os-collect-config/os_collect_config/collect.py

# Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
#
# 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 json
import os
import signal
import subprocess
import sys
import time

from openstack.common import log
from os_collect_config import cache
from os_collect_config import cfn
from os_collect_config import common
from os_collect_config import ec2
from os_collect_config import exc
from os_collect_config import heat_local
from oslo.config import cfg

DEFAULT_COLLECTORS = ['heat_local', 'ec2', 'cfn']
opts = [
    cfg.StrOpt('command', short='c',
               help='Command to run on metadata changes. If specified,'
                    ' os-collect-config will continue to run until killed. If'
                    ' not specified, os-collect-config will print the'
                    ' collected data as a json map and exit.'),
    cfg.StrOpt('cachedir',
               default='/var/run/os-collect-config',
               help='Directory in which to store local cache of metadata'),
    cfg.MultiStrOpt(
        'collectors',
        positional=True,
        default=DEFAULT_COLLECTORS,
        help='List the collectors to use. When command is specified the'
             'collections will be emitted in the order given by this option.'
        ' (default: %s)' % ' '.join(DEFAULT_COLLECTORS)),
    cfg.BoolOpt('one-time',
                default=False,
                help='Pass this option to make os-collect-config exit after'
                ' one execution of command. This behavior is implied if no'
                ' command is specified.'),
    cfg.FloatOpt('polling-interval', short='i', default=300,
                 help='When running continuously, pause this many seconds'
                      ' between collecting data.'),
]

CONF = cfg.CONF
logger = log.getLogger('os-collect-config')

COLLECTORS = {ec2.name: ec2,
              cfn.name: cfn,
              heat_local.name: heat_local}


def setup_conf():
    ec2_group = cfg.OptGroup(name='ec2',
                             title='EC2 Metadata options')

    cfn_group = cfg.OptGroup(name='cfn',
                             title='CloudFormation API Metadata options')

    heat_local_group = cfg.OptGroup(name='heat_local',
                                    title='Heat Local Metadata options')

    CONF.register_group(ec2_group)
    CONF.register_group(cfn_group)
    CONF.register_group(heat_local_group)
    CONF.register_cli_opts(ec2.opts, group='ec2')
    CONF.register_cli_opts(cfn.opts, group='cfn')
    CONF.register_cli_opts(heat_local.opts, group='heat_local')

    CONF.register_cli_opts(opts)


def collect_all(collectors, store=False, requests_impl_map=None):
    any_changed = False
    if store:
        paths_or_content = []
    else:
        paths_or_content = {}

    for collector in collectors:
        module = COLLECTORS[collector]
        if requests_impl_map and collector in requests_impl_map:
            requests_impl = requests_impl_map[collector]
        else:
            requests_impl = common.requests

        try:
            content = module.Collector(
                requests_impl=requests_impl).collect()
        except exc.SourceNotAvailable:
            logger.warn('Source [%s] Unavailable.' % collector)
            continue

        if store:
            (changed, path) = cache.store(collector, content)
            any_changed |= changed
            paths_or_content.append(path)
        else:
            paths_or_content[collector] = content

    return (any_changed, paths_or_content)


def reexec_self(signal=None, frame=None):
    if signal:
        logger.info('Signal received. Re-executing %s' % sys.argv)
    # Close all but stdin/stdout/stderr
    os.closerange(3, 255)
    os.execv(sys.argv[0], sys.argv)


def call_command(files, command):
    env = dict(os.environ)
    env["OS_CONFIG_FILES"] = ':'.join(files)
    logger.info("Executing %s" % command)
    subprocess.check_call(CONF.command, env=env, shell=True)


def __main__(args=sys.argv, requests_impl_map=None):
    signal.signal(signal.SIGHUP, reexec_self)
    setup_conf()
    CONF(args=args[1:], prog="os-collect-config")

    unknown_collectors = set(CONF.collectors) - set(DEFAULT_COLLECTORS)
    if unknown_collectors:
        raise exc.InvalidArguments(
            'Unknown collectors %s. Valid collectors are: %s' %
            (list(unknown_collectors), DEFAULT_COLLECTORS))

    while True:
        (any_changed, content) = collect_all(
            cfg.CONF.collectors,
            store=bool(CONF.command),
            requests_impl_map=requests_impl_map)
        if CONF.command:
            if any_changed:
                # ignore HUP now since we will reexec after commit anyway
                signal.signal(signal.SIGHUP, signal.SIG_IGN)
                try:
                    call_command(content, CONF.command)
                except subprocess.CalledProcessError as e:
                    logger.error('Command failed, will not cache new data. %s'
                                 % e)
                    if not CONF.one_time:
                        logger.warn('Sleeping %.2f seconds before re-exec.' %
                                    CONF.polling_interval)
                        time.sleep(CONF.polling_interval)
                else:
                    for collector in cfg.CONF.collectors:
                        cache.commit(collector)
                if not CONF.one_time:
                    reexec_self()
            else:
                logger.debug("No changes detected.")
            if CONF.one_time:
                break
            else:
                logger.info("Sleeping %.2f seconds.", CONF.polling_interval)
                time.sleep(CONF.polling_interval)
        else:
            print(json.dumps(content, indent=1))
            break


if __name__ == '__main__':
    # This resets the logging infrastructure which prevents capturing log
    # output in tests cleanly, so do it only if we're running as an actual
    # process.
    log.setup("os-collect-config")
    __main__()