optimize the callback receiver to buffer writes on high throughput

additionaly, optimize away several per-event host lookups and
changed/failed propagation lookups

we've always performed these (fairly expensive) queries *on every event
save* - if you're processing tens of thousands of events in short
bursts, this is way too slow

this commit also introduces a new command for profiling the insertion
rate of events, `awx-manage callback_stats`

see: https://github.com/ansible/awx/issues/5514

awx/main/tests/unit/commands/test_replay_job_events.py

@@ -60,7 +60,7 @@ class TestReplayJobEvents():
         r.emit_job_status = lambda job, status: True
         return r
 
-    @mock.patch('awx.main.management.commands.replay_job_events.emit_channel_notification', lambda *a, **kw: None)
+    @mock.patch('awx.main.management.commands.replay_job_events.emit_event_detail', lambda *a, **kw: None)
     def test_sleep(self, mocker, replayer):
         replayer.run(3, 1)
 
@@ -74,7 +74,7 @@ class TestReplayJobEvents():
             mock.call(0.000001),
         ])
 
-    @mock.patch('awx.main.management.commands.replay_job_events.emit_channel_notification', lambda *a, **kw: None)
+    @mock.patch('awx.main.management.commands.replay_job_events.emit_event_detail', lambda *a, **kw: None)
     def test_speed(self, mocker, replayer):
         replayer.run(3, 2)
 

awx/main/tests/unit/models/test_events.py

@@ -1,6 +1,5 @@
 from datetime import datetime
 from django.utils.timezone import utc
-from unittest import mock
 import pytest
 
 from awx.main.models import (JobEvent, ProjectUpdateEvent, AdHocCommandEvent,
@@ -18,16 +17,11 @@ from awx.main.models import (JobEvent, ProjectUpdateEvent, AdHocCommandEvent,
     datetime(2018, 1, 1).isoformat(), datetime(2018, 1, 1)
 ])
 def test_event_parse_created(job_identifier, cls, created):
-    with mock.patch.object(cls, 'objects') as manager:
-        cls.create_from_data(**{
-            job_identifier: 123,
-            'created': created
-        })
-        expected_created = datetime(2018, 1, 1).replace(tzinfo=utc)
-        manager.create.assert_called_with(**{
-            job_identifier: 123,
-            'created': expected_created
-        })
+    event = cls.create_from_data(**{
+        job_identifier: 123,
+        'created': created
+    })
+    assert event.created == datetime(2018, 1, 1).replace(tzinfo=utc)
 
 
 @pytest.mark.parametrize('job_identifier, cls', [
@@ -38,24 +32,20 @@ def test_event_parse_created(job_identifier, cls, created):
     ['system_job_id', SystemJobEvent],
 ])
 def test_playbook_event_strip_invalid_keys(job_identifier, cls):
-    with mock.patch.object(cls, 'objects') as manager:
-        cls.create_from_data(**{
-            job_identifier: 123,
-            'extra_key': 'extra_value'
-        })
-        manager.create.assert_called_with(**{job_identifier: 123})
+    event = cls.create_from_data(**{
+        job_identifier: 123,
+        'extra_key': 'extra_value'
+    })
+    assert getattr(event, job_identifier) == 123
+    assert not hasattr(event, 'extra_key')
 
 
 @pytest.mark.parametrize('field', [
     'play', 'role', 'task', 'playbook'
 ])
 def test_really_long_event_fields(field):
-    with mock.patch.object(JobEvent, 'objects') as manager:
-        JobEvent.create_from_data(**{
-            'job_id': 123,
-            'event_data': {field: 'X' * 4096}
-        })
-        manager.create.assert_called_with(**{
-            'job_id': 123,
-            'event_data': {field: 'X' * 1023 + '…'}
-        })
+    event = JobEvent.create_from_data(**{
+        'job_id': 123,
+        'event_data': {field: 'X' * 4096}
+    })
+    assert event.event_data[field] == 'X' * 1023 + '…'