terraform: outputs show up in the graph

terraform/graph_config_node.go

@@ -94,6 +94,37 @@ func (n *GraphNodeConfigModule) ProvidedBy() []string {
 	return result
 }
 
+// GraphNodeConfigOutput represents an output configured within the
+// configuration.
+type GraphNodeConfigOutput struct {
+	Output *config.Output
+}
+
+func (n *GraphNodeConfigOutput) Name() string {
+	return fmt.Sprintf("output.%s", n.Output.Name)
+}
+
+func (n *GraphNodeConfigOutput) DependableName() []string {
+	return []string{n.Name()}
+}
+
+func (n *GraphNodeConfigOutput) DependentOn() []string {
+	vars := n.Output.RawConfig.Variables
+	result := make([]string, 0, len(vars))
+	for _, v := range vars {
+		if vn := varNameForVar(v); vn != "" {
+			result = append(result, vn)
+		}
+	}
+
+	return result
+}
+
+// GraphNodeEvalable impl.
+func (n *GraphNodeConfigOutput) EvalTree() EvalNode {
+	return nil
+}
+
 // GraphNodeConfigProvider represents a configured provider within the
 // configuration graph. These are only immediately in the graph when an
 // explicit `provider` configuration block is in the configuration.

terraform/test-fixtures/graph-outputs/main.tf

@@ -0,0 +1,5 @@
+resource "aws_instance" "foo" {}
+
+output "foo" {
+    value = "${aws_instance.foo.value}"
+}

terraform/transform_config.go

@@ -63,6 +63,11 @@ func (t *ConfigTransformer) Transform(g *Graph) error {
 		})
 	}
 
+	// Write all the outputs out
+	for _, o := range config.Outputs {
+		nodes = append(nodes, &GraphNodeConfigOutput{Output: o})
+	}
+
 	// Err is where the final error value will go if there is one
 	var err error
 

terraform/transform_config_test.go

@@ -72,6 +72,20 @@ func TestConfigTransformer_modules(t *testing.T) {
 	}
 }
 
+func TestConfigTransformer_outputs(t *testing.T) {
+	g := Graph{Path: RootModulePath}
+	tf := &ConfigTransformer{Module: testModule(t, "graph-outputs")}
+	if err := tf.Transform(&g); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(testGraphOutputsStr)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
 func TestConfigTransformer_errMissingDeps(t *testing.T) {
 	g := Graph{Path: RootModulePath}
 	tf := &ConfigTransformer{Module: testModule(t, "graph-missing-deps")}
@@ -106,3 +120,9 @@ module.consul
   aws_security_group.firewall
 provider.aws
 `
+
+const testGraphOutputsStr = `
+aws_instance.foo
+output.foo
+  aws_instance.foo
+`