[freyes,r=hopem]

Install python-memcache, configure nova.conf adding the key
memcached_servers when a relationship with memcached service
is established.

If multiple units of memcached are available, all of them
are used i.e. memcached_servers = host1:port1,host2:port,host3:port3

To secure memcached access this relies in the memcached charm
ability to use iptables rules to only allow access to related
machines.

Closes-Bug: 1386271

hooks/memcache-relation-broken

@@ -0,0 +1 @@
+nova_cc_hooks.py

hooks/memcache-relation-changed

@@ -0,0 +1 @@
+nova_cc_hooks.py

hooks/memcache-relation-departed

@@ -0,0 +1 @@
+nova_cc_hooks.py

hooks/memcache-relation-joined

@@ -0,0 +1 @@
+nova_cc_hooks.py

hooks/nova_cc_context.py

@@ -6,6 +6,7 @@ from charmhelpers.core.hookenv import (
     ERROR,
     unit_get,
     related_units,
+    relations_for_id,
     relation_get,
 )
 from charmhelpers.fetch import (
@@ -299,3 +300,24 @@ class NovaIPv6Context(context.BindHostContext):
         ctxt = super(NovaIPv6Context, self).__call__()
         ctxt['use_ipv6'] = config('prefer-ipv6')
         return ctxt
+
+
+class InstanceConsoleContext(context.OSContextGenerator):
+    interfaces = []
+
+    def __call__(self):
+        ctxt = {}
+        servers = []
+        try:
+            for rid in relation_ids('memcache'):
+                for rel in relations_for_id(rid):
+                    priv_addr = rel['private-address']
+                    # Format it as IPv6 address if needed
+                    priv_addr = format_ipv6_addr(priv_addr) or priv_addr
+                    servers.append("%s:%s" % (priv_addr, rel['port']))
+        except Exception as ex:
+            log("Could not get memcache servers: %s" % (ex), level='WARNING')
+            servers = []
+
+        ctxt['memcached_servers'] = ','.join(servers)
+        return ctxt

hooks/nova_cc_hooks.py

@@ -849,6 +849,15 @@ def neutron_api_relation_broken():
         quantum_joined(rid=rid)
 
 
+@hooks.hook('memcache-relation-joined',
+            'memcache-relation-departed',
+            'memcache-relation-changed',
+            'memcache-relation-broken')
+@restart_on_change(restart_map())
+def memcached_joined():
+    CONFIGS.write(NOVA_CONF)
+
+
 def main():
     try:
         hooks.execute(sys.argv)

hooks/nova_cc_utils.py

@@ -69,6 +69,7 @@ BASE_PACKAGES = [
     'python-psutil',
     'python-six',
     'uuid',
+    'python-memcache',
 ]
 
 BASE_SERVICES = [
@@ -124,7 +125,8 @@ BASE_RESOURCE_MAP = OrderedDict([
                      nova_cc_context.VolumeServiceContext(),
                      nova_cc_context.NovaIPv6Context(),
                      nova_cc_context.NeutronCCContext(),
-                     nova_cc_context.NovaConfigContext()],
+                     nova_cc_context.NovaConfigContext(),
+                     nova_cc_context.InstanceConsoleContext()],
     }),
     (NOVA_API_PASTE, {
         'services': [s for s in BASE_SERVICES if 'api' in s],

metadata.yaml

@@ -40,6 +40,8 @@ requires:
   nova-vmware:
     interface: nova-vmware
     scope: container
+  memcache:
+    interface: memcache
 peers:
   cluster:
     interface: nova-ha

templates/folsom/nova.conf

@@ -21,6 +21,11 @@ volumes_path=/var/lib/nova/volumes
 enabled_apis=ec2,osapi_compute,metadata
 auth_strategy=keystone
 compute_driver=libvirt.LibvirtDriver
+
+{% if memcached_servers %}
+memcached_servers = {{ memcached_servers }}
+{% endif %}
+
 {% if keystone_ec2_url -%}
 keystone_ec2_url = {{ keystone_ec2_url }}
 {% endif -%}

templates/grizzly/nova.conf

@@ -20,6 +20,11 @@ volumes_path=/var/lib/nova/volumes
 enabled_apis=ec2,osapi_compute,metadata
 auth_strategy=keystone
 compute_driver=libvirt.LibvirtDriver
+
+{% if memcached_servers %}
+memcached_servers = {{ memcached_servers }}
+{% endif %}
+
 {% if keystone_ec2_url -%}
 keystone_ec2_url = {{ keystone_ec2_url }}
 {% endif -%}

templates/havana/nova.conf

@@ -27,6 +27,10 @@ cpu_allocation_ratio = {{ cpu_allocation_ratio }}
 use_syslog={{ use_syslog }}
 my_ip = {{ host_ip }}
 
+{% if memcached_servers %}
+memcached_servers = {{ memcached_servers }}
+{% endif %}
+
 {% if keystone_ec2_url -%}
 keystone_ec2_url = {{ keystone_ec2_url }}
 {% endif -%}

templates/icehouse/nova.conf

@@ -38,6 +38,10 @@ ram_allocation_ratio = {{ ram_allocation_ratio }}
 use_syslog={{ use_syslog }}
 my_ip = {{ host_ip }}
 
+{% if memcached_servers %}
+memcached_servers = {{ memcached_servers }}
+{% endif %}
+
 {% if keystone_ec2_url -%}
 keystone_ec2_url = {{ keystone_ec2_url }}
 {% endif -%}

unit_tests/test_nova_cc_contexts.py

@@ -0,0 +1,87 @@
+from __future__ import print_function
+
+import mock
+
+#####
+# NOTE(freyes): this is a workaround to patch config() function imported by
+# nova_cc_utils before it gets a reference to the actual config() provided by
+# hookenv module.
+from charmhelpers.core import hookenv
+_conf = hookenv.config
+hookenv.config = mock.MagicMock()
+import nova_cc_utils as _utils
+# this assert is a double check + to avoid pep8 warning
+assert _utils.config == hookenv.config
+hookenv.config = _conf
+#####
+
+import nova_cc_context as context
+
+from charmhelpers.contrib.openstack import utils
+
+from test_utils import CharmTestCase
+
+
+TO_PATCH = [
+    'apt_install',
+    'filter_installed_packages',
+    'relation_ids',
+    'relation_get',
+    'related_units',
+    'config',
+    'log',
+    'unit_get',
+    'relations_for_id',
+]
+
+
+def fake_log(msg, level=None):
+    level = level or 'INFO'
+    print('[juju test log (%s)] %s' % (level, msg))
+
+
+class NovaComputeContextTests(CharmTestCase):
+    def setUp(self):
+        super(NovaComputeContextTests, self).setUp(context, TO_PATCH)
+        self.relation_get.side_effect = self.test_relation.get
+        self.config.side_effect = self.test_config.get
+        self.log.side_effect = fake_log
+
+    @mock.patch.object(utils, 'os_release')
+    @mock.patch('charmhelpers.contrib.network.ip.log')
+    def test_instance_console_context_without_memcache(self, os_release, log_):
+        self.unit_get.return_value = '127.0.0.1'
+        self.relation_ids.return_value = 'cache:0'
+        self.related_units.return_value = 'memcached/0'
+        instance_console = context.InstanceConsoleContext()
+        os_release.return_value = 'icehouse'
+        self.assertEqual({'memcached_servers': ''},
+                         instance_console())
+
+    @mock.patch.object(utils, 'os_release')
+    @mock.patch('charmhelpers.contrib.network.ip.log')
+    def test_instance_console_context_with_memcache(self, os_release, log_):
+        self.check_instance_console_context_with_memcache(os_release,
+                                                          '127.0.1.1',
+                                                          '127.0.1.1')
+
+    @mock.patch.object(utils, 'os_release')
+    @mock.patch('charmhelpers.contrib.network.ip.log')
+    def test_instance_console_context_with_memcache_ipv6(self, os_release,
+                                                         log_):
+        self.check_instance_console_context_with_memcache(os_release, '::1',
+                                                          '[::1]')
+
+    def check_instance_console_context_with_memcache(self, os_release, ip,
+                                                     formated_ip):
+        memcached_servers = [{'private-address': formated_ip,
+                              'port': '11211'}]
+        self.unit_get.return_value = ip
+        self.relation_ids.return_value = ['cache:0']
+        self.relations_for_id.return_value = memcached_servers
+        self.related_units.return_value = 'memcached/0'
+        instance_console = context.InstanceConsoleContext()
+        os_release.return_value = 'icehouse'
+        self.maxDiff = None
+        self.assertEqual({'memcached_servers': "%s:11211" % (formated_ip, )},
+                         instance_console())

unit_tests/test_nova_cc_hooks.py

@@ -1,6 +1,7 @@
 from mock import MagicMock, patch, call
 from test_utils import CharmTestCase, patch_open
 import os
+
 with patch('charmhelpers.core.hookenv.config') as config:
     config.return_value = 'neutron'
     import nova_cc_utils as utils