Adding a class for using templates directly within resources

(i.e., client-side templates).  This would really only be used
for composite resources that pass the results of the template
on to generated resources.

1 files changed, 38 insertions, 0 deletions

diff --git a/lib/puppet/util/resource_template.rb b/lib/puppet/util/resource_template.rb
new file mode 100644
index 000000000..f85078005
--- /dev/null
+++ b/lib/puppet/util/resource_template.rb
@@ -0,0 +1,38 @@
+require 'puppet/util'
+require 'puppet/util/logging'
+require 'erb'
+
+# A template wrapper that evaluates a template in the
+# context of a resource, allowing the resource attributes
+# to be looked up from within the template.
+#  This provides functionality essentially equivalent to
+# the language's template() function.  You pass your file
+# path and the resource you want to use into the initialization
+# method, then call result() on the instance, and you get back
+# a chunk of text.
+#  The resource's parameters are available as instance variables
+# (as opposed to the language, where we use a method_missing trick).
+class Puppet::Util::ResourceTemplate
+    include Puppet::Util::Logging
+
+    def evaluate
+        set_resource_variables
+        ERB.new(File.read(@file), 0, "-").result(binding)
+    end
+
+    def initialize(file, resource)
+        raise ArgumentError, "Template %s does not exist" % file unless FileTest.exist?(file)
+        @file = file
+        @resource = resource
+    end
+
+    private
+
+    def set_resource_variables
+        @resource.to_hash.each do |param, value|
+            var = "@#{param.to_s}"
+            instance_variable_set(var, value)
+        end
+    end
+end
+