Better TempAuth storage URL guessing

I know it's just TempAuth, but bug #959953 just caught my eye as
something interesting to solve.

This does a best guess on the storage URL to return for a given
request. It allows $HOST to be used in the storage URL configuration,
where $HOST will resolve to scheme://host:port. It bases the scheme
on how the server is running or on storage_url_scheme if set. The
host:port comes from the request's Host header if it exists, and
falls back to the WSGI SERVER_NAME:SERVER_PORT otherwise.

Fixes: bug #959953
DocImpact

Change-Id: Ia494bcb99a04490911ee8d2cb8b12a94e77820c5
Fix 500 on GET of many-segment manifest.

The proxy_logging middleware was asserting that the response contained
either a Content-Length header or a Transfer-Encoding header. If not,
it would either add one (if app_iter was a list) or blow up
(otherwise). This blowing up is observable on a GET request to a
manifest object that references more than
swift.common.constraints.CONTAINER_LISTING_LIMIT segments.

If a response makes it up to eventlet.wsgi without a Content-Length
header, then a "Transfer-Encoding: chunked" header is automatically
stuffed into the response by eventlet. Therefore, it's not an error
for a response to not have a Content-Length header, and proxy_logging
should just let it happen.

Fixes bug 1078113.

Change-Id: I3751a8ae14dc68bab546f2746b61267a5115e252
Remove outdated Debian packaging guide.

There are 3 sections in there, all useless.

Section 1 tells you how to install Swift packages from the swift-core
PPA. However, the latest version there is ancient.

Section 2 tells you how to build your own Swift packages. However, it
talks about getting the source code from the "debian" branch in bzr,
which is obviously really old.

Section 3 tells you how to take the packages from section 2 and
install them. This isn't too out-of-date, but since section 2 doesn't
work any more, section 3 is useless.

Since stale docs are worse than no docs, there's no current
information in this document, and bringing it up-to-date requires a
whole pile of work, I've chosen to delete it entirely.

Also pulled out a couple references to the PPA elsewhere.

Fixes bug 917385.
Fixes bug 1026145.

Change-Id: I510bd8619531fe110419e5488bd20d3602868d66
check response status in WSGIContext._app_call

Only re-chain response iter if start_response hasn't been called yet.

Change-Id: I9670f49419104fb8f949e6edc12d9047d1289cde
Merge "Better TempAuth storage URL guessing"
Merge "Fix 500 on GET of many-segment manifest."
Refactor DiskFile to hide temp file names and exts

This set of changes reworks the DiskFile class to remove the "extension"
parameter from the put() method, offering the new put_metadata() method with
an optional tombstone keyword boolean, and changes the mkstemp method to only
return the file descriptor.

Reviewing the code it was found that the temporary file name created as a
result of calling DiskFile.mkstemp() was never used by the caller, but the
caller was responsible for passing it back to the DiskFile.put() method. That
seems like too much information is exposed to the caller, when all the caller
requires is the file descriptor to write data into it.

Upon further review, the mkstemp() method was used in three places: PUT, POST
and DELETE method handling. Of those three cases, only PUT requires the file
descriptor, since it is responsible for writing the object contents. For POST
and DELETE, DiskFile only needs to associate metadata with the correct file
name. We abstract the pattern that those two use (once we also refactor the
code to move the fetch of the delete-at metadata, and subsequent
delete-at-update initiation, from under the mkstemp context) by adding the new
put_metadata() method.

As a result, the DiskFile class is then free to do whatever file system
operations it must to meet the API, without the caller having to know more
than just how to write data to a file descriptor. Note that DiskFile itself
key'd off of the '.ts' and '.meta' extensions for its operations, and for that
to work properly, the caller had to know to use those correctly. With this
change, the caller has no knowledge of how the file system is being used to
accomplish data and metadata storage.

See also Question 213796 at:
    https://answers.launchpad.net/swift/+question/213796

Change-Id: I267f68e64391ba627b2a13682393bec62600159d
Signed-off-by: Peter Portante <peter.portante@redhat.com>
change catch_errors to use WSGIContext

The current catch_errors (ie without this patch) relinquishes control
before the underlying middleware/app has been evaluated. This results
in not catching errors in the stack when they occur in either the
start_response or in generating the first chunk sent to the client of
the underlying stack.

Change-Id: Iecd21e4fc7e30fa20239d011f69216354b50baf1
Refactor db_replicator's roundrobin_datadirs

roundrobin_datadirs was returning any .db file at any depth in the
accounts/containers structure. Since xfs corruption can cause such
files to appear in odd places at times (only happened on one drive of
ours so far, but still...), I've refactored this function to only
return .db files at the proper depth.

Change-Id: Id06ef6584941f8a572e286f69dfa3d96fe451355
Merge "Remove outdated Debian packaging guide."
Merge "Refactor db_replicator's roundrobin_datadirs"
Updating doc reflecting the move of auth_token.

The auth_token middleware has moved, updating the doc.

Change-Id: I8133b876a53d61bf94169cf08c8b1fa6bbf9681a
Refactor http_connect() to use http_connect_raw()

Change-Id: I889c5eecf860cc947763c5d79148419f9741a2c2
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Merge "Updating doc reflecting the move of auth_token."
Merge "Refactor http_connect() to use http_connect_raw()"
Use a delta timeout for memcache where possible

We use a delta timeout value for timeouts under 30 days (in seconds)
since that is the limit which the memcached protocols will recognize a
timeout as a delta. Greater than 30 days and it interprets it as an
absolute time in seconds since the epoch.

This helps to address an often difficult-to-debug problem of time
drift between memcache clients and the memcache servers. Prior to this
change, if a client's time drifts behind the servers, short timeouts
run the danger of not being cached at all. If a client's time drifts
ahead of the servers, short timeouts run the danger of persisting too
long. Using delta's avoids this affect. For absolute timeouts 30 days
or more in the future small time drifts between clients and servers
are inconsequential.

See also bug 1076148 (https://bugs.launchpad.net/swift/+bug/1076148).

This also fixes incr and decr to handle timeout values in the same way
timeouts are handled for set operations.

Change-Id: Ie36dbcedfe9b4db9f77ed4ea9b70ff86c5773310
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Merge "change catch_errors to use WSGIContext"
Merge "Use a delta timeout for memcache where possible"
Merge "check response status in WSGIContext._app_call"
Merge "Refactor DiskFile to hide temp file names and exts"