Add REST API support for list/enable/disable nova services

Implements one workitem of blueprint apis-for-nova-manage

This adds an extension that provides REST API for list/enable/
disable nova service. The interface ia accessed via

GET /v2/{tenant_id}/os-services
PUT /v2/{tenant_id}/os-services/enable
PUT /v2/{tenant_id}/os-services/disable

And the command:nova host-describe have implemented the functionality
of nova-manage service describe_resource. So we needn't add a REST
API for it.

DocImpact
Change-Id: I030a7e00b878d7931456e7e323db37b7c47fce48

1 files changed, 141 insertions, 0 deletions

diff --git a/nova/api/openstack/compute/contrib/services.py b/nova/api/openstack/compute/contrib/services.py
new file mode 100644
index 000000000..3da00a8c8
--- /dev/null
+++ b/nova/api/openstack/compute/contrib/services.py
@@ -0,0 +1,141 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 IBM
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+import webob.exc
+
+from nova.api.openstack import extensions
+from nova.api.openstack import wsgi
+from nova.api.openstack import xmlutil
+from nova import db
+from nova import exception
+from nova import flags
+from nova.openstack.common import log as logging
+from nova.openstack.common import timeutils
+from nova import utils
+
+
+LOG = logging.getLogger(__name__)
+authorize = extensions.extension_authorizer('compute', 'services')
+FLAGS = flags.FLAGS
+
+
+class ServicesIndexTemplate(xmlutil.TemplateBuilder):
+    def construct(self):
+        root = xmlutil.TemplateElement('services')
+        elem = xmlutil.SubTemplateElement(root, 'service', selector='services')
+        elem.set('binary')
+        elem.set('host')
+        elem.set('zone')
+        elem.set('status')
+        elem.set('state')
+        elem.set('update_at')
+
+        return xmlutil.MasterTemplate(root, 1)
+
+
+class ServicesUpdateTemplate(xmlutil.TemplateBuilder):
+    def construct(self):
+        root = xmlutil.TemplateElement('host')
+        root.set('host')
+        root.set('service')
+        root.set('disabled')
+
+        return xmlutil.MasterTemplate(root, 1)
+
+
+class ServiceController(object):
+    @wsgi.serializers(xml=ServicesIndexTemplate)
+    def index(self, req):
+        """
+        Return a list of all running services. Filter by host & service name.
+        """
+        context = req.environ['nova.context']
+        authorize(context)
+        now = timeutils.utcnow()
+        services = db.service_get_all(context)
+
+        host = ''
+        if 'host' in req.GET:
+            host = req.GET['host']
+        service = ''
+        if 'service' in req.GET:
+            service = req.GET['service']
+        if host:
+            services = [s for s in services if s['host'] == host]
+        if service:
+            services = [s for s in services if s['binary'] == service]
+
+        svcs = []
+        for svc in services:
+            delta = now - (svc['updated_at'] or svc['created_at'])
+            alive = abs(utils.total_seconds(delta)) <= FLAGS.service_down_time
+            art = (alive and "up") or "down"
+            active = 'enabled'
+            if svc['disabled']:
+                active = 'disabled'
+            svcs.append({"binary": svc['binary'], 'host': svc['host'],
+                         'zone': svc['availability_zone'],
+                         'status': active, 'state': art,
+                         'updated_at': svc['updated_at']})
+        return {'services': svcs}
+
+    @wsgi.serializers(xml=ServicesUpdateTemplate)
+    def update(self, req, id, body):
+        """Enable/Disable scheduling for a service"""
+        context = req.environ['nova.context']
+        authorize(context)
+
+        if id == "enable":
+            disabled = False
+        elif id == "disable":
+            disabled = True
+        else:
+            raise webob.exc.HTTPNotFound("Unknown action")
+
+        try:
+            host = body['host']
+            service = body['service']
+        except (TypeError, KeyError):
+            raise webob.exc.HTTPUnprocessableEntity()
+
+        try:
+            svc = db.service_get_by_args(context, host, service)
+            if not svc:
+                raise webob.exc.HTTPNotFound('Unknown service')
+
+            db.service_update(context, svc['id'], {'disabled': disabled})
+        except exception.ServiceNotFound:
+            raise webob.exc.HTTPNotFound("service not found")
+
+        return {'host': host, 'service': service, 'disabled': disabled}
+
+
+class Services(extensions.ExtensionDescriptor):
+    """Services support"""
+
+    name = "Services"
+    alias = "os-services"
+    namespace = "http://docs.openstack.org/compute/ext/services/api/v2"
+    updated = "2012-10-28T00:00:00-00:00"
+
+    def get_resources(self):
+        resources = []
+        resource = extensions.ResourceExtension('os-services',
+                                                ServiceController())
+        resources.append(resource)
+        return resources