Merge lp:~cbjchen/charms/trusty/ubuntu/lxc-network-config into lp:charms/trusty/ubuntu

[Liang Chen]

This patch provides a config option for the ubuntu
charm, so that users can choose whether to create
a different subnet or just bridge to the exist
network that the ubuntu instance is in for lxc
containers running in the ubuntu instance.

[Review Queue (review-queue)]

This items has failed automated testing! Results available here http://reports.vapour.ws/charm-tests/charm-bundle-test-11062-results

review: Needs Fixing (automated testing)

[Adam Israel (aisrael)]

Hi Liang,

Thanks for your work on improving this charm's functionality. It's passing tests for me, but it would be really useful to update the README to reflect the new config option and how to use it. Once that is done, I'm happy to retest.

review: Needs Fixing

[Antonio Rosales (arosales)]

The failed automated testing was due to HP Cloud not standing up in time[0] all other tests on the other substrates passed:

[0] http://reports.vapour.ws/all-bundle-and-charm-results/charm-bundle-test-11062-results/charm/charm-testing-hp/2

I'll work on a branch to update the README.md per Adam's comments.

-thanks,
Antonio

review: Approve (community)

[Antonio Rosales (arosales)]

I have an MP against this branch to:
  -Add documenetation to the readme about the new new-lxc-network network option for LXC.
  -Add Amulet tests to ensure the new-lxc-network config option is operating correctly.
  -Update the default to be false for new-lxc-network. Reason is the goal of the Ubuntu charm is to be a very simple charm, and is a good indicator juju functions are working correctly.

-thanks,
Antonio

[Antonio Rosales (arosales)]

For reference that MP is at:
https://code.launchpad.net/~a.rosales/charms/trusty/ubuntu/update-readme-test-for-lxc-network/+merge/254147

-thanks,
Antonio

[Liang Chen (cbjchen)]

Hi Adam and Antonio,

Thanks for the review, and thanks for the help to supply the the documentation and tests. It makes sense to me to set the default value to false. I was just trying to make sure the behavior is the same as the previous version by default. I took a look at the patch, and it looks good to me.

[Charles Butler (lazypower)]

Liang,

Thank you for the contribution to the Ubuntu charm. I've taken some time to review your changes, and the follow up documentation + test from Antonio.

I've taken the liberty of merging his additions to your branch, and have pushed them to the store.

Thank you for the high quality submission, tests, and documentation. This is exactly the type of merge that makes me happy to perform a final review on. Keep up the great work!

review: Approve

=== added file 'charm-helpers-hooks.yaml'
--- charm-helpers-hooks.yaml	1970-01-01 00:00:00 +0000
+++ charm-helpers-hooks.yaml	2015-02-23 19:08:44 +0000
@@ -0,0 +1,5 @@
+branch: lp:charm-helpers
+destination: hooks/charmhelpers
+include:
+    - core
+    - fetch

=== added file 'config.yaml'
--- config.yaml	1970-01-01 00:00:00 +0000
+++ config.yaml	2015-02-23 19:08:44 +0000
@@ -0,0 +1,8 @@
+options:
+  new-lxc-network:
+    type: boolean
+    default: True
+    description: |
+      If True creates new network for lxc containers, otherwise using the
+      same network of the node for lxc containers.
+

=== added file 'hooks/__init__.py'
=== added directory 'hooks/charmhelpers'
=== added file 'hooks/charmhelpers/__init__.py'
=== added directory 'hooks/charmhelpers/core'
=== added file 'hooks/charmhelpers/core/__init__.py'
--- hooks/charmhelpers/core/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/__init__.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,15 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.

=== added file 'hooks/charmhelpers/core/decorators.py'
--- hooks/charmhelpers/core/decorators.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/decorators.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,57 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+#
+# Copyright 2014 Canonical Ltd.
+#
+# Authors:
+#  Edward Hope-Morley <[e-mail]>
+#
+
+import time
+
+from charmhelpers.core.hookenv import (
+    log,
+    INFO,
+)
+
+
+def retry_on_exception(num_retries, base_delay=0, exc_type=Exception):
+    """If the decorated function raises exception exc_type, allow num_retries
+    retry attempts before raise the exception.
+    """
+    def _retry_on_exception_inner_1(f):
+        def _retry_on_exception_inner_2(*args, **kwargs):
+            retries = num_retries
+            multiplier = 1
+            while True:
+                try:
+                    return f(*args, **kwargs)
+                except exc_type:
+                    if not retries:
+                        raise
+
+                delay = base_delay * multiplier
+                multiplier += 1
+                log("Retrying '%s' %d more times (delay=%s)" %
+                    (f.__name__, retries, delay), level=INFO)
+                retries -= 1
+                if delay:
+                    time.sleep(delay)
+
+        return _retry_on_exception_inner_2
+
+    return _retry_on_exception_inner_1

=== added file 'hooks/charmhelpers/core/fstab.py'
--- hooks/charmhelpers/core/fstab.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/fstab.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,134 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import io
+import os
+
+__author__ = 'Jorge Niedbalski R. <[e-mail]>'
+
+
+class Fstab(io.FileIO):
+    """This class extends file in order to implement a file reader/writer
+    for file `/etc/fstab`
+    """
+
+    class Entry(object):
+        """Entry class represents a non-comment line on the `/etc/fstab` file
+        """
+        def __init__(self, device, mountpoint, filesystem,
+                     options, d=0, p=0):
+            self.device = device
+            self.mountpoint = mountpoint
+            self.filesystem = filesystem
+
+            if not options:
+                options = "defaults"
+
+            self.options = options
+            self.d = int(d)
+            self.p = int(p)
+
+        def __eq__(self, o):
+            return str(self) == str(o)
+
+        def __str__(self):
+            return "{} {} {} {} {} {}".format(self.device,
+                                              self.mountpoint,
+                                              self.filesystem,
+                                              self.options,
+                                              self.d,
+                                              self.p)
+
+    DEFAULT_PATH = os.path.join(os.path.sep, 'etc', 'fstab')
+
+    def __init__(self, path=None):
+        if path:
+            self._path = path
+        else:
+            self._path = self.DEFAULT_PATH
+        super(Fstab, self).__init__(self._path, 'rb+')
+
+    def _hydrate_entry(self, line):
+        # NOTE: use split with no arguments to split on any
+        #       whitespace including tabs
+        return Fstab.Entry(*filter(
+            lambda x: x not in ('', None),
+            line.strip("\n").split()))
+
+    @property
+    def entries(self):
+        self.seek(0)
+        for line in self.readlines():
+            line = line.decode('us-ascii')
+            try:
+                if line.strip() and not line.strip().startswith("#"):
+                    yield self._hydrate_entry(line)
+            except ValueError:
+                pass
+
+    def get_entry_by_attr(self, attr, value):
+        for entry in self.entries:
+            e_attr = getattr(entry, attr)
+            if e_attr == value:
+                return entry
+        return None
+
+    def add_entry(self, entry):
+        if self.get_entry_by_attr('device', entry.device):
+            return False
+
+        self.write((str(entry) + '\n').encode('us-ascii'))
+        self.truncate()
+        return entry
+
+    def remove_entry(self, entry):
+        self.seek(0)
+
+        lines = [l.decode('us-ascii') for l in self.readlines()]
+
+        found = False
+        for index, line in enumerate(lines):
+            if line.strip() and not line.strip().startswith("#"):
+                if self._hydrate_entry(line) == entry:
+                    found = True
+                    break
+
+        if not found:
+            return False
+
+        lines.remove(line)
+
+        self.seek(0)
+        self.write(''.join(lines).encode('us-ascii'))
+        self.truncate()
+        return True
+
+    @classmethod
+    def remove_by_mountpoint(cls, mountpoint, path=None):
+        fstab = cls(path=path)
+        entry = fstab.get_entry_by_attr('mountpoint', mountpoint)
+        if entry:
+            return fstab.remove_entry(entry)
+        return False
+
+    @classmethod
+    def add(cls, device, mountpoint, filesystem, options=None, path=None):
+        return cls(path=path).add_entry(Fstab.Entry(device,
+                                                    mountpoint, filesystem,
+                                                    options=options))

=== added file 'hooks/charmhelpers/core/hookenv.py'
--- hooks/charmhelpers/core/hookenv.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/hookenv.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,568 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+"Interactions with the Juju environment"
+# Copyright 2013 Canonical Ltd.
+#
+# Authors:
+#  Charm Helpers Developers <[e-mail]>
+
+import os
+import json
+import yaml
+import subprocess
+import sys
+from subprocess import CalledProcessError
+
+import six
+if not six.PY3:
+    from UserDict import UserDict
+else:
+    from collections import UserDict
+
+CRITICAL = "CRITICAL"
+ERROR = "ERROR"
+WARNING = "WARNING"
+INFO = "INFO"
+DEBUG = "DEBUG"
+MARKER = object()
+
+cache = {}
+
+
+def cached(func):
+    """Cache return values for multiple executions of func + args
+
+    For example::
+
+        @cached
+        def unit_get(attribute):
+            pass
+
+        unit_get('test')
+
+    will cache the result of unit_get + 'test' for future calls.
+    """
+    def wrapper(*args, **kwargs):
+        global cache
+        key = str((func, args, kwargs))
+        try:
+            return cache[key]
+        except KeyError:
+            res = func(*args, **kwargs)
+            cache[key] = res
+            return res
+    return wrapper
+
+
+def flush(key):
+    """Flushes any entries from function cache where the
+    key is found in the function+args """
+    flush_list = []
+    for item in cache:
+        if key in item:
+            flush_list.append(item)
+    for item in flush_list:
+        del cache[item]
+
+
+def log(message, level=None):
+    """Write a message to the juju log"""
+    command = ['juju-log']
+    if level:
+        command += ['-l', level]
+    if not isinstance(message, six.string_types):
+        message = repr(message)
+    command += [message]
+    subprocess.call(command)
+
+
+class Serializable(UserDict):
+    """Wrapper, an object that can be serialized to yaml or json"""
+
+    def __init__(self, obj):
+        # wrap the object
+        UserDict.__init__(self)
+        self.data = obj
+
+    def __getattr__(self, attr):
+        # See if this object has attribute.
+        if attr in ("json", "yaml", "data"):
+            return self.__dict__[attr]
+        # Check for attribute in wrapped object.
+        got = getattr(self.data, attr, MARKER)
+        if got is not MARKER:
+            return got
+        # Proxy to the wrapped object via dict interface.
+        try:
+            return self.data[attr]
+        except KeyError:
+            raise AttributeError(attr)
+
+    def __getstate__(self):
+        # Pickle as a standard dictionary.
+        return self.data
+
+    def __setstate__(self, state):
+        # Unpickle into our wrapper.
+        self.data = state
+
+    def json(self):
+        """Serialize the object to json"""
+        return json.dumps(self.data)
+
+    def yaml(self):
+        """Serialize the object to yaml"""
+        return yaml.dump(self.data)
+
+
+def execution_environment():
+    """A convenient bundling of the current execution context"""
+    context = {}
+    context['conf'] = config()
+    if relation_id():
+        context['reltype'] = relation_type()
+        context['relid'] = relation_id()
+        context['rel'] = relation_get()
+    context['unit'] = local_unit()
+    context['rels'] = relations()
+    context['env'] = os.environ
+    return context
+
+
+def in_relation_hook():
+    """Determine whether we're running in a relation hook"""
+    return 'JUJU_RELATION' in os.environ
+
+
+def relation_type():
+    """The scope for the current relation hook"""
+    return os.environ.get('JUJU_RELATION', None)
+
+
+def relation_id():
+    """The relation ID for the current relation hook"""
+    return os.environ.get('JUJU_RELATION_ID', None)
+
+
+def local_unit():
+    """Local unit ID"""
+    return os.environ['JUJU_UNIT_NAME']
+
+
+def remote_unit():
+    """The remote unit for the current relation hook"""
+    return os.environ['JUJU_REMOTE_UNIT']
+
+
+def service_name():
+    """The name service group this unit belongs to"""
+    return local_unit().split('/')[0]
+
+
+def hook_name():
+    """The name of the currently executing hook"""
+    return os.path.basename(sys.argv[0])
+
+
+class Config(dict):
+    """A dictionary representation of the charm's config.yaml, with some
+    extra features:
+
+    - See which values in the dictionary have changed since the previous hook.
+    - For values that have changed, see what the previous value was.
+    - Store arbitrary data for use in a later hook.
+
+    NOTE: Do not instantiate this object directly - instead call
+    ``hookenv.config()``, which will return an instance of :class:`Config`.
+
+    Example usage::
+
+        >>> # inside a hook
+        >>> from charmhelpers.core import hookenv
+        >>> config = hookenv.config()
+        >>> config['foo']
+        'bar'
+        >>> # store a new key/value for later use
+        >>> config['mykey'] = 'myval'
+
+
+        >>> # user runs `juju set mycharm foo=baz`
+        >>> # now we're inside subsequent config-changed hook
+        >>> config = hookenv.config()
+        >>> config['foo']
+        'baz'
+        >>> # test to see if this val has changed since last hook
+        >>> config.changed('foo')
+        True
+        >>> # what was the previous value?
+        >>> config.previous('foo')
+        'bar'
+        >>> # keys/values that we add are preserved across hooks
+        >>> config['mykey']
+        'myval'
+
+    """
+    CONFIG_FILE_NAME = '.juju-persistent-config'
+
+    def __init__(self, *args, **kw):
+        super(Config, self).__init__(*args, **kw)
+        self.implicit_save = True
+        self._prev_dict = None
+        self.path = os.path.join(charm_dir(), Config.CONFIG_FILE_NAME)
+        if os.path.exists(self.path):
+            self.load_previous()
+
+    def __getitem__(self, key):
+        """For regular dict lookups, check the current juju config first,
+        then the previous (saved) copy. This ensures that user-saved values
+        will be returned by a dict lookup.
+
+        """
+        try:
+            return dict.__getitem__(self, key)
+        except KeyError:
+            return (self._prev_dict or {})[key]
+
+    def keys(self):
+        prev_keys = []
+        if self._prev_dict is not None:
+            prev_keys = self._prev_dict.keys()
+        return list(set(prev_keys + list(dict.keys(self))))
+
+    def load_previous(self, path=None):
+        """Load previous copy of config from disk.
+
+        In normal usage you don't need to call this method directly - it
+        is called automatically at object initialization.
+
+        :param path:
+
+            File path from which to load the previous config. If `None`,
+            config is loaded from the default location. If `path` is
+            specified, subsequent `save()` calls will write to the same
+            path.
+
+        """
+        self.path = path or self.path
+        with open(self.path) as f:
+            self._prev_dict = json.load(f)
+
+    def changed(self, key):
+        """Return True if the current value for this key is different from
+        the previous value.
+
+        """
+        if self._prev_dict is None:
+            return True
+        return self.previous(key) != self.get(key)
+
+    def previous(self, key):
+        """Return previous value for this key, or None if there
+        is no previous value.
+
+        """
+        if self._prev_dict:
+            return self._prev_dict.get(key)
+        return None
+
+    def save(self):
+        """Save this config to disk.
+
+        If the charm is using the :mod:`Services Framework <services.base>`
+        or :meth:'@hook <Hooks.hook>' decorator, this
+        is called automatically at the end of successful hook execution.
+        Otherwise, it should be called directly by user code.
+
+        To disable automatic saves, set ``implicit_save=False`` on this
+        instance.
+
+        """
+        if self._prev_dict:
+            for k, v in six.iteritems(self._prev_dict):
+                if k not in self:
+                    self[k] = v
+        with open(self.path, 'w') as f:
+            json.dump(self, f)
+
+
+@cached
+def config(scope=None):
+    """Juju charm configuration"""
+    config_cmd_line = ['config-get']
+    if scope is not None:
+        config_cmd_line.append(scope)
+    config_cmd_line.append('--format=json')
+    try:
+        config_data = json.loads(
+            subprocess.check_output(config_cmd_line).decode('UTF-8'))
+        if scope is not None:
+            return config_data
+        return Config(config_data)
+    except ValueError:
+        return None
+
+
+@cached
+def relation_get(attribute=None, unit=None, rid=None):
+    """Get relation information"""
+    _args = ['relation-get', '--format=json']
+    if rid:
+        _args.append('-r')
+        _args.append(rid)
+    _args.append(attribute or '-')
+    if unit:
+        _args.append(unit)
+    try:
+        return json.loads(subprocess.check_output(_args).decode('UTF-8'))
+    except ValueError:
+        return None
+    except CalledProcessError as e:
+        if e.returncode == 2:
+            return None
+        raise
+
+
+def relation_set(relation_id=None, relation_settings=None, **kwargs):
+    """Set relation information for the current unit"""
+    relation_settings = relation_settings if relation_settings else {}
+    relation_cmd_line = ['relation-set']
+    if relation_id is not None:
+        relation_cmd_line.extend(('-r', relation_id))
+    for k, v in (list(relation_settings.items()) + list(kwargs.items())):
+        if v is None:
+            relation_cmd_line.append('{}='.format(k))
+        else:
+            relation_cmd_line.append('{}={}'.format(k, v))
+    subprocess.check_call(relation_cmd_line)
+    # Flush cache of any relation-gets for local unit
+    flush(local_unit())
+
+
+@cached
+def relation_ids(reltype=None):
+    """A list of relation_ids"""
+    reltype = reltype or relation_type()
+    relid_cmd_line = ['relation-ids', '--format=json']
+    if reltype is not None:
+        relid_cmd_line.append(reltype)
+        return json.loads(
+            subprocess.check_output(relid_cmd_line).decode('UTF-8')) or []
+    return []
+
+
+@cached
+def related_units(relid=None):
+    """A list of related units"""
+    relid = relid or relation_id()
+    units_cmd_line = ['relation-list', '--format=json']
+    if relid is not None:
+        units_cmd_line.extend(('-r', relid))
+    return json.loads(
+        subprocess.check_output(units_cmd_line).decode('UTF-8')) or []
+
+
+@cached
+def relation_for_unit(unit=None, rid=None):
+    """Get the json represenation of a unit's relation"""
+    unit = unit or remote_unit()
+    relation = relation_get(unit=unit, rid=rid)
+    for key in relation:
+        if key.endswith('-list'):
+            relation[key] = relation[key].split()
+    relation['__unit__'] = unit
+    return relation
+
+
+@cached
+def relations_for_id(relid=None):
+    """Get relations of a specific relation ID"""
+    relation_data = []
+    relid = relid or relation_ids()
+    for unit in related_units(relid):
+        unit_data = relation_for_unit(unit, relid)
+        unit_data['__relid__'] = relid
+        relation_data.append(unit_data)
+    return relation_data
+
+
+@cached
+def relations_of_type(reltype=None):
+    """Get relations of a specific type"""
+    relation_data = []
+    reltype = reltype or relation_type()
+    for relid in relation_ids(reltype):
+        for relation in relations_for_id(relid):
+            relation['__relid__'] = relid
+            relation_data.append(relation)
+    return relation_data
+
+
+@cached
+def metadata():
+    """Get the current charm metadata.yaml contents as a python object"""
+    with open(os.path.join(charm_dir(), 'metadata.yaml')) as md:
+        return yaml.safe_load(md)
+
+
+@cached
+def relation_types():
+    """Get a list of relation types supported by this charm"""
+    rel_types = []
+    md = metadata()
+    for key in ('provides', 'requires', 'peers'):
+        section = md.get(key)
+        if section:
+            rel_types.extend(section.keys())
+    return rel_types
+
+
+@cached
+def charm_name():
+    """Get the name of the current charm as is specified on metadata.yaml"""
+    return metadata().get('name')
+
+
+@cached
+def relations():
+    """Get a nested dictionary of relation data for all related units"""
+    rels = {}
+    for reltype in relation_types():
+        relids = {}
+        for relid in relation_ids(reltype):
+            units = {local_unit(): relation_get(unit=local_unit(), rid=relid)}
+            for unit in related_units(relid):
+                reldata = relation_get(unit=unit, rid=relid)
+                units[unit] = reldata
+            relids[relid] = units
+        rels[reltype] = relids
+    return rels
+
+
+@cached
+def is_relation_made(relation, keys='private-address'):
+    '''
+    Determine whether a relation is established by checking for
+    presence of key(s).  If a list of keys is provided, they
+    must all be present for the relation to be identified as made
+    '''
+    if isinstance(keys, str):
+        keys = [keys]
+    for r_id in relation_ids(relation):
+        for unit in related_units(r_id):
+            context = {}
+            for k in keys:
+                context[k] = relation_get(k, rid=r_id,
+                                          unit=unit)
+            if None not in context.values():
+                return True
+    return False
+
+
+def open_port(port, protocol="TCP"):
+    """Open a service network port"""
+    _args = ['open-port']
+    _args.append('{}/{}'.format(port, protocol))
+    subprocess.check_call(_args)
+
+
+def close_port(port, protocol="TCP"):
+    """Close a service network port"""
+    _args = ['close-port']
+    _args.append('{}/{}'.format(port, protocol))
+    subprocess.check_call(_args)
+
+
+@cached
+def unit_get(attribute):
+    """Get the unit ID for the remote unit"""
+    _args = ['unit-get', '--format=json', attribute]
+    try:
+        return json.loads(subprocess.check_output(_args).decode('UTF-8'))
+    except ValueError:
+        return None
+
+
+def unit_private_ip():
+    """Get this unit's private IP address"""
+    return unit_get('private-address')
+
+
+class UnregisteredHookError(Exception):
+    """Raised when an undefined hook is called"""
+    pass
+
+
+class Hooks(object):
+    """A convenient handler for hook functions.
+
+    Example::
+
+        hooks = Hooks()
+
+        # register a hook, taking its name from the function name
+        @hooks.hook()
+        def install():
+            pass  # your code here
+
+        # register a hook, providing a custom hook name
+        @hooks.hook("config-changed")
+        def config_changed():
+            pass  # your code here
+
+        if __name__ == "__main__":
+            # execute a hook based on the name the program is called by
+            hooks.execute(sys.argv)
+    """
+
+    def __init__(self, config_save=True):
+        super(Hooks, self).__init__()
+        self._hooks = {}
+        self._config_save = config_save
+
+    def register(self, name, function):
+        """Register a hook"""
+        self._hooks[name] = function
+
+    def execute(self, args):
+        """Execute a registered hook based on args[0]"""
+        hook_name = os.path.basename(args[0])
+        if hook_name in self._hooks:
+            self._hooks[hook_name]()
+            if self._config_save:
+                cfg = config()
+                if cfg.implicit_save:
+                    cfg.save()
+        else:
+            raise UnregisteredHookError(hook_name)
+
+    def hook(self, *hook_names):
+        """Decorator, registering them as hooks"""
+        def wrapper(decorated):
+            for hook_name in hook_names:
+                self.register(hook_name, decorated)
+            else:
+                self.register(decorated.__name__, decorated)
+                if '_' in decorated.__name__:
+                    self.register(
+                        decorated.__name__.replace('_', '-'), decorated)
+            return decorated
+        return wrapper
+
+
+def charm_dir():
+    """Return the root directory of the current charm"""
+    return os.environ.get('CHARM_DIR')

=== added file 'hooks/charmhelpers/core/host.py'
--- hooks/charmhelpers/core/host.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/host.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,446 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Tools for working with the host system"""
+# Copyright 2012 Canonical Ltd.
+#
+# Authors:
+#  Nick Moffitt <[e-mail]>
+#  Matthew Wedgwood <[e-mail]>
+
+import os
+import re
+import pwd
+import grp
+import random
+import string
+import subprocess
+import hashlib
+from contextlib import contextmanager
+from collections import OrderedDict
+
+import six
+
+from .hookenv import log
+from .fstab import Fstab
+
+
+def service_start(service_name):
+    """Start a system service"""
+    return service('start', service_name)
+
+
+def service_stop(service_name):
+    """Stop a system service"""
+    return service('stop', service_name)
+
+
+def service_restart(service_name):
+    """Restart a system service"""
+    return service('restart', service_name)
+
+
+def service_reload(service_name, restart_on_failure=False):
+    """Reload a system service, optionally falling back to restart if
+    reload fails"""
+    service_result = service('reload', service_name)
+    if not service_result and restart_on_failure:
+        service_result = service('restart', service_name)
+    return service_result
+
+
+def service(action, service_name):
+    """Control a system service"""
+    cmd = ['service', service_name, action]
+    return subprocess.call(cmd) == 0
+
+
+def service_running(service):
+    """Determine whether a system service is running"""
+    try:
+        output = subprocess.check_output(
+            ['service', service, 'status'],
+            stderr=subprocess.STDOUT).decode('UTF-8')
+    except subprocess.CalledProcessError:
+        return False
+    else:
+        if ("start/running" in output or "is running" in output):
+            return True
+        else:
+            return False
+
+
+def service_available(service_name):
+    """Determine whether a system service is available"""
+    try:
+        subprocess.check_output(
+            ['service', service_name, 'status'],
+            stderr=subprocess.STDOUT).decode('UTF-8')
+    except subprocess.CalledProcessError as e:
+        return 'unrecognized service' not in e.output
+    else:
+        return True
+
+
+def adduser(username, password=None, shell='/bin/bash', system_user=False):
+    """Add a user to the system"""
+    try:
+        user_info = pwd.getpwnam(username)
+        log('user {0} already exists!'.format(username))
+    except KeyError:
+        log('creating user {0}'.format(username))
+        cmd = ['useradd']
+        if system_user or password is None:
+            cmd.append('--system')
+        else:
+            cmd.extend([
+                '--create-home',
+                '--shell', shell,
+                '--password', password,
+            ])
+        cmd.append(username)
+        subprocess.check_call(cmd)
+        user_info = pwd.getpwnam(username)
+    return user_info
+
+
+def add_group(group_name, system_group=False):
+    """Add a group to the system"""
+    try:
+        group_info = grp.getgrnam(group_name)
+        log('group {0} already exists!'.format(group_name))
+    except KeyError:
+        log('creating group {0}'.format(group_name))
+        cmd = ['addgroup']
+        if system_group:
+            cmd.append('--system')
+        else:
+            cmd.extend([
+                '--group',
+            ])
+        cmd.append(group_name)
+        subprocess.check_call(cmd)
+        group_info = grp.getgrnam(group_name)
+    return group_info
+
+
+def add_user_to_group(username, group):
+    """Add a user to a group"""
+    cmd = [
+        'gpasswd', '-a',
+        username,
+        group
+    ]
+    log("Adding user {} to group {}".format(username, group))
+    subprocess.check_call(cmd)
+
+
+def rsync(from_path, to_path, flags='-r', options=None):
+    """Replicate the contents of a path"""
+    options = options or ['--delete', '--executability']
+    cmd = ['/usr/bin/rsync', flags]
+    cmd.extend(options)
+    cmd.append(from_path)
+    cmd.append(to_path)
+    log(" ".join(cmd))
+    return subprocess.check_output(cmd).decode('UTF-8').strip()
+
+
+def symlink(source, destination):
+    """Create a symbolic link"""
+    log("Symlinking {} as {}".format(source, destination))
+    cmd = [
+        'ln',
+        '-sf',
+        source,
+        destination,
+    ]
+    subprocess.check_call(cmd)
+
+
+def mkdir(path, owner='root', group='root', perms=0o555, force=False):
+    """Create a directory"""
+    log("Making dir {} {}:{} {:o}".format(path, owner, group,
+                                          perms))
+    uid = pwd.getpwnam(owner).pw_uid
+    gid = grp.getgrnam(group).gr_gid
+    realpath = os.path.abspath(path)
+    path_exists = os.path.exists(realpath)
+    if path_exists and force:
+        if not os.path.isdir(realpath):
+            log("Removing non-directory file {} prior to mkdir()".format(path))
+            os.unlink(realpath)
+            os.makedirs(realpath, perms)
+    elif not path_exists:
+        os.makedirs(realpath, perms)
+    os.chown(realpath, uid, gid)
+    os.chmod(realpath, perms)
+
+
+def write_file(path, content, owner='root', group='root', perms=0o444):
+    """Create or overwrite a file with the contents of a byte string."""
+    log("Writing file {} {}:{} {:o}".format(path, owner, group, perms))
+    uid = pwd.getpwnam(owner).pw_uid
+    gid = grp.getgrnam(group).gr_gid
+    with open(path, 'wb') as target:
+        os.fchown(target.fileno(), uid, gid)
+        os.fchmod(target.fileno(), perms)
+        target.write(content)
+
+
+def fstab_remove(mp):
+    """Remove the given mountpoint entry from /etc/fstab
+    """
+    return Fstab.remove_by_mountpoint(mp)
+
+
+def fstab_add(dev, mp, fs, options=None):
+    """Adds the given device entry to the /etc/fstab file
+    """
+    return Fstab.add(dev, mp, fs, options=options)
+
+
+def mount(device, mountpoint, options=None, persist=False, filesystem="ext3"):
+    """Mount a filesystem at a particular mountpoint"""
+    cmd_args = ['mount']
+    if options is not None:
+        cmd_args.extend(['-o', options])
+    cmd_args.extend([device, mountpoint])
+    try:
+        subprocess.check_output(cmd_args)
+    except subprocess.CalledProcessError as e:
+        log('Error mounting {} at {}\n{}'.format(device, mountpoint, e.output))
+        return False
+
+    if persist:
+        return fstab_add(device, mountpoint, filesystem, options=options)
+    return True
+
+
+def umount(mountpoint, persist=False):
+    """Unmount a filesystem"""
+    cmd_args = ['umount', mountpoint]
+    try:
+        subprocess.check_output(cmd_args)
+    except subprocess.CalledProcessError as e:
+        log('Error unmounting {}\n{}'.format(mountpoint, e.output))
+        return False
+
+    if persist:
+        return fstab_remove(mountpoint)
+    return True
+
+
+def mounts():
+    """Get a list of all mounted volumes as [[mountpoint,device],[...]]"""
+    with open('/proc/mounts') as f:
+        # [['/mount/point','/dev/path'],[...]]
+        system_mounts = [m[1::-1] for m in [l.strip().split()
+                                            for l in f.readlines()]]
+    return system_mounts
+
+
+def file_hash(path, hash_type='md5'):
+    """
+    Generate a hash checksum of the contents of 'path' or None if not found.
+
+    :param str hash_type: Any hash alrgorithm supported by :mod:`hashlib`,
+                          such as md5, sha1, sha256, sha512, etc.
+    """
+    if os.path.exists(path):
+        h = getattr(hashlib, hash_type)()
+        with open(path, 'rb') as source:
+            h.update(source.read())
+        return h.hexdigest()
+    else:
+        return None
+
+
+def check_hash(path, checksum, hash_type='md5'):
+    """
+    Validate a file using a cryptographic checksum.
+
+    :param str checksum: Value of the checksum used to validate the file.
+    :param str hash_type: Hash algorithm used to generate `checksum`.
+        Can be any hash alrgorithm supported by :mod:`hashlib`,
+        such as md5, sha1, sha256, sha512, etc.
+    :raises ChecksumError: If the file fails the checksum
+
+    """
+    actual_checksum = file_hash(path, hash_type)
+    if checksum != actual_checksum:
+        raise ChecksumError("'%s' != '%s'" % (checksum, actual_checksum))
+
+
+class ChecksumError(ValueError):
+    pass
+
+
+def restart_on_change(restart_map, stopstart=False):
+    """Restart services based on configuration files changing
+
+    This function is used a decorator, for example::
+
+        @restart_on_change({
+            '/etc/ceph/ceph.conf': [ 'cinder-api', 'cinder-volume' ]
+            })
+        def ceph_client_changed():
+            pass  # your code here
+
+    In this example, the cinder-api and cinder-volume services
+    would be restarted if /etc/ceph/ceph.conf is changed by the
+    ceph_client_changed function.
+    """
+    def wrap(f):
+        def wrapped_f(*args, **kwargs):
+            checksums = {}
+            for path in restart_map:
+                checksums[path] = file_hash(path)
+            f(*args, **kwargs)
+            restarts = []
+            for path in restart_map:
+                if checksums[path] != file_hash(path):
+                    restarts += restart_map[path]
+            services_list = list(OrderedDict.fromkeys(restarts))
+            if not stopstart:
+                for service_name in services_list:
+                    service('restart', service_name)
+            else:
+                for action in ['stop', 'start']:
+                    for service_name in services_list:
+                        service(action, service_name)
+        return wrapped_f
+    return wrap
+
+
+def lsb_release():
+    """Return /etc/lsb-release in a dict"""
+    d = {}
+    with open('/etc/lsb-release', 'r') as lsb:
+        for l in lsb:
+            k, v = l.split('=')
+            d[k.strip()] = v.strip()
+    return d
+
+
+def pwgen(length=None):
+    """Generate a random pasword."""
+    if length is None:
+        length = random.choice(range(35, 45))
+    alphanumeric_chars = [
+        l for l in (string.ascii_letters + string.digits)
+        if l not in 'l0QD1vAEIOUaeiou']
+    random_chars = [
+        random.choice(alphanumeric_chars) for _ in range(length)]
+    return(''.join(random_chars))
+
+
+def list_nics(nic_type):
+    '''Return a list of nics of given type(s)'''
+    if isinstance(nic_type, six.string_types):
+        int_types = [nic_type]
+    else:
+        int_types = nic_type
+    interfaces = []
+    for int_type in int_types:
+        cmd = ['ip', 'addr', 'show', 'label', int_type + '*']
+        ip_output = subprocess.check_output(cmd).decode('UTF-8').split('\n')
+        ip_output = (line for line in ip_output if line)
+        for line in ip_output:
+            if line.split()[1].startswith(int_type):
+                matched = re.search('.*: (' + int_type + r'[0-9]+\.[0-9]+)@.*', line)
+                if matched:
+                    interface = matched.groups()[0]
+                else:
+                    interface = line.split()[1].replace(":", "")
+                interfaces.append(interface)
+
+    return interfaces
+
+
+def set_nic_mtu(nic, mtu):
+    '''Set MTU on a network interface'''
+    cmd = ['ip', 'link', 'set', nic, 'mtu', mtu]
+    subprocess.check_call(cmd)
+
+
+def get_nic_mtu(nic):
+    cmd = ['ip', 'addr', 'show', nic]
+    ip_output = subprocess.check_output(cmd).decode('UTF-8').split('\n')
+    mtu = ""
+    for line in ip_output:
+        words = line.split()
+        if 'mtu' in words:
+            mtu = words[words.index("mtu") + 1]
+    return mtu
+
+
+def get_nic_hwaddr(nic):
+    cmd = ['ip', '-o', '-0', 'addr', 'show', nic]
+    ip_output = subprocess.check_output(cmd).decode('UTF-8')
+    hwaddr = ""
+    words = ip_output.split()
+    if 'link/ether' in words:
+        hwaddr = words[words.index('link/ether') + 1]
+    return hwaddr
+
+
+def cmp_pkgrevno(package, revno, pkgcache=None):
+    '''Compare supplied revno with the revno of the installed package
+
+    *  1 => Installed revno is greater than supplied arg
+    *  0 => Installed revno is the same as supplied arg
+    * -1 => Installed revno is less than supplied arg
+
+    This function imports apt_cache function from charmhelpers.fetch if
+    the pkgcache argument is None. Be sure to add charmhelpers.fetch if
+    you call this function, or pass an apt_pkg.Cache() instance.
+    '''
+    import apt_pkg
+    if not pkgcache:
+        from charmhelpers.fetch import apt_cache
+        pkgcache = apt_cache()
+    pkg = pkgcache[package]
+    return apt_pkg.version_compare(pkg.current_ver.ver_str, revno)
+
+
+@contextmanager
+def chdir(d):
+    cur = os.getcwd()
+    try:
+        yield os.chdir(d)
+    finally:
+        os.chdir(cur)
+
+
+def chownr(path, owner, group, follow_links=True):
+    uid = pwd.getpwnam(owner).pw_uid
+    gid = grp.getgrnam(group).gr_gid
+    if follow_links:
+        chown = os.chown
+    else:
+        chown = os.lchown
+
+    for root, dirs, files in os.walk(path):
+        for name in dirs + files:
+            full = os.path.join(root, name)
+            broken_symlink = os.path.lexists(full) and not os.path.exists(full)
+            if not broken_symlink:
+                chown(full, uid, gid)
+
+
+def lchownr(path, owner, group):
+    chownr(path, owner, group, follow_links=False)

=== added directory 'hooks/charmhelpers/core/services'
=== added file 'hooks/charmhelpers/core/services/__init__.py'
--- hooks/charmhelpers/core/services/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/services/__init__.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,18 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+from .base import *  # NOQA
+from .helpers import *  # NOQA

=== added file 'hooks/charmhelpers/core/services/base.py'
--- hooks/charmhelpers/core/services/base.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/services/base.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,329 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import re
+import json
+from collections import Iterable
+
+from charmhelpers.core import host
+from charmhelpers.core import hookenv
+
+
+__all__ = ['ServiceManager', 'ManagerCallback',
+           'PortManagerCallback', 'open_ports', 'close_ports', 'manage_ports',
+           'service_restart', 'service_stop']
+
+
+class ServiceManager(object):
+    def __init__(self, services=None):
+        """
+        Register a list of services, given their definitions.
+
+        Service definitions are dicts in the following formats (all keys except
+        'service' are optional)::
+
+            {
+                "service": <service name>,
+                "required_data": <list of required data contexts>,
+                "provided_data": <list of provided data contexts>,
+                "data_ready": <one or more callbacks>,
+                "data_lost": <one or more callbacks>,
+                "start": <one or more callbacks>,
+                "stop": <one or more callbacks>,
+                "ports": <list of ports to manage>,
+            }
+
+        The 'required_data' list should contain dicts of required data (or
+        dependency managers that act like dicts and know how to collect the data).
+        Only when all items in the 'required_data' list are populated are the list
+        of 'data_ready' and 'start' callbacks executed.  See `is_ready()` for more
+        information.
+
+        The 'provided_data' list should contain relation data providers, most likely
+        a subclass of :class:`charmhelpers.core.services.helpers.RelationContext`,
+        that will indicate a set of data to set on a given relation.
+
+        The 'data_ready' value should be either a single callback, or a list of
+        callbacks, to be called when all items in 'required_data' pass `is_ready()`.
+        Each callback will be called with the service name as the only parameter.
+        After all of the 'data_ready' callbacks are called, the 'start' callbacks
+        are fired.
+
+        The 'data_lost' value should be either a single callback, or a list of
+        callbacks, to be called when a 'required_data' item no longer passes
+        `is_ready()`.  Each callback will be called with the service name as the
+        only parameter.  After all of the 'data_lost' callbacks are called,
+        the 'stop' callbacks are fired.
+
+        The 'start' value should be either a single callback, or a list of
+        callbacks, to be called when starting the service, after the 'data_ready'
+        callbacks are complete.  Each callback will be called with the service
+        name as the only parameter.  This defaults to
+        `[host.service_start, services.open_ports]`.
+
+        The 'stop' value should be either a single callback, or a list of
+        callbacks, to be called when stopping the service.  If the service is
+        being stopped because it no longer has all of its 'required_data', this
+        will be called after all of the 'data_lost' callbacks are complete.
+        Each callback will be called with the service name as the only parameter.
+        This defaults to `[services.close_ports, host.service_stop]`.
+
+        The 'ports' value should be a list of ports to manage.  The default
+        'start' handler will open the ports after the service is started,
+        and the default 'stop' handler will close the ports prior to stopping
+        the service.
+
+
+        Examples:
+
+        The following registers an Upstart service called bingod that depends on
+        a mongodb relation and which runs a custom `db_migrate` function prior to
+        restarting the service, and a Runit service called spadesd::
+
+            manager = services.ServiceManager([
+                {
+                    'service': 'bingod',
+                    'ports': [80, 443],
+                    'required_data': [MongoRelation(), config(), {'my': 'data'}],
+                    'data_ready': [
+                        services.template(source='bingod.conf'),
+                        services.template(source='bingod.ini',
+                                          target='/etc/bingod.ini',
+                                          owner='bingo', perms=0400),
+                    ],
+                },
+                {
+                    'service': 'spadesd',
+                    'data_ready': services.template(source='spadesd_run.j2',
+                                                    target='/etc/sv/spadesd/run',
+                                                    perms=0555),
+                    'start': runit_start,
+                    'stop': runit_stop,
+                },
+            ])
+            manager.manage()
+        """
+        self._ready_file = os.path.join(hookenv.charm_dir(), 'READY-SERVICES.json')
+        self._ready = None
+        self.services = {}
+        for service in services or []:
+            service_name = service['service']
+            self.services[service_name] = service
+
+    def manage(self):
+        """
+        Handle the current hook by doing The Right Thing with the registered services.
+        """
+        hook_name = hookenv.hook_name()
+        if hook_name == 'stop':
+            self.stop_services()
+        else:
+            self.provide_data()
+            self.reconfigure_services()
+        cfg = hookenv.config()
+        if cfg.implicit_save:
+            cfg.save()
+
+    def provide_data(self):
+        """
+        Set the relation data for each provider in the ``provided_data`` list.
+
+        A provider must have a `name` attribute, which indicates which relation
+        to set data on, and a `provide_data()` method, which returns a dict of
+        data to set.
+        """
+        hook_name = hookenv.hook_name()
+        for service in self.services.values():
+            for provider in service.get('provided_data', []):
+                if re.match(r'{}-relation-(joined|changed)'.format(provider.name), hook_name):
+                    data = provider.provide_data()
+                    _ready = provider._is_ready(data) if hasattr(provider, '_is_ready') else data
+                    if _ready:
+                        hookenv.relation_set(None, data)
+
+    def reconfigure_services(self, *service_names):
+        """
+        Update all files for one or more registered services, and,
+        if ready, optionally restart them.
+
+        If no service names are given, reconfigures all registered services.
+        """
+        for service_name in service_names or self.services.keys():
+            if self.is_ready(service_name):
+                self.fire_event('data_ready', service_name)
+                self.fire_event('start', service_name, default=[
+                    service_restart,
+                    manage_ports])
+                self.save_ready(service_name)
+            else:
+                if self.was_ready(service_name):
+                    self.fire_event('data_lost', service_name)
+                self.fire_event('stop', service_name, default=[
+                    manage_ports,
+                    service_stop])
+                self.save_lost(service_name)
+
+    def stop_services(self, *service_names):
+        """
+        Stop one or more registered services, by name.
+
+        If no service names are given, stops all registered services.
+        """
+        for service_name in service_names or self.services.keys():
+            self.fire_event('stop', service_name, default=[
+                manage_ports,
+                service_stop])
+
+    def get_service(self, service_name):
+        """
+        Given the name of a registered service, return its service definition.
+        """
+        service = self.services.get(service_name)
+        if not service:
+            raise KeyError('Service not registered: %s' % service_name)
+        return service
+
+    def fire_event(self, event_name, service_name, default=None):
+        """
+        Fire a data_ready, data_lost, start, or stop event on a given service.
+        """
+        service = self.get_service(service_name)
+        callbacks = service.get(event_name, default)
+        if not callbacks:
+            return
+        if not isinstance(callbacks, Iterable):
+            callbacks = [callbacks]
+        for callback in callbacks:
+            if isinstance(callback, ManagerCallback):
+                callback(self, service_name, event_name)
+            else:
+                callback(service_name)
+
+    def is_ready(self, service_name):
+        """
+        Determine if a registered service is ready, by checking its 'required_data'.
+
+        A 'required_data' item can be any mapping type, and is considered ready
+        if `bool(item)` evaluates as True.
+        """
+        service = self.get_service(service_name)
+        reqs = service.get('required_data', [])
+        return all(bool(req) for req in reqs)
+
+    def _load_ready_file(self):
+        if self._ready is not None:
+            return
+        if os.path.exists(self._ready_file):
+            with open(self._ready_file) as fp:
+                self._ready = set(json.load(fp))
+        else:
+            self._ready = set()
+
+    def _save_ready_file(self):
+        if self._ready is None:
+            return
+        with open(self._ready_file, 'w') as fp:
+            json.dump(list(self._ready), fp)
+
+    def save_ready(self, service_name):
+        """
+        Save an indicator that the given service is now data_ready.
+        """
+        self._load_ready_file()
+        self._ready.add(service_name)
+        self._save_ready_file()
+
+    def save_lost(self, service_name):
+        """
+        Save an indicator that the given service is no longer data_ready.
+        """
+        self._load_ready_file()
+        self._ready.discard(service_name)
+        self._save_ready_file()
+
+    def was_ready(self, service_name):
+        """
+        Determine if the given service was previously data_ready.
+        """
+        self._load_ready_file()
+        return service_name in self._ready
+
+
+class ManagerCallback(object):
+    """
+    Special case of a callback that takes the `ServiceManager` instance
+    in addition to the service name.
+
+    Subclasses should implement `__call__` which should accept three parameters:
+
+        * `manager`       The `ServiceManager` instance
+        * `service_name`  The name of the service it's being triggered for
+        * `event_name`    The name of the event that this callback is handling
+    """
+    def __call__(self, manager, service_name, event_name):
+        raise NotImplementedError()
+
+
+class PortManagerCallback(ManagerCallback):
+    """
+    Callback class that will open or close ports, for use as either
+    a start or stop action.
+    """
+    def __call__(self, manager, service_name, event_name):
+        service = manager.get_service(service_name)
+        new_ports = service.get('ports', [])
+        port_file = os.path.join(hookenv.charm_dir(), '.{}.ports'.format(service_name))
+        if os.path.exists(port_file):
+            with open(port_file) as fp:
+                old_ports = fp.read().split(',')
+            for old_port in old_ports:
+                if bool(old_port):
+                    old_port = int(old_port)
+                    if old_port not in new_ports:
+                        hookenv.close_port(old_port)
+        with open(port_file, 'w') as fp:
+            fp.write(','.join(str(port) for port in new_ports))
+        for port in new_ports:
+            if event_name == 'start':
+                hookenv.open_port(port)
+            elif event_name == 'stop':
+                hookenv.close_port(port)
+
+
+def service_stop(service_name):
+    """
+    Wrapper around host.service_stop to prevent spurious "unknown service"
+    messages in the logs.
+    """
+    if host.service_running(service_name):
+        host.service_stop(service_name)
+
+
+def service_restart(service_name):
+    """
+    Wrapper around host.service_restart to prevent spurious "unknown service"
+    messages in the logs.
+    """
+    if host.service_available(service_name):
+        if host.service_running(service_name):
+            host.service_restart(service_name)
+        else:
+            host.service_start(service_name)
+
+
+# Convenience aliases
+open_ports = close_ports = manage_ports = PortManagerCallback()

=== added file 'hooks/charmhelpers/core/services/helpers.py'
--- hooks/charmhelpers/core/services/helpers.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/services/helpers.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,259 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import yaml
+from charmhelpers.core import hookenv
+from charmhelpers.core import templating
+
+from charmhelpers.core.services.base import ManagerCallback
+
+
+__all__ = ['RelationContext', 'TemplateCallback',
+           'render_template', 'template']
+
+
+class RelationContext(dict):
+    """
+    Base class for a context generator that gets relation data from juju.
+
+    Subclasses must provide the attributes `name`, which is the name of the
+    interface of interest, `interface`, which is the type of the interface of
+    interest, and `required_keys`, which is the set of keys required for the
+    relation to be considered complete.  The data for all interfaces matching
+    the `name` attribute that are complete will used to populate the dictionary
+    values (see `get_data`, below).
+
+    The generated context will be namespaced under the relation :attr:`name`,
+    to prevent potential naming conflicts.
+
+    :param str name: Override the relation :attr:`name`, since it can vary from charm to charm
+    :param list additional_required_keys: Extend the list of :attr:`required_keys`
+    """
+    name = None
+    interface = None
+    required_keys = []
+
+    def __init__(self, name=None, additional_required_keys=None):
+        if name is not None:
+            self.name = name
+        if additional_required_keys is not None:
+            self.required_keys.extend(additional_required_keys)
+        self.get_data()
+
+    def __bool__(self):
+        """
+        Returns True if all of the required_keys are available.
+        """
+        return self.is_ready()
+
+    __nonzero__ = __bool__
+
+    def __repr__(self):
+        return super(RelationContext, self).__repr__()
+
+    def is_ready(self):
+        """
+        Returns True if all of the `required_keys` are available from any units.
+        """
+        ready = len(self.get(self.name, [])) > 0
+        if not ready:
+            hookenv.log('Incomplete relation: {}'.format(self.__class__.__name__), hookenv.DEBUG)
+        return ready
+
+    def _is_ready(self, unit_data):
+        """
+        Helper method that tests a set of relation data and returns True if
+        all of the `required_keys` are present.
+        """
+        return set(unit_data.keys()).issuperset(set(self.required_keys))
+
+    def get_data(self):
+        """
+        Retrieve the relation data for each unit involved in a relation and,
+        if complete, store it in a list under `self[self.name]`.  This
+        is automatically called when the RelationContext is instantiated.
+
+        The units are sorted lexographically first by the service ID, then by
+        the unit ID.  Thus, if an interface has two other services, 'db:1'
+        and 'db:2', with 'db:1' having two units, 'wordpress/0' and 'wordpress/1',
+        and 'db:2' having one unit, 'mediawiki/0', all of which have a complete
+        set of data, the relation data for the units will be stored in the
+        order: 'wordpress/0', 'wordpress/1', 'mediawiki/0'.
+
+        If you only care about a single unit on the relation, you can just
+        access it as `{{ interface[0]['key'] }}`.  However, if you can at all
+        support multiple units on a relation, you should iterate over the list,
+        like::
+
+            {% for unit in interface -%}
+                {{ unit['key'] }}{% if not loop.last %},{% endif %}
+            {%- endfor %}
+
+        Note that since all sets of relation data from all related services and
+        units are in a single list, if you need to know which service or unit a
+        set of data came from, you'll need to extend this class to preserve
+        that information.
+        """
+        if not hookenv.relation_ids(self.name):
+            return
+
+        ns = self.setdefault(self.name, [])
+        for rid in sorted(hookenv.relation_ids(self.name)):
+            for unit in sorted(hookenv.related_units(rid)):
+                reldata = hookenv.relation_get(rid=rid, unit=unit)
+                if self._is_ready(reldata):
+                    ns.append(reldata)
+
+    def provide_data(self):
+        """
+        Return data to be relation_set for this interface.
+        """
+        return {}
+
+
+class MysqlRelation(RelationContext):
+    """
+    Relation context for the `mysql` interface.
+
+    :param str name: Override the relation :attr:`name`, since it can vary from charm to charm
+    :param list additional_required_keys: Extend the list of :attr:`required_keys`
+    """
+    name = 'db'
+    interface = 'mysql'
+    required_keys = ['host', 'user', 'password', 'database']
+
+
+class HttpRelation(RelationContext):
+    """
+    Relation context for the `http` interface.
+
+    :param str name: Override the relation :attr:`name`, since it can vary from charm to charm
+    :param list additional_required_keys: Extend the list of :attr:`required_keys`
+    """
+    name = 'website'
+    interface = 'http'
+    required_keys = ['host', 'port']
+
+    def provide_data(self):
+        return {
+            'host': hookenv.unit_get('private-address'),
+            'port': 80,
+        }
+
+
+class RequiredConfig(dict):
+    """
+    Data context that loads config options with one or more mandatory options.
+
+    Once the required options have been changed from their default values, all
+    config options will be available, namespaced under `config` to prevent
+    potential naming conflicts (for example, between a config option and a
+    relation property).
+
+    :param list *args: List of options that must be changed from their default values.
+    """
+
+    def __init__(self, *args):
+        self.required_options = args
+        self['config'] = hookenv.config()
+        with open(os.path.join(hookenv.charm_dir(), 'config.yaml')) as fp:
+            self.config = yaml.load(fp).get('options', {})
+
+    def __bool__(self):
+        for option in self.required_options:
+            if option not in self['config']:
+                return False
+            current_value = self['config'][option]
+            default_value = self.config[option].get('default')
+            if current_value == default_value:
+                return False
+            if current_value in (None, '') and default_value in (None, ''):
+                return False
+        return True
+
+    def __nonzero__(self):
+        return self.__bool__()
+
+
+class StoredContext(dict):
+    """
+    A data context that always returns the data that it was first created with.
+
+    This is useful to do a one-time generation of things like passwords, that
+    will thereafter use the same value that was originally generated, instead
+    of generating a new value each time it is run.
+    """
+    def __init__(self, file_name, config_data):
+        """
+        If the file exists, populate `self` with the data from the file.
+        Otherwise, populate with the given data and persist it to the file.
+        """
+        if os.path.exists(file_name):
+            self.update(self.read_context(file_name))
+        else:
+            self.store_context(file_name, config_data)
+            self.update(config_data)
+
+    def store_context(self, file_name, config_data):
+        if not os.path.isabs(file_name):
+            file_name = os.path.join(hookenv.charm_dir(), file_name)
+        with open(file_name, 'w') as file_stream:
+            os.fchmod(file_stream.fileno(), 0o600)
+            yaml.dump(config_data, file_stream)
+
+    def read_context(self, file_name):
+        if not os.path.isabs(file_name):
+            file_name = os.path.join(hookenv.charm_dir(), file_name)
+        with open(file_name, 'r') as file_stream:
+            data = yaml.load(file_stream)
+            if not data:
+                raise OSError("%s is empty" % file_name)
+            return data
+
+
+class TemplateCallback(ManagerCallback):
+    """
+    Callback class that will render a Jinja2 template, for use as a ready
+    action.
+
+    :param str source: The template source file, relative to
+    `$CHARM_DIR/templates`
+
+    :param str target: The target to write the rendered template to
+    :param str owner: The owner of the rendered file
+    :param str group: The group of the rendered file
+    :param int perms: The permissions of the rendered file
+    """
+    def __init__(self, source, target,
+                 owner='root', group='root', perms=0o444):
+        self.source = source
+        self.target = target
+        self.owner = owner
+        self.group = group
+        self.perms = perms
+
+    def __call__(self, manager, service_name, event_name):
+        service = manager.get_service(service_name)
+        context = {}
+        for ctx in service.get('required_data', []):
+            context.update(ctx)
+        templating.render(self.source, self.target, context,
+                          self.owner, self.group, self.perms)
+
+
+# Convenience aliases for templates
+render_template = template = TemplateCallback

=== added file 'hooks/charmhelpers/core/strutils.py'
--- hooks/charmhelpers/core/strutils.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/strutils.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import six
+
+
+def bool_from_string(value):
+    """Interpret string value as boolean.
+
+    Returns True if value translates to True otherwise False.
+    """
+    if isinstance(value, six.string_types):
+        value = six.text_type(value)
+    else:
+        msg = "Unable to interpret non-string value '%s' as boolean" % (value)
+        raise ValueError(msg)
+
+    value = value.strip().lower()
+
+    if value in ['y', 'yes', 'true', 't']:
+        return True
+    elif value in ['n', 'no', 'false', 'f']:
+        return False
+
+    msg = "Unable to interpret string value '%s' as boolean" % (value)
+    raise ValueError(msg)

=== added file 'hooks/charmhelpers/core/sysctl.py'
--- hooks/charmhelpers/core/sysctl.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/sysctl.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import yaml
+
+from subprocess import check_call
+
+from charmhelpers.core.hookenv import (
+    log,
+    DEBUG,
+    ERROR,
+)
+
+__author__ = 'Jorge Niedbalski R. <[e-mail]>'
+
+
+def create(sysctl_dict, sysctl_file):
+    """Creates a sysctl.conf file from a YAML associative array
+
+    :param sysctl_dict: a YAML-formatted string of sysctl options eg "{ 'kernel.max_pid': 1337 }"
+    :type sysctl_dict: str
+    :param sysctl_file: path to the sysctl file to be saved
+    :type sysctl_file: str or unicode
+    :returns: None
+    """
+    try:
+        sysctl_dict_parsed = yaml.safe_load(sysctl_dict)
+    except yaml.YAMLError:
+        log("Error parsing YAML sysctl_dict: {}".format(sysctl_dict),
+            level=ERROR)
+        return
+
+    with open(sysctl_file, "w") as fd:
+        for key, value in sysctl_dict_parsed.items():
+            fd.write("{}={}\n".format(key, value))
+
+    log("Updating sysctl_file: %s values: %s" % (sysctl_file, sysctl_dict_parsed),
+        level=DEBUG)
+
+    check_call(["sysctl", "-p", sysctl_file])

=== added file 'hooks/charmhelpers/core/templating.py'
--- hooks/charmhelpers/core/templating.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/templating.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,68 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+from charmhelpers.core import host
+from charmhelpers.core import hookenv
+
+
+def render(source, target, context, owner='root', group='root',
+           perms=0o444, templates_dir=None, encoding='UTF-8'):
+    """
+    Render a template.
+
+    The `source` path, if not absolute, is relative to the `templates_dir`.
+
+    The `target` path should be absolute.
+
+    The context should be a dict containing the values to be replaced in the
+    template.
+
+    The `owner`, `group`, and `perms` options will be passed to `write_file`.
+
+    If omitted, `templates_dir` defaults to the `templates` folder in the charm.
+
+    Note: Using this requires python-jinja2; if it is not installed, calling
+    this will attempt to use charmhelpers.fetch.apt_install to install it.
+    """
+    try:
+        from jinja2 import FileSystemLoader, Environment, exceptions
+    except ImportError:
+        try:
+            from charmhelpers.fetch import apt_install
+        except ImportError:
+            hookenv.log('Could not import jinja2, and could not import '
+                        'charmhelpers.fetch to install it',
+                        level=hookenv.ERROR)
+            raise
+        apt_install('python-jinja2', fatal=True)
+        from jinja2 import FileSystemLoader, Environment, exceptions
+
+    if templates_dir is None:
+        templates_dir = os.path.join(hookenv.charm_dir(), 'templates')
+    loader = Environment(loader=FileSystemLoader(templates_dir))
+    try:
+        source = source
+        template = loader.get_template(source)
+    except exceptions.TemplateNotFound as e:
+        hookenv.log('Could not load template %s from %s.' %
+                    (source, templates_dir),
+                    level=hookenv.ERROR)
+        raise e
+    content = template.render(context)
+    host.mkdir(os.path.dirname(target), owner, group, perms=0o755)
+    host.write_file(target, content.encode(encoding), owner, group, perms)

=== added file 'hooks/charmhelpers/core/unitdata.py'
--- hooks/charmhelpers/core/unitdata.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/unitdata.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,477 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+# Authors:
+#  Kapil Thangavelu <[e-mail]>
+#
+"""
+Intro
+-----
+
+A simple way to store state in units. This provides a key value
+storage with support for versioned, transactional operation,
+and can calculate deltas from previous values to simplify unit logic
+when processing changes.
+
+
+Hook Integration
+----------------
+
+There are several extant frameworks for hook execution, including
+
+ - charmhelpers.core.hookenv.Hooks
+ - charmhelpers.core.services.ServiceManager
+
+The storage classes are framework agnostic, one simple integration is
+via the HookData contextmanager. It will record the current hook
+execution environment (including relation data, config data, etc.),
+setup a transaction and allow easy access to the changes from
+previously seen values. One consequence of the integration is the
+reservation of particular keys ('rels', 'unit', 'env', 'config',
+'charm_revisions') for their respective values.
+
+Here's a fully worked integration example using hookenv.Hooks::
+
+       from charmhelper.core import hookenv, unitdata
+
+       hook_data = unitdata.HookData()
+       db = unitdata.kv()
+       hooks = hookenv.Hooks()
+
+       @hooks.hook
+       def config_changed():
+           # Print all changes to configuration from previously seen
+           # values.
+           for changed, (prev, cur) in hook_data.conf.items():
+               print('config changed', changed,
+                     'previous value', prev,
+                     'current value',  cur)
+
+           # Get some unit specific bookeeping
+           if not db.get('pkg_key'):
+               key = urllib.urlopen('https://example.com/pkg_key').read()
+               db.set('pkg_key', key)
+
+           # Directly access all charm config as a mapping.
+           conf = db.getrange('config', True)
+
+           # Directly access all relation data as a mapping
+           rels = db.getrange('rels', True)
+
+       if __name__ == '__main__':
+           with hook_data():
+               hook.execute()
+
+
+A more basic integration is via the hook_scope context manager which simply
+manages transaction scope (and records hook name, and timestamp)::
+
+  >>> from unitdata import kv
+  >>> db = kv()
+  >>> with db.hook_scope('install'):
+  ...    # do work, in transactional scope.
+  ...    db.set('x', 1)
+  >>> db.get('x')
+  1
+
+
+Usage
+-----
+
+Values are automatically json de/serialized to preserve basic typing
+and complex data struct capabilities (dicts, lists, ints, booleans, etc).
+
+Individual values can be manipulated via get/set::
+
+   >>> kv.set('y', True)
+   >>> kv.get('y')
+   True
+
+   # We can set complex values (dicts, lists) as a single key.
+   >>> kv.set('config', {'a': 1, 'b': True'})
+
+   # Also supports returning dictionaries as a record which
+   # provides attribute access.
+   >>> config = kv.get('config', record=True)
+   >>> config.b
+   True
+
+
+Groups of keys can be manipulated with update/getrange::
+
+   >>> kv.update({'z': 1, 'y': 2}, prefix="gui.")
+   >>> kv.getrange('gui.', strip=True)
+   {'z': 1, 'y': 2}
+
+When updating values, its very helpful to understand which values
+have actually changed and how have they changed. The storage
+provides a delta method to provide for this::
+
+   >>> data = {'debug': True, 'option': 2}
+   >>> delta = kv.delta(data, 'config.')
+   >>> delta.debug.previous
+   None
+   >>> delta.debug.current
+   True
+   >>> delta
+   {'debug': (None, True), 'option': (None, 2)}
+
+Note the delta method does not persist the actual change, it needs to
+be explicitly saved via 'update' method::
+
+   >>> kv.update(data, 'config.')
+
+Values modified in the context of a hook scope retain historical values
+associated to the hookname.
+
+   >>> with db.hook_scope('config-changed'):
+   ...      db.set('x', 42)
+   >>> db.gethistory('x')
+   [(1, u'x', 1, u'install', u'2015-01-21T16:49:30.038372'),
+    (2, u'x', 42, u'config-changed', u'2015-01-21T16:49:30.038786')]
+
+"""
+
+import collections
+import contextlib
+import datetime
+import json
+import os
+import pprint
+import sqlite3
+import sys
+
+__author__ = 'Kapil Thangavelu <[e-mail]>'
+
+
+class Storage(object):
+    """Simple key value database for local unit state within charms.
+
+    Modifications are automatically committed at hook exit. That's
+    currently regardless of exit code.
+
+    To support dicts, lists, integer, floats, and booleans values
+    are automatically json encoded/decoded.
+    """
+    def __init__(self, path=None):
+        self.db_path = path
+        if path is None:
+            self.db_path = os.path.join(
+                os.environ.get('CHARM_DIR', ''), '.unit-state.db')
+        self.conn = sqlite3.connect('%s' % self.db_path)
+        self.cursor = self.conn.cursor()
+        self.revision = None
+        self._closed = False
+        self._init()
+
+    def close(self):
+        if self._closed:
+            return
+        self.flush(False)
+        self.cursor.close()
+        self.conn.close()
+        self._closed = True
+
+    def _scoped_query(self, stmt, params=None):
+        if params is None:
+            params = []
+        return stmt, params
+
+    def get(self, key, default=None, record=False):
+        self.cursor.execute(
+            *self._scoped_query(
+                'select data from kv where key=?', [key]))
+        result = self.cursor.fetchone()
+        if not result:
+            return default
+        if record:
+            return Record(json.loads(result[0]))
+        return json.loads(result[0])
+
+    def getrange(self, key_prefix, strip=False):
+        stmt = "select key, data from kv where key like '%s%%'" % key_prefix
+        self.cursor.execute(*self._scoped_query(stmt))
+        result = self.cursor.fetchall()
+
+        if not result:
+            return None
+        if not strip:
+            key_prefix = ''
+        return dict([
+            (k[len(key_prefix):], json.loads(v)) for k, v in result])
+
+    def update(self, mapping, prefix=""):
+        for k, v in mapping.items():
+            self.set("%s%s" % (prefix, k), v)
+
+    def unset(self, key):
+        self.cursor.execute('delete from kv where key=?', [key])
+        if self.revision and self.cursor.rowcount:
+            self.cursor.execute(
+                'insert into kv_revisions values (?, ?, ?)',
+                [key, self.revision, json.dumps('DELETED')])
+
+    def set(self, key, value):
+        serialized = json.dumps(value)
+
+        self.cursor.execute(
+            'select data from kv where key=?', [key])
+        exists = self.cursor.fetchone()
+
+        # Skip mutations to the same value
+        if exists:
+            if exists[0] == serialized:
+                return value
+
+        if not exists:
+            self.cursor.execute(
+                'insert into kv (key, data) values (?, ?)',
+                (key, serialized))
+        else:
+            self.cursor.execute('''
+            update kv
+            set data = ?
+            where key = ?''', [serialized, key])
+
+        # Save
+        if not self.revision:
+            return value
+
+        self.cursor.execute(
+            'select 1 from kv_revisions where key=? and revision=?',
+            [key, self.revision])
+        exists = self.cursor.fetchone()
+
+        if not exists:
+            self.cursor.execute(
+                '''insert into kv_revisions (
+                revision, key, data) values (?, ?, ?)''',
+                (self.revision, key, serialized))
+        else:
+            self.cursor.execute(
+                '''
+                update kv_revisions
+                set data = ?
+                where key = ?
+                and   revision = ?''',
+                [serialized, key, self.revision])
+
+        return value
+
+    def delta(self, mapping, prefix):
+        """
+        return a delta containing values that have changed.
+        """
+        previous = self.getrange(prefix, strip=True)
+        if not previous:
+            pk = set()
+        else:
+            pk = set(previous.keys())
+        ck = set(mapping.keys())
+        delta = DeltaSet()
+
+        # added
+        for k in ck.difference(pk):
+            delta[k] = Delta(None, mapping[k])
+
+        # removed
+        for k in pk.difference(ck):
+            delta[k] = Delta(previous[k], None)
+
+        # changed
+        for k in pk.intersection(ck):
+            c = mapping[k]
+            p = previous[k]
+            if c != p:
+                delta[k] = Delta(p, c)
+
+        return delta
+
+    @contextlib.contextmanager
+    def hook_scope(self, name=""):
+        """Scope all future interactions to the current hook execution
+        revision."""
+        assert not self.revision
+        self.cursor.execute(
+            'insert into hooks (hook, date) values (?, ?)',
+            (name or sys.argv[0],
+             datetime.datetime.utcnow().isoformat()))
+        self.revision = self.cursor.lastrowid
+        try:
+            yield self.revision
+            self.revision = None
+        except:
+            self.flush(False)
+            self.revision = None
+            raise
+        else:
+            self.flush()
+
+    def flush(self, save=True):
+        if save:
+            self.conn.commit()
+        elif self._closed:
+            return
+        else:
+            self.conn.rollback()
+
+    def _init(self):
+        self.cursor.execute('''
+            create table if not exists kv (
+               key text,
+               data text,
+               primary key (key)
+               )''')
+        self.cursor.execute('''
+            create table if not exists kv_revisions (
+               key text,
+               revision integer,
+               data text,
+               primary key (key, revision)
+               )''')
+        self.cursor.execute('''
+            create table if not exists hooks (
+               version integer primary key autoincrement,
+               hook text,
+               date text
+               )''')
+        self.conn.commit()
+
+    def gethistory(self, key, deserialize=False):
+        self.cursor.execute(
+            '''
+            select kv.revision, kv.key, kv.data, h.hook, h.date
+            from kv_revisions kv,
+                 hooks h
+            where kv.key=?
+             and kv.revision = h.version
+            ''', [key])
+        if deserialize is False:
+            return self.cursor.fetchall()
+        return map(_parse_history, self.cursor.fetchall())
+
+    def debug(self, fh=sys.stderr):
+        self.cursor.execute('select * from kv')
+        pprint.pprint(self.cursor.fetchall(), stream=fh)
+        self.cursor.execute('select * from kv_revisions')
+        pprint.pprint(self.cursor.fetchall(), stream=fh)
+
+
+def _parse_history(d):
+    return (d[0], d[1], json.loads(d[2]), d[3],
+            datetime.datetime.strptime(d[-1], "%Y-%m-%dT%H:%M:%S.%f"))
+
+
+class HookData(object):
+    """Simple integration for existing hook exec frameworks.
+
+    Records all unit information, and stores deltas for processing
+    by the hook.
+
+    Sample::
+
+       from charmhelper.core import hookenv, unitdata
+
+       changes = unitdata.HookData()
+       db = unitdata.kv()
+       hooks = hookenv.Hooks()
+
+       @hooks.hook
+       def config_changed():
+           # View all changes to configuration
+           for changed, (prev, cur) in changes.conf.items():
+               print('config changed', changed,
+                     'previous value', prev,
+                     'current value',  cur)
+
+           # Get some unit specific bookeeping
+           if not db.get('pkg_key'):
+               key = urllib.urlopen('https://example.com/pkg_key').read()
+               db.set('pkg_key', key)
+
+       if __name__ == '__main__':
+           with changes():
+               hook.execute()
+
+    """
+    def __init__(self):
+        self.kv = kv()
+        self.conf = None
+        self.rels = None
+
+    @contextlib.contextmanager
+    def __call__(self):
+        from charmhelpers.core import hookenv
+        hook_name = hookenv.hook_name()
+
+        with self.kv.hook_scope(hook_name):
+            self._record_charm_version(hookenv.charm_dir())
+            delta_config, delta_relation = self._record_hook(hookenv)
+            yield self.kv, delta_config, delta_relation
+
+    def _record_charm_version(self, charm_dir):
+        # Record revisions.. charm revisions are meaningless
+        # to charm authors as they don't control the revision.
+        # so logic dependnent on revision is not particularly
+        # useful, however it is useful for debugging analysis.
+        charm_rev = open(
+            os.path.join(charm_dir, 'revision')).read().strip()
+        charm_rev = charm_rev or '0'
+        revs = self.kv.get('charm_revisions', [])
+        if charm_rev not in revs:
+            revs.append(charm_rev.strip() or '0')
+            self.kv.set('charm_revisions', revs)
+
+    def _record_hook(self, hookenv):
+        data = hookenv.execution_environment()
+        self.conf = conf_delta = self.kv.delta(data['conf'], 'config')
+        self.rels = rels_delta = self.kv.delta(data['rels'], 'rels')
+        self.kv.set('env', data['env'])
+        self.kv.set('unit', data['unit'])
+        self.kv.set('relid', data.get('relid'))
+        return conf_delta, rels_delta
+
+
+class Record(dict):
+
+    __slots__ = ()
+
+    def __getattr__(self, k):
+        if k in self:
+            return self[k]
+        raise AttributeError(k)
+
+
+class DeltaSet(Record):
+
+    __slots__ = ()
+
+
+Delta = collections.namedtuple('Delta', ['previous', 'current'])
+
+
+_KV = None
+
+
+def kv():
+    global _KV
+    if _KV is None:
+        _KV = Storage()
+    return _KV

=== added directory 'hooks/charmhelpers/fetch'
=== added file 'hooks/charmhelpers/fetch/__init__.py'
--- hooks/charmhelpers/fetch/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/fetch/__init__.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,439 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import importlib
+from tempfile import NamedTemporaryFile
+import time
+from yaml import safe_load
+from charmhelpers.core.host import (
+    lsb_release
+)
+import subprocess
+from charmhelpers.core.hookenv import (
+    config,
+    log,
+)
+import os
+
+import six
+if six.PY3:
+    from urllib.parse import urlparse, urlunparse
+else:
+    from urlparse import urlparse, urlunparse
+
+
+CLOUD_ARCHIVE = """# Ubuntu Cloud Archive
+deb http://ubuntu-cloud.archive.canonical.com/ubuntu {} main
+"""
+PROPOSED_POCKET = """# Proposed
+deb http://archive.ubuntu.com/ubuntu {}-proposed main universe multiverse restricted
+"""
+CLOUD_ARCHIVE_POCKETS = {
+    # Folsom
+    'folsom': 'precise-updates/folsom',
+    'precise-folsom': 'precise-updates/folsom',
+    'precise-folsom/updates': 'precise-updates/folsom',
+    'precise-updates/folsom': 'precise-updates/folsom',
+    'folsom/proposed': 'precise-proposed/folsom',
+    'precise-folsom/proposed': 'precise-proposed/folsom',
+    'precise-proposed/folsom': 'precise-proposed/folsom',
+    # Grizzly
+    'grizzly': 'precise-updates/grizzly',
+    'precise-grizzly': 'precise-updates/grizzly',
+    'precise-grizzly/updates': 'precise-updates/grizzly',
+    'precise-updates/grizzly': 'precise-updates/grizzly',
+    'grizzly/proposed': 'precise-proposed/grizzly',
+    'precise-grizzly/proposed': 'precise-proposed/grizzly',
+    'precise-proposed/grizzly': 'precise-proposed/grizzly',
+    # Havana
+    'havana': 'precise-updates/havana',
+    'precise-havana': 'precise-updates/havana',
+    'precise-havana/updates': 'precise-updates/havana',
+    'precise-updates/havana': 'precise-updates/havana',
+    'havana/proposed': 'precise-proposed/havana',
+    'precise-havana/proposed': 'precise-proposed/havana',
+    'precise-proposed/havana': 'precise-proposed/havana',
+    # Icehouse
+    'icehouse': 'precise-updates/icehouse',
+    'precise-icehouse': 'precise-updates/icehouse',
+    'precise-icehouse/updates': 'precise-updates/icehouse',
+    'precise-updates/icehouse': 'precise-updates/icehouse',
+    'icehouse/proposed': 'precise-proposed/icehouse',
+    'precise-icehouse/proposed': 'precise-proposed/icehouse',
+    'precise-proposed/icehouse': 'precise-proposed/icehouse',
+    # Juno
+    'juno': 'trusty-updates/juno',
+    'trusty-juno': 'trusty-updates/juno',
+    'trusty-juno/updates': 'trusty-updates/juno',
+    'trusty-updates/juno': 'trusty-updates/juno',
+    'juno/proposed': 'trusty-proposed/juno',
+    'trusty-juno/proposed': 'trusty-proposed/juno',
+    'trusty-proposed/juno': 'trusty-proposed/juno',
+    # Kilo
+    'kilo': 'trusty-updates/kilo',
+    'trusty-kilo': 'trusty-updates/kilo',
+    'trusty-kilo/updates': 'trusty-updates/kilo',
+    'trusty-updates/kilo': 'trusty-updates/kilo',
+    'kilo/proposed': 'trusty-proposed/kilo',
+    'trusty-kilo/proposed': 'trusty-proposed/kilo',
+    'trusty-proposed/kilo': 'trusty-proposed/kilo',
+}
+
+# The order of this list is very important. Handlers should be listed in from
+# least- to most-specific URL matching.
+FETCH_HANDLERS = (
+    'charmhelpers.fetch.archiveurl.ArchiveUrlFetchHandler',
+    'charmhelpers.fetch.bzrurl.BzrUrlFetchHandler',
+    'charmhelpers.fetch.giturl.GitUrlFetchHandler',
+)
+
+APT_NO_LOCK = 100  # The return code for "couldn't acquire lock" in APT.
+APT_NO_LOCK_RETRY_DELAY = 10  # Wait 10 seconds between apt lock checks.
+APT_NO_LOCK_RETRY_COUNT = 30  # Retry to acquire the lock X times.
+
+
+class SourceConfigError(Exception):
+    pass
+
+
+class UnhandledSource(Exception):
+    pass
+
+
+class AptLockError(Exception):
+    pass
+
+
+class BaseFetchHandler(object):
+
+    """Base class for FetchHandler implementations in fetch plugins"""
+
+    def can_handle(self, source):
+        """Returns True if the source can be handled. Otherwise returns
+        a string explaining why it cannot"""
+        return "Wrong source type"
+
+    def install(self, source):
+        """Try to download and unpack the source. Return the path to the
+        unpacked files or raise UnhandledSource."""
+        raise UnhandledSource("Wrong source type {}".format(source))
+
+    def parse_url(self, url):
+        return urlparse(url)
+
+    def base_url(self, url):
+        """Return url without querystring or fragment"""
+        parts = list(self.parse_url(url))
+        parts[4:] = ['' for i in parts[4:]]
+        return urlunparse(parts)
+
+
+def filter_installed_packages(packages):
+    """Returns a list of packages that require installation"""
+    cache = apt_cache()
+    _pkgs = []
+    for package in packages:
+        try:
+            p = cache[package]
+            p.current_ver or _pkgs.append(package)
+        except KeyError:
+            log('Package {} has no installation candidate.'.format(package),
+                level='WARNING')
+            _pkgs.append(package)
+    return _pkgs
+
+
+def apt_cache(in_memory=True):
+    """Build and return an apt cache"""
+    import apt_pkg
+    apt_pkg.init()
+    if in_memory:
+        apt_pkg.config.set("Dir::Cache::pkgcache", "")
+        apt_pkg.config.set("Dir::Cache::srcpkgcache", "")
+    return apt_pkg.Cache()
+
+
+def apt_install(packages, options=None, fatal=False):
+    """Install one or more packages"""
+    if options is None:
+        options = ['--option=Dpkg::Options::=--force-confold']
+
+    cmd = ['apt-get', '--assume-yes']
+    cmd.extend(options)
+    cmd.append('install')
+    if isinstance(packages, six.string_types):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+    log("Installing {} with options: {}".format(packages,
+                                                options))
+    _run_apt_command(cmd, fatal)
+
+
+def apt_upgrade(options=None, fatal=False, dist=False):
+    """Upgrade all packages"""
+    if options is None:
+        options = ['--option=Dpkg::Options::=--force-confold']
+
+    cmd = ['apt-get', '--assume-yes']
+    cmd.extend(options)
+    if dist:
+        cmd.append('dist-upgrade')
+    else:
+        cmd.append('upgrade')
+    log("Upgrading with options: {}".format(options))
+    _run_apt_command(cmd, fatal)
+
+
+def apt_update(fatal=False):
+    """Update local apt cache"""
+    cmd = ['apt-get', 'update']
+    _run_apt_command(cmd, fatal)
+
+
+def apt_purge(packages, fatal=False):
+    """Purge one or more packages"""
+    cmd = ['apt-get', '--assume-yes', 'purge']
+    if isinstance(packages, six.string_types):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+    log("Purging {}".format(packages))
+    _run_apt_command(cmd, fatal)
+
+
+def apt_hold(packages, fatal=False):
+    """Hold one or more packages"""
+    cmd = ['apt-mark', 'hold']
+    if isinstance(packages, six.string_types):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+    log("Holding {}".format(packages))
+
+    if fatal:
+        subprocess.check_call(cmd)
+    else:
+        subprocess.call(cmd)
+
+
+def add_source(source, key=None):
+    """Add a package source to this system.
+
+    @param source: a URL or sources.list entry, as supported by
+    add-apt-repository(1). Examples::
+
+        ppa:charmers/example
+        deb https://stub:[e-mail]/ubuntu trusty main
+
+    In addition:
+        'proposed:' may be used to enable the standard 'proposed'
+        pocket for the release.
+        'cloud:' may be used to activate official cloud archive pockets,
+        such as 'cloud:icehouse'
+        'distro' may be used as a noop
+
+    @param key: A key to be added to the system's APT keyring and used
+    to verify the signatures on packages. Ideally, this should be an
+    ASCII format GPG public key including the block headers. A GPG key
+    id may also be used, but be aware that only insecure protocols are
+    available to retrieve the actual public key from a public keyserver
+    placing your Juju environment at risk. ppa and cloud archive keys
+    are securely added automtically, so sould not be provided.
+    """
+    if source is None:
+        log('Source is not present. Skipping')
+        return
+
+    if (source.startswith('ppa:') or
+        source.startswith('http') or
+        source.startswith('deb ') or
+            source.startswith('cloud-archive:')):
+        subprocess.check_call(['add-apt-repository', '--yes', source])
+    elif source.startswith('cloud:'):
+        apt_install(filter_installed_packages(['ubuntu-cloud-keyring']),
+                    fatal=True)
+        pocket = source.split(':')[-1]
+        if pocket not in CLOUD_ARCHIVE_POCKETS:
+            raise SourceConfigError(
+                'Unsupported cloud: source option %s' %
+                pocket)
+        actual_pocket = CLOUD_ARCHIVE_POCKETS[pocket]
+        with open('/etc/apt/sources.list.d/cloud-archive.list', 'w') as apt:
+            apt.write(CLOUD_ARCHIVE.format(actual_pocket))
+    elif source == 'proposed':
+        release = lsb_release()['DISTRIB_CODENAME']
+        with open('/etc/apt/sources.list.d/proposed.list', 'w') as apt:
+            apt.write(PROPOSED_POCKET.format(release))
+    elif source == 'distro':
+        pass
+    else:
+        log("Unknown source: {!r}".format(source))
+
+    if key:
+        if '-----BEGIN PGP PUBLIC KEY BLOCK-----' in key:
+            with NamedTemporaryFile('w+') as key_file:
+                key_file.write(key)
+                key_file.flush()
+                key_file.seek(0)
+                subprocess.check_call(['apt-key', 'add', '-'], stdin=key_file)
+        else:
+            # Note that hkp: is in no way a secure protocol. Using a
+            # GPG key id is pointless from a security POV unless you
+            # absolutely trust your network and DNS.
+            subprocess.check_call(['apt-key', 'adv', '--keyserver',
+                                   'hkp://keyserver.ubuntu.com:80', '--recv',
+                                   key])
+
+
+def configure_sources(update=False,
+                      sources_var='install_sources',
+                      keys_var='install_keys'):
+    """
+    Configure multiple sources from charm configuration.
+
+    The lists are encoded as yaml fragments in the configuration.
+    The frament needs to be included as a string. Sources and their
+    corresponding keys are of the types supported by add_source().
+
+    Example config:
+        install_sources: |
+          - "ppa:foo"
+          - "http://example.com/repo precise main"
+        install_keys: |
+          - null
+          - "a1b2c3d4"
+
+    Note that 'null' (a.k.a. None) should not be quoted.
+    """
+    sources = safe_load((config(sources_var) or '').strip()) or []
+    keys = safe_load((config(keys_var) or '').strip()) or None
+
+    if isinstance(sources, six.string_types):
+        sources = [sources]
+
+    if keys is None:
+        for source in sources:
+            add_source(source, None)
+    else:
+        if isinstance(keys, six.string_types):
+            keys = [keys]
+
+        if len(sources) != len(keys):
+            raise SourceConfigError(
+                'Install sources and keys lists are different lengths')
+        for source, key in zip(sources, keys):
+            add_source(source, key)
+    if update:
+        apt_update(fatal=True)
+
+
+def install_remote(source, *args, **kwargs):
+    """
+    Install a file tree from a remote source
+
+    The specified source should be a url of the form:
+        scheme://[host]/path[#[option=value][&...]]
+
+    Schemes supported are based on this modules submodules.
+    Options supported are submodule-specific.
+    Additional arguments are passed through to the submodule.
+
+    For example::
+
+        dest = install_remote('http://example.com/archive.tgz',
+                              checksum='deadbeef',
+                              hash_type='sha1')
+
+    This will download `archive.tgz`, validate it using SHA1 and, if
+    the file is ok, extract it and return the directory in which it
+    was extracted.  If the checksum fails, it will raise
+    :class:`charmhelpers.core.host.ChecksumError`.
+    """
+    # We ONLY check for True here because can_handle may return a string
+    # explaining why it can't handle a given source.
+    handlers = [h for h in plugins() if h.can_handle(source) is True]
+    installed_to = None
+    for handler in handlers:
+        try:
+            installed_to = handler.install(source, *args, **kwargs)
+        except UnhandledSource:
+            pass
+    if not installed_to:
+        raise UnhandledSource("No handler found for source {}".format(source))
+    return installed_to
+
+
+def install_from_config(config_var_name):
+    charm_config = config()
+    source = charm_config[config_var_name]
+    return install_remote(source)
+
+
+def plugins(fetch_handlers=None):
+    if not fetch_handlers:
+        fetch_handlers = FETCH_HANDLERS
+    plugin_list = []
+    for handler_name in fetch_handlers:
+        package, classname = handler_name.rsplit('.', 1)
+        try:
+            handler_class = getattr(
+                importlib.import_module(package),
+                classname)
+            plugin_list.append(handler_class())
+        except (ImportError, AttributeError):
+            # Skip missing plugins so that they can be ommitted from
+            # installation if desired
+            log("FetchHandler {} not found, skipping plugin".format(
+                handler_name))
+    return plugin_list
+
+
+def _run_apt_command(cmd, fatal=False):
+    """
+    Run an APT command, checking output and retrying if the fatal flag is set
+    to True.
+
+    :param: cmd: str: The apt command to run.
+    :param: fatal: bool: Whether the command's output should be checked and
+        retried.
+    """
+    env = os.environ.copy()
+
+    if 'DEBIAN_FRONTEND' not in env:
+        env['DEBIAN_FRONTEND'] = 'noninteractive'
+
+    if fatal:
+        retry_count = 0
+        result = None
+
+        # If the command is considered "fatal", we need to retry if the apt
+        # lock was not acquired.
+
+        while result is None or result == APT_NO_LOCK:
+            try:
+                result = subprocess.check_call(cmd, env=env)
+            except subprocess.CalledProcessError as e:
+                retry_count = retry_count + 1
+                if retry_count > APT_NO_LOCK_RETRY_COUNT:
+                    raise
+                result = e.returncode
+                log("Couldn't acquire DPKG lock. Will retry in {} seconds."
+                    "".format(APT_NO_LOCK_RETRY_DELAY))
+                time.sleep(APT_NO_LOCK_RETRY_DELAY)
+
+    else:
+        subprocess.call(cmd, env=env)

=== added file 'hooks/charmhelpers/fetch/archiveurl.py'
--- hooks/charmhelpers/fetch/archiveurl.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/fetch/archiveurl.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,161 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import hashlib
+import re
+
+from charmhelpers.fetch import (
+    BaseFetchHandler,
+    UnhandledSource
+)
+from charmhelpers.payload.archive import (
+    get_archive_handler,
+    extract,
+)
+from charmhelpers.core.host import mkdir, check_hash
+
+import six
+if six.PY3:
+    from urllib.request import (
+        build_opener, install_opener, urlopen, urlretrieve,
+        HTTPPasswordMgrWithDefaultRealm, HTTPBasicAuthHandler,
+    )
+    from urllib.parse import urlparse, urlunparse, parse_qs
+    from urllib.error import URLError
+else:
+    from urllib import urlretrieve
+    from urllib2 import (
+        build_opener, install_opener, urlopen,
+        HTTPPasswordMgrWithDefaultRealm, HTTPBasicAuthHandler,
+        URLError
+    )
+    from urlparse import urlparse, urlunparse, parse_qs
+
+
+def splituser(host):
+    '''urllib.splituser(), but six's support of this seems broken'''
+    _userprog = re.compile('^(.*)@(.*)$')
+    match = _userprog.match(host)
+    if match:
+        return match.group(1, 2)
+    return None, host
+
+
+def splitpasswd(user):
+    '''urllib.splitpasswd(), but six's support of this is missing'''
+    _passwdprog = re.compile('^([^:]*):(.*)$', re.S)
+    match = _passwdprog.match(user)
+    if match:
+        return match.group(1, 2)
+    return user, None
+
+
+class ArchiveUrlFetchHandler(BaseFetchHandler):
+    """
+    Handler to download archive files from arbitrary URLs.
+
+    Can fetch from http, https, ftp, and file URLs.
+
+    Can install either tarballs (.tar, .tgz, .tbz2, etc) or zip files.
+
+    Installs the contents of the archive in $CHARM_DIR/fetched/.
+    """
+    def can_handle(self, source):
+        url_parts = self.parse_url(source)
+        if url_parts.scheme not in ('http', 'https', 'ftp', 'file'):
+            return "Wrong source type"
+        if get_archive_handler(self.base_url(source)):
+            return True
+        return False
+
+    def download(self, source, dest):
+        """
+        Download an archive file.
+
+        :param str source: URL pointing to an archive file.
+        :param str dest: Local path location to download archive file to.
+        """
+        # propogate all exceptions
+        # URLError, OSError, etc
+        proto, netloc, path, params, query, fragment = urlparse(source)
+        if proto in ('http', 'https'):
+            auth, barehost = splituser(netloc)
+            if auth is not None:
+                source = urlunparse((proto, barehost, path, params, query, fragment))
+                username, password = splitpasswd(auth)
+                passman = HTTPPasswordMgrWithDefaultRealm()
+                # Realm is set to None in add_password to force the username and password
+                # to be used whatever the realm
+                passman.add_password(None, source, username, password)
+                authhandler = HTTPBasicAuthHandler(passman)
+                opener = build_opener(authhandler)
+                install_opener(opener)
+        response = urlopen(source)
+        try:
+            with open(dest, 'w') as dest_file:
+                dest_file.write(response.read())
+        except Exception as e:
+            if os.path.isfile(dest):
+                os.unlink(dest)
+            raise e
+
+    # Mandatory file validation via Sha1 or MD5 hashing.
+    def download_and_validate(self, url, hashsum, validate="sha1"):
+        tempfile, headers = urlretrieve(url)
+        check_hash(tempfile, hashsum, validate)
+        return tempfile
+
+    def install(self, source, dest=None, checksum=None, hash_type='sha1'):
+        """
+        Download and install an archive file, with optional checksum validation.
+
+        The checksum can also be given on the `source` URL's fragment.
+        For example::
+
+            handler.install('http://example.com/file.tgz#sha1=deadbeef')
+
+        :param str source: URL pointing to an archive file.
+        :param str dest: Local destination path to install to. If not given,
+            installs to `$CHARM_DIR/archives/archive_file_name`.
+        :param str checksum: If given, validate the archive file after download.
+        :param str hash_type: Algorithm used to generate `checksum`.
+            Can be any hash alrgorithm supported by :mod:`hashlib`,
+            such as md5, sha1, sha256, sha512, etc.
+
+        """
+        url_parts = self.parse_url(source)
+        dest_dir = os.path.join(os.environ.get('CHARM_DIR'), 'fetched')
+        if not os.path.exists(dest_dir):
+            mkdir(dest_dir, perms=0o755)
+        dld_file = os.path.join(dest_dir, os.path.basename(url_parts.path))
+        try:
+            self.download(source, dld_file)
+        except URLError as e:
+            raise UnhandledSource(e.reason)
+        except OSError as e:
+            raise UnhandledSource(e.strerror)
+        options = parse_qs(url_parts.fragment)
+        for key, value in options.items():
+            if not six.PY3:
+                algorithms = hashlib.algorithms
+            else:
+                algorithms = hashlib.algorithms_available
+            if key in algorithms:
+                check_hash(dld_file, value, key)
+        if checksum:
+            check_hash(dld_file, checksum, hash_type)
+        return extract(dld_file, dest)

=== added file 'hooks/charmhelpers/fetch/bzrurl.py'
--- hooks/charmhelpers/fetch/bzrurl.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/fetch/bzrurl.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,78 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+from charmhelpers.fetch import (
+    BaseFetchHandler,
+    UnhandledSource
+)
+from charmhelpers.core.host import mkdir
+
+import six
+if six.PY3:
+    raise ImportError('bzrlib does not support Python3')
+
+try:
+    from bzrlib.branch import Branch
+    from bzrlib import bzrdir, workingtree, errors
+except ImportError:
+    from charmhelpers.fetch import apt_install
+    apt_install("python-bzrlib")
+    from bzrlib.branch import Branch
+    from bzrlib import bzrdir, workingtree, errors
+
+
+class BzrUrlFetchHandler(BaseFetchHandler):
+    """Handler for bazaar branches via generic and lp URLs"""
+    def can_handle(self, source):
+        url_parts = self.parse_url(source)
+        if url_parts.scheme not in ('bzr+ssh', 'lp'):
+            return False
+        else:
+            return True
+
+    def branch(self, source, dest):
+        url_parts = self.parse_url(source)
+        # If we use lp:branchname scheme we need to load plugins
+        if not self.can_handle(source):
+            raise UnhandledSource("Cannot handle {}".format(source))
+        if url_parts.scheme == "lp":
+            from bzrlib.plugin import load_plugins
+            load_plugins()
+        try:
+            local_branch = bzrdir.BzrDir.create_branch_convenience(dest)
+        except errors.AlreadyControlDirError:
+            local_branch = Branch.open(dest)
+        try:
+            remote_branch = Branch.open(source)
+            remote_branch.push(local_branch)
+            tree = workingtree.WorkingTree.open(dest)
+            tree.update()
+        except Exception as e:
+            raise e
+
+    def install(self, source):
+        url_parts = self.parse_url(source)
+        branch_name = url_parts.path.strip("/").split("/")[-1]
+        dest_dir = os.path.join(os.environ.get('CHARM_DIR'), "fetched",
+                                branch_name)
+        if not os.path.exists(dest_dir):
+            mkdir(dest_dir, perms=0o755)
+        try:
+            self.branch(source, dest_dir)
+        except OSError as e:
+            raise UnhandledSource(e.strerror)
+        return dest_dir

=== added file 'hooks/charmhelpers/fetch/giturl.py'
--- hooks/charmhelpers/fetch/giturl.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/fetch/giturl.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,71 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+from charmhelpers.fetch import (
+    BaseFetchHandler,
+    UnhandledSource
+)
+from charmhelpers.core.host import mkdir
+
+import six
+if six.PY3:
+    raise ImportError('GitPython does not support Python 3')
+
+try:
+    from git import Repo
+except ImportError:
+    from charmhelpers.fetch import apt_install
+    apt_install("python-git")
+    from git import Repo
+
+from git.exc import GitCommandError  # noqa E402
+
+
+class GitUrlFetchHandler(BaseFetchHandler):
+    """Handler for git branches via generic and github URLs"""
+    def can_handle(self, source):
+        url_parts = self.parse_url(source)
+        # TODO (mattyw) no support for ssh git@ yet
+        if url_parts.scheme not in ('http', 'https', 'git'):
+            return False
+        else:
+            return True
+
+    def clone(self, source, dest, branch):
+        if not self.can_handle(source):
+            raise UnhandledSource("Cannot handle {}".format(source))
+
+        repo = Repo.clone_from(source, dest)
+        repo.git.checkout(branch)
+
+    def install(self, source, branch="master", dest=None):
+        url_parts = self.parse_url(source)
+        branch_name = url_parts.path.strip("/").split("/")[-1]
+        if dest:
+            dest_dir = os.path.join(dest, branch_name)
+        else:
+            dest_dir = os.path.join(os.environ.get('CHARM_DIR'), "fetched",
+                                    branch_name)
+        if not os.path.exists(dest_dir):
+            mkdir(dest_dir, perms=0o755)
+        try:
+            self.clone(source, dest_dir, branch)
+        except GitCommandError as e:
+            raise UnhandledSource(e.message)
+        except OSError as e:
+            raise UnhandledSource(e.strerror)
+        return dest_dir

=== added file 'hooks/config-changed'
--- hooks/config-changed	1970-01-01 00:00:00 +0000
+++ hooks/config-changed	2015-02-23 19:08:44 +0000
@@ -0,0 +1,43 @@
+#!/usr/bin/python
+
+#
+# Copyright 2015 Canonical Ltd.
+#
+# Authors:
+#  Liang Chen <[e-mail]>
+#
+import subprocess
+import sys
+
+from charmhelpers.core.hookenv import (
+    config,
+    Hooks, UnregisteredHookError,
+    log, ERROR,
+)
+
+from utils import render_template
+
+hooks = Hooks()
+
+
+def emit_lxc_br_conf():
+    lxc_context = {}
+    if config('new-lxc-network'):
+        lxc_context['new_network'] = True
+
+    lxc_bridge_conf = "/etc/network/interfaces.d/lxcbr0.cfg"
+    with open(lxc_bridge_conf, 'w') as lxc_br_conf:
+        lxc_br_conf.write(render_template('lxc-bridge.conf', lxc_context))
+
+
[e-mail]('config-changed')
+def config_changed():
+    emit_lxc_br_conf()
+    cmd = ['ifup', 'lxcbr0']
+    subprocess.check_call(cmd)
+
+if __name__ == '__main__':
+    try:
+        hooks.execute(sys.argv)
+    except UnregisteredHookError as e:
+        log('Unknown hook {} - skipping.'.format(e))

=== added file 'hooks/hooks.py'
--- hooks/hooks.py	1970-01-01 00:00:00 +0000
+++ hooks/hooks.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,45 @@
+#!/usr/bin/python
+
+#
+# Copyright 2015 Canonical Ltd.
+#
+# Authors:
+#  Liang Chen <[e-mail]>
+#
+
+import subprocess
+import sys
+
+from charmhelpers.core.hookenv import (
+    config,
+    Hooks, UnregisteredHookError,
+    log,
+)
+
+from utils import render_template
+
+hooks = Hooks()
+
+
+def emit_lxc_br_conf():
+    lxc_context = {}
+    if config('new-lxc-network'):
+        lxc_context['new_network'] = True
+
+    lxc_bridge_conf = "/etc/network/interfaces.d/lxcbr0.cfg"
+    with open(lxc_bridge_conf, 'w') as lxc_br_conf:
+        lxc_br_conf.write(render_template('lxc-bridge.conf', lxc_context))
+
+
[e-mail]('config-changed')
+def config_changed():
+    emit_lxc_br_conf()
+    cmd = ['ifup', 'lxcbr0']
+    subprocess.check_call(cmd)
+
+
+if __name__ == '__main__':
+    try:
+        hooks.execute(sys.argv)
+    except UnregisteredHookError as e:
+        log('Unknown hook {} - skipping.'.format(e))

=== added file 'hooks/utils.py'
--- hooks/utils.py	1970-01-01 00:00:00 +0000
+++ hooks/utils.py	2015-02-23 19:08:44 +0000
@@ -0,0 +1,27 @@
+#
+# Copyright 2015 Canonical Ltd.
+#
+# Authors:
+#  Liang Chen <[e-mail]>
+#
+
+TEMPLATES_DIR = 'templates'
+
+from charmhelpers.fetch import (
+    apt_install,
+    filter_installed_packages
+)
+
+try:
+    import jinja2
+except ImportError:
+    apt_install(filter_installed_packages(['python-jinja2']),
+                fatal=True)
+    import jinja2
+
+
+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)

=== added directory 'templates'
=== added file 'templates/lxc-bridge.conf'
--- templates/lxc-bridge.conf	1970-01-01 00:00:00 +0000
+++ templates/lxc-bridge.conf	2015-02-23 19:08:44 +0000
@@ -0,0 +1,10 @@
+    
+{% if new_network -%}
+auto eth0
+iface eth0 inet manual
+ 
+auto lxcbr0
+iface lxcbr0 inet dhcp
+    bridge_ports eth0
+ 
+{% endif -%}