From 2b75b70758c06fef733fcad98a15c77886eacf76 Mon Sep 17 00:00:00 2001
From: James Page <james.page@canonical.com>
Date: Thu, 10 Oct 2013 11:49:36 +0100
Subject: [PATCH 1/3] Sync with alternatives charmhelpers, installed ceph.conf
 as alternative for charm co-existence

---
 charm-helpers-sync.yaml                |   3 +-
 hooks/charmhelpers/core/hookenv.py     |  10 +-
 hooks/charmhelpers/core/host.py        | 124 +++++++++----------------
 hooks/charmhelpers/fetch/__init__.py   |  65 ++++++++++++-
 hooks/charmhelpers/fetch/archiveurl.py |  19 ++--
 hooks/hooks.py                         |  21 ++++-
 hooks/utils.py                         |   2 +-
 revision                               |   2 +-
 8 files changed, 147 insertions(+), 99 deletions(-)

diff --git a/charm-helpers-sync.yaml b/charm-helpers-sync.yaml
index 21c0bc63..38dc4108 100644
--- a/charm-helpers-sync.yaml
+++ b/charm-helpers-sync.yaml
@@ -1,7 +1,8 @@
-branch: lp:charm-helpers
+branch: lp:~openstack-charmers/charm-helpers/os-alternatives
 destination: hooks/charmhelpers
 include:
     - core
     - fetch
     - contrib.storage.linux:
         - utils
+    - contrib.openstack.alternatives
diff --git a/hooks/charmhelpers/core/hookenv.py b/hooks/charmhelpers/core/hookenv.py
index e57ea25c..2b06706c 100644
--- a/hooks/charmhelpers/core/hookenv.py
+++ b/hooks/charmhelpers/core/hookenv.py
@@ -143,6 +143,11 @@ def remote_unit():
     return os.environ['JUJU_REMOTE_UNIT']
 
 
+def service_name():
+    "The name service group this unit belongs to"
+    return local_unit().split('/')[0]
+
+
 @cached
 def config(scope=None):
     "Juju charm configuration"
@@ -192,7 +197,7 @@ def relation_ids(reltype=None):
     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))
+        return json.loads(subprocess.check_output(relid_cmd_line)) or []
     return []
 
 
@@ -203,7 +208,7 @@ def related_units(relid=None):
     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))
+    return json.loads(subprocess.check_output(units_cmd_line)) or []
 
 
 @cached
@@ -330,5 +335,6 @@ class Hooks(object):
             return decorated
         return wrapper
 
+
 def charm_dir():
     return os.environ.get('CHARM_DIR')
diff --git a/hooks/charmhelpers/core/host.py b/hooks/charmhelpers/core/host.py
index d60d982d..1a63bf89 100644
--- a/hooks/charmhelpers/core/host.py
+++ b/hooks/charmhelpers/core/host.py
@@ -5,33 +5,36 @@
 #  Nick Moffitt <nick.moffitt@canonical.com>
 #  Matthew Wedgwood <matthew.wedgwood@canonical.com>
 
-import apt_pkg
 import os
 import pwd
 import grp
+import random
+import string
 import subprocess
 import hashlib
 
 from collections import OrderedDict
 
-from hookenv import log, execution_environment
+from hookenv import log
 
 
 def service_start(service_name):
-    service('start', service_name)
+    return service('start', service_name)
 
 
 def service_stop(service_name):
-    service('stop', service_name)
+    return service('stop', service_name)
 
 
 def service_restart(service_name):
-    service('restart', service_name)
+    return service('restart', service_name)
 
 
 def service_reload(service_name, restart_on_failure=False):
-    if not service('reload', service_name) and restart_on_failure:
-        service('restart', service_name)
+    service_result = service('reload', service_name)
+    if not service_result and restart_on_failure:
+        service_result = service('restart', service_name)
+    return service_result
 
 
 def service(action, service_name):
@@ -39,6 +42,18 @@ def service(action, service_name):
     return subprocess.call(cmd) == 0
 
 
+def service_running(service):
+    try:
+        output = subprocess.check_output(['service', service, 'status'])
+    except subprocess.CalledProcessError:
+        return False
+    else:
+        if ("start/running" in output or "is running" in output):
+            return True
+        else:
+            return False
+
+
 def adduser(username, password=None, shell='/bin/bash', system_user=False):
     """Add a user"""
     try:
@@ -74,36 +89,33 @@ def add_user_to_group(username, group):
 
 def rsync(from_path, to_path, flags='-r', options=None):
     """Replicate the contents of a path"""
-    context = execution_environment()
     options = options or ['--delete', '--executability']
     cmd = ['/usr/bin/rsync', flags]
     cmd.extend(options)
-    cmd.append(from_path.format(**context))
-    cmd.append(to_path.format(**context))
+    cmd.append(from_path)
+    cmd.append(to_path)
     log(" ".join(cmd))
     return subprocess.check_output(cmd).strip()
 
 
 def symlink(source, destination):
     """Create a symbolic link"""
-    context = execution_environment()
     log("Symlinking {} as {}".format(source, destination))
     cmd = [
         'ln',
         '-sf',
-        source.format(**context),
-        destination.format(**context)
+        source,
+        destination,
     ]
     subprocess.check_call(cmd)
 
 
 def mkdir(path, owner='root', group='root', perms=0555, force=False):
     """Create a directory"""
-    context = execution_environment()
     log("Making dir {} {}:{} {:o}".format(path, owner, group,
                                           perms))
-    uid = pwd.getpwnam(owner.format(**context)).pw_uid
-    gid = grp.getgrnam(group.format(**context)).gr_gid
+    uid = pwd.getpwnam(owner).pw_uid
+    gid = grp.getgrnam(group).gr_gid
     realpath = os.path.abspath(path)
     if os.path.exists(realpath):
         if force and not os.path.isdir(realpath):
@@ -114,71 +126,15 @@ def mkdir(path, owner='root', group='root', perms=0555, force=False):
     os.chown(realpath, uid, gid)
 
 
-def write_file(path, fmtstr, owner='root', group='root', perms=0444, **kwargs):
+def write_file(path, content, owner='root', group='root', perms=0444):
     """Create or overwrite a file with the contents of a string"""
-    context = execution_environment()
-    context.update(kwargs)
-    log("Writing file {} {}:{} {:o}".format(path, owner, group,
-        perms))
-    uid = pwd.getpwnam(owner.format(**context)).pw_uid
-    gid = grp.getgrnam(group.format(**context)).gr_gid
-    with open(path.format(**context), 'w') as target:
+    log("Writing file {} {}:{} {:o}".format(path, owner, group, perms))
+    uid = pwd.getpwnam(owner).pw_uid
+    gid = grp.getgrnam(group).gr_gid
+    with open(path, 'w') as target:
         os.fchown(target.fileno(), uid, gid)
         os.fchmod(target.fileno(), perms)
-        target.write(fmtstr.format(**context))
-
-
-def render_template_file(source, destination, **kwargs):
-    """Create or overwrite a file using a template"""
-    log("Rendering template {} for {}".format(source,
-        destination))
-    context = execution_environment()
-    with open(source.format(**context), 'r') as template:
-        write_file(destination.format(**context), template.read(),
-                   **kwargs)
-
-
-def filter_installed_packages(packages):
-    """Returns a list of packages that require installation"""
-    apt_pkg.init()
-    cache = apt_pkg.Cache()
-    _pkgs = []
-    for package in packages:
-        try:
-            p = cache[package]
-            p.current_ver or _pkgs.append(package)
-        except KeyError:
-            log('Package {} has no installation candidate.'.format(package),
-                level='WARNING')
-            _pkgs.append(package)
-    return _pkgs
-
-
-def apt_install(packages, options=None, fatal=False):
-    """Install one or more packages"""
-    options = options or []
-    cmd = ['apt-get', '-y']
-    cmd.extend(options)
-    cmd.append('install')
-    if isinstance(packages, basestring):
-        cmd.append(packages)
-    else:
-        cmd.extend(packages)
-    log("Installing {} with options: {}".format(packages,
-                                                options))
-    if fatal:
-        subprocess.check_call(cmd)
-    else:
-        subprocess.call(cmd)
-
-
-def apt_update(fatal=False):
-    """Update local apt cache"""
-    cmd = ['apt-get', 'update']
-    if fatal:
-        subprocess.check_call(cmd)
-    else:
-        subprocess.call(cmd)
+        target.write(content)
 
 
 def mount(device, mountpoint, options=None, persist=False):
@@ -271,3 +227,15 @@ def lsb_release():
             k, v = l.split('=')
             d[k.strip()] = v.strip()
     return d
+
+
+def pwgen(length=None):
+    '''Generate a random pasword.'''
+    if length is None:
+        length = random.choice(range(35, 45))
+    alphanumeric_chars = [
+        l for l in (string.letters + string.digits)
+        if l not in 'l0QD1vAEIOUaeiou']
+    random_chars = [
+        random.choice(alphanumeric_chars) for _ in range(length)]
+    return(''.join(random_chars))
diff --git a/hooks/charmhelpers/fetch/__init__.py b/hooks/charmhelpers/fetch/__init__.py
index 5a306257..b2f96467 100644
--- a/hooks/charmhelpers/fetch/__init__.py
+++ b/hooks/charmhelpers/fetch/__init__.py
@@ -1,9 +1,6 @@
 import importlib
 from yaml import safe_load
 from charmhelpers.core.host import (
-    apt_install,
-    apt_update,
-    filter_installed_packages,
     lsb_release
 )
 from urlparse import (
@@ -15,6 +12,7 @@ from charmhelpers.core.hookenv import (
     config,
     log,
 )
+import apt_pkg
 
 CLOUD_ARCHIVE = """# Ubuntu Cloud Archive
 deb http://ubuntu-cloud.archive.canonical.com/ubuntu {} main
@@ -24,10 +22,67 @@ deb http://archive.ubuntu.com/ubuntu {}-proposed main universe multiverse restri
 """
 
 
+def filter_installed_packages(packages):
+    """Returns a list of packages that require installation"""
+    apt_pkg.init()
+    cache = apt_pkg.Cache()
+    _pkgs = []
+    for package in packages:
+        try:
+            p = cache[package]
+            p.current_ver or _pkgs.append(package)
+        except KeyError:
+            log('Package {} has no installation candidate.'.format(package),
+                level='WARNING')
+            _pkgs.append(package)
+    return _pkgs
+
+
+def apt_install(packages, options=None, fatal=False):
+    """Install one or more packages"""
+    options = options or []
+    cmd = ['apt-get', '-y']
+    cmd.extend(options)
+    cmd.append('install')
+    if isinstance(packages, basestring):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+    log("Installing {} with options: {}".format(packages,
+                                                options))
+    if fatal:
+        subprocess.check_call(cmd)
+    else:
+        subprocess.call(cmd)
+
+
+def apt_update(fatal=False):
+    """Update local apt cache"""
+    cmd = ['apt-get', 'update']
+    if fatal:
+        subprocess.check_call(cmd)
+    else:
+        subprocess.call(cmd)
+
+
+def apt_purge(packages, fatal=False):
+    """Purge one or more packages"""
+    cmd = ['apt-get', '-y', 'purge']
+    if isinstance(packages, basestring):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+    log("Purging {}".format(packages))
+    if fatal:
+        subprocess.check_call(cmd)
+    else:
+        subprocess.call(cmd)
+
+
 def add_source(source, key=None):
     if ((source.startswith('ppa:') or
          source.startswith('http:'))):
-        subprocess.check_call(['add-apt-repository', source])
+        subprocess.check_call(['add-apt-repository', '--yes', source])
     elif source.startswith('cloud:'):
         apt_install(filter_installed_packages(['ubuntu-cloud-keyring']),
                     fatal=True)
@@ -79,6 +134,7 @@ def configure_sources(update=False,
 # least- to most-specific URL matching.
 FETCH_HANDLERS = (
     'charmhelpers.fetch.archiveurl.ArchiveUrlFetchHandler',
+    'charmhelpers.fetch.bzrurl.BzrUrlFetchHandler',
 )
 
 
@@ -98,6 +154,7 @@ def install_remote(source):
     # 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)
diff --git a/hooks/charmhelpers/fetch/archiveurl.py b/hooks/charmhelpers/fetch/archiveurl.py
index 09ac69e3..e35b8f15 100644
--- a/hooks/charmhelpers/fetch/archiveurl.py
+++ b/hooks/charmhelpers/fetch/archiveurl.py
@@ -8,6 +8,7 @@ from charmhelpers.payload.archive import (
     get_archive_handler,
     extract,
 )
+from charmhelpers.core.host import mkdir
 
 
 class ArchiveUrlFetchHandler(BaseFetchHandler):
@@ -24,20 +25,24 @@ class ArchiveUrlFetchHandler(BaseFetchHandler):
         # propogate all exceptions
         # URLError, OSError, etc
         response = urllib2.urlopen(source)
-        with open(dest, 'w') as dest_file:
-            dest_file.write(response.read())
+        try:
+            with open(dest, 'w') as dest_file:
+                dest_file.write(response.read())
+        except Exception as e:
+            if os.path.isfile(dest):
+                os.unlink(dest)
+            raise e
 
     def install(self, source):
         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)
         dld_file = os.path.join(dest_dir, os.path.basename(url_parts.path))
         try:
             self.download(source, dld_file)
         except urllib2.URLError as e:
-            return UnhandledSource(e.reason)
+            raise UnhandledSource(e.reason)
         except OSError as e:
-            return UnhandledSource(e.strerror)
-        finally:
-            if os.path.isfile(dld_file):
-                os.unlink(dld_file)
+            raise UnhandledSource(e.strerror)
         return extract(dld_file)
diff --git a/hooks/hooks.py b/hooks/hooks.py
index 1424eef1..0176d651 100755
--- a/hooks/hooks.py
+++ b/hooks/hooks.py
@@ -21,21 +21,27 @@ from charmhelpers.core.hookenv import (
     related_units,
     relation_get,
     Hooks,
-    UnregisteredHookError
+    UnregisteredHookError,
+    service_name
 )
 from charmhelpers.core.host import (
+    umount,
+    mkdir
+)
+from charmhelpers.fetch import (
+    add_source,
     apt_install,
     apt_update,
     filter_installed_packages,
-    umount
 )
-from charmhelpers.fetch import add_source
 
 from utils import (
     render_template,
     get_host_ip,
 )
 
+from charmhelpers.contrib.openstack.alternatives import install_alternative
+
 hooks = Hooks()
 
 
@@ -66,9 +72,14 @@ def emit_cephconf():
         'fsid': get_fsid(),
         'version': ceph.get_ceph_version()
     }
-
-    with open('/etc/ceph/ceph.conf', 'w') as cephconf:
+    # Install ceph.conf as an alternative to support
+    # co-existence with other charms that write this file
+    charm_ceph_conf = "/var/lib/charm/{}/ceph.conf".format(service_name())
+    mkdir(os.path.dirname(charm_ceph_conf))
+    with open(charm_ceph_conf, 'w') as cephconf:
         cephconf.write(render_template('ceph.conf', cephcontext))
+    install_alternative('ceph.conf', '/etc/ceph/ceph.conf',
+                        charm_ceph_conf, 90)
 
 JOURNAL_ZAPPED = '/var/lib/ceph/journal_zapped'
 
diff --git a/hooks/utils.py b/hooks/utils.py
index a8868b69..c1044a45 100644
--- a/hooks/utils.py
+++ b/hooks/utils.py
@@ -13,7 +13,7 @@ from charmhelpers.core.hookenv import (
     unit_get,
     cached
 )
-from charmhelpers.core.host import (
+from charmhelpers.fetch import (
     apt_install,
     filter_installed_packages
 )
diff --git a/revision b/revision
index b4de3947..b1bd38b6 100644
--- a/revision
+++ b/revision
@@ -1 +1 @@
-11
+13

From 9c812298d9a3f6f3ed35b1c46dfb422750da257f Mon Sep 17 00:00:00 2001
From: James Page <james.page@canonical.com>
Date: Thu, 10 Oct 2013 11:49:40 +0100
Subject: [PATCH 2/3] Sync with alternatives charmhelpers, installed ceph.conf
 as alternative for charm co-existence

---
 .../contrib/openstack/__init__.py             |  0
 .../contrib/openstack/alternatives.py         | 17 +++++++
 hooks/charmhelpers/fetch/bzrurl.py            | 49 +++++++++++++++++++
 3 files changed, 66 insertions(+)
 create mode 100644 hooks/charmhelpers/contrib/openstack/__init__.py
 create mode 100644 hooks/charmhelpers/contrib/openstack/alternatives.py
 create mode 100644 hooks/charmhelpers/fetch/bzrurl.py

diff --git a/hooks/charmhelpers/contrib/openstack/__init__.py b/hooks/charmhelpers/contrib/openstack/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/hooks/charmhelpers/contrib/openstack/alternatives.py b/hooks/charmhelpers/contrib/openstack/alternatives.py
new file mode 100644
index 00000000..b413259c
--- /dev/null
+++ b/hooks/charmhelpers/contrib/openstack/alternatives.py
@@ -0,0 +1,17 @@
+''' Helper for managing alternatives for file conflict resolution '''
+
+import subprocess
+import shutil
+import os
+
+
+def install_alternative(name, target, source, priority=50):
+    ''' Install alternative configuration '''
+    if (os.path.exists(target) and not os.path.islink(target)):
+        # Move existing file/directory away before installing
+        shutil.move(target, '{}.bak'.format(target))
+    cmd = [
+        'update-alternatives', '--force', '--install',
+        target, name, source, str(priority)
+    ]
+    subprocess.check_call(cmd)
diff --git a/hooks/charmhelpers/fetch/bzrurl.py b/hooks/charmhelpers/fetch/bzrurl.py
new file mode 100644
index 00000000..c348b4bb
--- /dev/null
+++ b/hooks/charmhelpers/fetch/bzrurl.py
@@ -0,0 +1,49 @@
+import os
+from charmhelpers.fetch import (
+    BaseFetchHandler,
+    UnhandledSource
+)
+from charmhelpers.core.host import mkdir
+
+try:
+    from bzrlib.branch import Branch
+except ImportError:
+    from charmhelpers.fetch import apt_install
+    apt_install("python-bzrlib")
+    from bzrlib.branch import Branch
+
+class BzrUrlFetchHandler(BaseFetchHandler):
+    """Handler for bazaar branches via generic and lp URLs"""
+    def can_handle(self, source):
+        url_parts = self.parse_url(source)
+        if url_parts.scheme not in ('bzr+ssh', 'lp'):
+            return False
+        else:
+            return True
+
+    def branch(self, source, dest):
+        url_parts = self.parse_url(source)
+        # If we use lp:branchname scheme we need to load plugins
+        if not self.can_handle(source):
+            raise UnhandledSource("Cannot handle {}".format(source))
+        if url_parts.scheme == "lp":
+            from bzrlib.plugin import load_plugins
+            load_plugins()
+        try:
+            remote_branch = Branch.open(source)
+            remote_branch.bzrdir.sprout(dest).open_branch()
+        except Exception as e:
+            raise e
+
+    def install(self, source):
+        url_parts = self.parse_url(source)
+        branch_name = url_parts.path.strip("/").split("/")[-1]
+        dest_dir = os.path.join(os.environ.get('CHARM_DIR'), "fetched", branch_name)
+        if not os.path.exists(dest_dir):
+            mkdir(dest_dir, perms=0755)
+        try:
+            self.branch(source, dest_dir)
+        except OSError as e:
+            raise UnhandledSource(e.strerror)
+        return dest_dir
+

From bf06ac13500af8577a4ee724f93a5b897df6b1d6 Mon Sep 17 00:00:00 2001
From: James Page <james.page@canonical.com>
Date: Wed, 13 Nov 2013 22:10:09 +0000
Subject: [PATCH 3/3] Resync with charm-helpers trunk

---
 charm-helpers-sync.yaml              |   2 +-
 hooks/charmhelpers/core/hookenv.py   | 101 +++++++++++++++++++++------
 hooks/charmhelpers/core/host.py      |  24 ++++---
 hooks/charmhelpers/fetch/__init__.py |  86 +++++++++++++++++++----
 hooks/charmhelpers/fetch/bzrurl.py   |   2 +-
 5 files changed, 169 insertions(+), 46 deletions(-)

diff --git a/charm-helpers-sync.yaml b/charm-helpers-sync.yaml
index 38dc4108..c8ee8f59 100644
--- a/charm-helpers-sync.yaml
+++ b/charm-helpers-sync.yaml
@@ -1,4 +1,4 @@
-branch: lp:~openstack-charmers/charm-helpers/os-alternatives
+branch: lp:charm-helpers
 destination: hooks/charmhelpers
 include:
     - core
diff --git a/hooks/charmhelpers/core/hookenv.py b/hooks/charmhelpers/core/hookenv.py
index 2b06706c..bb196dfa 100644
--- a/hooks/charmhelpers/core/hookenv.py
+++ b/hooks/charmhelpers/core/hookenv.py
@@ -9,6 +9,7 @@ import json
 import yaml
 import subprocess
 import UserDict
+from subprocess import CalledProcessError
 
 CRITICAL = "CRITICAL"
 ERROR = "ERROR"
@@ -21,7 +22,7 @@ cache = {}
 
 
 def cached(func):
-    ''' Cache return values for multiple executions of func + args
+    """Cache return values for multiple executions of func + args
 
     For example:
 
@@ -32,7 +33,7 @@ def cached(func):
         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 +47,8 @@ def cached(func):
 
 
 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:
@@ -57,7 +58,7 @@ def flush(key):
 
 
 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]
@@ -66,7 +67,7 @@ def log(message, level=None):
 
 
 class Serializable(UserDict.IterableUserDict):
-    "Wrapper, an object that can be serialized to yaml or json"
+    """Wrapper, an object that can be serialized to yaml or json"""
 
     def __init__(self, obj):
         # wrap the object
@@ -96,11 +97,11 @@ class Serializable(UserDict.IterableUserDict):
         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)
 
 
@@ -119,38 +120,38 @@ def execution_environment():
 
 
 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]
 
 
 @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)
@@ -163,6 +164,7 @@ def config(scope=None):
 
 @cached
 def relation_get(attribute=None, unit=None, rid=None):
+    """Get relation information"""
     _args = ['relation-get', '--format=json']
     if rid:
         _args.append('-r')
@@ -174,9 +176,14 @@ def relation_get(attribute=None, unit=None, rid=None):
         return json.loads(subprocess.check_output(_args))
     except ValueError:
         return None
+    except CalledProcessError, e:
+        if e.returncode == 2:
+            return None
+        raise
 
 
 def relation_set(relation_id=None, relation_settings={}, **kwargs):
+    """Set relation information for the current unit"""
     relation_cmd_line = ['relation-set']
     if relation_id is not None:
         relation_cmd_line.extend(('-r', relation_id))
@@ -192,7 +199,7 @@ def relation_set(relation_id=None, relation_settings={}, **kwargs):
 
 @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:
@@ -203,7 +210,7 @@ def relation_ids(reltype=None):
 
 @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:
@@ -213,7 +220,7 @@ def related_units(relid=None):
 
 @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 +232,7 @@ def relation_for_unit(unit=None, rid=None):
 
 @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 +244,7 @@ def relations_for_id(relid=None):
 
 @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):
@@ -249,7 +256,7 @@ def relations_of_type(reltype=None):
 
 @cached
 def relation_types():
-    "Get a list of relation types supported by this charm"
+    """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)
@@ -264,6 +271,7 @@ def relation_types():
 
 @cached
 def relations():
+    """Get a nested dictionary of relation data for all related units"""
     rels = {}
     for reltype in relation_types():
         relids = {}
@@ -277,15 +285,35 @@ def relations():
     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)
@@ -293,6 +321,7 @@ def close_port(port, protocol="TCP"):
 
 @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))
@@ -301,22 +330,46 @@ def unit_get(attribute):
 
 
 def unit_private_ip():
+    """Get this unit's private IP address"""
     return unit_get('private-address')
 
 
 class UnregisteredHookError(Exception):
+    """Raised when an undefined hook is called"""
     pass
 
 
 class Hooks(object):
+    """A convenient handler for hook functions.
+
+    Example:
+        hooks = Hooks()
+
+        # register a hook, taking its name from the function name
+        @hooks.hook()
+        def install():
+            ...
+
+        # register a hook, providing a custom hook name
+        @hooks.hook("config-changed")
+        def config_changed():
+            ...
+
+        if __name__ == "__main__":
+            # execute a hook based on the name the program is called by
+            hooks.execute(sys.argv)
+    """
+
     def __init__(self):
         super(Hooks, self).__init__()
         self._hooks = {}
 
     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]()
@@ -324,6 +377,7 @@ class Hooks(object):
             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 +391,5 @@ class Hooks(object):
 
 
 def charm_dir():
+    """Return the root directory of the current charm"""
     return os.environ.get('CHARM_DIR')
diff --git a/hooks/charmhelpers/core/host.py b/hooks/charmhelpers/core/host.py
index 1a63bf89..4a6a4a8c 100644
--- a/hooks/charmhelpers/core/host.py
+++ b/hooks/charmhelpers/core/host.py
@@ -19,18 +19,22 @@ from hookenv import log
 
 
 def service_start(service_name):
+    """Start a system service"""
     return service('start', service_name)
 
 
 def service_stop(service_name):
+    """Stop a system service"""
     return service('stop', service_name)
 
 
 def service_restart(service_name):
+    """Restart a system service"""
     return service('restart', service_name)
 
 
 def service_reload(service_name, restart_on_failure=False):
+    """Reload a system service, optionally falling back to restart if reload fails"""
     service_result = service('reload', service_name)
     if not service_result and restart_on_failure:
         service_result = service('restart', service_name)
@@ -38,11 +42,13 @@ def service_reload(service_name, restart_on_failure=False):
 
 
 def service(action, service_name):
+    """Control a system service"""
     cmd = ['service', service_name, action]
     return subprocess.call(cmd) == 0
 
 
 def service_running(service):
+    """Determine whether a system service is running"""
     try:
         output = subprocess.check_output(['service', service, 'status'])
     except subprocess.CalledProcessError:
@@ -55,7 +61,7 @@ def service_running(service):
 
 
 def adduser(username, password=None, shell='/bin/bash', system_user=False):
-    """Add a user"""
+    """Add a user to the system"""
     try:
         user_info = pwd.getpwnam(username)
         log('user {0} already exists!'.format(username))
@@ -138,7 +144,7 @@ def write_file(path, content, owner='root', group='root', perms=0444):
 
 
 def mount(device, mountpoint, options=None, persist=False):
-    '''Mount a filesystem'''
+    """Mount a filesystem at a particular mountpoint"""
     cmd_args = ['mount']
     if options is not None:
         cmd_args.extend(['-o', options])
@@ -155,7 +161,7 @@ def mount(device, mountpoint, options=None, persist=False):
 
 
 def umount(mountpoint, persist=False):
-    '''Unmount a filesystem'''
+    """Unmount a filesystem"""
     cmd_args = ['umount', mountpoint]
     try:
         subprocess.check_output(cmd_args)
@@ -169,7 +175,7 @@ def umount(mountpoint, persist=False):
 
 
 def mounts():
-    '''List of all mounted volumes as [[mountpoint,device],[...]]'''
+    """Get a list of all mounted volumes as [[mountpoint,device],[...]]"""
     with open('/proc/mounts') as f:
         # [['/mount/point','/dev/path'],[...]]
         system_mounts = [m[1::-1] for m in [l.strip().split()
@@ -178,7 +184,7 @@ def mounts():
 
 
 def file_hash(path):
-    ''' Generate a md5 hash of the contents of 'path' or None if not found '''
+    """Generate a md5 hash of the contents of 'path' or None if not found """
     if os.path.exists(path):
         h = hashlib.md5()
         with open(path, 'r') as source:
@@ -189,7 +195,7 @@ def file_hash(path):
 
 
 def restart_on_change(restart_map):
-    ''' Restart services based on configuration files changing
+    """Restart services based on configuration files changing
 
     This function is used a decorator, for example
 
@@ -202,7 +208,7 @@ def restart_on_change(restart_map):
     In this example, the cinder-api and cinder-volume services
     would be restarted if /etc/ceph/ceph.conf is changed by the
     ceph_client_changed function.
-    '''
+    """
     def wrap(f):
         def wrapped_f(*args):
             checksums = {}
@@ -220,7 +226,7 @@ def restart_on_change(restart_map):
 
 
 def lsb_release():
-    '''Return /etc/lsb-release in a dict'''
+    """Return /etc/lsb-release in a dict"""
     d = {}
     with open('/etc/lsb-release', 'r') as lsb:
         for l in lsb:
@@ -230,7 +236,7 @@ def lsb_release():
 
 
 def pwgen(length=None):
-    '''Generate a random pasword.'''
+    """Generate a random pasword."""
     if length is None:
         length = random.choice(range(35, 45))
     alphanumeric_chars = [
diff --git a/hooks/charmhelpers/fetch/__init__.py b/hooks/charmhelpers/fetch/__init__.py
index b2f96467..f83e7b7d 100644
--- a/hooks/charmhelpers/fetch/__init__.py
+++ b/hooks/charmhelpers/fetch/__init__.py
@@ -13,6 +13,7 @@ from charmhelpers.core.hookenv import (
     log,
 )
 import apt_pkg
+import os
 
 CLOUD_ARCHIVE = """# Ubuntu Cloud Archive
 deb http://ubuntu-cloud.archive.canonical.com/ubuntu {} main
@@ -20,6 +21,32 @@ deb http://ubuntu-cloud.archive.canonical.com/ubuntu {} main
 PROPOSED_POCKET = """# Proposed
 deb http://archive.ubuntu.com/ubuntu {}-proposed main universe multiverse restricted
 """
+CLOUD_ARCHIVE_POCKETS = {
+    # Folsom
+    'folsom': 'precise-updates/folsom',
+    'precise-folsom': 'precise-updates/folsom',
+    'precise-folsom/updates': 'precise-updates/folsom',
+    'precise-updates/folsom': 'precise-updates/folsom',
+    'folsom/proposed': 'precise-proposed/folsom',
+    'precise-folsom/proposed': 'precise-proposed/folsom',
+    'precise-proposed/folsom': 'precise-proposed/folsom',
+    # Grizzly
+    'grizzly': 'precise-updates/grizzly',
+    'precise-grizzly': 'precise-updates/grizzly',
+    'precise-grizzly/updates': 'precise-updates/grizzly',
+    'precise-updates/grizzly': 'precise-updates/grizzly',
+    'grizzly/proposed': 'precise-proposed/grizzly',
+    'precise-grizzly/proposed': 'precise-proposed/grizzly',
+    'precise-proposed/grizzly': 'precise-proposed/grizzly',
+    # Havana
+    'havana': 'precise-updates/havana',
+    'precise-havana': 'precise-updates/havana',
+    'precise-havana/updates': 'precise-updates/havana',
+    'precise-updates/havana': 'precise-updates/havana',
+    'havana/proposed': 'precise-proposed/havana',
+    'precies-havana/proposed': 'precise-proposed/havana',
+    'precise-proposed/havana': 'precise-proposed/havana',
+}
 
 
 def filter_installed_packages(packages):
@@ -40,8 +67,10 @@ def filter_installed_packages(packages):
 
 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):
@@ -50,10 +79,14 @@ def apt_install(packages, options=None, fatal=False):
         cmd.extend(packages)
     log("Installing {} with options: {}".format(packages,
                                                 options))
+    env = os.environ.copy()
+    if 'DEBIAN_FRONTEND' not in env:
+        env['DEBIAN_FRONTEND'] = 'noninteractive'
+
     if fatal:
-        subprocess.check_call(cmd)
+        subprocess.check_call(cmd, env=env)
     else:
-        subprocess.call(cmd)
+        subprocess.call(cmd, env=env)
 
 
 def apt_update(fatal=False):
@@ -67,7 +100,7 @@ def apt_update(fatal=False):
 
 def apt_purge(packages, fatal=False):
     """Purge one or more packages"""
-    cmd = ['apt-get', '-y', 'purge']
+    cmd = ['apt-get', '--assume-yes', 'purge']
     if isinstance(packages, basestring):
         cmd.append(packages)
     else:
@@ -79,16 +112,37 @@ def apt_purge(packages, fatal=False):
         subprocess.call(cmd)
 
 
+def apt_hold(packages, fatal=False):
+    """Hold one or more packages"""
+    cmd = ['apt-mark', 'hold']
+    if isinstance(packages, basestring):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+    log("Holding {}".format(packages))
+    if fatal:
+        subprocess.check_call(cmd)
+    else:
+        subprocess.call(cmd)
+
+
 def add_source(source, key=None):
-    if ((source.startswith('ppa:') or
-         source.startswith('http:'))):
+    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:
@@ -118,8 +172,11 @@ def configure_sources(update=False,
     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):
+    keys = config(keys_var)
+    if keys is not None:
+        keys = safe_load(keys)
+    if isinstance(sources, basestring) and (
+            keys is None or isinstance(keys, basestring)):
         add_source(sources, keys)
     else:
         if not len(sources) == len(keys):
@@ -172,7 +229,9 @@ def install_from_config(config_var_name):
 
 
 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"""
@@ -200,10 +259,13 @@ def plugins(fetch_handlers=None):
     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
diff --git a/hooks/charmhelpers/fetch/bzrurl.py b/hooks/charmhelpers/fetch/bzrurl.py
index c348b4bb..db5dd9a3 100644
--- a/hooks/charmhelpers/fetch/bzrurl.py
+++ b/hooks/charmhelpers/fetch/bzrurl.py
@@ -12,6 +12,7 @@ except ImportError:
     apt_install("python-bzrlib")
     from bzrlib.branch import Branch
 
+
 class BzrUrlFetchHandler(BaseFetchHandler):
     """Handler for bazaar branches via generic and lp URLs"""
     def can_handle(self, source):
@@ -46,4 +47,3 @@ class BzrUrlFetchHandler(BaseFetchHandler):
         except OSError as e:
             raise UnhandledSource(e.strerror)
         return dest_dir
-