--- /dev/null
+# Test whether a given class or definition is defined
+require 'puppet/parser/functions'
+
+Puppet::Parser::Functions.newfunction(:ensure_resource,
+ :type => :statement,
+ :doc => <<-'ENDOFDOC'
+Takes a resource type, title, and a list of attributes that describe a
+resource.
+
+ user { 'dan':
+ ensure => present,
+ }
+
+This example only creates the resource if it does not already exist:
+
+ ensure_resource('user', 'dan', {'ensure' => 'present' })
+
+If the resource already exists but does not match the specified parameters,
+this function will attempt to recreate the resource leading to a duplicate
+resource definition error.
+
+An array of resources can also be passed in and each will be created with
+the type and parameters specified if it doesn't already exist.
+
+ ensure_resource('user', ['dan','alex'], {'ensure' => 'present'})
+
+ENDOFDOC
+) do |vals|
+ type, title, params = vals
+ raise(ArgumentError, 'Must specify a type') unless type
+ raise(ArgumentError, 'Must specify a title') unless title
+ params ||= {}
+
+ items = [title].flatten
+
+ items.each do |item|
+ Puppet::Parser::Functions.function(:defined_with_params)
+ if function_defined_with_params(["#{type}[#{item}]", params])
+ Puppet.debug("Resource #{type}[#{item}] with params #{params} not created because it already exists")
+ else
+ Puppet.debug("Create new resource #{type}[#{item}] with params #{params}")
+ Puppet::Parser::Functions.function(:create_resources)
+ function_create_resources([type.capitalize, { item => params }])
+ end
+ end
+end