Merge pull request #6005 from coderanger/template-lazy

Allow lazy{} to be used in template resource variables.

4 files changed, 59 insertions, 1 deletions

diff --git a/lib/chef/provider/template/content.rb b/lib/chef/provider/template/content.rb
index acf200621d..b40794564a 100644
--- a/lib/chef/provider/template/content.rb
+++ b/lib/chef/provider/template/content.rb
@@ -36,7 +36,30 @@ class Chef
         private
 
         def file_for_provider
-          context = TemplateContext.new(new_resource.variables)
+          # Deal with any DelayedEvaluator values in the template variables.
+          visitor = lambda do |obj|
+            case obj
+            when Hash
+              # If this is an Attribute object, we need to change class otherwise
+              # we get the immutable behavior. This could probably be fixed by
+              # using Hash#transform_values once we only support Ruby 2.4.
+              obj_class = obj.is_a?(Chef::Node::ImmutableMash) ? Mash : obj.class
+              # Avoid mutating hashes in the resource in case we're changing anything.
+              obj.each_with_object(obj_class.new) do |(key, value), memo|
+                memo[key] = visitor.call(value)
+              end
+            when Array
+              # Avoid mutating arrays in the resource in case we're changing anything.
+              obj.map { |value| visitor.call(value) }
+            when DelayedEvaluator
+              new_resource.instance_eval(&obj)
+            else
+              obj
+            end
+          end
+          variables = visitor.call(new_resource.variables)
+
+          context = TemplateContext.new(variables)
           context[:node] = run_context.node
           context[:template_finder] = template_finder
 
diff --git a/spec/data/cookbooks/openldap/templates/default/openldap_nested_variable_stuff.erb b/spec/data/cookbooks/openldap/templates/default/openldap_nested_variable_stuff.erb
new file mode 100644
index 0000000000..5ebee33806
--- /dev/null
+++ b/spec/data/cookbooks/openldap/templates/default/openldap_nested_variable_stuff.erb
@@ -0,0 +1 @@
+super secret is <%= @secret.first["key"] -%>
diff --git a/spec/functional/resource/template_spec.rb b/spec/functional/resource/template_spec.rb
index 32529fbb0c..b9a39255f4 100644
--- a/spec/functional/resource/template_spec.rb
+++ b/spec/functional/resource/template_spec.rb
@@ -32,6 +32,7 @@ describe Chef::Resource::Template do
   let(:node) do
     node = Chef::Node.new
     node.normal[:slappiness] = "a warm gun"
+    node.normal[:nested][:secret] = "value"
     node
   end
 
@@ -209,4 +210,36 @@ describe Chef::Resource::Template do
     end
   end
 
+  describe "when template variables contain lazy{} calls" do
+    it "resolves the DelayedEvaluator" do
+      resource.source("openldap_variable_stuff.conf.erb")
+      resource.variables(:secret => Chef::DelayedEvaluator.new { "nutella" })
+      resource.run_action(:create)
+      expect(IO.read(path)).to eq("super secret is nutella")
+    end
+
+    it "does not mutate the resource variables" do
+      resource.source("openldap_variable_stuff.conf.erb")
+      resource.variables(:secret => Chef::DelayedEvaluator.new { "nutella" })
+      resource.run_action(:create)
+      expect(resource.variables[:secret]).to be_a Chef::DelayedEvaluator
+    end
+
+    it "resolves the DelayedEvaluator when deeply nested" do
+      resource.source("openldap_nested_variable_stuff.erb")
+      resource.variables(:secret => [{ "key" => Chef::DelayedEvaluator.new { "nutella" } }])
+      resource.run_action(:create)
+      expect(IO.read(path)).to eq("super secret is nutella")
+    end
+  end
+
+  describe "when passing a node attribute mash as a template variable" do
+    it "uses the node attributes like a hash" do
+      resource.source("openldap_variable_stuff.conf.erb")
+      resource.variables(node[:nested])
+      resource.run_action(:create)
+      expect(IO.read(path)).to eq("super secret is value")
+    end
+  end
+
 end
diff --git a/spec/unit/cookbook/syntax_check_spec.rb b/spec/unit/cookbook/syntax_check_spec.rb
index aa6fe49eb9..a24fa3ab2a 100644
--- a/spec/unit/cookbook/syntax_check_spec.rb
+++ b/spec/unit/cookbook/syntax_check_spec.rb
@@ -60,6 +60,7 @@ describe Chef::Cookbook::SyntaxCheck do
                     openldap_stuff.conf.erb
                     nested_openldap_partials.erb
                     nested_partial.erb
+                    openldap_nested_variable_stuff.erb
                     openldap_variable_stuff.conf.erb
                     test.erb
                     some_windows_line_endings.erb