Add polling-batch-size config option

Samples collected can be batched together,
consequently increasing or reducing the
amount of API calls and body data
sent to the configured publisher.

This config is available since Rocky,
adding the config option to allow its
tuning.

Change-Id: I0e3f756aa0305d3a96e21c7498d6a56208c51007
Closes-bug: #1885190

config.yaml

@@ -278,3 +278,10 @@ options:
       From Pike onwards, the default ceilometer pollster collection runs a
       limited set of pollsters.  Enable this to run all the available pollsters.
       This setting only takes effect from Queens onwards.
+  polling-batch-size:
+    type: int
+    default: 50
+    description: |
+      The number of measures from same pollster to batch together for sending
+      to the notification agent and then to the publisher. Set to 0 to disable.
+      This config is only effective for OpenStack release Rocky or newer.

lib/ceilometer_contexts.py

@@ -112,6 +112,7 @@ class CeilometerContext(OSContextGenerator):
             'event_time_to_live': int(config('event-time-to-live')),
             'polling_interval': int(config('polling-interval')),
             'enable_all_pollsters': config('enable-all-pollsters'),
+            'polling_batch_size': config('polling-batch-size'),
         }
         return ctxt
 

templates/rocky/ceilometer.conf

@@ -0,0 +1,78 @@
+# rocky
+###############################################################################
+# [ WARNING ]
+# ceilometer configuration file maintained by Juju
+# local changes may be overwritten.
+###############################################################################
+[DEFAULT]
+debug = {{ debug }}
+verbose = {{ verbose }}
+use_syslog = {{ use_syslog }}
+event_pipeline_cfg_file = /etc/ceilometer/event_pipeline.yaml
+
+{% if gnocchi_url -%}
+meter_dispatchers = gnocchi
+event_dispatchers = gnocchi
+{% elif db_host or db_mongo_servers -%}
+meter_dispatchers = database
+{%- endif %}
+
+{% if transport_url -%}
+transport_url = {{ transport_url }}
+{%- endif %}
+
+[notification]
+workers = {{ workers }}
+{% if messaging_urls -%}
+{% for item in messaging_urls -%}
+messaging_urls = {{ item }}
+{% endfor %}
+{% endif %}
+
+[polling]
+batch_size = {{ polling_batch_size }}
+
+{% if service_host -%}
+[service_credentials]
+auth_url = {{ service_protocol }}://{{ service_host }}:{{ service_port }}
+project_name = {{ admin_tenant_name }}
+username = {{ admin_user }}
+password = {{ admin_password }}
+{% if api_version == "3" -%}
+project_domain_name = {{ admin_domain_name }}
+user_domain_name = {{ admin_domain_name }}
+{% else -%}
+project_domain_name = default
+user_domain_name = default
+{% endif -%}
+auth_type = password
+{% if use_internal_endpoints -%}
+interface = internalURL
+{%- endif %}
+{% endif -%}
+
+{% if db_host or db_mongo_servers -%}
+[database]
+{% if db_replset: -%}
+connection = mongodb://{{ db_mongo_servers }}/{{ db_name }}?readPreference=primaryPreferred&replicaSet={{ db_replset }}
+mongodb_replica_set = {{ db_replset }}
+{% else -%}
+connection = mongodb://{{ db_host }}:{{ db_port }}/{{ db_name }}
+{% endif %}
+metering_time_to_live = {{ metering_time_to_live }}
+event_time_to_live = {{ event_time_to_live }}
+{%- endif %}
+
+[publisher]
+telemetry_secret = {{ metering_secret }}
+
+{% if gnocchi_url -%}
+[dispatcher_gnocchi]
+filter_service_activity = False
+archive_policy = {{ archive_policy }}
+url = {{ gnocchi_url }}
+{%- endif %}
+
+{% include "section-keystone-authtoken-mitaka" %}
+
+{% include "section-oslo-messaging-rabbit-ocata" %}

unit_tests/test_ceilometer_contexts.py

@@ -133,6 +133,7 @@ class CeilometerContextsTest(CharmTestCase):
             'event_time_to_live': -1,
             'polling_interval': 300,
             'enable_all_pollsters': False,
+            'polling_batch_size': 50,
         })
 
     @patch.object(utils, 'get_shared_secret')
@@ -148,6 +149,7 @@ class CeilometerContextsTest(CharmTestCase):
             'event_time_to_live': 7776000,
             'polling_interval': 300,
             'enable_all_pollsters': False,
+            'polling_batch_size': 50,
         })
         self.assertTrue(type(context['metering_time_to_live']) is int)
         self.assertTrue(type(context['event_time_to_live']) is int)
@@ -164,6 +166,7 @@ class CeilometerContextsTest(CharmTestCase):
             'event_time_to_live': -1,
             'polling_interval': 300,
             'enable_all_pollsters': True,
+            'polling_batch_size': 50,
         })
 
     @patch.object(utils, 'get_shared_secret')
@@ -178,6 +181,7 @@ class CeilometerContextsTest(CharmTestCase):
             'event_time_to_live': -1,
             'polling_interval': 900,
             'enable_all_pollsters': False,
+            'polling_batch_size': 50,
         })
 
     def test_ceilometer_service_context(self):