Resync helpers

hooks/charmhelpers/contrib/hahelpers/cluster.py

@@ -170,6 +170,7 @@ def canonical_url(configs, vip_setting='vip', address=None):
 
     :configs    : OSTemplateRenderer: A config tempating object to inspect for
                                       a complete https context.
+
     :vip_setting:                str: Setting in charm config that specifies
                                       VIP address.
     '''

hooks/charmhelpers/contrib/network/ip.py

@@ -30,12 +30,12 @@ def get_address_in_network(network, fallback=None, fatal=False):
     """
     Get an IPv4 address within the network from the host.
 
-    Args:
-        network (str): CIDR presentation format. For example,
-                       '192.168.1.0/24'.
-        fallback (str): If no address is found, return fallback.
-        fatal (boolean): If no address is found, fallback is not
-                         set and fatal is True then exit(1).
+    :param network (str): CIDR presentation format. For example,
+        '192.168.1.0/24'.
+    :param fallback (str): If no address is found, return fallback.
+    :param fatal (boolean): If no address is found, fallback is not
+        set and fatal is True then exit(1).
+
     """
 
     def not_found_error_out():

hooks/charmhelpers/contrib/openstack/amulet/deployment.py

@@ -0,0 +1,38 @@
+from charmhelpers.contrib.amulet.deployment import (
+    AmuletDeployment
+)
+
+
+class OpenStackAmuletDeployment(AmuletDeployment):
+    """This class inherits from AmuletDeployment and has additional support
+       that is specifically for use by OpenStack charms."""
+
+    def __init__(self, series=None, openstack=None):
+        """Initialize the deployment environment."""
+        self.openstack = None
+        super(OpenStackAmuletDeployment, self).__init__(series)
+
+        if openstack:
+            self.openstack = openstack
+
+    def _configure_services(self, configs):
+        """Configure all of the services."""
+        for service, config in configs.iteritems():
+            if service == self.this_service:
+                config['openstack-origin'] = self.openstack
+            self.d.configure(service, config)
+
+    def _get_openstack_release(self):
+        """Return an integer representing the enum value of the openstack
+           release."""
+        self.precise_essex, self.precise_folsom, self.precise_grizzly, \
+            self.precise_havana, self.precise_icehouse, \
+            self.trusty_icehouse = range(6)
+        releases = {
+            ('precise', None): self.precise_essex,
+            ('precise', 'cloud:precise-folsom'): self.precise_folsom,
+            ('precise', 'cloud:precise-grizzly'): self.precise_grizzly,
+            ('precise', 'cloud:precise-havana'): self.precise_havana,
+            ('precise', 'cloud:precise-icehouse'): self.precise_icehouse,
+            ('trusty', None): self.trusty_icehouse}
+        return releases[(self.series, self.openstack)]

hooks/charmhelpers/contrib/openstack/amulet/utils.py

@@ -0,0 +1,209 @@
+import logging
+import os
+import time
+import urllib
+
+import glanceclient.v1.client as glance_client
+import keystoneclient.v2_0 as keystone_client
+import novaclient.v1_1.client as nova_client
+
+from charmhelpers.contrib.amulet.utils import (
+    AmuletUtils
+)
+
+DEBUG = logging.DEBUG
+ERROR = logging.ERROR
+
+
+class OpenStackAmuletUtils(AmuletUtils):
+    """This class inherits from AmuletUtils and has additional support
+       that is specifically for use by OpenStack charms."""
+
+    def __init__(self, log_level=ERROR):
+        """Initialize the deployment environment."""
+        super(OpenStackAmuletUtils, self).__init__(log_level)
+
+    def validate_endpoint_data(self, endpoints, admin_port, internal_port,
+                               public_port, expected):
+        """Validate actual endpoint data vs expected endpoint data. The ports
+           are used to find the matching endpoint."""
+        found = False
+        for ep in endpoints:
+            self.log.debug('endpoint: {}'.format(repr(ep)))
+            if admin_port in ep.adminurl and internal_port in ep.internalurl \
+               and public_port in ep.publicurl:
+                found = True
+                actual = {'id': ep.id,
+                          'region': ep.region,
+                          'adminurl': ep.adminurl,
+                          'internalurl': ep.internalurl,
+                          'publicurl': ep.publicurl,
+                          'service_id': ep.service_id}
+                ret = self._validate_dict_data(expected, actual)
+                if ret:
+                    return 'unexpected endpoint data - {}'.format(ret)
+
+        if not found:
+            return 'endpoint not found'
+
+    def validate_svc_catalog_endpoint_data(self, expected, actual):
+        """Validate a list of actual service catalog endpoints vs a list of
+           expected service catalog endpoints."""
+        self.log.debug('actual: {}'.format(repr(actual)))
+        for k, v in expected.iteritems():
+            if k in actual:
+                ret = self._validate_dict_data(expected[k][0], actual[k][0])
+                if ret:
+                    return self.endpoint_error(k, ret)
+            else:
+                return "endpoint {} does not exist".format(k)
+        return ret
+
+    def validate_tenant_data(self, expected, actual):
+        """Validate a list of actual tenant data vs list of expected tenant
+           data."""
+        self.log.debug('actual: {}'.format(repr(actual)))
+        for e in expected:
+            found = False
+            for act in actual:
+                a = {'enabled': act.enabled, 'description': act.description,
+                     'name': act.name, 'id': act.id}
+                if e['name'] == a['name']:
+                    found = True
+                    ret = self._validate_dict_data(e, a)
+                    if ret:
+                        return "unexpected tenant data - {}".format(ret)
+            if not found:
+                return "tenant {} does not exist".format(e.name)
+        return ret
+
+    def validate_role_data(self, expected, actual):
+        """Validate a list of actual role data vs a list of expected role
+           data."""
+        self.log.debug('actual: {}'.format(repr(actual)))
+        for e in expected:
+            found = False
+            for act in actual:
+                a = {'name': act.name, 'id': act.id}
+                if e['name'] == a['name']:
+                    found = True
+                    ret = self._validate_dict_data(e, a)
+                    if ret:
+                        return "unexpected role data - {}".format(ret)
+            if not found:
+                return "role {} does not exist".format(e.name)
+        return ret
+
+    def validate_user_data(self, expected, actual):
+        """Validate a list of actual user data vs a list of expected user
+           data."""
+        self.log.debug('actual: {}'.format(repr(actual)))
+        for e in expected:
+            found = False
+            for act in actual:
+                a = {'enabled': act.enabled, 'name': act.name,
+                     'email': act.email, 'tenantId': act.tenantId,
+                     'id': act.id}
+                if e['name'] == a['name']:
+                    found = True
+                    ret = self._validate_dict_data(e, a)
+                    if ret:
+                        return "unexpected user data - {}".format(ret)
+            if not found:
+                return "user {} does not exist".format(e.name)
+        return ret
+
+    def validate_flavor_data(self, expected, actual):
+        """Validate a list of actual flavors vs a list of expected flavors."""
+        self.log.debug('actual: {}'.format(repr(actual)))
+        act = [a.name for a in actual]
+        return self._validate_list_data(expected, act)
+
+    def tenant_exists(self, keystone, tenant):
+        """Return True if tenant exists"""
+        return tenant in [t.name for t in keystone.tenants.list()]
+
+    def authenticate_keystone_admin(self, keystone_sentry, user, password,
+                                    tenant):
+        """Authenticates admin user with the keystone admin endpoint."""
+        service_ip = \
+            keystone_sentry.relation('shared-db',
+                                     'mysql:shared-db')['private-address']
+        ep = "http://{}:35357/v2.0".format(service_ip.strip().decode('utf-8'))
+        return keystone_client.Client(username=user, password=password,
+                                      tenant_name=tenant, auth_url=ep)
+
+    def authenticate_keystone_user(self, keystone, user, password, tenant):
+        """Authenticates a regular user with the keystone public endpoint."""
+        ep = keystone.service_catalog.url_for(service_type='identity',
+                                              endpoint_type='publicURL')
+        return keystone_client.Client(username=user, password=password,
+                                      tenant_name=tenant, auth_url=ep)
+
+    def authenticate_glance_admin(self, keystone):
+        """Authenticates admin user with glance."""
+        ep = keystone.service_catalog.url_for(service_type='image',
+                                              endpoint_type='adminURL')
+        return glance_client.Client(ep, token=keystone.auth_token)
+
+    def authenticate_nova_user(self, keystone, user, password, tenant):
+        """Authenticates a regular user with nova-api."""
+        ep = keystone.service_catalog.url_for(service_type='identity',
+                                              endpoint_type='publicURL')
+        return nova_client.Client(username=user, api_key=password,
+                                  project_id=tenant, auth_url=ep)
+
+    def create_cirros_image(self, glance, image_name):
+        """Download the latest cirros image and upload it to glance."""
+        http_proxy = os.getenv('AMULET_HTTP_PROXY')
+        self.log.debug('AMULET_HTTP_PROXY: {}'.format(http_proxy))
+        if http_proxy:
+            proxies = {'http': http_proxy}
+            opener = urllib.FancyURLopener(proxies)
+        else:
+            opener = urllib.FancyURLopener()
+
+        f = opener.open("http://download.cirros-cloud.net/version/released")
+        version = f.read().strip()
+        cirros_img = "tests/cirros-{}-x86_64-disk.img".format(version)
+
+        if not os.path.exists(cirros_img):
+            cirros_url = "http://{}/{}/{}".format("download.cirros-cloud.net",
+                                                  version, cirros_img)
+            opener.retrieve(cirros_url, cirros_img)
+        f.close()
+
+        with open(cirros_img) as f:
+            image = glance.images.create(name=image_name, is_public=True,
+                                         disk_format='qcow2',
+                                         container_format='bare', data=f)
+        return image
+
+    def delete_image(self, glance, image):
+        """Delete the specified image."""
+        glance.images.delete(image)
+
+    def create_instance(self, nova, image_name, instance_name, flavor):
+        """Create the specified instance."""
+        image = nova.images.find(name=image_name)
+        flavor = nova.flavors.find(name=flavor)
+        instance = nova.servers.create(name=instance_name, image=image,
+                                       flavor=flavor)
+
+        count = 1
+        status = instance.status
+        while status == 'BUILD' and count < 10:
+            time.sleep(5)
+            instance = nova.servers.get(instance.id)
+            status = instance.status
+            self.log.debug('instance status: {}'.format(status))
+            count += 1
+
+        if status == 'BUILD':
+            return None
+
+        return instance
+
+    def delete_instance(self, nova, instance):
+        """Delete the specified instance."""
+        nova.servers.delete(instance)

hooks/charmhelpers/contrib/openstack/context.py

@@ -243,23 +243,31 @@ class IdentityServiceContext(OSContextGenerator):
 
 
 class AMQPContext(OSContextGenerator):
-    interfaces = ['amqp']
 
-    def __init__(self, ssl_dir=None):
+    def __init__(self, ssl_dir=None, rel_name='amqp', relation_prefix=None):
         self.ssl_dir = ssl_dir
+        self.rel_name = rel_name
+        self.relation_prefix = relation_prefix
+        self.interfaces = [rel_name]
 
     def __call__(self):
         log('Generating template context for amqp')
         conf = config()
+        user_setting = 'rabbit-user'
+        vhost_setting = 'rabbit-vhost'
+        if self.relation_prefix:
+            user_setting = self.relation_prefix + '-rabbit-user'
+            vhost_setting = self.relation_prefix + '-rabbit-vhost'
+
         try:
-            username = conf['rabbit-user']
-            vhost = conf['rabbit-vhost']
+            username = conf[user_setting]
+            vhost = conf[vhost_setting]
         except KeyError as e:
             log('Could not generate shared_db context. '
                 'Missing required charm config options: %s.' % e)
             raise OSContextError
         ctxt = {}
-        for rid in relation_ids('amqp'):
+        for rid in relation_ids(self.rel_name):
             ha_vip_only = False
             for unit in related_units(rid):
                 if relation_get('clustered', rid=rid, unit=unit):
@@ -420,12 +428,13 @@ class ApacheSSLContext(OSContextGenerator):
     """
     Generates a context for an apache vhost configuration that configures
     HTTPS reverse proxying for one or many endpoints.  Generated context
-    looks something like:
-    {
-        'namespace': 'cinder',
-        'private_address': 'iscsi.mycinderhost.com',
-        'endpoints': [(8776, 8766), (8777, 8767)]
-    }
+    looks something like::
+
+        {
+            'namespace': 'cinder',
+            'private_address': 'iscsi.mycinderhost.com',
+            'endpoints': [(8776, 8766), (8777, 8767)]
+        }
 
     The endpoints list consists of a tuples mapping external ports
     to internal ports.
@@ -543,6 +552,26 @@ class NeutronContext(OSContextGenerator):
 
         return nvp_ctxt
 
+    def n1kv_ctxt(self):
+        driver = neutron_plugin_attribute(self.plugin, 'driver',
+                                          self.network_manager)
+        n1kv_config = neutron_plugin_attribute(self.plugin, 'config',
+                                               self.network_manager)
+        n1kv_ctxt = {
+            'core_plugin': driver,
+            'neutron_plugin': 'n1kv',
+            'neutron_security_groups': self.neutron_security_groups,
+            'local_ip': unit_private_ip(),
+            'config': n1kv_config,
+            'vsm_ip': config('n1kv-vsm-ip'),
+            'vsm_username': config('n1kv-vsm-username'),
+            'vsm_password': config('n1kv-vsm-password'),
+            'restrict_policy_profiles': config(
+                'n1kv_restrict_policy_profiles'),
+        }
+
+        return n1kv_ctxt
+
     def neutron_ctxt(self):
         if https():
             proto = 'https'
@@ -574,6 +603,8 @@ class NeutronContext(OSContextGenerator):
             ctxt.update(self.ovs_ctxt())
         elif self.plugin in ['nvp', 'nsx']:
             ctxt.update(self.nvp_ctxt())
+        elif self.plugin == 'n1kv':
+            ctxt.update(self.n1kv_ctxt())
 
         alchemy_flags = config('neutron-alchemy-flags')
         if alchemy_flags:
@@ -613,7 +644,7 @@ class SubordinateConfigContext(OSContextGenerator):
     The subordinate interface allows subordinates to export their
     configuration requirements to the principle for multiple config
     files and multiple serivces.  Ie, a subordinate that has interfaces
-    to both glance and nova may export to following yaml blob as json:
+    to both glance and nova may export to following yaml blob as json::
 
         glance:
             /etc/glance/glance-api.conf:
@@ -632,7 +663,8 @@ class SubordinateConfigContext(OSContextGenerator):
 
     It is then up to the principle charms to subscribe this context to
     the service+config file it is interestd in.  Configuration data will
-    be available in the template context, in glance's case, as:
+    be available in the template context, in glance's case, as::
+
         ctxt = {
             ... other context ...
             'subordinate_config': {

hooks/charmhelpers/contrib/openstack/neutron.py

@@ -128,6 +128,20 @@ def neutron_plugins():
             'server_packages': ['neutron-server',
                                 'neutron-plugin-vmware'],
             'server_services': ['neutron-server']
+        },
+        'n1kv': {
+            'config': '/etc/neutron/plugins/cisco/cisco_plugins.ini',
+            'driver': 'neutron.plugins.cisco.network_plugin.PluginV2',
+            'contexts': [
+                context.SharedDBContext(user=config('neutron-database-user'),
+                                        database=config('neutron-database'),
+                                        relation_prefix='neutron',
+                                        ssl_dir=NEUTRON_CONF_DIR)],
+            'services': [],
+            'packages': [['neutron-plugin-cisco']],
+            'server_packages': ['neutron-server',
+                                'neutron-plugin-cisco'],
+            'server_services': ['neutron-server']
         }
     }
     if release >= 'icehouse':

hooks/charmhelpers/contrib/openstack/templating.py

@@ -30,17 +30,17 @@ def get_loader(templates_dir, os_release):
     loading dir.
 
     A charm may also ship a templates dir with this module
-    and it will be appended to the bottom of the search list, eg:
-    hooks/charmhelpers/contrib/openstack/templates.
+    and it will be appended to the bottom of the search list, eg::
 
-    :param templates_dir: str: Base template directory containing release
-                               sub-directories.
-    :param os_release   : str: OpenStack release codename to construct template
-                               loader.
+        hooks/charmhelpers/contrib/openstack/templates
 
-    :returns            : jinja2.ChoiceLoader constructed with a list of
-                          jinja2.FilesystemLoaders, ordered in descending
-                          order by OpenStack release.
+    :param templates_dir (str): Base template directory containing release
+        sub-directories.
+    :param os_release (str): OpenStack release codename to construct template
+        loader.
+    :returns: jinja2.ChoiceLoader constructed with a list of
+        jinja2.FilesystemLoaders, ordered in descending
+        order by OpenStack release.
     """
     tmpl_dirs = [(rel, os.path.join(templates_dir, rel))
                  for rel in OPENSTACK_CODENAMES.itervalues()]
@@ -111,7 +111,8 @@ class OSConfigRenderer(object):
     and ease the burden of managing config templates across multiple OpenStack
     releases.
 
-    Basic usage:
+    Basic usage::
+
         # import some common context generates from charmhelpers
         from charmhelpers.contrib.openstack import context
 
@@ -131,21 +132,19 @@ class OSConfigRenderer(object):
         # write out all registered configs
         configs.write_all()
 
-    Details:
+    **OpenStack Releases and template loading**
 
-    OpenStack Releases and template loading
-    ---------------------------------------
     When the object is instantiated, it is associated with a specific OS
     release.  This dictates how the template loader will be constructed.
 
     The constructed loader attempts to load the template from several places
     in the following order:
-        - from the most recent OS release-specific template dir (if one exists)
-        - the base templates_dir
-        - a template directory shipped in the charm with this helper file.
+    - from the most recent OS release-specific template dir (if one exists)
+    - the base templates_dir
+    - a template directory shipped in the charm with this helper file.
 
+    For the example above, '/tmp/templates' contains the following structure::
 
-    For the example above, '/tmp/templates' contains the following structure:
         /tmp/templates/nova.conf
         /tmp/templates/api-paste.ini
         /tmp/templates/grizzly/api-paste.ini
@@ -169,8 +168,8 @@ class OSConfigRenderer(object):
     $CHARM/hooks/charmhelpers/contrib/openstack/templates.  This allows
     us to ship common templates (haproxy, apache) with the helpers.
 
-    Context generators
-    ---------------------------------------
+    **Context generators**
+
     Context generators are used to generate template contexts during hook
     execution.  Doing so may require inspecting service relations, charm
     config, etc.  When registered, a config file is associated with a list

hooks/charmhelpers/contrib/openstack/utils.py

@@ -3,7 +3,6 @@
 # Common python helper functions used for OpenStack charms.
 from collections import OrderedDict
 
-import apt_pkg as apt
 import subprocess
 import os
 import socket
@@ -85,6 +84,8 @@ def get_os_codename_install_source(src):
     '''Derive OpenStack release codename from a given installation source.'''
     ubuntu_rel = lsb_release()['DISTRIB_CODENAME']
     rel = ''
+    if src is None:
+        return rel
     if src in ['distro', 'distro-proposed']:
         try:
             rel = UBUNTU_OPENSTACK_RELEASE[ubuntu_rel]
@@ -132,6 +133,7 @@ def get_os_version_codename(codename):
 
 def get_os_codename_package(package, fatal=True):
     '''Derive OpenStack release codename from an installed package.'''
+    import apt_pkg as apt
     apt.init()
 
     # Tell apt to build an in-memory cache to prevent race conditions (if
@@ -189,7 +191,7 @@ def get_os_version_package(pkg, fatal=True):
     for version, cname in vers_map.iteritems():
         if cname == codename:
             return version
-    #e = "Could not determine OpenStack version for package: %s" % pkg
+    # e = "Could not determine OpenStack version for package: %s" % pkg
     # error_out(e)
 
 
@@ -325,6 +327,7 @@ def openstack_upgrade_available(package):
 
     """
 
+    import apt_pkg as apt
     src = config('openstack-origin')
     cur_vers = get_os_version_package(package)
     available_vers = get_os_version_install_source(src)

hooks/charmhelpers/contrib/storage/linux/ceph.py

@@ -303,7 +303,7 @@ def ensure_ceph_storage(service, pool, rbd_img, sizemb, mount_point,
                         blk_device, fstype, system_services=[]):
     """
     NOTE: This function must only be called from a single service unit for
-          the same rbd_img otherwise data loss will occur.
+    the same rbd_img otherwise data loss will occur.
 
     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.

hooks/charmhelpers/contrib/storage/linux/utils.py

@@ -37,6 +37,7 @@ def zap_disk(block_device):
     check_call(['dd', 'if=/dev/zero', 'of=%s' % (block_device),
                 'bs=512', 'count=100', 'seek=%s' % (gpt_end)])
 
+
 def is_device_mounted(device):
     '''Given a device path, return True if that device is mounted, and False
     if it isn't.

hooks/charmhelpers/core/fstab.py

@@ -48,9 +48,11 @@ class Fstab(file):
         file.__init__(self, self._path, 'r+')
 
     def _hydrate_entry(self, line):
+        # NOTE: use split with no arguments to split on any
+        #       whitespace including tabs
         return Fstab.Entry(*filter(
             lambda x: x not in ('', None),
-            line.strip("\n").split(" ")))
+            line.strip("\n").split()))
 
     @property
     def entries(self):

hooks/charmhelpers/core/hookenv.py

@@ -25,7 +25,7 @@ cache = {}
 def cached(func):
     """Cache return values for multiple executions of func + args
 
-    For example:
+    For example::
 
         @cached
         def unit_get(attribute):
@@ -445,18 +445,19 @@ class UnregisteredHookError(Exception):
 class Hooks(object):
     """A convenient handler for hook functions.
 
-    Example:
+    Example::
+
         hooks = Hooks()
 
         # register a hook, taking its name from the function name
         @hooks.hook()
         def install():
-            ...
+            pass  # your code here
 
         # register a hook, providing a custom hook name
         @hooks.hook("config-changed")
         def config_changed():
-            ...
+            pass  # your code here
 
         if __name__ == "__main__":
             # execute a hook based on the name the program is called by

hooks/charmhelpers/core/host.py

@@ -12,7 +12,6 @@ import random
 import string
 import subprocess
 import hashlib
-import apt_pkg
 
 from collections import OrderedDict
 
@@ -212,13 +211,13 @@ def file_hash(path):
 def restart_on_change(restart_map, stopstart=False):
     """Restart services based on configuration files changing
 
-    This function is used a decorator, for example
+    This function is used a decorator, for example::
 
         @restart_on_change({
             '/etc/ceph/ceph.conf': [ 'cinder-api', 'cinder-volume' ]
             })
         def ceph_client_changed():
-            ...
+            pass  # your code here
 
     In this example, the cinder-api and cinder-volume services
     would be restarted if /etc/ceph/ceph.conf is changed by the
@@ -314,10 +313,13 @@ def get_nic_hwaddr(nic):
 
 def cmp_pkgrevno(package, revno, pkgcache=None):
     '''Compare supplied revno with the revno of the installed package
-       1 => Installed revno is greater than supplied arg
-       0 => Installed revno is the same as supplied arg
-      -1 => Installed revno is less than supplied arg
+
+    *  1 => Installed revno is greater than supplied arg
+    *  0 => Installed revno is the same as supplied arg
+    * -1 => Installed revno is less than supplied arg
+
     '''
+    import apt_pkg
     if not pkgcache:
         apt_pkg.init()
         pkgcache = apt_pkg.Cache()

hooks/charmhelpers/fetch/__init__.py

@@ -13,7 +13,6 @@ from charmhelpers.core.hookenv import (
     config,
     log,
 )
-import apt_pkg
 import os
 
 
@@ -117,6 +116,7 @@ class BaseFetchHandler(object):
 
 def filter_installed_packages(packages):
     """Returns a list of packages that require installation"""
+    import apt_pkg
     apt_pkg.init()
 
     # Tell apt to build an in-memory cache to prevent race conditions (if
@@ -235,31 +235,39 @@ def configure_sources(update=False,
                       sources_var='install_sources',
                       keys_var='install_keys'):
     """
-    Configure multiple sources from charm configuration
+    Configure multiple sources from charm configuration.
+
+    The lists are encoded as yaml fragments in the configuration.
+    The frament needs to be included as a string.
 
     Example config:
-        install_sources:
+        install_sources: |
           - "ppa:foo"
           - "http://example.com/repo precise main"
-        install_keys:
+        install_keys: |
           - null
           - "a1b2c3d4"
 
     Note that 'null' (a.k.a. None) should not be quoted.
     """
-    sources = safe_load(config(sources_var))
-    keys = 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)
+    sources = safe_load((config(sources_var) or '').strip()) or []
+    keys = safe_load((config(keys_var) or '').strip()) or None
+
+    if isinstance(sources, basestring):
+        sources = [sources]
+
+    if keys is None:
+        for source in sources:
+            add_source(source, None)
     else:
-        if not len(sources) == len(keys):
-            msg = 'Install sources and keys lists are different lengths'
-            raise SourceConfigError(msg)
-        for src_num in range(len(sources)):
-            add_source(sources[src_num], keys[src_num])
+        if isinstance(keys, basestring):
+            keys = [keys]
+
+        if len(sources) != len(keys):
+            raise SourceConfigError(
+                'Install sources and keys lists are different lengths')
+        for source, key in zip(sources, keys):
+            add_source(source, key)
     if update:
         apt_update(fatal=True)