charm-ceph-osd/hooks/utils.py

# Copyright 2016 Canonical Ltd
#
# 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 socket
import re
from charmhelpers.core.hookenv import (
    unit_get,
    cached,
    config,
    network_get_primary_address,
    log, DEBUG,
    status_set,
)
from charmhelpers.core import unitdata
from charmhelpers.fetch import (
    apt_install,
    filter_installed_packages
)

from charmhelpers.core.host import (
    lsb_release
)

from charmhelpers.contrib.network.ip import (
    get_address_in_network,
    get_ipv6_addr
)

TEMPLATES_DIR = 'templates'

try:
    import jinja2
except ImportError:
    apt_install(filter_installed_packages(['python-jinja2']),
                fatal=True)
    import jinja2

try:
    import dns.resolver
except ImportError:
    apt_install(filter_installed_packages(['python-dnspython']),
                fatal=True)
    import dns.resolver


def render_template(template_name, context, template_dir=TEMPLATES_DIR):
    templates = jinja2.Environment(
        loader=jinja2.FileSystemLoader(template_dir))
    template = templates.get_template(template_name)
    return template.render(context)


def enable_pocket(pocket):
    apt_sources = "/etc/apt/sources.list"
    with open(apt_sources, "r") as sources:
        lines = sources.readlines()
    with open(apt_sources, "w") as sources:
        for line in lines:
            if pocket in line:
                sources.write(re.sub('^# deb', 'deb', line))
            else:
                sources.write(line)


@cached
def get_unit_hostname():
    return socket.gethostname()


@cached
def get_host_ip(hostname=None):
    if config('prefer-ipv6'):
        return get_ipv6_addr()[0]

    hostname = hostname or unit_get('private-address')
    try:
        # Test to see if already an IPv4 address
        socket.inet_aton(hostname)
        return hostname
    except socket.error:
        # This may throw an NXDOMAIN exception; in which case
        # things are badly broken so just let it kill the hook
        answers = dns.resolver.query(hostname, 'A')
        if answers:
            return answers[0].address


@cached
def get_public_addr():
    if config('ceph-public-network'):
        return get_network_addrs('ceph-public-network')[0]

    try:
        return network_get_primary_address('public')
    except NotImplementedError:
        log("network-get not supported", DEBUG)

    return get_host_ip()


@cached
def get_cluster_addr():
    if config('ceph-cluster-network'):
        return get_network_addrs('ceph-cluster-network')[0]

    try:
        return network_get_primary_address('cluster')
    except NotImplementedError:
        log("network-get not supported", DEBUG)

    return get_host_ip()


def get_networks(config_opt='ceph-public-network'):
    """Get all configured networks from provided config option.

    If public network(s) are provided, go through them and return those for
    which we have an address configured.
    """
    networks = config(config_opt)
    if networks:
        networks = networks.split()
        return [n for n in networks if get_address_in_network(n)]

    return []


def get_network_addrs(config_opt):
    """Get all configured public networks addresses.

    If public network(s) are provided, go through them and return the
    addresses we have configured on any of those networks.
    """
    addrs = []
    networks = config(config_opt)
    if networks:
        networks = networks.split()
        addrs = [get_address_in_network(n) for n in networks]
        addrs = [a for a in addrs if a]

    if not addrs:
        if networks:
            msg = ("Could not find an address on any of '%s' - resolve this "
                   "error to retry" % (networks))
            status_set('blocked', msg)
            raise Exception(msg)
        else:
            return [get_host_ip()]

    return addrs


def assert_charm_supports_ipv6():
    """Check whether we are able to support charms ipv6."""
    if lsb_release()['DISTRIB_CODENAME'].lower() < "trusty":
        raise Exception("IPv6 is not supported in the charms for Ubuntu "
                        "versions less than Trusty 14.04")


# copied charmhelpers.contrib.openstack.utils so that the charm does need the
# entire set of dependencies that that module actually also has to bring in
# from charmhelpers.
def set_unit_paused():
    """Set the unit to a paused state in the local kv() store.
    This does NOT actually pause the unit
    """
    with unitdata.HookData()() as t:
        kv = t[0]
        kv.set('unit-paused', True)


def clear_unit_paused():
    """Clear the unit from a paused state in the local kv() store
    This does NOT actually restart any services - it only clears the
    local state.
    """
    with unitdata.HookData()() as t:
        kv = t[0]
        kv.set('unit-paused', False)


def is_unit_paused_set():
    """Return the state of the kv().get('unit-paused').
    This does NOT verify that the unit really is paused.

    To help with units that don't have HookData() (testing)
    if it excepts, return False
    """
    try:
        with unitdata.HookData()() as t:
            kv = t[0]
            # transform something truth-y into a Boolean.
            return not(not(kv.get('unit-paused')))
    except:
        return False