3 files changed, 86 insertions, 0 deletions
diff --git a/README.markdown b/README.markdown
index 21f7e7f..922383c 100644
--- a/README.markdown
+++ b/README.markdown
@@ -209,6 +209,25 @@ Example:
 
 - *Type*: rvalue
 
+getparam
+--------
+
+Takes a resource reference and name of the parameter and returns
+value of resource's parameter.
+
+For example:
+
+    define example_resource($param) {
+    }
+
+    example_resource { "example_resource_instance":
+        param => "param_value"
+    }
+
+    getparam(Example_resource["example_resource_instance"], "param")
+
+- *Type*: rvalue
+
 getvar
 ------
 Lookup a variable in a remote namespace.
diff --git a/lib/puppet/parser/functions/getparam.rb b/lib/puppet/parser/functions/getparam.rb
new file mode 100644
index 0000000..0962656
--- /dev/null
+++ b/lib/puppet/parser/functions/getparam.rb
@@ -0,0 +1,33 @@
+# Test whether a given class or definition is defined
+require 'puppet/parser/functions'
+
+Puppet::Parser::Functions.newfunction(:getparam,
+                                      :type => :rvalue,
+                                      :doc => <<-'ENDOFDOC'
+Takes a resource reference and name of the parameter and
+returns value of resource's parameter.
+
+*Examples:*
+
+    define example_resource($param) {
+    }
+
+    example_resource { "example_resource_instance":
+        param => "param_value"
+    }
+
+    getparam(Example_resource["example_resource_instance"], "param")
+
+Would return: param_value
+ENDOFDOC
+) do |vals|
+  reference, param = vals
+  raise(ArgumentError, 'Must specify a reference') unless reference
+  raise(ArgumentError, 'Must specify name of a parameter') unless param and param.instance_of? String
+
+  if resource = findresource(reference.to_s)
+    return resource[param] if resource[param]
+  end
+
+  return ''
+end
diff --git a/spec/functions/getparam_spec.rb b/spec/functions/getparam_spec.rb
new file mode 100644
index 0000000..d9c50a6
--- /dev/null
+++ b/spec/functions/getparam_spec.rb
@@ -0,0 +1,34 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper'
+
+require 'rspec-puppet'
+describe 'getparam' do
+  describe 'when a resource is not specified' do
+    it do
+      should run.with_params().and_raise_error(ArgumentError)
+      should run.with_params('User[dan]').and_raise_error(ArgumentError)
+      should run.with_params('User[dan]', {}).and_raise_error(ArgumentError)
+      should run.with_params('User[dan]', '').and_return('')
+    end
+  end
+  describe 'when compared against a resource with no params' do
+    let :pre_condition do
+      'user { "dan": }'
+    end
+    it do
+      should run.with_params('User[dan]', 'shell').and_return('')
+    end
+  end
+
+  describe 'when compared against a resource with params' do
+    let :pre_condition do
+      'user { "dan": ensure => present, shell => "/bin/sh", managehome => false}'
+    end
+    it do
+      should run.with_params('User[dan]', 'shell').and_return('/bin/sh')
+      should run.with_params('User[dan]', '').and_return('')
+      should run.with_params('User[dan]', 'ensure').and_return('present')
+      should run.with_params('User[dan]', 'managehome').and_return(false)
+    end
+  end
+end