fire down in the proxy server, so the
leaked connection would eventually go away. However, a flurry of
client disconnects could leave a big pile of useless connections.
* If a conditional request receives a 304 or 412, the underlying
app_iter is not closed. This mostly affects conditional requests
for large objects.
The leaked connections were noticed by this patch's co-author, who
made the changes to SegmentedIterable. Those changes helped, but did
not completely fix, the issue. The rest of the patch is an attempt to
plug the rest of the holes.
Co-Authored-By: Romain LE DISEZ <romain.ledisez@ovh.net>
Change-Id: I168e147aae7c1728e7e3fdabb7fba6f2d747d937
Closes-Bug: #1466549
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://docs.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.
If you would like to start contributing, check out these notes to help you get started.
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