paster_commands: remove unused imports

Remove some unused imports, using 'autoflake' followed by manual redacting.
find kallithea/lib/paster_commands/ -name "*.py" \
| xargs autoflake --remove-all-unused-imports -i

This same command could be applied gradually throughout the code base as
areas are touched. Since autoflake may be too greedy in special cases, it is
more difficult to do a big-bang action over all code.

celery: let celerypylons.app be the actual app, not a factory

Change extracted by Mads Kiilerich.

celeryd: let the gearbox command use db session as most other gearbox commands do

304aae43194c changed the common gearbox wrapper so make_app_without_logging
only was run for commands tagged as requires_db_session. That broke celeryd -
even a plain 'gearbox celeryd -c my.ini' would fail on the safety check in
celerypylons asserting on tg.config having 'celery.imports' configuration.

The gearbox celeryd command did not really require a db session - it just
required app configuration so it could create db sessions on the fly.

To to get the missing make_app_without_logging invocation back, set
requires_db_session (the default for our gearbox commands).

requires_db_session not only calls make_app_without_logging (which undo the
effect from 304aae43194c), it also calls setup_cache_regions,
engine_from_config, and init_model. These were also invoked explicitly in
celeryd code - these double invocations are dropped too.

Also, make_app_without_logging will call into tg and thus invoke the
setup_configuration hook which will set kallithea.CELERY_ON and call
load_rcextensions. The celeryd code for doing that is thus dropped.

gearbox: if a config file is specified, store it in the command instance so it is available without tg

This will prevent a plain 'gearbox make-rcext -c kallithea.ini' from crashing in

here = config['here']

Note:
kallithea.CONFIG serves a very similar purpose.

Modified by Mads Kiilerich.

gearbox: replace paster with something TurboGears2-ish that still works with the Pylons stack

This is a step towards moving away from the Pylons stack to TurboGears2, but
still independent of it.


Some notes from the porting - it could perhaps be the missing(?) documentation
for migrating from paster to gearbox:

Note: 'gearbox' without parameters will crash - specify '-h' to get started
testing.

Replace paster
summary = 'yada yada'
with the first line of the docstring of the Command class ... or override
get_description.

Note: All newlines in the docstring will be collapsed and mangle the long help
text.

Grouping of commands is not possible. Standard commands (for development) can't
be customized under the same name or hidden. (Like for paster, the conceptual
model also assumes that the sub-command naming is namespaced so commands from
other packages won't conflict.)

The usage help is fully automated from the declared options.

For all deprecated Commands, replace paster
hidden = True
with gearbox
deprecated = True

Note: config_file, takes_config_file, min_args and max_args are not available /
relevant.

The gearbox parser is customized by overriding get_parser - there is nothing
like paster update_parser.

Gearbox is using argparse instead of optparse ... but argparse add_argument is
mostly backwards compatible with optparse add_option.

Instead of overriding command or run as in paster, override take_action in
gearbox. The parsed arguments are passed to take_action, not available on the
command instance.

Paster BadCommand is not available and must be handled manually, terminating
with sys.exit(1).

There is no standard make-config command in gearbox.

Paster appinstall has been replaced by the somewhat different setup_app module
in gearbox. There is still no clean way to pass parameters to SetupAppCommand
and it relies on websetup and other apparently unnecessary complexity. Instead,
implement setup-db from scratch.


Minor change by Thomas De Schampheleire: add gearbox logging configuration.
Because we use logging.config.fileConfig(.inifile) during gearbox command
execution, the logging settings need to be correct and contain a block for
gearbox logging itself. Otherwise, errors in command processing are not even
visible and the command exits silently.

tg: minimize future diff by some mocking and replacing some pylons imports with tg

No actual tg dependency yet, just a temporary hack faking tg as an alias for
pylons.

Based on work by Alessandro Molina.

celery: upgrade to Celery 3

Celery 3 is more than 2 and is the future and should be more stable than Celery 2.

There might be problems like
PRECONDITION_FAILED - cannot redeclare exchange 'celeryresults' in vhost 'kallithea' with different type, durable, internal or autodelete value
when celery is upgraded and it tries to upgrade existing tasks.

One way to avoid that problem:
- make sure celery has run to completion and there are no important pending tasks,
- delete the old vhost,
- upgrade celery,
- create new vhost
- set permissions for vhost
- profit

celeryd: move the celeryd paster command to the place where paster commands live

Also, partial implementations of other Celery functionality is dropped.