Openstack-swift proxy server.
swift-proxy-server [CONFIG] [-h|--help] [-v|--verbose]
The Swift Proxy Server is responsible for tying together the rest of the Swift architecture. For each request, it will look up the location of the account, container, or object in the ring and route the request accordingly. The public API is also exposed through the Proxy Server. A large number of failures are also handled in the Proxy Server. For example, if a server is unavailable for an object PUT, it will ask the ring for a handoff server and route there instead. When objects are streamed to or from an object server, they are streamed directly through the proxy server to or from the user the proxy server does not spool them.
More in depth documentation in regards to swift-proxy-server and also about Openstack-Swift as a whole can be found at http://swift.openstack.org/index.html