Merge lp:~bloodearnest/charms/trusty/apache2/update-charm-helpers into lp:charms/trusty/apache2

[Simon Davy]

Update charm-helpers to latest rev.

Update charm-helpers to latest rev.

Replace old nrpe tests with new simpler tests that actually test the code in this char, not test the implementation details of the charm-helpers library

Fix a lint bug, duplicate test method.

[Tom Haddon (mthaddon)]

Looks like a pretty self-contained update, and tests still pass, so I'll approve and merge

review: Approve

=== modified file 'Makefile'
--- Makefile	2014-11-20 00:06:41 +0000
+++ Makefile	2015-03-09 16:35:13 +0000
@@ -24,7 +24,7 @@
 
 test: .venv
 	@echo Starting tests...
-	@CHARM_DIR=$(CHARM_DIR) $(TEST_PREFIX) .venv/bin/nosetests $(TEST_DIR)
+	@CHARM_DIR=$(CHARM_DIR) $(TEST_PREFIX) .venv/bin/nosetests -s $(TEST_DIR)
 
 lint:
 	@echo Checking for Python syntax...

=== modified file 'charm-helpers.yaml'
--- charm-helpers.yaml	2013-10-10 22:47:57 +0000
+++ charm-helpers.yaml	2015-03-09 16:35:13 +0000
@@ -1,4 +1,4 @@
 include:
-    - core
+    - core.hookenv
     - fetch
-    - contrib.charmsupport
\ No newline at end of file
+    - contrib.charmsupport

=== modified file 'config-manager.txt'
--- config-manager.txt	2013-10-10 22:47:57 +0000
+++ config-manager.txt	2015-03-09 16:35:13 +0000
@@ -3,4 +3,4 @@
 #
 #   make sourcedeps
 
-./build/charm-helpers                   lp:charm-helpers;revno=70
+./build/charm-helpers                   lp:charm-helpers;revno=330

=== modified file 'hooks/charmhelpers/__init__.py'
--- hooks/charmhelpers/__init__.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/__init__.py	2015-03-09 16:35:13 +0000
@@ -0,0 +1,38 @@
+# 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/>.
+
+# Bootstrap charm-helpers, installing its dependencies if necessary using
+# only standard libraries.
+import subprocess
+import sys
+
+try:
+    import six  # flake8: noqa
+except ImportError:
+    if sys.version_info.major == 2:
+        subprocess.check_call(['apt-get', 'install', '-y', 'python-six'])
+    else:
+        subprocess.check_call(['apt-get', 'install', '-y', 'python3-six'])
+    import six  # flake8: noqa
+
+try:
+    import yaml  # flake8: noqa
+except ImportError:
+    if sys.version_info.major == 2:
+        subprocess.check_call(['apt-get', 'install', '-y', 'python-yaml'])
+    else:
+        subprocess.check_call(['apt-get', 'install', '-y', 'python3-yaml'])
+    import yaml  # flake8: noqa

=== modified file 'hooks/charmhelpers/contrib/__init__.py'
--- hooks/charmhelpers/contrib/__init__.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/contrib/__init__.py	2015-03-09 16:35:13 +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/>.

=== modified file 'hooks/charmhelpers/contrib/charmsupport/__init__.py'
--- hooks/charmhelpers/contrib/charmsupport/__init__.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/contrib/charmsupport/__init__.py	2015-03-09 16:35:13 +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/>.

=== modified file 'hooks/charmhelpers/contrib/charmsupport/nrpe.py'
--- hooks/charmhelpers/contrib/charmsupport/nrpe.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/contrib/charmsupport/nrpe.py	2015-03-09 16:35:13 +0000
@@ -1,3 +1,19 @@
+# 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/>.
+
 """Compatibility with the nrpe-external-master charm"""
 # Copyright 2012 Canonical Ltd.
 #
@@ -8,6 +24,8 @@
 import pwd
 import grp
 import os
+import glob
+import shutil
 import re
 import shlex
 import yaml
@@ -18,6 +36,7 @@
     log,
     relation_ids,
     relation_set,
+    relations_of_type,
 )
 
 from charmhelpers.core.host import service
@@ -54,6 +73,12 @@
 #            juju-myservice-0
 #        If you're running multiple environments with the same services in them
 #        this allows you to differentiate between them.
+#    nagios_servicegroups:
+#      default: ""
+#      type: string
+#      description: |
+#        A comma-separated list of nagios servicegroups.
+#        If left empty, the nagios_context will be used as the servicegroup
 #
 # 3. Add custom checks (Nagios plugins) to files/nrpe-external-master
 #
@@ -125,10 +150,8 @@
 
     def _locate_cmd(self, check_cmd):
         search_path = (
-            '/',
-            os.path.join(os.environ['CHARM_DIR'],
-                         'files/nrpe-external-master'),
             '/usr/lib/nagios/plugins',
+            '/usr/local/lib/nagios/plugins',
         )
         parts = shlex.split(check_cmd)
         for path in search_path:
@@ -140,7 +163,7 @@
         log('Check command not found: {}'.format(parts[0]))
         return ''
 
-    def write(self, nagios_context, hostname):
+    def write(self, nagios_context, hostname, nagios_servicegroups):
         nrpe_check_file = '/etc/nagios/nrpe.d/{}.cfg'.format(
             self.command)
         with open(nrpe_check_file, 'w') as nrpe_check_config:
@@ -152,16 +175,18 @@
             log('Not writing service config as {} is not accessible'.format(
                 NRPE.nagios_exportdir))
         else:
-            self.write_service_config(nagios_context, hostname)
+            self.write_service_config(nagios_context, hostname,
+                                      nagios_servicegroups)
 
-    def write_service_config(self, nagios_context, hostname):
+    def write_service_config(self, nagios_context, hostname,
+                             nagios_servicegroups):
         for f in os.listdir(NRPE.nagios_exportdir):
             if re.search('.*{}.cfg'.format(self.command), f):
                 os.remove(os.path.join(NRPE.nagios_exportdir, f))
 
         templ_vars = {
             'nagios_hostname': hostname,
-            'nagios_servicegroup': nagios_context,
+            'nagios_servicegroup': nagios_servicegroups,
             'description': self.description,
             'shortname': self.shortname,
             'command': self.command,
@@ -181,12 +206,19 @@
     nagios_exportdir = '/var/lib/nagios/export'
     nrpe_confdir = '/etc/nagios/nrpe.d'
 
-    def __init__(self):
+    def __init__(self, hostname=None):
         super(NRPE, self).__init__()
         self.config = config()
         self.nagios_context = self.config['nagios_context']
+        if 'nagios_servicegroups' in self.config and self.config['nagios_servicegroups']:
+            self.nagios_servicegroups = self.config['nagios_servicegroups']
+        else:
+            self.nagios_servicegroups = self.nagios_context
         self.unit_name = local_unit().replace('/', '-')
-        self.hostname = "{}-{}".format(self.nagios_context, self.unit_name)
+        if hostname:
+            self.hostname = hostname
+        else:
+            self.hostname = "{}-{}".format(self.nagios_context, self.unit_name)
         self.checks = []
 
     def add_check(self, *args, **kwargs):
@@ -207,7 +239,8 @@
         nrpe_monitors = {}
         monitors = {"monitors": {"remote": {"nrpe": nrpe_monitors}}}
         for nrpecheck in self.checks:
-            nrpecheck.write(self.nagios_context, self.hostname)
+            nrpecheck.write(self.nagios_context, self.hostname,
+                            self.nagios_servicegroups)
             nrpe_monitors[nrpecheck.shortname] = {
                 "command": nrpecheck.command,
             }
@@ -216,3 +249,110 @@
 
         for rid in relation_ids("local-monitors"):
             relation_set(relation_id=rid, monitors=yaml.dump(monitors))
+
+
+def get_nagios_hostcontext(relation_name='nrpe-external-master'):
+    """
+    Query relation with nrpe subordinate, return the nagios_host_context
+
+    :param str relation_name: Name of relation nrpe sub joined to
+    """
+    for rel in relations_of_type(relation_name):
+        if 'nagios_hostname' in rel:
+            return rel['nagios_host_context']
+
+
+def get_nagios_hostname(relation_name='nrpe-external-master'):
+    """
+    Query relation with nrpe subordinate, return the nagios_hostname
+
+    :param str relation_name: Name of relation nrpe sub joined to
+    """
+    for rel in relations_of_type(relation_name):
+        if 'nagios_hostname' in rel:
+            return rel['nagios_hostname']
+
+
+def get_nagios_unit_name(relation_name='nrpe-external-master'):
+    """
+    Return the nagios unit name prepended with host_context if needed
+
+    :param str relation_name: Name of relation nrpe sub joined to
+    """
+    host_context = get_nagios_hostcontext(relation_name)
+    if host_context:
+        unit = "%s:%s" % (host_context, local_unit())
+    else:
+        unit = local_unit()
+    return unit
+
+
+def add_init_service_checks(nrpe, services, unit_name):
+    """
+    Add checks for each service in list
+
+    :param NRPE nrpe: NRPE object to add check to
+    :param list services: List of services to check
+    :param str unit_name: Unit name to use in check description
+    """
+    for svc in services:
+        upstart_init = '/etc/init/%s.conf' % svc
+        sysv_init = '/etc/init.d/%s' % svc
+        if os.path.exists(upstart_init):
+            nrpe.add_check(
+                shortname=svc,
+                description='process check {%s}' % unit_name,
+                check_cmd='check_upstart_job %s' % svc
+            )
+        elif os.path.exists(sysv_init):
+            cronpath = '/etc/cron.d/nagios-service-check-%s' % svc
+            cron_file = ('*/5 * * * * root '
+                         '/usr/local/lib/nagios/plugins/check_exit_status.pl '
+                         '-s /etc/init.d/%s status > '
+                         '/var/lib/nagios/service-check-%s.txt\n' % (svc,
+                                                                     svc)
+                         )
+            f = open(cronpath, 'w')
+            f.write(cron_file)
+            f.close()
+            nrpe.add_check(
+                shortname=svc,
+                description='process check {%s}' % unit_name,
+                check_cmd='check_status_file.py -f '
+                          '/var/lib/nagios/service-check-%s.txt' % svc,
+            )
+
+
+def copy_nrpe_checks():
+    """
+    Copy the nrpe checks into place
+
+    """
+    NAGIOS_PLUGINS = '/usr/local/lib/nagios/plugins'
+    nrpe_files_dir = os.path.join(os.getenv('CHARM_DIR'), 'hooks',
+                                  'charmhelpers', 'contrib', 'openstack',
+                                  'files')
+
+    if not os.path.exists(NAGIOS_PLUGINS):
+        os.makedirs(NAGIOS_PLUGINS)
+    for fname in glob.glob(os.path.join(nrpe_files_dir, "check_*")):
+        if os.path.isfile(fname):
+            shutil.copy2(fname,
+                         os.path.join(NAGIOS_PLUGINS, os.path.basename(fname)))
+
+
+def add_haproxy_checks(nrpe, unit_name):
+    """
+    Add checks for each service in list
+
+    :param NRPE nrpe: NRPE object to add check to
+    :param str unit_name: Unit name to use in check description
+    """
+    nrpe.add_check(
+        shortname='haproxy_servers',
+        description='Check HAProxy {%s}' % unit_name,
+        check_cmd='check_haproxy.sh')
+    nrpe.add_check(
+        shortname='haproxy_queue',
+        description='Check HAProxy queue depth {%s}' % unit_name,
+        check_cmd='check_haproxy_queue_depth.sh')

=== modified file 'hooks/charmhelpers/contrib/charmsupport/volumes.py'
--- hooks/charmhelpers/contrib/charmsupport/volumes.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/contrib/charmsupport/volumes.py	2015-03-09 16:35:13 +0000
@@ -1,8 +1,25 @@
+# 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/>.
+
 '''
 Functions for managing volumes in juju units. One volume is supported per unit.
 Subordinates may have their own storage, provided it is on its own partition.
 
-Configuration stanzas:
+Configuration stanzas::
+
   volume-ephemeral:
     type: boolean
     default: true
@@ -20,7 +37,8 @@
       is 'true' and no volume-map value is set. Use 'juju set' to set a
       value and 'juju resolved' to complete configuration.
 
-Usage:
+Usage::
+
     from charmsupport.volumes import configure_volume, VolumeConfigurationError
     from charmsupport.hookenv import log, ERROR
     def post_mount_hook():
@@ -34,6 +52,7 @@
                              after_change=post_mount_hook)
         except VolumeConfigurationError:
             log('Storage could not be configured', ERROR)
+
 '''
 
 # XXX: Known limitations

=== modified file 'hooks/charmhelpers/core/__init__.py'
--- hooks/charmhelpers/core/__init__.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/core/__init__.py	2015-03-09 16:35:13 +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/>.

=== modified file 'hooks/charmhelpers/core/hookenv.py'
--- hooks/charmhelpers/core/hookenv.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/core/hookenv.py	2015-03-09 16:35:13 +0000
@@ -1,3 +1,19 @@
+# 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.
 #
@@ -8,7 +24,14 @@
 import json
 import yaml
 import subprocess
-import UserDict
+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"
@@ -21,9 +44,9 @@
 
 
 def cached(func):
-    ''' Cache return values for multiple executions of func + args
+    """Cache return values for multiple executions of func + args
 
-    For example:
+    For example::
 
         @cached
         def unit_get(attribute):
@@ -32,7 +55,7 @@
         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))
@@ -46,8 +69,8 @@
 
 
 def flush(key):
-    ''' Flushes any entries from function cache where the
-    key is found in the function+args '''
+    """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:
@@ -57,20 +80,22 @@
 
 
 def log(message, level=None):
-    "Write a message to the juju log"
+    """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.IterableUserDict):
-    "Wrapper, an object that can be serialized to yaml or json"
+class Serializable(UserDict):
+    """Wrapper, an object that can be serialized to yaml or json"""
 
     def __init__(self, obj):
         # wrap the object
-        UserDict.IterableUserDict.__init__(self)
+        UserDict.__init__(self)
         self.data = obj
 
     def __getattr__(self, attr):
@@ -96,11 +121,11 @@
         self.data = state
 
     def json(self):
-        "Serialize the object to json"
+        """Serialize the object to json"""
         return json.dumps(self.data)
 
     def yaml(self):
-        "Serialize the object to yaml"
+        """Serialize the object to yaml"""
         return yaml.dump(self.data)
 
 
@@ -119,50 +144,181 @@
 
 
 def in_relation_hook():
-    "Determine whether we're running in a 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"
+    """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"
+    """The relation ID for the current relation hook"""
     return os.environ.get('JUJU_RELATION_ID', None)
 
 
 def local_unit():
-    "Local unit ID"
+    """Local unit ID"""
     return os.environ['JUJU_UNIT_NAME']
 
 
 def remote_unit():
-    "The remote unit for the current relation hook"
+    """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"
+    """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"
+    """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:
-        return json.loads(subprocess.check_output(config_cmd_line))
+        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')
@@ -171,16 +327,22 @@
     if unit:
         _args.append(unit)
     try:
-        return json.loads(subprocess.check_output(_args))
+        return json.loads(subprocess.check_output(_args).decode('UTF-8'))
     except ValueError:
         return None
-
-
-def relation_set(relation_id=None, relation_settings={}, **kwargs):
+    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 (relation_settings.items() + kwargs.items()):
+    for k, v in (list(relation_settings.items()) + list(kwargs.items())):
         if v is None:
             relation_cmd_line.append('{}='.format(k))
         else:
@@ -192,28 +354,30 @@
 
 @cached
 def relation_ids(reltype=None):
-    "A list of relation_ids"
+    """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)) or []
+        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"
+    """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)) or []
+    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"
+    """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:
@@ -225,7 +389,7 @@
 
 @cached
 def relations_for_id(relid=None):
-    "Get relations of a specific relation ID"
+    """Get relations of a specific relation ID"""
     relation_data = []
     relid = relid or relation_ids()
     for unit in related_units(relid):
@@ -237,7 +401,7 @@
 
 @cached
 def relations_of_type(reltype=None):
-    "Get relations of a specific type"
+    """Get relations of a specific type"""
     relation_data = []
     reltype = reltype or relation_type()
     for relid in relation_ids(reltype):
@@ -248,22 +412,33 @@
 
 
 @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"
-    charmdir = os.environ.get('CHARM_DIR', '')
-    mdf = open(os.path.join(charmdir, 'metadata.yaml'))
-    md = yaml.safe_load(mdf)
+    """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())
-    mdf.close()
     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 = {}
@@ -277,15 +452,35 @@
     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"
+    """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"
+    """Close a service network port"""
     _args = ['close-port']
     _args.append('{}/{}'.format(port, protocol))
     subprocess.check_call(_args)
@@ -293,37 +488,69 @@
 
 @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))
+        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):
-    def __init__(self):
+    """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)
@@ -337,4 +564,5 @@
 
 
 def charm_dir():
+    """Return the root directory of the current charm"""
     return os.environ.get('CHARM_DIR')

=== modified file 'hooks/charmhelpers/fetch/__init__.py'
--- hooks/charmhelpers/fetch/__init__.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/fetch/__init__.py	2015-03-09 16:35:13 +0000
@@ -1,18 +1,39 @@
+# 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
 )
-from urlparse import (
-    urlparse,
-    urlunparse,
-)
 import subprocess
 from charmhelpers.core.hookenv import (
     config,
     log,
 )
-import apt_pkg
+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
@@ -20,12 +41,109 @@
 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"""
-    apt_pkg.init()
-    cache = apt_pkg.Cache()
+    cache = apt_cache()
     _pkgs = []
     for package in packages:
         try:
@@ -38,41 +156,74 @@
     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"""
-    options = options or []
-    cmd = ['apt-get', '-y']
+    if options is None:
+        options = ['--option=Dpkg::Options::=--force-confold']
+
+    cmd = ['apt-get', '--assume-yes']
     cmd.extend(options)
     cmd.append('install')
-    if isinstance(packages, basestring):
+    if isinstance(packages, six.string_types):
         cmd.append(packages)
     else:
         cmd.extend(packages)
     log("Installing {} with options: {}".format(packages,
                                                 options))
-    if fatal:
-        subprocess.check_call(cmd)
+    _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:
-        subprocess.call(cmd)
+        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']
-    if fatal:
-        subprocess.check_call(cmd)
-    else:
-        subprocess.call(cmd)
+    _run_apt_command(cmd, fatal)
 
 
 def apt_purge(packages, fatal=False):
     """Purge one or more packages"""
-    cmd = ['apt-get', '-y', 'purge']
-    if isinstance(packages, basestring):
+    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:
@@ -80,84 +231,145 @@
 
 
 def add_source(source, key=None):
-    if ((source.startswith('ppa:') or
-         source.startswith('http:'))):
+    """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(pocket))
+            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:
-        subprocess.check_call(['apt-key', 'import', key])
-
-
-class SourceConfigError(Exception):
-    pass
+        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
+    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:
+        install_sources: |
           - "ppa:foo"
           - "http://example.com/repo precise main"
-        install_keys:
+        install_keys: |
           - null
           - "a1b2c3d4"
 
     Note that 'null' (a.k.a. None) should not be quoted.
     """
-    sources = safe_load(config(sources_var))
-    keys = safe_load(config(keys_var))
-    if isinstance(sources, basestring) and isinstance(keys, basestring):
-        add_source(sources, keys)
+    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 not len(sources) == len(keys):
-            msg = 'Install sources and keys lists are different lengths'
-            raise SourceConfigError(msg)
-        for src_num in range(len(sources)):
-            add_source(sources[src_num], keys[src_num])
+        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)
 
-# 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',
-)
-
-
-class UnhandledSource(Exception):
-    pass
-
-
-def install_remote(source):
+
+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"""
+    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)
+            installed_to = handler.install(source, *args, **kwargs)
         except UnhandledSource:
             pass
     if not installed_to:
@@ -171,28 +383,6 @@
     return install_remote(source)
 
 
-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 plugins(fetch_handlers=None):
     if not fetch_handlers:
         fetch_handlers = FETCH_HANDLERS
@@ -200,10 +390,50 @@
     for handler_name in fetch_handlers:
         package, classname = handler_name.rsplit('.', 1)
         try:
-            handler_class = getattr(importlib.import_module(package), classname)
+            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))
+            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)

=== modified file 'hooks/charmhelpers/fetch/archiveurl.py'
--- hooks/charmhelpers/fetch/archiveurl.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/fetch/archiveurl.py	2015-03-09 16:35:13 +0000
@@ -1,5 +1,23 @@
+# 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 urllib2
+import hashlib
+import re
+
 from charmhelpers.fetch import (
     BaseFetchHandler,
     UnhandledSource
@@ -8,11 +26,54 @@
     get_archive_handler,
     extract,
 )
-from charmhelpers.core.host import mkdir
+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 for archives via generic URLs"""
+    """
+    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'):
@@ -22,9 +83,28 @@
         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
-        response = urllib2.urlopen(source)
+        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())
@@ -33,16 +113,49 @@
                 os.unlink(dest)
             raise e
 
-    def install(self, source):
+    # 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=0755)
+            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 urllib2.URLError as e:
+        except URLError as e:
             raise UnhandledSource(e.reason)
         except OSError as e:
             raise UnhandledSource(e.strerror)
-        return extract(dld_file)
+        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)

=== modified file 'hooks/charmhelpers/fetch/bzrurl.py'
--- hooks/charmhelpers/fetch/bzrurl.py	2013-10-10 22:47:57 +0000
+++ hooks/charmhelpers/fetch/bzrurl.py	2015-03-09 16:35:13 +0000
@@ -1,11 +1,39 @@
+# 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 bzrlib.branch import Branch
 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"""
@@ -25,20 +53,26 @@
             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.bzrdir.sprout(dest).open_branch()
+            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)
+        dest_dir = os.path.join(os.environ.get('CHARM_DIR'), "fetched",
+                                branch_name)
         if not os.path.exists(dest_dir):
-            mkdir(dest_dir, perms=0755)
+            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	2015-03-09 16:35:13 +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

=== modified file 'hooks/tests/test_create_vhost.py'
--- hooks/tests/test_create_vhost.py	2015-02-27 13:48:16 +0000
+++ hooks/tests/test_create_vhost.py	2015-03-09 16:35:13 +0000
@@ -109,7 +109,7 @@
     @patch('hooks.site_filename')
     @patch('hooks.open_port')
     @patch('hooks.subprocess.call')
-    def test_create_vhost_template_config(
+    def test_create_vhost_template_config_template_vars(
             self, mock_call, mock_open_port, mock_site_filename,
             mock_close_port):
         """Template passed in as config setting."""

=== modified file 'hooks/tests/test_nrpe_hooks.py'
--- hooks/tests/test_nrpe_hooks.py	2014-11-20 00:06:41 +0000
+++ hooks/tests/test_nrpe_hooks.py	2015-03-09 16:35:13 +0000
@@ -1,134 +1,30 @@
-import os
-import grp
-import pwd
-import subprocess
 from testtools import TestCase
-from mock import patch, call
+from mock import patch
 
 import hooks
-from charmhelpers.contrib.charmsupport import nrpe
-from charmhelpers.core.hookenv import Serializable
 
 
 class NRPERelationTest(TestCase):
-    """Tests for the update_nrpe_checks hook.
-
-    Half of this is already tested in the tests for charmsupport.nrpe, but
-    as the hook in the charm pre-dates that, the tests are left here to ensure
-    backwards-compatibility.
-
-    """
-    patches = {
-        'config': {'object': nrpe},
-        'log': {'object': nrpe},
-        'getpwnam': {'object': pwd},
-        'getgrnam': {'object': grp},
-        'mkdir': {'object': os},
-        'chown': {'object': os},
-        'exists': {'object': os.path},
-        'listdir': {'object': os},
-        'remove': {'object': os},
-        'open': {'object': nrpe, 'create': True},
-        'isfile': {'object': os.path},
-        'call': {'object': subprocess},
-        'relation_ids': {'object': nrpe},
-        'relation_set': {'object': nrpe},
-    }
-
-    def setUp(self):
-        super(NRPERelationTest, self).setUp()
-        self.patched = {}
-        # Mock the universe.
-        for attr, data in self.patches.items():
-            create = data.get('create', False)
-            patcher = patch.object(data['object'], attr, create=create)
-            self.patched[attr] = patcher.start()
-            self.addCleanup(patcher.stop)
-        if 'JUJU_UNIT_NAME' not in os.environ:
-            os.environ['JUJU_UNIT_NAME'] = 'test'
-
-    def check_call_counts(self, **kwargs):
-        for attr, expected in kwargs.items():
-            patcher = self.patched[attr]
-            self.assertEqual(expected, patcher.call_count, attr)
-
-    def test_update_nrpe_no_nagios_bails(self):
-        config = {'nagios_context': 'test'}
-        self.patched['config'].return_value = Serializable(config)
-        self.patched['getpwnam'].side_effect = KeyError
-
-        self.assertEqual(None, hooks.update_nrpe_checks())
-
-        expected = 'Nagios user not set up, nrpe checks not updated'
-        self.patched['log'].assert_called_once_with(expected)
-        self.check_call_counts(log=1, config=1, getpwnam=1)
-
-    def test_update_nrpe_removes_existing_config(self):
-        config = {
-            'nagios_context': 'test',
-            'nagios_check_http_params': '-u http://example.com/url',
-        }
-        self.patched['config'].return_value = Serializable(config)
-        self.patched['exists'].return_value = True
-        self.patched['listdir'].return_value = [
-            'foo', 'bar.cfg', 'check_vhost.cfg']
-
-        self.assertEqual(None, hooks.update_nrpe_checks())
-
-        expected = '/var/lib/nagios/export/check_vhost.cfg'
-        self.patched['remove'].assert_called_once_with(expected)
-        self.check_call_counts(config=1, getpwnam=1, getgrnam=1,
-                               exists=3, remove=1, open=2, listdir=1)
-
-    def test_update_nrpe_with_check_url(self):
-        config = {
-            'nagios_context': 'test',
+    """Tests for the update_nrpe_checks hook."""
+
+    @patch('hooks.nrpe.NRPE')
+    def test_update_nrpe_with_check(self, mock_nrpe):
+        nrpe = mock_nrpe.return_value
+        nrpe.config = {
             'nagios_check_http_params': '-u foo -H bar',
         }
-        self.patched['config'].return_value = Serializable(config)
-        self.patched['exists'].return_value = True
-        self.patched['isfile'].return_value = False
-
-        self.assertEqual(None, hooks.update_nrpe_checks())
-        self.assertEqual(2, self.patched['open'].call_count)
-        filename = 'check_vhost.cfg'
-
-        service_file_contents = """
-#---------------------------------------------------
-# This file is Juju managed
-#---------------------------------------------------
-define service {
-    use                             active-service
-    host_name                       test-test
-    service_description             test-test[vhost] Check Virtual Host
-    check_command                   check_nrpe!check_vhost
-    servicegroups                   test
-}
-"""
-        self.patched['open'].assert_has_calls(
-            [call('/etc/nagios/nrpe.d/%s' % filename, 'w'),
-             call('/var/lib/nagios/export/service__test-test_%s' %
-                  filename, 'w'),
-             call().__enter__().write(service_file_contents),
-             call().__enter__().write('# check vhost\n'),
-             call().__enter__().write(
-                 'command[check_vhost]=/check_http -u foo -H bar\n')],
-            any_order=True)
-
-        self.check_call_counts(config=1, getpwnam=1, getgrnam=1,
-                               exists=3, open=2, listdir=1)
-
-    def test_update_nrpe_restarts_service(self):
-        config = {
-            'nagios_context': 'test',
-            'nagios_check_http_params': '-u foo -p 3128'
-        }
-        self.patched['config'].return_value = Serializable(config)
-        self.patched['exists'].return_value = True
-
-        self.assertEqual(None, hooks.update_nrpe_checks())
-
-        expected = ['service', 'nagios-nrpe-server', 'restart']
-        self.assertEqual(expected, self.patched['call'].call_args[0][0])
-        self.check_call_counts(config=1, getpwnam=1, getgrnam=1,
-                               exists=3, open=2, listdir=1, call=1)
+        hooks.update_nrpe_checks()
+        nrpe.add_check.assert_called_once_with(
+            shortname='vhost',
+            description='Check Virtual Host',
+            check_cmd='check_http -u foo -H bar'
+        )
+        nrpe.write.assert_called_once_with()
+
+    @patch('hooks.nrpe.NRPE')
+    def test_update_nrpe_no_check(self, mock_nrpe):
+        nrpe = mock_nrpe.return_value
+        nrpe.config = {}
+        hooks.update_nrpe_checks()
+        self.assertFalse(nrpe.add_check.called)
+        nrpe.write.assert_called_once_with()