(PDB-3060) Add concurrent-writes parameter.

Add a parameter to govern the command-processing config section's
`concurrent-writes` setting.

Author: aperiodic

README.md

@@ -664,6 +664,11 @@ If `true`, puppet will manage your iptables rules for PuppetDB via the
 The number of command processing threads to use. Defaults to `undef`, using the
 PuppetDB built-in default.
 
+####`concurrent_writes`
+
+The number of threads allowed to write to disk at any one time. Defaults to
+`undef`, which uses the PuppetDB built-in default.
+
 ####`store_usage`
 
 The amount of disk space (in MB) to allow for persistent message storage.

manifests/init.pp

@@ -66,6 +66,7 @@
   $merge_default_java_args           = $puppetdb::params::merge_default_java_args,
   $max_threads                       = $puppetdb::params::max_threads,
   $command_threads                   = $puppetdb::params::command_threads,
+  $concurrent_writes                 = $puppetdb::params::concurrent_writes,
   $store_usage                       = $puppetdb::params::store_usage,
   $temp_usage                        = $puppetdb::params::temp_usage,
   $certificate_whitelist_file        = $puppetdb::params::certificate_whitelist_file,
@@ -136,6 +137,7 @@
     puppetdb_group                    => $puppetdb_group,
     manage_firewall                   => $manage_firewall,
     command_threads                   => $command_threads,
+    concurrent_writes                 => $concurrent_writes,
     store_usage                       => $store_usage,
     temp_usage                        => $temp_usage,
     certificate_whitelist_file        => $certificate_whitelist_file,

manifests/params.pp

@@ -158,6 +158,7 @@
   $puppetdb_service_status  = 'running'
 
   $command_threads          = undef
+  $concurrent_writes        = undef
   $store_usage              = undef
   $temp_usage               = undef
 

manifests/server.pp

@@ -61,6 +61,7 @@
   $merge_default_java_args           = $puppetdb::params::merge_default_java_args,
   $max_threads                       = $puppetdb::params::max_threads,
   $command_threads                   = $puppetdb::params::command_threads,
+  $concurrent_writes                 = $puppetdb::params::concurrent_writes,
   $store_usage                       = $puppetdb::params::store_usage,
   $temp_usage                        = $puppetdb::params::temp_usage,
   $certificate_whitelist_file        = $puppetdb::params::certificate_whitelist_file,
@@ -147,11 +148,12 @@
   }
 
   class { 'puppetdb::server::command_processing':
-    command_threads => $command_threads,
-    store_usage     => $store_usage,
-    temp_usage      => $temp_usage,
-    confdir         => $confdir,
-    notify          => Service[$puppetdb_service],
+    command_threads   => $command_threads,
+    concurrent_writes => $concurrent_writes,
+    store_usage       => $store_usage,
+    temp_usage        => $temp_usage,
+    confdir           => $confdir,
+    notify            => Service[$puppetdb_service],
   }
 
   class { 'puppetdb::server::database':

manifests/server/command_processing.pp

@@ -1,9 +1,10 @@
 # PRIVATE CLASS - do not use directly
 class puppetdb::server::command_processing (
-  $command_threads = $puppetdb::params::command_threads,
-  $store_usage     = $puppetdb::params::store_usage,
-  $temp_usage      = $puppetdb::params::temp_usage,
-  $confdir         = $puppetdb::params::confdir,
+  $command_threads   = $puppetdb::params::command_threads,
+  $concurrent_writes = $puppetdb::params::concurrent_writes,
+  $store_usage       = $puppetdb::params::store_usage,
+  $temp_usage        = $puppetdb::params::temp_usage,
+  $confdir           = $puppetdb::params::confdir,
 ) inherits puppetdb::params {
 
   $config_ini = "${confdir}/config.ini"
@@ -28,6 +29,18 @@
     }
   }
 
+  if $concurrent_writes {
+    ini_setting { 'puppetdb_command_processing_concurrent_writes':
+      setting => 'concurrent-writes',
+      value   => $concurrent_writes,
+    }
+  } else {
+    ini_setting { 'puppetdb_command_processing_concurrent_writes':
+      ensure  => 'absent',
+      setting => 'concurrent-writes',
+    }
+  }
+
   if $store_usage {
     ini_setting { 'puppetdb_command_processing_store_usage':
       setting => 'store-usage',

spec/unit/classes/server/command_processing_spec.rb

@@ -19,6 +19,13 @@
              'section' => 'command-processing',
              'setting' => 'threads'
              )}
+      it { should contain_ini_setting('puppetdb_command_processing_concurrent_writes').
+        with(
+             'ensure'  => 'absent',
+             'path'    => '/etc/puppetlabs/puppetdb/conf.d/config.ini',
+             'section' => 'command-processing',
+             'setting' => 'concurrent-writes'
+             )}
       it { should contain_ini_setting('puppetdb_command_processing_store_usage').
         with(
              'ensure'  => 'absent',
@@ -63,9 +70,10 @@
     describe 'when using custom values' do
       let(:params) do
         {
-          'command_threads' => 10,
-          'store_usage'     => 4000,
-          'temp_usage'      => 2000,
+          'command_threads'   => 10,
+          'concurrent_writes' => 3,
+          'store_usage'       => 4000,
+          'temp_usage'        => 2000,
         }
       end
       it { should contain_ini_setting('puppetdb_command_processing_threads').
@@ -76,6 +84,14 @@
              'setting' => 'threads',
              'value'   => '10'
              )}
+      it { should contain_ini_setting('puppetdb_command_processing_concurrent_writes').
+        with(
+             'ensure'  => 'present',
+             'path'    => '/etc/puppetlabs/puppetdb/conf.d/config.ini',
+             'section' => 'command-processing',
+             'setting' => 'concurrent-writes',
+             'value'   => '3'
+             )}
       it { should contain_ini_setting('puppetdb_command_processing_store_usage').
         with(
              'ensure'  => 'present',