Use concat to define the process plugin config.

Adding a parser function to keep it compatible with the old way
to define process matches.

lib/puppet/parser/functions/collectd_convert_processmatch.rb

@@ -0,0 +1,32 @@
+module Puppet::Parser::Functions
+
+  newfunction(:collectd_convert_processmatch, :type => :rvalue, :arity => 1, :doc => <<-ENDDOC
+    Converts the array from the old style to define process matches in the
+    processes plugin into a create_resources compatible hash which
+    can be used with the new style define.
+    
+    Example:
+      [ { 'name' => 'foo', 'regex' => '.*' } , { 'name' => 'bar', 'regex' => '[0-9]+' } ]
+    will be converted to
+      { 'foo' => { 'regex' => '.*' } , 'bar' => { 'regex' => '[0-9]+' } }
+    ENDDOC
+  ) do |args|
+    if args.size != 1 then
+      raise(Puppet::ParseError, "convert_process_match_array(): Needs exactly one argument")
+    end
+
+    parray = args[0]
+    unless parray.is_a?(Array)
+      raise(Puppet::ParseError, "convert_process_match_array(): Needs an array as argument")
+    end
+
+    phash = Hash.new
+
+    parray.each do |p|
+      phash[p['name']] = { 'regex' => p['regex'] }
+    end
+
+    return phash
+  end
+end
+

manifests/plugin/processes.pp

@@ -10,7 +10,41 @@
 
   collectd::plugin {'processes':
     ensure   => $ensure,
-    content  => template('collectd/plugin/processes.conf.erb'),
-    interval => $interval,
   }
+
+  concat{"${collectd::params::plugin_conf_dir}/processes-config.conf":
+    ensure         => $ensure,
+    mode           => '0640',
+    owner          => 'root',
+    group          => $collectd::params::root_group,
+    notify         => Service['collectd'],
+    ensure_newline => true,
+  }
+  concat::fragment{'collectd_plugin_processes_conf_header':
+    ensure  => $ensure,
+    order   => '00',
+    content => '<Plugin processes>',
+    target  => "${collectd::params::plugin_conf_dir}/processes-config.conf",
+  }
+  concat::fragment{'collectd_plugin_processes_conf_footer':
+    ensure  => $ensure,
+    order   => '99',
+    content => '</Plugin>',
+    target  => "${collectd::params::plugin_conf_dir}/processes-config.conf",
+  }
+
+
+  if $processes {
+    collectd::plugin::processes::process { $processes : }
+  }
+  if $process_matches {
+    $process_matches_resources = collectd_convert_processmatch($process_matches)
+    $defaults = { 'ensure' => $ensure }
+    create_resources(
+      collectd::plugin::processes::processmatch,
+      $process_matches_resources,
+      $defaults
+    )
+  }
+
 }

manifests/plugin/processes/process.pp

@@ -0,0 +1,16 @@
+define collectd::plugin::processes::process (
+  $process   = $name,
+  $ensure    = 'present'
+){
+
+  include collectd::plugin::processes
+  include collectd::params
+
+  concat::fragment{"collectd_plugin_processes_conf_process_${process}":
+    ensure  => $ensure,
+    order   => '50',
+    content => "Process \"${process}\"\n",
+    target  => "${collectd::params::plugin_conf_dir}/processes-config.conf"
+  }
+
+}

manifests/plugin/processes/processmatch.pp

@@ -0,0 +1,17 @@
+define collectd::plugin::processes::processmatch (
+  $regex,
+  $ensure    = 'present',
+  $matchname = $name
+){
+
+  include collectd::plugin::processes
+  include collectd::params
+
+  concat::fragment{"collectd_plugin_processes_conf_processmatch_${matchname}":
+    ensure  => $ensure,
+    order   => '51',
+    content => "ProcessMatch \"${matchname}\" \"${regex}\"\n",
+    target  => "${collectd::params::plugin_conf_dir}/processes-config.conf"
+  }
+
+}