Replace the following items with Python 3 style code.

- six.moves.configparser
- six.moves.StringIO
- six.moves.cStringIO
- six.moves.urllib
- six.moves.builtins
- six.moves.range
- six.moves.xmlrpc_client
- six.moves.http_client
- six.moves.http_cookies
- six.moves.queue
- six.moves.zip
- six.moves.reload_module
- six.StringIO
- six.BytesIO

Subsequent patches will replace other six usages.

Change-Id: Ib2c406327fef2fb4868d8050fc476a7d17706e23
Implements: blueprint six-removal
Signed-off-by: Takashi Natsume <takanattie@gmail.com>

This is a partial revert of commit
9606c80402f6db20d62b689c58aa8f024183628a which added the 'path' query
parameter to work with noVNC v1.1.0. This broke all other console types
using websockify server (serial, spice) because the websockify server
itself doesn't know how to handle the 'path' query parameter. It is the
noVNC vnc_lite.html file which parses the 'path' variable and uses it
as the url to the websockify server. So, all other console types should
*not* be generating a console access url with a 'path' query parameter,
only noVNC.

Closes-Bug: #1845243

TODO(melwitt): Figure out how to test serial and/or spice console in
the gate

Change-Id: I9521f21a685edc44121d75bdf534c201fa87c2d7

The periodic task to clean up expired console_auth tokens
does not work properly because there are cases that 'host'
in the 'console_auth_tokens' table is different from
hosts where nova-compute processes run.

So make the periodic task to clear all expired console tokens
regardless of hosts where nova-compute processes run.

Change-Id: I61cee4245e612b4bef1ffaacc634a8302cf836e9
Closes-Bug: #1816399

Starting in noVNC v1.1.0, the token query parameter is no longer
forwarded via cookie [1]. We must instead use the 'path' query
parameter to pass the token through to the websocketproxy [2].
This means that if someone deploys noVNC v1.1.0, VNC consoles will
break in nova because the code is relying on the cookie functionality
that v1.1.0 removed.

This modifies the ConsoleAuthToken.access_url property to include the
'path' query parameter as part of the returned access_url that the
client will use to call the console proxy service.

This change is backward compatible with noVNC < v1.1.0. The 'path' query
parameter is a long supported feature in noVNC.

Co-Authored-By: melanie witt <melwittt@gmail.com>

Closes-Bug: #1822676

[1] https://github.com/novnc/noVNC/commit/51f9f0098d306bbc67cc8e02ae547921b6f6585c
[2] https://github.com/novnc/noVNC/pull/1220

Change-Id: I2ddf0f4d768b698e980594dd67206464a9cea37b

This is only used in three places now, each of which can be removed.

Part of blueprint remove-consoleauth

Change-Id: I89df8f8fa111b730ddd0aa73ae09a8cd5d152dad
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

In Rocky, we deprecated the nova-consoleauth service but there were
unconditional calls to nova-consoleauth in the compute/api, which
made it impossible to avoid running the nova-consoleauth service.

This adds conditional checks to call nova-consoleauth only if the
[workarounds]enable_consoleauth configuration option is True. The
option defaults to False because the default console token auth TTL
is 10 minutes and only operators who have configured much longer TTL
or otherwise wish to avoid resetting all consoles at upgrade time
need to use the option.

This also updates the /os-console-auth-tokens/{console_token} API to
use nova-consoleauth only if the [workarounds] option is enabled. This
had to be done in the same change because the conditional checks in
the compute/api code caused the /os-console-auth-tokens API functional
tests to fail to find token authorizations in nova-consoleauth.

Closes-Bug: #1788470
Closes-Bug: #1795982

Change-Id: Iff6020f1a10afc476864f979faf251ef5a1a6184

nova/db/__init__.py was importing * from nova.db.api. This meant that
any time any code anywhere within the nova.db package was imported
then nova.db.api was too, leading to a cascade of imports that may
not have been desired. Also, in general, code in __init__.py is a pain.

Therefore, this change adjusts code that so that either:

* nova.db.api is used directly
* nova.db.api is imported as 'db'

In either case, the functionality remains the same.

The primary goal of this change was to make it possible to import the
model files without having to import the db api. Moving the model files
to a different place in the directory hierarchy was considered, but
given that "code in __init__.py is a pain" this mode was chosen.

This looks like a very large change, but it is essentially adjusting
package names, many in mocks.

Change-Id: Ic1fd7c87ceda05eeb96735da2a415ef37060bb1a

There are a bunch of files that define CONF but don't ever reference
it. This cleans that up, removing unnecessary imports.

In order to get flake8 to pass I also had to remove some (unrelated)
unused imports from touched files.

Change-Id: Ib96ebeeb5e4bfedb20afb02c56da1521df9fac4f

Console connection authorizations will be saved in
the database instead of in memory in a console auth
server.

The ConsoleAuthToken object has class methods
that replace the rpc methods used by the console
auth service. To use this object instead of that
service the calling code will use these methods
instead of call the service rpc API.

Co-Authored-By: Eli Qiao <qiaoliyong@gmail.com>
Co-Authored-By: melanie witt <melwittt@gmail.com>

partially-implements: blueprint convert-consoles-to-objects

Change-Id: Ia13591906ab2b3b7b7d5bc8f4b965c117f08fc9b