Expand recon middleware support

Expand recon middleware to include support for account and container
servers in addition to the existing object servers. Also add support
for retrieving recent information from auditors, replicators, and
updaters. In the case of certain checks (such as container auditors)
the stats returned are only for the most recent path processed.

The middleware has also been refactored and should now also handle
errors better in cases where stats are unavailable.

While new check's have been added the output from pre-existing
check's has not changed. This should allow existing 3rd party
utilities such as the Swift ZenPack to continue to function.

Change-Id: Ib9893a77b9b8a2f03179f2a73639bc4a6e264df7
Fixed the one new thing PEP8 1.1 found

Change-Id: Iaa15bd47ff5ba48bd971ccc8c1707930977116df
Move proxy server logging to middleware.

Change-Id: I771c87207d4e1821e32c3424b341d182cc7ea7c0
Merge "Expand recon middleware support"
Fixed query removal bug in make_pre_authed_request

Change-Id: I1b8238fb2ffe07b1474f7d8f040fdc620b6897d7
Updated AUTHORS, CHANGELOG, and version for 1.5.0 release

Change-Id: I9e0e26394a1892d757e33806511940cbe43be4d5
1.5.1 version bump to continue dev

Change-Id: Ied84c8274b3aee5f63a11e557c6c59729666d99f
fixed doc table format

Change-Id: I319de933ecfb1e3853e3064656968c36980ce5f5
Adding missing files in generated tarballs

Fix MANIFEST.in to include tools/, tox.ini and test/sample.conf
in generated tarballs. Fixes bug 960018 and bug 1005801.

Change-Id: Ifa83eab62300e3aec71ced217dc3cdcb2846ea0e
Fixed another make_pre_auth bug (wsgi.input)

Change-Id: I8b3c182ab85d4c5545e0a4259a64a496ebaf2bcb
Merge "Fixed query removal bug in make_pre_authed_request"
Merge "Fixed another make_pre_auth bug (wsgi.input)"
Fixed bug where 204 would sometimes be chunked

Not sure how this got introduced (which really annoys me)
but here's the fix to make sure the content-length /
transfer-encoding headers are set properly. Specifically,
the proxy was sometimes returning transfer-encoding: chunked
with no content-length on 204 No Content responses where it
used to return content-length: 0 and no transfer-encoding
header at all.

Change-Id: I0927d102bc5e4324e38dbbb44be9033a6cd8ee20
Ensure empty results are returned

Make sure that empty but still valid results (like no unmounted drives)
aren't treated as 500 errors.

Change-Id: I9588e2711d7916406f15613d5a26b9f0cf38235a
Merge "Fixed bug where 204 would sometimes be chunked"
Proxy logging content-length fix

Change-Id: Iad2f12b3db44378c1369481c567b3d13b9a4b75f
Fix starvation in object server with fast clients.

When an object server was handling concurrent GET or POST requests
from very fast clients, it would starve other connected clients. The
greenthreads responsible for servicing the fast clients would hog the
processor and only rarely yield to another greenthread.

The reason this happens for GET requests is found in
eventlet.greenio.GreenSocket, in the send() method. When you call
.send(data) on a GreenSocket, it immediately calls .send(data) on its
underlying real socket (socket._socketobject). If the real socket
accepts all the data, then GreenSocket.send() returns without yielding
to another greenthread. Only if the real socket failed to accept all
the data (either .send(data) < len(data) or by raising EWOULDBLOCK)
does the GreenSocket yield control.

Under most workloads, this isn't a problem. The TCP connection to
client X can only consume data so quickly, and therefore the
greenthread serving client X will frequently encounter a full socket
buffer and yield control, so no clients starve. However, when there's
a lot of contention for a single object from a large number of fast
clients (e.g. on a LAN connected w/10Gb Ethernet), then one winds up
in a situation where reading from the disk is slower than writing to
the network, and so full socket buffers become rare, and therefore so
do context switches. The end result is that many clients time out
waiting for data.

The situation for PUT requests is analogous; GreenSocket.recv() seldom
encounters EWOULDBLOCK, so greenthreads seldom yield.

This patch calls eventlet.sleep() to yield control after each chunk,
preventing any one greenthread's IO from blocking the hub for very
long.

This code has the flaw that it will greenthread-switch twice when a
send() or recv() does block, but since there isn't a way to find out
if a switch occurred or not, there's no way to avoid it. Since
greenlet switches are quite fast (faster than system calls, which the
object server does a lot of), this shouldn't have a significant
performance impact.

Change-Id: I8549adfb4a198739b80979236c27b76df607eebf