Adds service request parameter filter for V3 API os-hosts request

Both V2 and V3 API do not support service request parameter filter
for os-hosts request. For V2 API, there is no need to having two
different clouds having different APIs (one with service filter
one without) but just take V2 API as a document bug. This patch
will only fix V3 API.

DocImpact
Adds the ability to filter a hosts list request by service for
the V3 API.

Change-Id: I42163707049300b0dee677558ed49280bcc7369d
Partial-Bug: #1224763

doc/v3/api_samples/os-hosts/hosts-list-compute-service-resp.json

@@ -0,0 +1,9 @@
+{
+    "hosts": [
+        {
+            "host_name": "09c025b0efc64211bd23fc50fa974cdf",
+            "service": "compute",
+            "zone": "nova"
+        }
+    ]
+}

nova/api/openstack/compute/plugins/v3/hosts.py

@@ -80,6 +80,9 @@ class HostController(wsgi.Controller):
         zone = req.GET.get('zone', None)
         if zone:
             filters['availability_zone'] = zone
+        service = req.GET.get('service')
+        if service:
+            filters['topic'] = service
         services = self.api.service_get_all(context, filters=filters,
                                             set_zones=True)
         hosts = []

nova/tests/api/openstack/compute/plugins/v3/test_hosts.py

@@ -132,6 +132,16 @@ class FakeRequestWithNovaZone(object):
     GET = {"zone": "nova"}
 
 
+class FakeRequestWithNovaService(object):
+    environ = {"nova.context": context_maker.get_admin_context()}
+    GET = {"service": "compute"}
+
+
+class FakeRequestWithInvalidNovaService(object):
+    environ = {"nova.context": context_maker.get_admin_context()}
+    GET = {"service": "invalid"}
+
+
 class HostTestCase(test.TestCase):
     """Test Case for hosts."""
 
@@ -174,6 +184,14 @@ class HostTestCase(test.TestCase):
         hosts = result['hosts']
         self.assertEqual(fake_hosts.HOST_LIST_NOVA_ZONE, hosts)
 
+    def test_list_hosts_with_service(self):
+        result = self.controller.index(FakeRequestWithNovaService())
+        self.assertEqual(fake_hosts.HOST_LIST_NOVA_ZONE, result['hosts'])
+
+    def test_list_hosts_with_invalid_service(self):
+        result = self.controller.index(FakeRequestWithInvalidNovaService())
+        self.assertEqual([], result['hosts'])
+
     def test_disable_host(self):
         self._test_host_update('host_c1', 'status', 'disable', 'disabled')
         self._test_host_update('host_c2', 'status', 'disable', 'enabled')

nova/tests/integrated/v3/api_samples/os-hosts/hosts-list-compute-service-resp.json.tpl

@@ -0,0 +1,9 @@
+{
+    "hosts": [
+        {
+            "host_name": "%(host_name)s",
+            "service": "compute",
+            "zone": "nova"
+        }
+    ]
+}

nova/tests/integrated/v3/test_hosts.py

@@ -49,3 +49,9 @@ class HostsSampleJsonTest(api_sample_base.ApiSampleTestBaseV3):
         response = self._do_get('os-hosts')
         subs = self._get_regexes()
         self._verify_response('hosts-list-resp', subs, response, 200)
+
+    def test_hosts_list_compute_service(self):
+        response = self._do_get('os-hosts?service=compute')
+        subs = self._get_regexes()
+        self._verify_response('hosts-list-compute-service-resp',
+                               subs, response, 200)