Merge lp:~stub/charms/trusty/postgresql/rewrite-charmhelpers into lp:charms/trusty/postgresql

[Stuart Bishop]

Charmhelpers sync for lp:~stub/charms/trusty/postgresql/rewrite.

This branch contains charmhelpers updates, and not worth reviewing. It serves as a dependant branch to remove the noise from the main merge proposal.

[Charles Butler (lazypower)]

Stub,

I did a quick sanity check and found some proof/lint errors that were pre-existing. Unrelated to this merge +1 LGTM.

Merged and pushed, thanks for breaking apart the noise.

review: Approve

=== modified file 'charm-helpers.yaml'
--- charm-helpers.yaml	2015-06-25 11:39:19 +0000
+++ charm-helpers.yaml	2015-08-11 11:19:35 +0000
@@ -1,6 +1,9 @@
 destination: hooks/charmhelpers
 branch: lp:~stub/charm-helpers/integration
 include:
+    - context
     - coordinator
     - core
     - fetch
+    - payload
+    - contrib.charmsupport.nrpe

=== added file 'hooks/charmhelpers/context.py'
--- hooks/charmhelpers/context.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/context.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,206 @@
+# Copyright 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/>.
+'''
+A Pythonic API to interact with the charm hook environment.
+
+:author: Stuart Bishop <[e-mail]>
+'''
+
+import six
+
+from charmhelpers.core import hookenv
+
+from collections import OrderedDict
+if six.PY3:
+    from collections import UserDict  # pragma: nocover
+else:
+    from UserDict import IterableUserDict as UserDict  # pragma: nocover
+
+
+class Relations(OrderedDict):
+    '''Mapping relation name -> relation id -> Relation.
+
+    >>> rels = Relations()
+    >>> rels['sprog']['sprog:12']['client/6']['widget']
+    'remote widget'
+    >>> rels['sprog']['sprog:12'].local['widget'] = 'local widget'
+    >>> rels['sprog']['sprog:12'].local['widget']
+    'local widget'
+    >>> rels.peer.local['widget']
+    'local widget on the peer relation'
+    '''
+    def __init__(self):
+        super(Relations, self).__init__()
+        for relname in sorted(hookenv.relation_types()):
+            self[relname] = OrderedDict()
+            relids = hookenv.relation_ids(relname)
+            relids.sort(key=lambda x: int(x.split(':', 1)[-1]))
+            for relid in relids:
+                self[relname][relid] = Relation(relid)
+
+    @property
+    def peer(self):
+        peer_relid = hookenv.peer_relation_id()
+        for rels in self.values():
+            if peer_relid in rels:
+                return rels[peer_relid]
+
+
+class Relation(OrderedDict):
+    '''Mapping of unit -> remote RelationInfo for a relation.
+
+    This is an OrderedDict mapping, ordered numerically by
+    by unit number.
+
+    Also provides access to the local RelationInfo, and peer RelationInfo
+    instances by the 'local' and 'peers' attributes.
+
+    >>> r = Relation('sprog:12')
+    >>> r.keys()
+    ['client/9', 'client/10']     # Ordered numerically
+    >>> r['client/10']['widget']  # A remote RelationInfo setting
+    'remote widget'
+    >>> r.local['widget']         # The local RelationInfo setting
+    'local widget'
+    '''
+    relid = None    # The relation id.
+    relname = None  # The relation name (also known as relation type).
+    service = None  # The remote service name, if known.
+    local = None    # The local end's RelationInfo.
+    peers = None    # Map of peer -> RelationInfo. None if no peer relation.
+
+    def __init__(self, relid):
+        remote_units = hookenv.related_units(relid)
+        remote_units.sort(key=lambda u: int(u.split('/', 1)[-1]))
+        super(Relation, self).__init__((unit, RelationInfo(relid, unit))
+                                       for unit in remote_units)
+
+        self.relname = relid.split(':', 1)[0]
+        self.relid = relid
+        self.local = RelationInfo(relid, hookenv.local_unit())
+
+        for relinfo in self.values():
+            self.service = relinfo.service
+            break
+
+        # If we have peers, and they have joined both the provided peer
+        # relation and this relation, we can peek at their data too.
+        # This is useful for creating consensus without leadership.
+        peer_relid = hookenv.peer_relation_id()
+        if peer_relid and peer_relid != relid:
+            peers = hookenv.related_units(peer_relid)
+            if peers:
+                peers.sort(key=lambda u: int(u.split('/', 1)[-1]))
+                self.peers = OrderedDict((peer, RelationInfo(relid, peer))
+                                         for peer in peers)
+            else:
+                self.peers = OrderedDict()
+        else:
+            self.peers = None
+
+    def __str__(self):
+        return '{} ({})'.format(self.relid, self.service)
+
+
+class RelationInfo(UserDict):
+    '''The bag of data at an end of a relation.
+
+    Every unit participating in a relation has a single bag of
+    data associated with that relation. This is that bag.
+
+    The bag of data for the local unit may be updated. Remote data
+    is immutable and will remain static for the duration of the hook.
+
+    Changes made to the local units relation data only become visible
+    to other units after the hook completes successfully. If the hook
+    does not complete successfully, the changes are rolled back.
+
+    Unlike standard Python mappings, setting an item to None is the
+    same as deleting it.
+
+    >>> relinfo = RelationInfo('db:12')  # Default is the local unit.
+    >>> relinfo['user'] = 'fred'
+    >>> relinfo['user']
+    'fred'
+    >>> relinfo['user'] = None
+    >>> 'fred' in relinfo
+    False
+
+    This class wraps hookenv.relation_get and hookenv.relation_set.
+    All caching is left up to these two methods to avoid synchronization
+    issues. Data is only loaded on demand.
+    '''
+    relid = None    # The relation id.
+    relname = None  # The relation name (also know as the relation type).
+    unit = None     # The unit id.
+    number = None   # The unit number (integer).
+    service = None  # The service name.
+
+    def __init__(self, relid, unit):
+        self.relname = relid.split(':', 1)[0]
+        self.relid = relid
+        self.unit = unit
+        self.service, num = self.unit.split('/', 1)
+        self.number = int(num)
+
+    def __str__(self):
+        return '{} ({})'.format(self.relid, self.unit)
+
+    @property
+    def data(self):
+        return hookenv.relation_get(rid=self.relid, unit=self.unit)
+
+    def __setitem__(self, key, value):
+        if self.unit != hookenv.local_unit():
+            raise TypeError('Attempting to set {} on remote unit {}'
+                            ''.format(key, self.unit))
+        if value is not None and not isinstance(value, six.string_types):
+            # We don't do implicit casting. This would cause simple
+            # types like integers to be read back as strings in subsequent
+            # hooks, and mutable types would require a lot of wrapping
+            # to ensure relation-set gets called when they are mutated.
+            raise ValueError('Only string values allowed')
+        hookenv.relation_set(self.relid, {key: value})
+
+    def __delitem__(self, key):
+        # Deleting a key and setting it to null is the same thing in
+        # Juju relations.
+        self[key] = None
+
+
+class Leader(UserDict):
+    def __init__(self):
+        pass  # Don't call superclass initializer, as it will nuke self.data
+
+    @property
+    def data(self):
+        return hookenv.leader_get()
+
+    def __setitem__(self, key, value):
+        if not hookenv.is_leader():
+            raise TypeError('Not the leader. Cannot change leader settings.')
+        if value is not None and not isinstance(value, six.string_types):
+            # We don't do implicit casting. This would cause simple
+            # types like integers to be read back as strings in subsequent
+            # hooks, and mutable types would require a lot of wrapping
+            # to ensure leader-set gets called when they are mutated.
+            raise ValueError('Only string values allowed')
+        hookenv.leader_set({key: value})
+
+    def __delitem__(self, key):
+        # Deleting a key and setting it to null is the same thing in
+        # Juju leadership settings.
+        self[key] = None

=== added directory 'hooks/charmhelpers/contrib'
=== added file 'hooks/charmhelpers/contrib/__init__.py'
--- hooks/charmhelpers/contrib/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/__init__.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,15 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.

=== added directory 'hooks/charmhelpers/contrib/charmsupport'
=== added file 'hooks/charmhelpers/contrib/charmsupport/__init__.py'
--- hooks/charmhelpers/contrib/charmsupport/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/charmsupport/__init__.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,15 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.

=== added file 'hooks/charmhelpers/contrib/charmsupport/nrpe.py'
--- hooks/charmhelpers/contrib/charmsupport/nrpe.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/contrib/charmsupport/nrpe.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,360 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Compatibility with the nrpe-external-master charm"""
+# Copyright 2012 Canonical Ltd.
+#
+# Authors:
+#  Matthew Wedgwood <[e-mail]>
+
+import subprocess
+import pwd
+import grp
+import os
+import glob
+import shutil
+import re
+import shlex
+import yaml
+
+from charmhelpers.core.hookenv import (
+    config,
+    local_unit,
+    log,
+    relation_ids,
+    relation_set,
+    relations_of_type,
+)
+
+from charmhelpers.core.host import service
+
+# This module adds compatibility with the nrpe-external-master and plain nrpe
+# subordinate charms. To use it in your charm:
+#
+# 1. Update metadata.yaml
+#
+#   provides:
+#     (...)
+#     nrpe-external-master:
+#       interface: nrpe-external-master
+#       scope: container
+#
+#   and/or
+#
+#   provides:
+#     (...)
+#     local-monitors:
+#       interface: local-monitors
+#       scope: container
+
+#
+# 2. Add the following to config.yaml
+#
+#    nagios_context:
+#      default: "juju"
+#      type: string
+#      description: |
+#        Used by the nrpe subordinate charms.
+#        A string that will be prepended to instance name to set the host name
+#        in nagios. So for instance the hostname would be something like:
+#            juju-myservice-0
+#        If you're running multiple environments with the same services in them
+#        this allows you to differentiate between them.
+#    nagios_servicegroups:
+#      default: ""
+#      type: string
+#      description: |
+#        A comma-separated list of nagios servicegroups.
+#        If left empty, the nagios_context will be used as the servicegroup
+#
+# 3. Add custom checks (Nagios plugins) to files/nrpe-external-master
+#
+# 4. Update your hooks.py with something like this:
+#
+#    from charmsupport.nrpe import NRPE
+#    (...)
+#    def update_nrpe_config():
+#        nrpe_compat = NRPE()
+#        nrpe_compat.add_check(
+#            shortname = "myservice",
+#            description = "Check MyService",
+#            check_cmd = "check_http -w 2 -c 10 http://localhost"
+#            )
+#        nrpe_compat.add_check(
+#            "myservice_other",
+#            "Check for widget failures",
+#            check_cmd = "/srv/myapp/scripts/widget_check"
+#            )
+#        nrpe_compat.write()
+#
+#    def config_changed():
+#        (...)
+#        update_nrpe_config()
+#
+#    def nrpe_external_master_relation_changed():
+#        update_nrpe_config()
+#
+#    def local_monitors_relation_changed():
+#        update_nrpe_config()
+#
+# 5. ln -s hooks.py nrpe-external-master-relation-changed
+#    ln -s hooks.py local-monitors-relation-changed
+
+
+class CheckException(Exception):
+    pass
+
+
+class Check(object):
+    shortname_re = '[A-Za-z0-9-_]+$'
+    service_template = ("""
+#---------------------------------------------------
+# This file is Juju managed
+#---------------------------------------------------
+define service {{
+    use                             active-service
+    host_name                       {nagios_hostname}
+    service_description             {nagios_hostname}[{shortname}] """
+                        """{description}
+    check_command                   check_nrpe!{command}
+    servicegroups                   {nagios_servicegroup}
+}}
+""")
+
+    def __init__(self, shortname, description, check_cmd):
+        super(Check, self).__init__()
+        # XXX: could be better to calculate this from the service name
+        if not re.match(self.shortname_re, shortname):
+            raise CheckException("shortname must match {}".format(
+                Check.shortname_re))
+        self.shortname = shortname
+        self.command = "check_{}".format(shortname)
+        # Note: a set of invalid characters is defined by the
+        # Nagios server config
+        # The default is: illegal_object_name_chars=`~!$%^&*"|'<>?,()=
+        self.description = description
+        self.check_cmd = self._locate_cmd(check_cmd)
+
+    def _locate_cmd(self, check_cmd):
+        search_path = (
+            '/usr/lib/nagios/plugins',
+            '/usr/local/lib/nagios/plugins',
+        )
+        parts = shlex.split(check_cmd)
+        for path in search_path:
+            if os.path.exists(os.path.join(path, parts[0])):
+                command = os.path.join(path, parts[0])
+                if len(parts) > 1:
+                    command += " " + " ".join(parts[1:])
+                return command
+        log('Check command not found: {}'.format(parts[0]))
+        return ''
+
+    def write(self, nagios_context, hostname, nagios_servicegroups):
+        nrpe_check_file = '/etc/nagios/nrpe.d/{}.cfg'.format(
+            self.command)
+        with open(nrpe_check_file, 'w') as nrpe_check_config:
+            nrpe_check_config.write("# check {}\n".format(self.shortname))
+            nrpe_check_config.write("command[{}]={}\n".format(
+                self.command, self.check_cmd))
+
+        if not os.path.exists(NRPE.nagios_exportdir):
+            log('Not writing service config as {} is not accessible'.format(
+                NRPE.nagios_exportdir))
+        else:
+            self.write_service_config(nagios_context, hostname,
+                                      nagios_servicegroups)
+
+    def write_service_config(self, nagios_context, hostname,
+                             nagios_servicegroups):
+        for f in os.listdir(NRPE.nagios_exportdir):
+            if re.search('.*{}.cfg'.format(self.command), f):
+                os.remove(os.path.join(NRPE.nagios_exportdir, f))
+
+        templ_vars = {
+            'nagios_hostname': hostname,
+            'nagios_servicegroup': nagios_servicegroups,
+            'description': self.description,
+            'shortname': self.shortname,
+            'command': self.command,
+        }
+        nrpe_service_text = Check.service_template.format(**templ_vars)
+        nrpe_service_file = '{}/service__{}_{}.cfg'.format(
+            NRPE.nagios_exportdir, hostname, self.command)
+        with open(nrpe_service_file, 'w') as nrpe_service_config:
+            nrpe_service_config.write(str(nrpe_service_text))
+
+    def run(self):
+        subprocess.call(self.check_cmd)
+
+
+class NRPE(object):
+    nagios_logdir = '/var/log/nagios'
+    nagios_exportdir = '/var/lib/nagios/export'
+    nrpe_confdir = '/etc/nagios/nrpe.d'
+
+    def __init__(self, hostname=None):
+        super(NRPE, self).__init__()
+        self.config = config()
+        self.nagios_context = self.config['nagios_context']
+        if 'nagios_servicegroups' in self.config and self.config['nagios_servicegroups']:
+            self.nagios_servicegroups = self.config['nagios_servicegroups']
+        else:
+            self.nagios_servicegroups = self.nagios_context
+        self.unit_name = local_unit().replace('/', '-')
+        if hostname:
+            self.hostname = hostname
+        else:
+            self.hostname = "{}-{}".format(self.nagios_context, self.unit_name)
+        self.checks = []
+
+    def add_check(self, *args, **kwargs):
+        self.checks.append(Check(*args, **kwargs))
+
+    def write(self):
+        try:
+            nagios_uid = pwd.getpwnam('nagios').pw_uid
+            nagios_gid = grp.getgrnam('nagios').gr_gid
+        except:
+            log("Nagios user not set up, nrpe checks not updated")
+            return
+
+        if not os.path.exists(NRPE.nagios_logdir):
+            os.mkdir(NRPE.nagios_logdir)
+            os.chown(NRPE.nagios_logdir, nagios_uid, nagios_gid)
+
+        nrpe_monitors = {}
+        monitors = {"monitors": {"remote": {"nrpe": nrpe_monitors}}}
+        for nrpecheck in self.checks:
+            nrpecheck.write(self.nagios_context, self.hostname,
+                            self.nagios_servicegroups)
+            nrpe_monitors[nrpecheck.shortname] = {
+                "command": nrpecheck.command,
+            }
+
+        service('restart', 'nagios-nrpe-server')
+
+        monitor_ids = relation_ids("local-monitors") + \
+            relation_ids("nrpe-external-master")
+        for rid in monitor_ids:
+            relation_set(relation_id=rid, monitors=yaml.dump(monitors))
+
+
+def get_nagios_hostcontext(relation_name='nrpe-external-master'):
+    """
+    Query relation with nrpe subordinate, return the nagios_host_context
+
+    :param str relation_name: Name of relation nrpe sub joined to
+    """
+    for rel in relations_of_type(relation_name):
+        if 'nagios_hostname' in rel:
+            return rel['nagios_host_context']
+
+
+def get_nagios_hostname(relation_name='nrpe-external-master'):
+    """
+    Query relation with nrpe subordinate, return the nagios_hostname
+
+    :param str relation_name: Name of relation nrpe sub joined to
+    """
+    for rel in relations_of_type(relation_name):
+        if 'nagios_hostname' in rel:
+            return rel['nagios_hostname']
+
+
+def get_nagios_unit_name(relation_name='nrpe-external-master'):
+    """
+    Return the nagios unit name prepended with host_context if needed
+
+    :param str relation_name: Name of relation nrpe sub joined to
+    """
+    host_context = get_nagios_hostcontext(relation_name)
+    if host_context:
+        unit = "%s:%s" % (host_context, local_unit())
+    else:
+        unit = local_unit()
+    return unit
+
+
+def add_init_service_checks(nrpe, services, unit_name):
+    """
+    Add checks for each service in list
+
+    :param NRPE nrpe: NRPE object to add check to
+    :param list services: List of services to check
+    :param str unit_name: Unit name to use in check description
+    """
+    for svc in services:
+        upstart_init = '/etc/init/%s.conf' % svc
+        sysv_init = '/etc/init.d/%s' % svc
+        if os.path.exists(upstart_init):
+            nrpe.add_check(
+                shortname=svc,
+                description='process check {%s}' % unit_name,
+                check_cmd='check_upstart_job %s' % svc
+            )
+        elif os.path.exists(sysv_init):
+            cronpath = '/etc/cron.d/nagios-service-check-%s' % svc
+            cron_file = ('*/5 * * * * root '
+                         '/usr/local/lib/nagios/plugins/check_exit_status.pl '
+                         '-s /etc/init.d/%s status > '
+                         '/var/lib/nagios/service-check-%s.txt\n' % (svc,
+                                                                     svc)
+                         )
+            f = open(cronpath, 'w')
+            f.write(cron_file)
+            f.close()
+            nrpe.add_check(
+                shortname=svc,
+                description='process check {%s}' % unit_name,
+                check_cmd='check_status_file.py -f '
+                          '/var/lib/nagios/service-check-%s.txt' % svc,
+            )
+
+
+def copy_nrpe_checks():
+    """
+    Copy the nrpe checks into place
+
+    """
+    NAGIOS_PLUGINS = '/usr/local/lib/nagios/plugins'
+    nrpe_files_dir = os.path.join(os.getenv('CHARM_DIR'), 'hooks',
+                                  'charmhelpers', 'contrib', 'openstack',
+                                  'files')
+
+    if not os.path.exists(NAGIOS_PLUGINS):
+        os.makedirs(NAGIOS_PLUGINS)
+    for fname in glob.glob(os.path.join(nrpe_files_dir, "check_*")):
+        if os.path.isfile(fname):
+            shutil.copy2(fname,
+                         os.path.join(NAGIOS_PLUGINS, os.path.basename(fname)))
+
+
+def add_haproxy_checks(nrpe, unit_name):
+    """
+    Add checks for each service in list
+
+    :param NRPE nrpe: NRPE object to add check to
+    :param str unit_name: Unit name to use in check description
+    """
+    nrpe.add_check(
+        shortname='haproxy_servers',
+        description='Check HAProxy {%s}' % unit_name,
+        check_cmd='check_haproxy.sh')
+    nrpe.add_check(
+        shortname='haproxy_queue',
+        description='Check HAProxy queue depth {%s}' % unit_name,
+        check_cmd='check_haproxy_queue_depth.sh')

=== added file 'hooks/charmhelpers/core/files.py'
--- hooks/charmhelpers/core/files.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/core/files.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,45 @@
+#!/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/>.
+
+__author__ = 'Jorge Niedbalski <[e-mail]>'
+
+import os
+import subprocess
+
+
+def sed(filename, before, after, flags='g'):
+    """
+    Search and replaces the given pattern on filename.
+
+    :param filename: relative or absolute file path.
+    :param before: expression to be replaced (see 'man sed')
+    :param after: expression to replace with (see 'man sed')
+    :param flags: sed-compatible regex flags in example, to make
+    the  search and replace case insensitive, specify ``flags="i"``.
+    The ``g`` flag is always specified regardless, so you do not
+    need to remember to include it when overriding this parameter.
+    :returns: If the sed command exit code was zero then return,
+    otherwise raise CalledProcessError.
+    """
+    expression = r's/{0}/{1}/{2}'.format(before,
+                                         after, flags)
+
+    return subprocess.check_call(["sed", "-i", "-r", "-e",
+                                  expression,
+                                  os.path.expanduser(filename)])

=== modified file 'hooks/charmhelpers/core/hookenv.py'
--- hooks/charmhelpers/core/hookenv.py	2015-06-25 11:39:19 +0000
+++ hooks/charmhelpers/core/hookenv.py	2015-08-11 11:19:35 +0000
@@ -21,6 +21,7 @@
 #  Charm Helpers Developers <[e-mail]>
 
 from __future__ import print_function
+import copy
 from distutils.version import LooseVersion
 from functools import wraps
 import glob
@@ -263,7 +264,7 @@
         self.path = path or self.path
         with open(self.path) as f:
             self._prev_dict = json.load(f)
-        for k, v in self._prev_dict.items():
+        for k, v in copy.deepcopy(self._prev_dict).items():
             if k not in self:
                 self[k] = v
 
@@ -468,6 +469,19 @@
 
 
 @cached
+def peer_relation_id():
+    '''Get a peer relation id if a peer relation has been joined, else None.'''
+    md = metadata()
+    section = md.get('peers')
+    if section:
+        for key in section:
+            relids = relation_ids(key)
+            if relids:
+                return relids[0]
+    return None
+
+
+@cached
 def charm_name():
     """Get the name of the current charm as is specified on metadata.yaml"""
     return metadata().get('name')
@@ -691,6 +705,7 @@
 
 def translate_exc(from_exc, to_exc):
     def inner_translate_exc1(f):
+        @wraps(f)
         def inner_translate_exc2(*args, **kwargs):
             try:
                 return f(*args, **kwargs)
@@ -761,6 +776,7 @@
 
     This is useful for modules and classes to perform initialization
     and inject behavior. In particular:
+
         - Run common code before all of your hooks, such as logging
           the hook name or interesting relation data.
         - Defer object or module initialization that requires a hook

=== modified file 'hooks/charmhelpers/core/host.py'
--- hooks/charmhelpers/core/host.py	2015-06-25 07:56:30 +0000
+++ hooks/charmhelpers/core/host.py	2015-08-11 11:19:35 +0000
@@ -63,6 +63,36 @@
     return service_result
 
 
+def service_pause(service_name, init_dir=None):
+    """Pause a system service.
+
+    Stop it, and prevent it from starting again at boot."""
+    if init_dir is None:
+        init_dir = "/etc/init"
+    stopped = service_stop(service_name)
+    # XXX: Support systemd too
+    override_path = os.path.join(
+        init_dir, '{}.conf.override'.format(service_name))
+    with open(override_path, 'w') as fh:
+        fh.write("manual\n")
+    return stopped
+
+
+def service_resume(service_name, init_dir=None):
+    """Resume a system service.
+
+    Reenable starting again at boot. Start the service"""
+    # XXX: Support systemd too
+    if init_dir is None:
+        init_dir = "/etc/init"
+    override_path = os.path.join(
+        init_dir, '{}.conf.override'.format(service_name))
+    if os.path.exists(override_path):
+        os.unlink(override_path)
+    started = service_start(service_name)
+    return started
+
+
 def service(action, service_name):
     """Control a system service"""
     cmd = ['service', service_name, action]
@@ -140,11 +170,7 @@
 
 def add_user_to_group(username, group):
     """Add a user to a group"""
-    cmd = [
-        'gpasswd', '-a',
-        username,
-        group
-    ]
+    cmd = ['gpasswd', '-a', username, group]
     log("Adding user {} to group {}".format(username, group))
     subprocess.check_call(cmd)
 
@@ -466,3 +492,19 @@
 
 def lchownr(path, owner, group):
     chownr(path, owner, group, follow_links=False)
+
+
+def get_total_ram():
+    '''The total amount of system RAM in bytes.
+
+    This is what is reported by the OS, and may be overcommitted when
+    there are multiple containers hosted on the same machine.
+    '''
+    with open('/proc/meminfo', 'r') as f:
+        for line in f.readlines():
+            if line:
+                key, value, unit = line.split()
+                if key == 'MemTotal:':
+                    assert unit == 'kB', 'Unknown unit'
+                    return int(value) * 1024  # Classic, not KiB.
+        raise NotImplementedError()

=== modified file 'hooks/charmhelpers/core/services/helpers.py'
--- hooks/charmhelpers/core/services/helpers.py	2015-06-25 07:56:30 +0000
+++ hooks/charmhelpers/core/services/helpers.py	2015-08-11 11:19:35 +0000
@@ -239,12 +239,12 @@
     action.
 
     :param str source: The template source file, relative to
-    `$CHARM_DIR/templates`
-
+        `$CHARM_DIR/templates`
     :param str target: The target to write the rendered template to
     :param str owner: The owner of the rendered file
     :param str group: The group of the rendered file
     :param int perms: The permissions of the rendered file
+
     """
     def __init__(self, source, target,
                  owner='root', group='root', perms=0o444):

=== modified file 'hooks/charmhelpers/core/templating.py'
--- hooks/charmhelpers/core/templating.py	2015-06-25 07:56:30 +0000
+++ hooks/charmhelpers/core/templating.py	2015-08-11 11:19:35 +0000
@@ -64,5 +64,9 @@
                     level=hookenv.ERROR)
         raise e
     content = template.render(context)
-    host.mkdir(os.path.dirname(target), owner, group, perms=0o755)
+    target_dir = os.path.dirname(target)
+    if not os.path.exists(target_dir):
+        # This is a terrible default directory permission, as the file
+        # or its siblings will often contain secrets.
+        host.mkdir(os.path.dirname(target), owner, group, perms=0o755)
     host.write_file(target, content.encode(encoding), owner, group, perms)

=== modified file 'hooks/charmhelpers/fetch/__init__.py'
--- hooks/charmhelpers/fetch/__init__.py	2015-06-25 07:56:30 +0000
+++ hooks/charmhelpers/fetch/__init__.py	2015-08-11 11:19:35 +0000
@@ -215,19 +215,27 @@
     _run_apt_command(cmd, fatal)
 
 
+def apt_mark(packages, mark, fatal=False):
+    """Flag one or more packages using apt-mark"""
+    log("Marking {} as {}".format(packages, mark))
+    cmd = ['apt-mark', mark]
+    if isinstance(packages, six.string_types):
+        cmd.append(packages)
+    else:
+        cmd.extend(packages)
+
+    if fatal:
+        subprocess.check_call(cmd, universal_newlines=True)
+    else:
+        subprocess.call(cmd, universal_newlines=True)
+
+
 def apt_hold(packages, fatal=False):
-    """Hold one or more packages"""
-    cmd = ['apt-mark', 'hold']
-    if isinstance(packages, six.string_types):
-        cmd.append(packages)
-    else:
-        cmd.extend(packages)
-    log("Holding {}".format(packages))
-
-    if fatal:
-        subprocess.check_call(cmd)
-    else:
-        subprocess.call(cmd)
+    return apt_mark(packages, 'hold', fatal=fatal)
+
+
+def apt_unhold(packages, fatal=False):
+    return apt_mark(packages, 'unhold', fatal=fatal)
 
 
 def add_source(source, key=None):
@@ -370,8 +378,9 @@
     for handler in handlers:
         try:
             installed_to = handler.install(source, *args, **kwargs)
-        except UnhandledSource:
-            pass
+        except UnhandledSource as e:
+            log('Install source attempt unsuccessful: {}'.format(e),
+                level='WARNING')
     if not installed_to:
         raise UnhandledSource("No handler found for source {}".format(source))
     return installed_to

=== modified file 'hooks/charmhelpers/fetch/archiveurl.py'
--- hooks/charmhelpers/fetch/archiveurl.py	2015-06-25 07:56:30 +0000
+++ hooks/charmhelpers/fetch/archiveurl.py	2015-08-11 11:19:35 +0000
@@ -77,6 +77,8 @@
     def can_handle(self, source):
         url_parts = self.parse_url(source)
         if url_parts.scheme not in ('http', 'https', 'ftp', 'file'):
+            # XXX: Why is this returning a boolean and a string? It's
+            # doomed to fail since "bool(can_handle('foo://'))"  will be True.
             return "Wrong source type"
         if get_archive_handler(self.base_url(source)):
             return True
@@ -155,7 +157,11 @@
             else:
                 algorithms = hashlib.algorithms_available
             if key in algorithms:
-                check_hash(dld_file, value, key)
+                if len(value) != 1:
+                    raise TypeError(
+                        "Expected 1 hash value, not %d" % len(value))
+                expected = value[0]
+                check_hash(dld_file, expected, key)
         if checksum:
             check_hash(dld_file, checksum, hash_type)
         return extract(dld_file, dest)

=== modified file 'hooks/charmhelpers/fetch/giturl.py'
--- hooks/charmhelpers/fetch/giturl.py	2015-06-25 07:56:30 +0000
+++ hooks/charmhelpers/fetch/giturl.py	2015-08-11 11:19:35 +0000
@@ -67,7 +67,7 @@
         try:
             self.clone(source, dest_dir, branch, depth)
         except GitCommandError as e:
-            raise UnhandledSource(e.message)
+            raise UnhandledSource(e)
         except OSError as e:
             raise UnhandledSource(e.strerror)
         return dest_dir

=== added directory 'hooks/charmhelpers/payload'
=== added file 'hooks/charmhelpers/payload/__init__.py'
--- hooks/charmhelpers/payload/__init__.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/payload/__init__.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,17 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+"Tools for working with files injected into a charm just before deployment."

=== added file 'hooks/charmhelpers/payload/archive.py'
--- hooks/charmhelpers/payload/archive.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/payload/archive.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,73 @@
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import tarfile
+import zipfile
+from charmhelpers.core import (
+    host,
+    hookenv,
+)
+
+
+class ArchiveError(Exception):
+    pass
+
+
+def get_archive_handler(archive_name):
+    if os.path.isfile(archive_name):
+        if tarfile.is_tarfile(archive_name):
+            return extract_tarfile
+        elif zipfile.is_zipfile(archive_name):
+            return extract_zipfile
+    else:
+        # look at the file name
+        for ext in ('.tar', '.tar.gz', '.tgz', 'tar.bz2', '.tbz2', '.tbz'):
+            if archive_name.endswith(ext):
+                return extract_tarfile
+        for ext in ('.zip', '.jar'):
+            if archive_name.endswith(ext):
+                return extract_zipfile
+
+
+def archive_dest_default(archive_name):
+    archive_file = os.path.basename(archive_name)
+    return os.path.join(hookenv.charm_dir(), "archives", archive_file)
+
+
+def extract(archive_name, destpath=None):
+    handler = get_archive_handler(archive_name)
+    if handler:
+        if not destpath:
+            destpath = archive_dest_default(archive_name)
+        if not os.path.isdir(destpath):
+            host.mkdir(destpath)
+        handler(archive_name, destpath)
+        return destpath
+    else:
+        raise ArchiveError("No handler for archive")
+
+
+def extract_tarfile(archive_name, destpath):
+    "Unpack a tar archive, optionally compressed"
+    archive = tarfile.open(archive_name)
+    archive.extractall(destpath)
+
+
+def extract_zipfile(archive_name, destpath):
+    "Unpack a zip file"
+    archive = zipfile.ZipFile(archive_name)
+    archive.extractall(destpath)

=== added file 'hooks/charmhelpers/payload/execd.py'
--- hooks/charmhelpers/payload/execd.py	1970-01-01 00:00:00 +0000
+++ hooks/charmhelpers/payload/execd.py	2015-08-11 11:19:35 +0000
@@ -0,0 +1,66 @@
+#!/usr/bin/env python
+
+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import sys
+import subprocess
+from charmhelpers.core import hookenv
+
+
+def default_execd_dir():
+    return os.path.join(os.environ['CHARM_DIR'], 'exec.d')
+
+
+def execd_module_paths(execd_dir=None):
+    """Generate a list of full paths to modules within execd_dir."""
+    if not execd_dir:
+        execd_dir = default_execd_dir()
+
+    if not os.path.exists(execd_dir):
+        return
+
+    for subpath in os.listdir(execd_dir):
+        module = os.path.join(execd_dir, subpath)
+        if os.path.isdir(module):
+            yield module
+
+
+def execd_submodule_paths(command, execd_dir=None):
+    """Generate a list of full paths to the specified command within exec_dir.
+    """
+    for module_path in execd_module_paths(execd_dir):
+        path = os.path.join(module_path, command)
+        if os.access(path, os.X_OK) and os.path.isfile(path):
+            yield path
+
+
+def execd_run(command, execd_dir=None, die_on_error=False, stderr=None):
+    """Run command for each module within execd_dir which defines it."""
+    for submodule_path in execd_submodule_paths(command, execd_dir):
+        try:
+            subprocess.check_call(submodule_path, shell=True, stderr=stderr)
+        except subprocess.CalledProcessError as e:
+            hookenv.log("Error ({}) running  {}. Output: {}".format(
+                e.returncode, e.cmd, e.output))
+            if die_on_error:
+                sys.exit(e.returncode)
+
+
+def execd_preinstall(execd_dir=None):
+    """Run charm-pre-install for each module within execd_dir."""
+    execd_run('charm-pre-install', execd_dir=execd_dir)