Replace validate_apache_loglevel() with data type

The function was introduced before Puppet 4 was released.  It was
originally created to reduce duplicated use of stdlib's `validate_re`.

See #1097

manifests/init.pp

@@ -195,8 +195,8 @@
 #   > **Note**: Do not configure this parameter manually without special reason.
 #
 # @param log_level
-#   Changes the error log's verbosity. Valid options are: `alert`, `crit`, `debug`, `emerg`, `error`, 
-#   `info`, `notice` and `warn`.
+#   Configures the apache [LogLevel](https://httpd.apache.org/docs/current/mod/core.html#loglevel) directive
+#   which adjusts the verbosity of the messages recorded in the error logs.
 #
 # @param log_formats
 #   Define additional `LogFormat` directives. Values: A hash, such as:
@@ -520,7 +520,7 @@
   $limitreqfields                                                       = '100',
   $logroot                                                              = $::apache::params::logroot,
   $logroot_mode                                                         = $::apache::params::logroot_mode,
-  $log_level                                                            = $::apache::params::log_level,
+  Apache::LogLevel $log_level                                           = $::apache::params::log_level,
   $log_formats                                                          = {},
   $ssl_file                                                             = undef,
   $ports_file                                                           = $::apache::params::ports_file,
@@ -602,8 +602,6 @@
     }
   }
 
-  apache::validate_apache_log_level($log_level)
-
   class { '::apache::service':
     service_name    => $service_name,
     service_enable  => $service_enable,

manifests/vhost.pp

@@ -1735,7 +1735,7 @@
   $logroot_mode                                                                     = undef,
   $logroot_owner                                                                    = undef,
   $logroot_group                                                                    = undef,
-  $log_level                                                                        = undef,
+  Optional[Apache::LogLevel] $log_level                                             = undef,
   Boolean $access_log                                                               = true,
   $access_log_file                                                                  = false,
   $access_log_pipe                                                                  = false,
@@ -1940,10 +1940,6 @@
 
   # Input validation begins
 
-  if $log_level {
-    apache::validate_apache_log_level($log_level)
-  }
-
   if $access_log_file and $access_log_pipe {
     fail("Apache::Vhost[${name}]: 'access_log_file' and 'access_log_pipe' cannot be defined at the same time")
   }

spec/type_aliases/loglevel_spec.rb

@@ -0,0 +1,23 @@
+require 'spec_helper'
+
+describe 'Apache::LogLevel' do
+  [
+    'info',
+    'warn ssl:info',
+    'warn mod_ssl.c:info',
+    'warn mod_ssl.c:info',
+    'warn ssl_module:info',
+    'trace4',
+  ].each do |allowed_value|
+    it { is_expected.to allow_value(allowed_value) }
+  end
+
+  [
+    'garbage',
+    '',
+    [],
+    ['info'],
+  ].each do |invalid_value|
+    it { is_expected.not_to allow_value(invalid_value) }
+  end
+end

types/loglevel.pp

@@ -0,0 +1,27 @@
+# @summary A string that conforms to the Apache `LogLevel` syntax.
+#
+# A string that conforms to the Apache `LogLevel` syntax.
+# Different levels can be specified for individual apache modules.
+#
+# ie. `[module:]level [module:level] ...`
+#
+# The levels are (in order of decreasing significance):
+# * `emerg`
+# * `alert`
+# * `crit`
+# * `error`
+# * `warn`
+# * `notice`
+# * `info`
+# * `debug`
+# * `trace1`
+# * `trace2`
+# * `trace3`
+# * `trace4`
+# * `trace5`
+# * `trace6`
+# * `trace7`
+# * `trace8`
+#
+# @see https://httpd.apache.org/docs/current/mod/core.html#loglevel
+type Apache::LogLevel = Pattern[/(emerg|alert|crit|error|warn|notice|info|debug|trace[1-8])/]