Add retrying options to oslo.cache

This patch specifies a set of options required to setup the retrying wrapper
feature of pymemcache (dogpile.cache) cache backend.

Original oslo.cache change:
https://review.opendev.org/c/openstack/oslo.cache/+/803747

Change-Id: If4622f85e1e7f715805b205bfc3c16cb1e53b943

manifests/cache.pp

@@ -168,6 +168,21 @@
 #   be available.
 #   Default to $::os_service_default
 #
+# [*enable_retry_client*]
+#   (Optional) Enable retry client mechanisms to handle failure.
+#   Those mechanisms can be used to wrap all kind of pymemcache
+#   clients. The wrapper allows you to define how many attempts
+#   to make and how long to wait between attemots.
+#   Default to $::os_service_default
+#
+# [*retry_attempts*]
+#   (Optional) Number of times to attempt an action before failing.
+#   Default to $::os_service_default
+#
+# [*retry_delay*]
+#   (Optional) Number of seconds to sleep between each attempt.
+#   Default to $::os_service_default
+#
 # [*manage_backend_package*]
 #   (Optional) Whether to install the backend package.
 #   Defaults to true.
@@ -199,6 +214,9 @@ define oslo::cache(
   $tls_certfile                         = $::os_service_default,
   $tls_keyfile                          = $::os_service_default,
   $tls_allowed_ciphers                  = $::os_service_default,
+  $enable_retry_client                  = $::os_service_default,
+  $retry_attempts                       = $::os_service_default,
+  $retry_delay                          = $::os_service_default,
   $manage_backend_package               = true,
   $package_ensure                       = 'present',
 ){
@@ -260,6 +278,9 @@ define oslo::cache(
     'cache/tls_certfile'                         => { value => $tls_certfile },
     'cache/tls_keyfile'                          => { value => $tls_keyfile },
     'cache/tls_allowed_ciphers'                  => { value => $tls_allowed_ciphers },
+    'cache/enable_retry_client'                  => { value => $enable_retry_client },
+    'cache/retry_attempts'                       => { value => $retry_attempts },
+    'cache/retry_delay'                          => { value => $retry_delay },
   }
 
   create_resources($name, $cache_options)

releasenotes/notes/pymemcache_retrying-4fa326e3bc913a97.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    Add retrying options for pymemcache (dogpile.cache) backend.

spec/defines/oslo_cache_spec.rb

@@ -30,6 +30,9 @@ describe 'oslo::cache' do
         is_expected.to contain_keystone_config('cache/tls_certfile').with_value('<SERVICE DEFAULT>')
         is_expected.to contain_keystone_config('cache/tls_keyfile').with_value('<SERVICE DEFAULT>')
         is_expected.to contain_keystone_config('cache/tls_allowed_ciphers').with_value('<SERVICE DEFAULT>')
+        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>')
       end
     end
 
@@ -58,6 +61,9 @@ describe 'oslo::cache' do
           :tls_certfile                         => nil,
           :tls_keyfile                          => nil,
           :tls_allowed_ciphers                  => nil,
+          :enable_retry_client                  => false,
+          :retry_attempts                       => 2,
+          :retry_delay                          => 0,
         }
       end
 
@@ -84,6 +90,9 @@ describe 'oslo::cache' do
         is_expected.to contain_keystone_config('cache/tls_certfile').with_value('nil')
         is_expected.to contain_keystone_config('cache/tls_keyfile').with_value('nil')
         is_expected.to contain_keystone_config('cache/tls_allowed_ciphers').with_value('nil')
+        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')
       end
     end