#!/usr/bin/python
# -*- coding: utf-8 -*-

DOCUMENTATION = '''
---
module: nova_manage
short_description: Initialize OpenStack Compute (nova) database
description: Create the tables for the database backend used by nova
options:
  action:
    description:
      - action to perform. Currently only dbsync is supported
    required: true
requirements: [ nova ]
'''

EXAMPLES = '''
nova_manage: action=dbsync
'''

import subprocess

try:
    from nova.db.sqlalchemy import migration
    from nova import config
except ImportError:
    nova_found = False
else:
    nova_found = True


def load_config_file():
    config.parse_args([])


def will_db_change():
    """ Check if the database version will change after the sync.

    """
    # Load the config file options
    current_version = migration.db_version()
    repository = migration._find_migrate_repo()
    repo_version = repository.latest
    return current_version != repo_version


def do_dbsync():
    """Do the dbsync. Returns (returncode, stdout, stderr)"""
    # We call nova-manage db_sync on the shell rather than trying to
    # do this in Python since we have no guarantees about changes to the
    # internals.
    args = ['nova-manage', 'db', 'sync']

    call = subprocess.Popen(args, shell=False,
                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    out, err = call.communicate()
    return (call.returncode, out, err)


def main():

    module = AnsibleModule(
        argument_spec=dict(
            action=dict(required=True),
        ),
        supports_check_mode=True
    )

    if not nova_found:
        module.fail_json(msg="nova package could not be found")

    action = module.params['action']

    if action not in ['dbsync', 'db_sync']:
        module.fail_json(msg="Only supported action is 'dbsync'")

    load_config_file()

    changed = will_db_change()
    if module.check_mode:
        module.exit_json(changed=changed)

    (res, stdout, stderr) = do_dbsync()

    if res == 0:
        module.exit_json(changed=changed, stdout=stdout, stderr=stderr)
    else:
        module.fail_json(msg="nova-manage returned non-zero value: %d" % res,
                         stdout=stdout, stderr=stderr)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()