designate/moniker/utils.py

# Copyright 2012 Managed I.T.
#
# Author: Kiall Mac Innes <kiall@managedit.ie>
#
# 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.
import os
import pkg_resources
import json
from jinja2 import Template
from moniker.openstack.common import log as logging
from moniker.openstack.common import cfg
from moniker.openstack.common import processutils
from moniker.openstack.common import timeutils
from moniker.openstack.common.notifier import api as notifier_api
from moniker import exceptions

LOG = logging.getLogger(__name__)


cfg.CONF.register_opts([
    cfg.StrOpt('root-helper',
               default='sudo moniker-rootwrap /etc/moniker/rootwrap.conf')
])


def notify(context, service, event_type, payload):
    priority = 'INFO'
    publisher_id = notifier_api.publisher_id(service)
    event_type = "dns.%s" % event_type
    notifier_api.notify(context, publisher_id, event_type, priority, payload)


def find_config(config_path):
    """
    Find a configuration file using the given hint.

    Code nabbed from cinder.

    :param config_path: Full or relative path to the config.
    :returns: List of config paths
    """
    possible_locations = [
        config_path,
        os.path.join(cfg.CONF.state_path, "etc", "moniker", config_path),
        os.path.join(cfg.CONF.state_path, "etc", config_path),
        os.path.join(cfg.CONF.state_path, config_path),
        "/etc/moniker/%s" % config_path,
    ]

    found_locations = []

    for path in possible_locations:
        LOG.debug('Searching for configuration at path: %s' % path)
        if os.path.exists(path):
            LOG.debug('Found configuration at path: %s' % path)
            found_locations.append(os.path.abspath(path))

    return found_locations


def read_config(prog, argv):
    config_files = find_config('%s.conf' % prog)

    cfg.CONF(argv[1:], project='moniker', prog=prog,
             default_config_files=config_files)


def resource_string(*args):
    if len(args) == 0:
        raise ValueError()

    resource_path = os.path.join('resources', *args)

    if not pkg_resources.resource_exists('moniker', resource_path):
        raise exceptions.ResourceNotFound('Could not find the requested '
                                          'resource: %s' % resource_path)

    return pkg_resources.resource_string('moniker', resource_path)


def load_schema(version, name):
    schema_string = resource_string('schemas', version, '%s.json' % name)

    return json.loads(schema_string)


def load_template(template_name):
    template_string = resource_string('templates', template_name)

    return Template(template_string)


def render_template(template, **template_context):
    if not isinstance(template, Template):
        template = load_template(template)

    return template.render(**template_context)


def render_template_to_file(template_name, output_path, makedirs=True,
                            **template_context):
    output_folder = os.path.dirname(output_path)

    # Create the output folder tree if necessary
    if makedirs and not os.path.exists(output_folder):
        os.makedirs(output_folder)

    # Render the template
    content = render_template(template_name, **template_context)

    with open(output_path, 'w') as output_fh:
        output_fh.write(content)


def execute(*cmd, **kw):
    root_helper = kw.pop('root_helper', cfg.CONF.root_helper)
    run_as_root = kw.pop('run_as_root', True)
    return processutils.execute(*cmd, run_as_root=run_as_root,
                                root_helper=root_helper, **kw)


def get_item_properties(item, fields, mixed_case_fields=[], formatters={}):
    """Return a tuple containing the item properties.

    :param item: a single item resource (e.g. Server, Tenant, etc)
    :param fields: tuple of strings with the desired field names
    :param mixed_case_fields: tuple of field names to preserve case
    :param formatters: dictionary mapping field names to callables
        to format the values
    """
    row = []

    for field in fields:
        if field in formatters:
            row.append(formatters[field](item))
        else:
            if field in mixed_case_fields:
                field_name = field.replace(' ', '_')
            else:
                field_name = field.lower().replace(' ', '_')
            if not hasattr(item, field_name) and \
                    (isinstance(item, dict) and field_name in item):
                data = item[field_name]
            else:
                data = getattr(item, field_name, '')
            if data is None:
                data = ''
            row.append(data)
    return tuple(row)


def get_columns(data):
    """
    Some row's might have variable count of columns, ensure that we have the
    same.

    :param data: Results in [{}, {]}]
    """
    columns = set()

    def _seen(col):
        columns.add(str(col))

    map(lambda item: map(_seen, item.keys()), data)
    return list(columns)


def increment_serial(serial=0):
    # This provides for *roughly* unix timestamp based serial numbers
    new_serial = timeutils.utcnow_ts()

    if new_serial <= serial:
        new_serial = serial + 1

    return new_serial