Allow configuration of limit of batch size for exirer

Adds new configuration option for panko-expirer for limiting detele
batch size.

Change-Id: I7ca0ab9e42352645e463c49f8ce58793115543c0
(cherry picked from commit 89c3f384f0)
(cherry picked from commit c954ebf149)

manifests/expirer.pp

@@ -25,13 +25,18 @@
 #  [*weekday*]
 #    (optional) Defaults to '*'.
 #
+#  [*events_delete_batch_size*]
+#    (optional) Limit number of deleted events in single purge run.
+#    Defaults to $::os_service_default.
+#
 class panko::expirer (
-  $enable_cron = true,
-  $minute      = 1,
-  $hour        = 0,
-  $monthday    = '*',
-  $month       = '*',
-  $weekday     = '*',
+  $enable_cron              = true,
+  $minute                   = 1,
+  $hour                     = 0,
+  $monthday                 = '*',
+  $month                    = '*',
+  $weekday                  = '*',
+  $events_delete_batch_size = $::os_service_default,
 ) {
 
   include ::panko::params
@@ -45,6 +50,10 @@ class panko::expirer (
     $ensure = 'absent'
   }
 
+  panko_config { 'database/events_delete_batch_size':
+    value => $events_delete_batch_size
+  }
+
   cron { 'panko-expirer':
     ensure      => $ensure,
     command     => $panko::params::expirer_command,

releasenotes/notes/batchsize-9f201b538828370d.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Added events_delete_batch_size parameter to the expirer class to enable configuration
+    of the parameter with same name. It serves the purpose of limiting number of deleted
+    events in single purge run.

spec/classes/panko_expirer_spec.rb

@@ -9,6 +9,7 @@ describe 'panko::expirer' do
     context 'with default' do
       it { is_expected.to contain_class('panko::deps') }
       it { is_expected.to contain_class('panko::params') }
+      it { is_expected.to contain_panko_config('database/events_delete_batch_size').with_value('<SERVICE DEFAULT>') }
 
       it { is_expected.to contain_cron('panko-expirer').with(
         :ensure      => 'present',
@@ -23,6 +24,18 @@ describe 'panko::expirer' do
       )}
     end
 
+    context 'with overridden parameters' do
+      before do
+        params.merge!(
+          :events_delete_batch_size => 500
+        )
+      end
+
+      it { is_expected.to contain_class('panko::deps') }
+      it { is_expected.to contain_class('panko::params') }
+      it { is_expected.to contain_panko_config('database/events_delete_batch_size').with_value(500) }
+    end
+
     context 'with cron not enabled' do
       before do
         params.merge!( :enable_cron => false )