Add support for serial console access

Enable instance serial console based on flags provided from
nova-cloud-controller charm.

This is only supported in OpenStack Juno or later, and replaces
the standard output to the nova console-log.

Change-Id: I147166d9b273964d34ba81724b0311f269b9fea0
Depends-On: I3bfcca88bd6147be337e6d770db7348170b914e6

hooks/nova_compute_context.py

@@ -281,6 +281,34 @@ class NovaComputeCephContext(context.CephContext):
         return ctxt
 
 
+class SerialConsoleContext(context.OSContextGenerator):
+
+    @property
+    def enable_serial_console(self):
+        for rid in relation_ids('cloud-compute'):
+            for unit in related_units(rid):
+                if bool(relation_get('enable_serial_console',
+                                     rid=rid, unit=unit)) is True:
+                    return 'true'
+        return 'false'
+
+    @property
+    def serial_console_base_url(self):
+        for rid in relation_ids('cloud-compute'):
+            for unit in related_units(rid):
+                base_url = relation_get('serial_console_base_url',
+                                        rid=rid, unit=unit)
+                if base_url is not None:
+                    return base_url
+        return 'ws://127.0.0.1:6083/'
+
+    def __call__(self):
+        return {
+            'enable_serial_console': self.enable_serial_console,
+            'serial_console_base_url': self.serial_console_base_url,
+        }
+
+
 class CloudComputeContext(context.OSContextGenerator):
 
     '''

hooks/nova_compute_utils.py

@@ -108,6 +108,7 @@ from nova_compute_context import (
     NovaAPIAppArmorContext,
     NovaComputeAppArmorContext,
     NovaNetworkAppArmorContext,
+    SerialConsoleContext,
 )
 
 CA_CERT_PATH = '/usr/local/share/ca-certificates/keystone_juju_ca_cert.crt'
@@ -222,7 +223,8 @@ BASE_RESOURCE_MAP = {
                      DesignateContext(),
                      NovaComputeVirtContext(),
                      context.LogLevelContext(),
-                     context.InternalEndpointContext()],
+                     context.InternalEndpointContext(),
+                     SerialConsoleContext()],
     },
     NOVA_API_AA_PROFILE_PATH: {
         'services': ['nova-api'],

templates/juno/nova.conf

@@ -170,3 +170,5 @@ disk_cachemodes = {{ disk_cachemodes }}
 {% include "parts/section-cinder" %}
 
 {% include "parts/section-ephemeral" %}
+
+{% include "parts/section-serial-console" %}

templates/kilo/nova.conf

@@ -197,3 +197,5 @@ lock_path=/var/lock/nova
 disable_libvirt_livesnapshot = False
 
 {% include "parts/section-ephemeral" %}
+
+{% include "parts/section-serial-console" %}

templates/liberty/nova.conf

@@ -203,3 +203,5 @@ lock_path=/var/lock/nova
 disable_libvirt_livesnapshot = False
 
 {% include "parts/section-ephemeral" %}
+
+{% include "parts/section-serial-console" %}

templates/mitaka/nova.conf

@@ -219,3 +219,5 @@ lock_path=/var/lock/nova
 disable_libvirt_livesnapshot = False
 
 {% include "parts/section-ephemeral" %}
+
+{% include "parts/section-serial-console" %}

templates/parts/section-serial-console

@@ -0,0 +1,4 @@
+[serial_console]
+enabled = {{ enable_serial_console }}
+proxyclient_address = {{ console_listen_addr }}
+base_url = {{ serial_console_base_url }}

unit_tests/test_nova_compute_contexts.py

@@ -404,3 +404,34 @@ class DesignateContextTests(CharmTestCase):
         self.assertEqual(designatectxt(), {
             'enable_designate': False,
         })
+
+
+class SerialConsoleContextTests(CharmTestCase):
+
+    def setUp(self):
+        super(SerialConsoleContextTests, self).setUp(context, TO_PATCH)
+        self.relation_get.side_effect = self.test_relation.get
+        self.config.side_effect = self.test_config.get
+        self.host_uuid = 'e46e530d-18ae-4a67-9ff0-e6e2ba7c60a7'
+
+    def test_serial_console_not_provided(self):
+        self.relation_ids.return_value = ['cloud-compute:0']
+        self.related_units.return_value = 'nova-cloud-controller/0'
+        self.assertEqual(
+            context.SerialConsoleContext()(),
+            {'enable_serial_console': 'false',
+             'serial_console_base_url': 'ws://127.0.0.1:6083/'}
+        )
+
+    def test_serial_console_provided(self):
+        self.relation_ids.return_value = ['cloud-compute:0']
+        self.related_units.return_value = 'nova-cloud-controller/0'
+        self.test_relation.set({
+            'enable_serial_console': 'true',
+            'serial_console_base_url': 'ws://10.10.10.1:6083/'
+        })
+        self.assertEqual(
+            context.SerialConsoleContext()(),
+            {'enable_serial_console': 'true',
+             'serial_console_base_url': 'ws://10.10.10.1:6083/'}
+        )