Added method for creating k8s events object.

Kubernetes provides a convenient way for examining resource life cycle.
Ephemeral Event objects are created for some of the steps during
resource object change of the state. Those event can be accessed using
`kubectl get events` or for particular object `kubectl describe <type>
<resource name>`, so that operator can examine the state and the reason
for potential failure of given resource object.

In this patch there is a method added for creating Event objects, so
that anything wrong regarding Kubernetes object life cycle can be
"annotated" with such object.

Change-Id: I291613adf9282ec5399fbe5de75e82472c2bc9c0

kuryr_kubernetes/k8s_client.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 import contextlib
+import datetime
 import functools
 import itertools
 import os
@@ -23,6 +24,7 @@ import urllib3
 
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
+import pytz
 import requests
 from requests import adapters
 
@@ -445,3 +447,55 @@ class K8sClient(object):
                     params.get('resourceVersion'))
                 time.sleep(t)
                 attempt += 1
+
+    def add_event(self, resource, reason, message, type_='Normal'):
+        """Create an Event object for the provided resource."""
+        involved_object = {'apiVersion': resource['apiVersion'],
+                           'kind': resource['kind'],
+                           'name': resource['metadata']['name'],
+                           'namespace': resource['metadata']['namespace'],
+                           'uid': resource['metadata']['uid']}
+
+        # This is needed for Event date, otherwise LAST SEEN/Age will be empty
+        # and misleading.
+        now = datetime.datetime.utcnow().replace(tzinfo=pytz.UTC)
+        date_time = now.strftime("%Y-%m-%dT%H:%M:%SZ")
+
+        name = ".".join((resource['metadata']['name'],
+                         self._get_hex_timestamp(now)))
+
+        event = {'kind': 'Event',
+                 'apiVersion': 'v1',
+                 'firstTimestamp': date_time,
+                 'metadata': {'name': name},
+                 'reason': reason,
+                 'message': message,
+                 'type': type_,
+                 'involvedObject': involved_object}
+
+        try:
+            return self.post(f'{constants.K8S_API_BASE}/namespaces/'
+                             f'{resource["metadata"]["namespace"]}/events',
+                             event)
+        except exc.K8sClientException:
+            LOG.warning(f'There was non critical error during creating an '
+                        'Event for resource: "{resource}", with reason: '
+                        f'"{reason}", message: "{message}" and type: '
+                        f'"{type_}"')
+            return {}
+
+    def _get_hex_timestamp(self, datetimeobj):
+        """Get hex representation for timestamp.
+
+        In Kuberenets, Event name is constructed name of the bounded object
+        and timestamp in hexadecimal representation.
+        Note, that Python timestamp is represented as floating figure:
+          1631622163.8534190654754638671875
+        while those which origin from K8s, after change to int:
+          1631622163915909162
+        so, to get similar integer, we need to multiply the float by
+        100000000 to get the same precision and cast to integer, to get rid
+        of the fractures, and finally convert it to hex representation.
+        """
+        timestamp = datetime.datetime.timestamp(datetimeobj)
+        return format(int(timestamp * 100000000), 'x')

kuryr_kubernetes/tests/fake.py

@@ -163,7 +163,8 @@ def get_sgr_obj(sgr_id='7621d1e0-a2d2-4496-94eb-ffd375d20877',
     return os_sgr.SecurityGroupRule(**sgr_data)
 
 
-def get_k8s_pod():
+def get_k8s_pod(name='pod-5bb648d658-55n76', namespace='namespace',
+                uid='683da866-6bb1-4da2-bf6a-a5f4137c38e7'):
 
     return {'apiVersion': 'v1',
             'kind': 'Pod',
@@ -173,9 +174,9 @@ def get_k8s_pod():
                          'labels': {'app': 'pod',
                                     'pod-template-hash': '5bb648d658'},
                          'operation': 'Update',
-                         'name': 'pod-5bb648d658-55n76',
-                         'namespace': 'default',
+                         'name': name,
+                         'namespace': namespace,
                          'resourceVersion': '19416',
-                         'uid': '683da866-6bb1-4da2-bf6a-a5f4137c38e7'},
+                         'uid': uid},
             'spec': {},
             'status': {}}

kuryr_kubernetes/tests/unit/test_k8s_client.py

@@ -23,6 +23,7 @@ import requests
 from kuryr_kubernetes import exceptions as exc
 from kuryr_kubernetes import k8s_client
 from kuryr_kubernetes.tests import base as test_base
+from kuryr_kubernetes.tests import fake
 
 
 class TestK8sClient(test_base.TestCase):
@@ -482,3 +483,43 @@ class TestK8sClient(test_base.TestCase):
         m_resp.status_code = 500
         self.assertRaises(exc.K8sClientException,
                           self.client._raise_from_response, m_resp)
+
+    def test_add_event(self):
+        self.client.post = mock.MagicMock()
+        get_hex_ts = self.client._get_hex_timestamp = mock.MagicMock()
+        get_hex_ts.return_value = 'deadc0de'
+
+        namespace = 'n1'
+        uid = 'deadbeef'
+        name = 'pod-123'
+        pod = fake.get_k8s_pod(name=name, namespace=namespace, uid=uid)
+        event_name = f'{name}.deadc0de'
+
+        self.client.add_event(pod, 'reason', 'message')
+
+        # Event path
+        url = self.client.post.call_args[0][0]
+        data = self.client.post.call_args[0][1]
+        self.assertEqual(url, f'/api/v1/namespaces/{namespace}/events')
+
+        # Event fields
+        self.assertEqual(data['metadata']['name'], event_name)
+        self.assertEqual(data['reason'], 'reason')
+        self.assertEqual(data['message'], 'message')
+        self.assertEqual(data['type'], 'Normal')
+
+        # involvedObject
+        self.assertDictEqual(data['involvedObject'],
+                             {'apiVersion': pod['apiVersion'],
+                              'kind': pod['kind'],
+                              'name': name,
+                              'namespace': namespace,
+                              'uid': uid})
+
+    def test_add_event_k8s_exception(self):
+        self.client.post = mock.MagicMock()
+        self.client.post.side_effect = exc.K8sClientException
+        pod = fake.get_k8s_pod()
+
+        self.assertDictEqual(self.client.add_event(pod, 'reason1', 'message2'),
+                             {})