Allow setting batch size for expirer

This change introduces a new option to set batch size for expirer,
which allows limiting number of alamr histories purged in a single run.

Depends-on: https://review.opendev.org/755983
Change-Id: Ie37a3c377c455dbafa9cc57ddecb8b8963fc9a82

manifests/expirer.pp

@@ -34,15 +34,20 @@
 #    all cron jobs at the same time on all hosts this job is configured.
 #    Defaults to 0.
 #
+#  [*alarm_histories_delete_batch_size*]
+#    (optional) Limit number of deleted alarm histories in single purge run
+#    Defaults to $::os_service_default.
+#
 class aodh::expirer (
-  $ensure         = 'present',
+  $ensure                            = 'present',
-  $package_ensure = 'present',
+  $package_ensure                    = 'present',
-  $minute         = 1,
+  $minute                            = 1,
-  $hour           = 0,
+  $hour                              = 0,
-  $monthday       = '*',
+  $monthday                          = '*',
-  $month          = '*',
+  $month                             = '*',
-  $weekday        = '*',
+  $weekday                           = '*',
-  $maxdelay       = 0,
+  $maxdelay                          = 0,
+  $alarm_histories_delete_batch_size = $::os_service_default,
 ) {
 
   include aodh::params
@@ -59,6 +64,10 @@ class aodh::expirer (
     $sleep = "sleep `expr \${RANDOM} \\% ${maxdelay}`; "
   }
 
+  aodh_config { 'database/alarm_histories_delete_batch_size':
+    value => $alarm_histories_delete_batch_size
+  }
+
   cron { 'aodh-expirer':
     ensure      => $ensure,
     command     => "${sleep}${aodh::params::expirer_command}",

releasenotes/notes/batchsize-6f6d2382eeb7e025.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Added alarm_histories_delete_batch_size parameter to the expire class to
+    enable configuration of the parameter with the same name. It allows
+    limiting number of alarm histories purged by a single purge run.

spec/classes/aodh_expirer_spec.rb

@@ -9,6 +9,7 @@ describe 'aodh::expirer' do
     context 'with default' do
       it { is_expected.to contain_class('aodh::deps') }
       it { is_expected.to contain_class('aodh::params') }
+      it { is_expected.to contain_aodh_config('database/alarm_histories_delete_batch_size').with_value('<SERVICE DEFAULT>') }
 
       it 'installs aodh-expirer package' do
         is_expected.to contain_package(platform_params[:expirer_package_name]).with(
@@ -34,13 +35,15 @@ describe 'aodh::expirer' do
     context 'with overridden parameters' do
       before do
         params.merge!(
-          :ensure   => 'absent',
+          :ensure                            => 'absent',
-          :maxdelay => 300
+          :maxdelay                          => 300,
+          :alarm_histories_delete_batch_size => 500
         )
       end
 
       it { is_expected.to contain_class('aodh::deps') }
       it { is_expected.to contain_class('aodh::params') }
+      it { is_expected.to contain_aodh_config('database/alarm_histories_delete_batch_size').with_value(500) }
 
       it 'installs aodh-expirer package' do
         is_expected.to contain_package(platform_params[:expirer_package_name]).with(