added templatewlv function (allows passing local variables to templates)

2 files changed, 80 insertions, 0 deletions

diff --git a/puppet/modules/templatewlv/lib/puppet/parser/functions/templatewlv.rb b/puppet/modules/templatewlv/lib/puppet/parser/functions/templatewlv.rb
new file mode 100644
index 00000000..c9579e2c
--- /dev/null
+++ b/puppet/modules/templatewlv/lib/puppet/parser/functions/templatewlv.rb
@@ -0,0 +1,41 @@
+require File.join(File.dirname(__FILE__),'../templatewrapperwlv')
+Puppet::Parser::Functions::newfunction(:templatewlv, :type => :rvalue, :arity => -2, :doc =>
+  "A wrapper around puppet's template function. See
+  [the templating docs](http://docs.puppetlabs.com/guides/templating.html) for 
+  the basic functionality.
+
+  Additionally, you can pass a hash, as the last argument, which will be turned into
+  local variables and available to the template itself. This will allow you  to define
+  variables in a template and pass them down to a template you include in the current
+  template. An example:
+
+    scope.function_templatewlv(['sub_template', { 'local_var' => 'value' }])
+  
+  Note that if multiple templates are specified, their output is all
+  concatenated and returned as the output of the function.") do |vals|
+
+    if vals.last.is_a?(Hash)
+      local_vars = vals.last
+      local_vals = vals[0..-2]
+    else
+      local_vars = {}
+      local_vals = vals
+    end
+
+    result = nil
+    local_vals.collect do |file|
+      # Use a wrapper, so the template can't get access to the full
+      # Scope object.
+      debug "Retrieving template #{file}"
+
+      wrapper = Puppet::Parser::TemplateWrapperWlv.new(self,local_vars)
+      wrapper.file = file
+      begin
+        wrapper.result
+      rescue => detail
+        info = detail.backtrace.first.split(':')
+        raise Puppet::ParseError,
+          "Failed to parse template #{file}:\n  Filepath: #{info[0]}\n  Line: #{info[1]}\n  Detail: #{detail}\n"
+      end
+    end.join("")
+end
diff --git a/puppet/modules/templatewlv/lib/puppet/parser/templatewrapperwlv.rb b/puppet/modules/templatewlv/lib/puppet/parser/templatewrapperwlv.rb
new file mode 100644
index 00000000..f1753e18
--- /dev/null
+++ b/puppet/modules/templatewlv/lib/puppet/parser/templatewrapperwlv.rb
@@ -0,0 +1,39 @@
+# A wrapper for templates, that allows you to additionally define
+# local variables
+class Puppet::Parser::TemplateWrapperWlv < Puppet::Parser::TemplateWrapper
+  attr_reader :local_vars
+  def initialize(scope, local_vars)
+    super(scope)
+    @local_vars = local_vars
+  end
+
+  # Should return true if a variable is defined, false if it is not
+  def has_variable?(name)
+    super(name) || local_vars.keys.include?(name.to_s)
+  end
+
+  def method_missing(name, *args)
+    if local_vars.keys.include?(n=name.to_s)
+      local_vars[n]
+    else
+      super(name, *args)
+    end
+  end
+
+  def result(string = nil)
+    # Expose all the variables in our scope as instance variables of the
+    # current object, making it possible to access them without conflict
+    # to the regular methods.
+    benchmark(:debug, "Bound local template variables for #{@__file__}") do
+      local_vars.each do |name, value|
+        if name.kind_of?(String)
+          realname = name.gsub(/[^\w]/, "_")
+        else
+          realname = name
+        end
+        instance_variable_set("@#{realname}", value)
+      end
+    end
+    super(string)
+  end
+end