Deprecate min_pool_size option

min_pool_size option is not used，see:

https://review.opendev.org/#/c/565090/

Change-Id: I82efcf730dd2b919bd96ae2d4965df26d98a0b4f
Closes-Bug: #1868511

manifests/db.pp

@@ -26,10 +26,6 @@
 #   (Optional) Interval between retries of opening a database connection.
 #   Defaults to $::os_service_default
 #
-# [*database_min_pool_size*]
-#   (Optional) Minimum number of SQL connections to keep open in a pool.
-#   Defaults to $::os_service_default
-#
 # [*database_max_pool_size*]
 #   (Optional)Maximum number of SQL connections to keep open in a pool.
 #   Defaults to $::os_service_default
@@ -42,27 +38,37 @@
 #   (Optional) If set, use this value for pool_timeout with SQLAlchemy.
 #   Defaults to $::os_service_default
 #
+# DEPRECATED PARAMETERS
+#
+# [*database_min_pool_size*]
+#   (Optional) Minimum number of SQL connections to keep open in a pool.
+#   Defaults to undef
+#
 class panko::db (
   $database_connection              = 'sqlite:////var/lib/panko/panko.sqlite',
   $database_connection_recycle_time = $::os_service_default,
-  $database_min_pool_size           = $::os_service_default,
   $database_max_pool_size           = $::os_service_default,
   $database_db_max_retries          = $::os_service_default,
   $database_max_retries             = $::os_service_default,
   $database_retry_interval          = $::os_service_default,
   $database_max_overflow            = $::os_service_default,
   $database_pool_timeout            = $::os_service_default,
+  # DEPRECATED PARAMETERS
+  $database_min_pool_size           = undef,
 ) {
 
   include panko::deps
 
+  if $database_min_pool_size {
+    warning('The database_min_pool_size parameter is deprecated, and will be removed in a future release.')
+  }
+
   validate_legacy(Oslo::Dbconn, 'validate_re', $database_connection,
     ['^(sqlite|mysql(\+pymysql)?|postgresql(\+psycopg2)?):\/\/(\S+:\S+@\S+\/\S+)?'])
 
   oslo::db { 'panko_config':
     connection              => $database_connection,
     connection_recycle_time => $database_connection_recycle_time,
-    min_pool_size           => $database_min_pool_size,
     db_max_retries          => $database_db_max_retries,
     max_retries             => $database_max_retries,
     retry_interval          => $database_retry_interval,

releasenotes/notes/deprecate_database_min_pool_size-option-a72d11a510c51344.yaml

@@ -0,0 +1,4 @@
+---
+deprecations:
+  - database_min_pool_size option is now deprecated for removal, the
+    parameter has no effect.

spec/classes/panko_db_spec.rb

@@ -9,7 +9,6 @@ describe 'panko::db' do
         :db_max_retries          => '<SERVICE DEFAULT>',
         :connection              => 'sqlite:////var/lib/panko/panko.sqlite',
         :connection_recycle_time => '<SERVICE DEFAULT>',
-        :min_pool_size           => '<SERVICE DEFAULT>',
         :max_pool_size           => '<SERVICE DEFAULT>',
         :max_retries             => '<SERVICE DEFAULT>',
         :retry_interval          => '<SERVICE DEFAULT>',
@@ -22,7 +21,6 @@ describe 'panko::db' do
       let :params do
         { :database_connection              => 'mysql+pymysql://panko:panko@localhost/panko',
           :database_connection_recycle_time => '3601',
-          :database_min_pool_size           => '2',
           :database_db_max_retries          => '-1',
           :database_max_retries             => '11',
           :database_retry_interval          => '11',
@@ -38,7 +36,6 @@ describe 'panko::db' do
         :db_max_retries          => '-1',
         :connection              => 'mysql+pymysql://panko:panko@localhost/panko',
         :connection_recycle_time => '3601',
-        :min_pool_size           => '2',
         :max_pool_size           => '11',
         :max_retries             => '11',
         :retry_interval          => '11',