Add pymemcache's HashClient retrying options to oslo.cache

This patch specifies a set of options required to setup pymemcache's
HashClient retrying feature (dogpile.cache) cache backend.

Original oslo.cache change:
https://review.opendev.org/c/openstack/oslo.cache/+/824944

Change-Id: I90d8e2b0cf231c9bd0fe97d4f363795886ccf8c7

manifests/cache.pp

@@ -183,6 +183,22 @@
 #   (Optional) Number of seconds to sleep between each attempt.
 #   Default to $::os_service_default
 #
+# [*hashclient_retry_attempts*]
+#   (Optional) Amount of times a client should be tried
+#   before it is marked dead and removed from the pool in
+#   the HashClient's internal mechanisms.
+#   Default to $::os_service_default
+#
+# [*hashclient_retry_delay*]
+#   (Optional) Time in seconds that should pass between
+#   retry attempts in the HashClient's internal mechanisms.
+#   Default to $::os_service_default
+#
+# [*dead_timeout*]
+#   (Optional) Time in seconds before attempting to add a node
+#   back in the pool in the HashClient's internal mechanisms.
+#   Default to $::os_service_default
+#
 # [*manage_backend_package*]
 #   (Optional) Whether to install the backend package.
 #   Defaults to true.
@@ -217,6 +233,9 @@ define oslo::cache(
   $enable_retry_client                  = $::os_service_default,
   $retry_attempts                       = $::os_service_default,
   $retry_delay                          = $::os_service_default,
+  $hashclient_retry_attempts            = $::os_service_default,
+  $hashclient_retry_delay               = $::os_service_default,
+  $dead_timeout                         = $::os_service_default,
   $manage_backend_package               = true,
   $package_ensure                       = 'present',
 ){
@@ -281,6 +300,9 @@ define oslo::cache(
     'cache/enable_retry_client'                  => { value => $enable_retry_client },
     'cache/retry_attempts'                       => { value => $retry_attempts },
     'cache/retry_delay'                          => { value => $retry_delay },
+    'cache/hashclient_retry_attempts'            => { value => $hashclient_retry_attempts },
+    'cache/hashclient_retry_delay'               => { value => $hashclient_retry_delay },
+    'cache/dead_timeout'                         => { value => $dead_timeout },
   }
 
   create_resources($name, $cache_options)

releasenotes/notes/pymemcache_hashclient_retrying-10a756708ad9894b.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Add options to configure pymemcache's HashClient retrying mechanisms
+    (dogpile.cache) backend.

spec/defines/oslo_cache_spec.rb

@@ -33,6 +33,9 @@ describe 'oslo::cache' do
         is_expected.to contain_keystone_config('cache/enable_retry_client').with_value('<SERVICE DEFAULT>')
         is_expected.to contain_keystone_config('cache/retry_attempts').with_value('<SERVICE DEFAULT>')
         is_expected.to contain_keystone_config('cache/retry_delay').with_value('<SERVICE DEFAULT>')
+        is_expected.to contain_keystone_config('cache/hashclient_retry_attempts').with_value('<SERVICE DEFAULT>')
+        is_expected.to contain_keystone_config('cache/hashclient_retry_delay').with_value('<SERVICE DEFAULT>')
+        is_expected.to contain_keystone_config('cache/dead_timeout').with_value('<SERVICE DEFAULT>')
       end
     end
 
@@ -64,6 +67,9 @@ describe 'oslo::cache' do
           :enable_retry_client                  => false,
           :retry_attempts                       => 2,
           :retry_delay                          => 0,
+          :hashclient_retry_attempts            => 2,
+          :hashclient_retry_delay               => 1,
+          :dead_timeout                         => 60,
         }
       end
 
@@ -93,6 +99,9 @@ describe 'oslo::cache' do
         is_expected.to contain_keystone_config('cache/enable_retry_client').with_value('false')
         is_expected.to contain_keystone_config('cache/retry_attempts').with_value('2')
         is_expected.to contain_keystone_config('cache/retry_delay').with_value('0')
+        is_expected.to contain_keystone_config('cache/hashclient_retry_attempts').with_value('2')
+        is_expected.to contain_keystone_config('cache/hashclient_retry_delay').with_value('1')
+        is_expected.to contain_keystone_config('cache/dead_timeout').with_value('60')
       end
     end