Uses the LoadPlugin syntax with bracket when supported

This is fully backwards compatible.

The version check is done exactly how it's supposed to ; I checked the
sources of collectd to be sure there's no conflict.

Globals has always defaulted to false so I'm making it default to false
in this module. I'm not setting it undef because that's a boolean and we
got issues with checking if a boolean is false or undef (see redhat-openstack#182).

manifests/plugin.pp

@@ -1,9 +1,11 @@
 #
 define collectd::plugin (
-  $ensure  = 'present',
-  $content = undef,
-  $order   = '10',
-  $plugin  = $name
+  $ensure   = 'present',
+  $content  = undef,
+  $order    = '10',
+  $globals  = false,
+  $interval = undef,
+  $plugin   = $name
 ) {
 
   include collectd::params
@@ -16,7 +18,7 @@
     owner   => root,
     group   => $root_group,
     mode    => '0640',
-    content => "# Generated by Puppet\nLoadPlugin ${plugin}\n\n${content}",
+    content => template('collectd/loadplugin.conf.erb'),
     notify  => Service['collectd'],
   }
 

spec/classes/collectd_plugin_swap_spec.rb

@@ -26,7 +26,7 @@
       should contain_file('swap.load').with({
         :ensure  => 'present',
         :path    => '/etc/collectd.d/10-swap.conf',
-        :content => "# Generated by Puppet\nLoadPlugin swap\n\n<Plugin swap>\n  ReportByDevice false\n</Plugin>\n",
+        :content => "# Generated by Puppet\n<LoadPlugin swap>\n  Globals false\n</LoadPlugin>\n\n<Plugin swap>\n  ReportByDevice false\n</Plugin>\n\n",
       })
     end
   end
@@ -42,7 +42,7 @@
       should contain_file('swap.load').with({
         :ensure  => 'present',
         :path    => '/etc/collectd.d/10-swap.conf',
-        :content => "# Generated by Puppet\nLoadPlugin swap\n\n<Plugin swap>\n  ReportByDevice false\n  ReportBytes true\n</Plugin>\n",
+        :content => "# Generated by Puppet\n<LoadPlugin swap>\n  Globals false\n</LoadPlugin>\n\n<Plugin swap>\n  ReportByDevice false\n  ReportBytes true\n</Plugin>\n\n",
       })
     end
   end

templates/loadplugin.conf.erb

@@ -0,0 +1,13 @@
+# Generated by Puppet
+<% if @collectd_version and (scope.function_versioncmp([@collectd_version, '4.9.4']) >= 0) -%>
+<LoadPlugin <%= @plugin %>>
+  Globals <%= @globals %>
+<% if @interval and @collectd_version and (scope.function_versioncmp([@collectd_version, '5.2']) >= 0) -%>
+  Interval <%= @interval %>
+<% end -%>
+</LoadPlugin>
+<% else -%>
+LoadPlugin <%= @plugin %>
+<% end -%>
+
+<%= @content %>