# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

from oslo_config import cfg

from keystone.conf import utils


key_repository = cfg.StrOpt(
    'key_repository',
    default='/etc/keystone/fernet-keys/',
    help=utils.fmt("""
Directory containing Fernet token keys. This directory must exist before using
`keystone-manage fernet_setup` for the first time, must be writable by the user
running `keystone-manage fernet_setup` or `keystone-manage fernet_rotate`, and
of course must be readable by keystone's server process. The repository may
contain keys in one of three states: a single staged key (always index 0) used
for token validation, a single primary key (always the highest index) used for
token creation and validation, and any number of secondary keys (all other
index values) used for token validation. With multiple keystone nodes, each
node must share the same key repository contents, with the exception of the
staged key (index 0). It is safe to run `keystone-manage fernet_rotate` once on
any one node to promote a staged key (index 0) to be the new primary
(incremented from the previous highest index), and produce a new staged key (a
new key with index 0); the resulting repository can then be atomically
replicated to other nodes without any risk of race conditions (for example, it
is safe to run `keystone-manage fernet_rotate` on host A, wait any amount of
time, create a tarball of the directory on host A, unpack it on host B to a
temporary location, and atomically move (`mv`) the directory into place on host
B). Running `keystone-manage fernet_rotate` *twice* on a key repository without
syncing other nodes will result in tokens that can not be validated by all
nodes.
"""))

max_active_keys = cfg.IntOpt(
    'max_active_keys',
    default=3,
    min=1,
    help=utils.fmt("""
This controls how many keys are held in rotation by `keystone-manage
fernet_rotate` before they are discarded. The default value of 3 means that
keystone will maintain one staged key (always index 0), one primary key (the
highest numerical index), and one secondary key (every other index). Increasing
this value means that additional secondary keys will be kept in the rotation.
"""))


GROUP_NAME = __name__.split('.')[-1]
ALL_OPTS = [
    key_repository,
    max_active_keys,
]


def register_opts(conf):
    conf.register_opts(ALL_OPTS, group=GROUP_NAME)


def list_opts():
    return {GROUP_NAME: ALL_OPTS}
