Add action that returns list of registered compute nodes.

List contains only nodes registered to the same nova-cloud-controller
as the nova-compute service running on targeted unit.

Closes-Bug: #1911013
Change-Id: I28d1a9bd18b3a87fc31ff4bca5bfe58449cdae57

README.md

@@ -301,6 +301,7 @@ deployed then see file `actions.yaml`.
 * `disable`
 * `enable`
 * `hugepagereport`
+* `list-compute-nodes`
 * `node-name`
 * `openstack-upgrade`
 * `pause`

actions.yaml

@@ -12,6 +12,8 @@ register-to-cloud:
     README.md, section 'Cloud downscaling'.
 openstack-upgrade:
   description: Perform openstack upgrades. Config option action-managed-upgrade must be set to True.
+list-compute-nodes:
+  description: List all nova-compute nodes registered in the Openstack cloud.
 node-name:
   description: Return nova-compute node name. This can be used to identify this unit in the list of nova-compute services.
 pause:

actions/cloud.py

@@ -14,6 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
 import os
 import sys
 from enum import Enum
@@ -136,7 +137,17 @@ def register_to_cloud():
     })
 
 
+def list_computes():
+    """Implementation of `list-compute-nodes` action."""
+    nova = cloud_utils.nova_client()
+    function_set({'node-name': cloud_utils.service_hostname()})
+    computes = [service.to_dict()
+                for service in nova.services.list(binary='nova-compute')]
+    function_set({'compute-nodes': json.dumps(computes)})
+
+
 def node_name():
+    """Implementation of 'node-name' action."""
     function_set({'node-name': cloud_utils.service_hostname()})
 
 
@@ -145,6 +156,7 @@ ACTIONS = {
     'enable': enable,
     'remove-from-cloud': remove_from_cloud,
     'register-to-cloud': register_to_cloud,
+    'list-compute-nodes': list_computes,
     'node-name': node_name,
 }
 

actions/list-compute-nodes

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

unit_tests/test_actions_cloud.py

@@ -11,15 +11,29 @@
 # 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 json
 import sys
 from unittest import TestCase
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock, patch, call
 
 sys.modules['nova_compute_hooks'] = MagicMock()
 import cloud
 del sys.modules['nova_compute_hooks']
 
 
+class _MockComputeHost:
+
+    def __init__(self, node_name, state='enabled', binary='nova-compute'):
+        self.node_name = node_name
+        self.state = state
+        self.binary = binary
+
+    def to_dict(self):
+        return {'node_name': self.node_name,
+                'state': self.state,
+                'binary': self.binary}
+
+
 class _ActionTestCase(TestCase):
 
     NAME = ''
@@ -233,6 +247,37 @@ class TestRegisterToCloud(_ActionTestCase):
         cloud.function_fail.assert_not_called()
 
 
+class TestListComputeNodes(_ActionTestCase):
+    NAME = 'list-compute-nodes'
+
+    MOCK_LIST = [_MockComputeHost('compute0'),
+                 _MockComputeHost('compute1')]
+
+    def setUp(self, to_mock=None):
+        super(TestListComputeNodes, self).setUp()
+        self.nova_client = MagicMock()
+        services = MagicMock()
+        services.list.return_value = self.MOCK_LIST
+        self.nova_client.services = services
+
+    def test_list_compute_nodes(self):
+        """Test listing nov-compute services."""
+        cloud.cloud_utils.nova_client.return_value = self.nova_client
+        expected_identity = 'compute-0'
+        cloud.cloud_utils.service_hostname.return_value = expected_identity
+        self.call_action()
+
+        expected_nodes = [host.to_dict() for host in self.MOCK_LIST
+                          if host.binary == 'nova-compute']
+
+        expected_calls = [call({'node-name': expected_identity}),
+                          call({'compute-nodes': json.dumps(expected_nodes)})]
+
+        self.nova_client.services.list.assert_called_with(
+            binary='nova-compute')
+        cloud.function_set.assert_has_calls(expected_calls)
+
+
 class TestNodeName(_ActionTestCase):
     NAME = 'node-name'