Merge lp:~brad-marshall/charms/trusty/nova-compute/fix-nagios into lp:~openstack-charmers-archive/charms/trusty/nova-compute/next

[Brad Marshall]

Synced charmhelpers, added nagios_servicegroup config option

[lp:~brad-marshall/charms/trusty/nova-compute/fix-nagios]

105. By Edward Hope-Morley on 2015-02-24

[trivial] charmhelpers sync

[uosci-testing-bot (uosci-testing-bot)]

charm_lint_check #2218 nova-compute-next for brad-marshall mp250703
    LINT OK: passed

Build: http://10.245.162.77:8080/job/charm_lint_check/2218/

[uosci-testing-bot (uosci-testing-bot)]

charm_unit_test #2007 nova-compute-next for brad-marshall mp250703
    UNIT FAIL: unit-test failed

UNIT Results (max last 2 lines):
  FAILED (SKIP=5, failures=1)
  make: *** [unit_test] Error 1

Full unit test output: http://paste.ubuntu.com/10396098/
Build: http://10.245.162.77:8080/job/charm_unit_test/2007/

[uosci-testing-bot (uosci-testing-bot)]

charm_amulet_test #2164 nova-compute-next for brad-marshall mp250703
    AMULET FAIL: amulet-test failed

AMULET Results (max last 2 lines):
  ERROR subprocess encountered error code 1
  make: *** [test] Error 1

Full amulet test output: http://paste.ubuntu.com/10396800/
Build: http://10.245.162.77:8080/job/charm_amulet_test/2164/

[lp:~brad-marshall/charms/trusty/nova-compute/fix-nagios]

106. By Brad Marshall on 2015-02-26

[bradm] Fixed text conflicts

[Liam Young (gnuoy)]

Approve

review: Approve

=== modified file 'config.yaml'
--- config.yaml	2015-02-16 09:26:23 +0000
+++ config.yaml	2015-02-26 00:02:34 +0000
@@ -122,6 +122,12 @@
           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
   disable-neutron-security-groups:
     type: boolean
     default: False

=== removed file 'hooks/charmhelpers/contrib/hahelpers/ceph.py'
--- hooks/charmhelpers/contrib/hahelpers/ceph.py	2013-09-20 16:40:54 +0000
+++ hooks/charmhelpers/contrib/hahelpers/ceph.py	1970-01-01 00:00:00 +0000
@@ -1,294 +0,0 @@
-#
-# Copyright 2012 Canonical Ltd.
-#
-# This file is sourced from lp:openstack-charm-helpers
-#
-# Authors:
-#  James Page <[e-mail]>
-#  Adam Gandelman <[e-mail]>
-#
-
-import commands
-import os
-import shutil
-import time
-
-from subprocess import (
-    check_call,
-    check_output,
-    CalledProcessError
-)
-
-from charmhelpers.core.hookenv import (
-    relation_get,
-    relation_ids,
-    related_units,
-    log,
-    INFO,
-    ERROR
-)
-
-from charmhelpers.fetch import (
-    apt_install,
-)
-
-from charmhelpers.core.host import (
-    mount,
-    mounts,
-    service_start,
-    service_stop,
-    umount,
-)
-
-KEYRING = '/etc/ceph/ceph.client.%s.keyring'
-KEYFILE = '/etc/ceph/ceph.client.%s.key'
-
-CEPH_CONF = """[global]
- auth supported = %(auth)s
- keyring = %(keyring)s
- mon host = %(mon_hosts)s
-"""
-
-
-def running(service):
-    # this local util can be dropped as soon the following branch lands
-    # in lp:charm-helpers
-    # https://code.launchpad.net/~gandelman-a/charm-helpers/service_running/
-    try:
-        output = check_output(['service', service, 'status'])
-    except CalledProcessError:
-        return False
-    else:
-        if ("start/running" in output or "is running" in output):
-            return True
-        else:
-            return False
-
-
-def install():
-    ceph_dir = "/etc/ceph"
-    if not os.path.isdir(ceph_dir):
-        os.mkdir(ceph_dir)
-    apt_install('ceph-common', fatal=True)
-
-
-def rbd_exists(service, pool, rbd_img):
-    (rc, out) = commands.getstatusoutput('rbd list --id %s --pool %s' %
-                                         (service, pool))
-    return rbd_img in out
-
-
-def create_rbd_image(service, pool, image, sizemb):
-    cmd = [
-        'rbd',
-        'create',
-        image,
-        '--size',
-        str(sizemb),
-        '--id',
-        service,
-        '--pool',
-        pool
-    ]
-    check_call(cmd)
-
-
-def pool_exists(service, name):
-    (rc, out) = commands.getstatusoutput("rados --id %s lspools" % service)
-    return name in out
-
-
-def create_pool(service, name):
-    cmd = [
-        'rados',
-        '--id',
-        service,
-        'mkpool',
-        name
-    ]
-    check_call(cmd)
-
-
-def keyfile_path(service):
-    return KEYFILE % service
-
-
-def keyring_path(service):
-    return KEYRING % service
-
-
-def create_keyring(service, key):
-    keyring = keyring_path(service)
-    if os.path.exists(keyring):
-        log('ceph: Keyring exists at %s.' % keyring, level=INFO)
-    cmd = [
-        'ceph-authtool',
-        keyring,
-        '--create-keyring',
-        '--name=client.%s' % service,
-        '--add-key=%s' % key
-    ]
-    check_call(cmd)
-    log('ceph: Created new ring at %s.' % keyring, level=INFO)
-
-
-def create_key_file(service, key):
-    # create a file containing the key
-    keyfile = keyfile_path(service)
-    if os.path.exists(keyfile):
-        log('ceph: Keyfile exists at %s.' % keyfile, level=INFO)
-    fd = open(keyfile, 'w')
-    fd.write(key)
-    fd.close()
-    log('ceph: Created new keyfile at %s.' % keyfile, level=INFO)
-
-
-def get_ceph_nodes():
-    hosts = []
-    for r_id in relation_ids('ceph'):
-        for unit in related_units(r_id):
-            hosts.append(relation_get('private-address', unit=unit, rid=r_id))
-    return hosts
-
-
-def configure(service, key, auth):
-    create_keyring(service, key)
-    create_key_file(service, key)
-    hosts = get_ceph_nodes()
-    mon_hosts = ",".join(map(str, hosts))
-    keyring = keyring_path(service)
-    with open('/etc/ceph/ceph.conf', 'w') as ceph_conf:
-        ceph_conf.write(CEPH_CONF % locals())
-    modprobe_kernel_module('rbd')
-
-
-def image_mapped(image_name):
-    (rc, out) = commands.getstatusoutput('rbd showmapped')
-    return image_name in out
-
-
-def map_block_storage(service, pool, image):
-    cmd = [
-        'rbd',
-        'map',
-        '%s/%s' % (pool, image),
-        '--user',
-        service,
-        '--secret',
-        keyfile_path(service),
-    ]
-    check_call(cmd)
-
-
-def filesystem_mounted(fs):
-    return fs in [f for m, f in mounts()]
-
-
-def make_filesystem(blk_device, fstype='ext4', timeout=10):
-    count = 0
-    e_noent = os.errno.ENOENT
-    while not os.path.exists(blk_device):
-        if count >= timeout:
-            log('ceph: gave up waiting on block device %s' % blk_device,
-                level=ERROR)
-            raise IOError(e_noent, os.strerror(e_noent), blk_device)
-        log('ceph: waiting for block device %s to appear' % blk_device,
-            level=INFO)
-        count += 1
-        time.sleep(1)
-    else:
-        log('ceph: Formatting block device %s as filesystem %s.' %
-            (blk_device, fstype), level=INFO)
-        check_call(['mkfs', '-t', fstype, blk_device])
-
-
-def place_data_on_ceph(service, blk_device, data_src_dst, fstype='ext4'):
-    # mount block device into /mnt
-    mount(blk_device, '/mnt')
-
-    # copy data to /mnt
-    try:
-        copy_files(data_src_dst, '/mnt')
-    except:
-        pass
-
-    # umount block device
-    umount('/mnt')
-
-    _dir = os.stat(data_src_dst)
-    uid = _dir.st_uid
-    gid = _dir.st_gid
-
-    # re-mount where the data should originally be
-    mount(blk_device, data_src_dst, persist=True)
-
-    # ensure original ownership of new mount.
-    cmd = ['chown', '-R', '%s:%s' % (uid, gid), data_src_dst]
-    check_call(cmd)
-
-
-# TODO: re-use
-def modprobe_kernel_module(module):
-    log('ceph: Loading kernel module', level=INFO)
-    cmd = ['modprobe', module]
-    check_call(cmd)
-    cmd = 'echo %s >> /etc/modules' % module
-    check_call(cmd, shell=True)
-
-
-def copy_files(src, dst, symlinks=False, ignore=None):
-    for item in os.listdir(src):
-        s = os.path.join(src, item)
-        d = os.path.join(dst, item)
-        if os.path.isdir(s):
-            shutil.copytree(s, d, symlinks, ignore)
-        else:
-            shutil.copy2(s, d)
-
-
-def ensure_ceph_storage(service, pool, rbd_img, sizemb, mount_point,
-                        blk_device, fstype, system_services=[]):
-    """
-    To be called from the current cluster leader.
-    Ensures given pool and RBD image exists, is mapped to a block device,
-    and the device is formatted and mounted at the given mount_point.
-
-    If formatting a device for the first time, data existing at mount_point
-    will be migrated to the RBD device before being remounted.
-
-    All services listed in system_services will be stopped prior to data
-    migration and restarted when complete.
-    """
-    # Ensure pool, RBD image, RBD mappings are in place.
-    if not pool_exists(service, pool):
-        log('ceph: Creating new pool %s.' % pool, level=INFO)
-        create_pool(service, pool)
-
-    if not rbd_exists(service, pool, rbd_img):
-        log('ceph: Creating RBD image (%s).' % rbd_img, level=INFO)
-        create_rbd_image(service, pool, rbd_img, sizemb)
-
-    if not image_mapped(rbd_img):
-        log('ceph: Mapping RBD Image as a Block Device.', level=INFO)
-        map_block_storage(service, pool, rbd_img)
-
-    # make file system
-    # TODO: What happens if for whatever reason this is run again and
-    # the data is already in the rbd device and/or is mounted??
-    # When it is mounted already, it will fail to make the fs
-    # XXX: This is really sketchy!  Need to at least add an fstab entry
-    #      otherwise this hook will blow away existing data if its executed
-    #      after a reboot.
-    if not filesystem_mounted(mount_point):
-        make_filesystem(blk_device, fstype)
-
-        for svc in system_services:
-            if running(svc):
-                log('Stopping services %s prior to migrating data.' % svc,
-                    level=INFO)
-                service_stop(svc)
-
-        place_data_on_ceph(service, blk_device, mount_point, fstype)
-
-        for svc in system_services:
-            service_start(svc)

=== modified file 'hooks/charmhelpers/contrib/openstack/context.py'
--- hooks/charmhelpers/contrib/openstack/context.py	2015-01-26 09:46:57 +0000
+++ hooks/charmhelpers/contrib/openstack/context.py	2015-02-26 00:02:34 +0000
@@ -279,9 +279,25 @@
 class IdentityServiceContext(OSContextGenerator):
     interfaces = ['identity-service']
 
+    def __init__(self, service=None, service_user=None):
+        self.service = service
+        self.service_user = service_user
+
     def __call__(self):
         log('Generating template context for identity-service', level=DEBUG)
         ctxt = {}
+
+        if self.service and self.service_user:
+            # This is required for pki token signing if we don't want /tmp to
+            # be used.
+            cachedir = '/var/cache/%s' % (self.service)
+            if not os.path.isdir(cachedir):
+                log("Creating service cache dir %s" % (cachedir), level=DEBUG)
+                mkdir(path=cachedir, owner=self.service_user,
+                      group=self.service_user, perms=0o700)
+
+            ctxt['signing_dir'] = cachedir
+
         for rid in relation_ids('identity-service'):
             for unit in related_units(rid):
                 rdata = relation_get(rid=rid, unit=unit)
@@ -291,15 +307,16 @@
                 auth_host = format_ipv6_addr(auth_host) or auth_host
                 svc_protocol = rdata.get('service_protocol') or 'http'
                 auth_protocol = rdata.get('auth_protocol') or 'http'
-                ctxt = {'service_port': rdata.get('service_port'),
-                        'service_host': serv_host,
-                        'auth_host': auth_host,
-                        'auth_port': rdata.get('auth_port'),
-                        'admin_tenant_name': rdata.get('service_tenant'),
-                        'admin_user': rdata.get('service_username'),
-                        'admin_password': rdata.get('service_password'),
-                        'service_protocol': svc_protocol,
-                        'auth_protocol': auth_protocol}
+                ctxt.update({'service_port': rdata.get('service_port'),
+                             'service_host': serv_host,
+                             'auth_host': auth_host,
+                             'auth_port': rdata.get('auth_port'),
+                             'admin_tenant_name': rdata.get('service_tenant'),
+                             'admin_user': rdata.get('service_username'),
+                             'admin_password': rdata.get('service_password'),
+                             'service_protocol': svc_protocol,
+                             'auth_protocol': auth_protocol})
+
                 if context_complete(ctxt):
                     # NOTE(jamespage) this is required for >= icehouse
                     # so a missing value just indicates keystone needs
@@ -1021,6 +1038,8 @@
                     for unit in related_units(rid):
                         ctxt['zmq_nonce'] = relation_get('nonce', unit, rid)
                         ctxt['zmq_host'] = relation_get('host', unit, rid)
+                        ctxt['zmq_redis_address'] = relation_get(
+                            'zmq_redis_address', unit, rid)
 
         return ctxt
 

=== added directory 'hooks/charmhelpers/contrib/openstack/files'
=== removed directory 'hooks/charmhelpers/contrib/openstack/files'
=== added file 'hooks/charmhelpers/contrib/openstack/files/__init__.py'
--- hooks/charmhelpers/contrib/openstack/files/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/openstack/files/__init__.py	2015-02-26 00:02:34 +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/>.
+
+# dummy __init__.py to fool syncer into thinking this is a syncable python
+# module

=== removed file 'hooks/charmhelpers/contrib/openstack/files/__init__.py'
--- hooks/charmhelpers/contrib/openstack/files/__init__.py	2015-02-24 11:07:48 +0000
+++ hooks/charmhelpers/contrib/openstack/files/__init__.py	1970-01-01 00:00:00 +0000
@@ -1,18 +0,0 @@
-# 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/>.
-
-# dummy __init__.py to fool syncer into thinking this is a syncable python
-# module

=== added file 'hooks/charmhelpers/contrib/openstack/files/check_haproxy.sh'
--- hooks/charmhelpers/contrib/openstack/files/check_haproxy.sh	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/openstack/files/check_haproxy.sh	2015-02-26 00:02:34 +0000
@@ -0,0 +1,32 @@
+#!/bin/bash
+#--------------------------------------------
+# This file is managed by Juju
+#--------------------------------------------
+#
+# Copyright 2009,2012 Canonical Ltd.
+# Author: Tom Haddon
+
+CRITICAL=0
+NOTACTIVE=''
+LOGFILE=/var/log/nagios/check_haproxy.log
+AUTH=$(grep -r "stats auth" /etc/haproxy | head -1 | awk '{print $4}')
+
+for appserver in $(grep '    server' /etc/haproxy/haproxy.cfg | awk '{print $2'});
+do
+    output=$(/usr/lib/nagios/plugins/check_http -a ${AUTH} -I 127.0.0.1 -p 8888 --regex="class=\"(active|backup)(2|3).*${appserver}" -e ' 200 OK')
+    if [ $? != 0 ]; then
+        date >> $LOGFILE
+        echo $output >> $LOGFILE
+        /usr/lib/nagios/plugins/check_http -a ${AUTH} -I 127.0.0.1 -p 8888 -v | grep $appserver >> $LOGFILE 2>&1
+        CRITICAL=1
+        NOTACTIVE="${NOTACTIVE} $appserver"
+    fi
+done
+
+if [ $CRITICAL = 1 ]; then
+    echo "CRITICAL:${NOTACTIVE}"
+    exit 2
+fi
+
+echo "OK: All haproxy instances looking good"
+exit 0

=== removed file 'hooks/charmhelpers/contrib/openstack/files/check_haproxy.sh'
--- hooks/charmhelpers/contrib/openstack/files/check_haproxy.sh	2015-02-24 11:07:48 +0000
+++ hooks/charmhelpers/contrib/openstack/files/check_haproxy.sh	1970-01-01 00:00:00 +0000
@@ -1,32 +0,0 @@
-#!/bin/bash
-#--------------------------------------------
-# This file is managed by Juju
-#--------------------------------------------
-#
-# Copyright 2009,2012 Canonical Ltd.
-# Author: Tom Haddon
-
-CRITICAL=0
-NOTACTIVE=''
-LOGFILE=/var/log/nagios/check_haproxy.log
-AUTH=$(grep -r "stats auth" /etc/haproxy | head -1 | awk '{print $4}')
-
-for appserver in $(grep '    server' /etc/haproxy/haproxy.cfg | awk '{print $2'});
-do
-    output=$(/usr/lib/nagios/plugins/check_http -a ${AUTH} -I 127.0.0.1 -p 8888 --regex="class=\"(active|backup)(2|3).*${appserver}" -e ' 200 OK')
-    if [ $? != 0 ]; then
-        date >> $LOGFILE
-        echo $output >> $LOGFILE
-        /usr/lib/nagios/plugins/check_http -a ${AUTH} -I 127.0.0.1 -p 8888 -v | grep $appserver >> $LOGFILE 2>&1
-        CRITICAL=1
-        NOTACTIVE="${NOTACTIVE} $appserver"
-    fi
-done
-
-if [ $CRITICAL = 1 ]; then
-    echo "CRITICAL:${NOTACTIVE}"
-    exit 2
-fi
-
-echo "OK: All haproxy instances looking good"
-exit 0

=== added file 'hooks/charmhelpers/contrib/openstack/files/check_haproxy_queue_depth.sh'
--- hooks/charmhelpers/contrib/openstack/files/check_haproxy_queue_depth.sh	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/openstack/files/check_haproxy_queue_depth.sh	2015-02-26 00:02:34 +0000
@@ -0,0 +1,30 @@
+#!/bin/bash
+#--------------------------------------------
+# This file is managed by Juju
+#--------------------------------------------
+#                                       
+# Copyright 2009,2012 Canonical Ltd.
+# Author: Tom Haddon
+
+# These should be config options at some stage
+CURRQthrsh=0
+MAXQthrsh=100
+
+AUTH=$(grep -r "stats auth" /etc/haproxy | head -1 | awk '{print $4}')
+
+HAPROXYSTATS=$(/usr/lib/nagios/plugins/check_http -a ${AUTH} -I 127.0.0.1 -p 8888 -u '/;csv' -v)
+
+for BACKEND in $(echo $HAPROXYSTATS| xargs -n1 | grep BACKEND | awk -F , '{print $1}')
+do
+    CURRQ=$(echo "$HAPROXYSTATS" | grep $BACKEND | grep BACKEND | cut -d , -f 3)
+    MAXQ=$(echo "$HAPROXYSTATS"  | grep $BACKEND | grep BACKEND | cut -d , -f 4)
+
+    if [[ $CURRQ -gt $CURRQthrsh || $MAXQ -gt $MAXQthrsh ]] ; then
+        echo "CRITICAL: queue depth for $BACKEND - CURRENT:$CURRQ MAX:$MAXQ"
+        exit 2
+    fi
+done
+
+echo "OK: All haproxy queue depths looking good"
+exit 0
+

=== removed file 'hooks/charmhelpers/contrib/openstack/files/check_haproxy_queue_depth.sh'
--- hooks/charmhelpers/contrib/openstack/files/check_haproxy_queue_depth.sh	2015-02-24 11:07:48 +0000
+++ hooks/charmhelpers/contrib/openstack/files/check_haproxy_queue_depth.sh	1970-01-01 00:00:00 +0000
@@ -1,30 +0,0 @@
-#!/bin/bash
-#--------------------------------------------
-# This file is managed by Juju
-#--------------------------------------------
-#                                       
-# Copyright 2009,2012 Canonical Ltd.
-# Author: Tom Haddon
-
-# These should be config options at some stage
-CURRQthrsh=0
-MAXQthrsh=100
-
-AUTH=$(grep -r "stats auth" /etc/haproxy | head -1 | awk '{print $4}')
-
-HAPROXYSTATS=$(/usr/lib/nagios/plugins/check_http -a ${AUTH} -I 127.0.0.1 -p 8888 -u '/;csv' -v)
-
-for BACKEND in $(echo $HAPROXYSTATS| xargs -n1 | grep BACKEND | awk -F , '{print $1}')
-do
-    CURRQ=$(echo "$HAPROXYSTATS" | grep $BACKEND | grep BACKEND | cut -d , -f 3)
-    MAXQ=$(echo "$HAPROXYSTATS"  | grep $BACKEND | grep BACKEND | cut -d , -f 4)
-
-    if [[ $CURRQ -gt $CURRQthrsh || $MAXQ -gt $MAXQthrsh ]] ; then
-        echo "CRITICAL: queue depth for $BACKEND - CURRENT:$CURRQ MAX:$MAXQ"
-        exit 2
-    fi
-done
-
-echo "OK: All haproxy queue depths looking good"
-exit 0
-

=== added file 'hooks/charmhelpers/contrib/openstack/templates/zeromq'
--- hooks/charmhelpers/contrib/openstack/templates/zeromq	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/openstack/templates/zeromq	2015-02-26 00:02:34 +0000
@@ -0,0 +1,14 @@
+{% if zmq_host -%}
+# ZeroMQ configuration (restart-nonce: {{ zmq_nonce }})
+rpc_backend = zmq
+rpc_zmq_host = {{ zmq_host }}
+{% if zmq_redis_address -%}
+rpc_zmq_matchmaker = oslo.messaging._drivers.matchmaker_redis.MatchMakerRedis
+matchmaker_heartbeat_freq = 15
+matchmaker_heartbeat_ttl = 30
+[matchmaker_redis]
+host = {{ zmq_redis_address }}
+{% else -%}
+rpc_zmq_matchmaker = oslo.messaging._drivers.matchmaker_ring.MatchMakerRing
+{% endif -%}
+{% endif -%}

=== added file 'hooks/charmhelpers/core/strutils.py'
--- hooks/charmhelpers/core/strutils.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/strutils.py	2015-02-26 00:02:34 +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)

=== removed file 'hooks/charmhelpers/core/strutils.py'
--- hooks/charmhelpers/core/strutils.py	2015-02-24 11:07:48 +0000
+++ hooks/charmhelpers/core/strutils.py	1970-01-01 00:00:00 +0000
@@ -1,42 +0,0 @@
-#!/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/unitdata.py'
--- hooks/charmhelpers/core/unitdata.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/unitdata.py	2015-02-26 00:02:34 +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

=== removed file 'hooks/charmhelpers/core/unitdata.py'
--- hooks/charmhelpers/core/unitdata.py	2015-02-24 11:07:48 +0000
+++ hooks/charmhelpers/core/unitdata.py	1970-01-01 00:00:00 +0000
@@ -1,477 +0,0 @@
-#!/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