From 3d4937b7840e157f5b0134f6cdd1bb1b9370de7b Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Wed, 21 Sep 2016 14:43:18 -0700
Subject: [PATCH] terraform: FlatConfigTransformer

---
 .../transform-flat-config-basic/child/main.tf |  1 +
 .../transform-flat-config-basic/main.tf       |  6 ++
 terraform/transform_config_flat.go            | 72 +++++++++++++++++++
 terraform/transform_config_flat_test.go       | 40 +++++++++++
 4 files changed, 119 insertions(+)
 create mode 100644 terraform/test-fixtures/transform-flat-config-basic/child/main.tf
 create mode 100644 terraform/test-fixtures/transform-flat-config-basic/main.tf
 create mode 100644 terraform/transform_config_flat.go
 create mode 100644 terraform/transform_config_flat_test.go

diff --git a/terraform/test-fixtures/transform-flat-config-basic/child/main.tf b/terraform/test-fixtures/transform-flat-config-basic/child/main.tf
new file mode 100644
index 000000000..0c70b1b5d
--- /dev/null
+++ b/terraform/test-fixtures/transform-flat-config-basic/child/main.tf
@@ -0,0 +1 @@
+resource "aws_instance" "baz" {}
diff --git a/terraform/test-fixtures/transform-flat-config-basic/main.tf b/terraform/test-fixtures/transform-flat-config-basic/main.tf
new file mode 100644
index 000000000..c588350d4
--- /dev/null
+++ b/terraform/test-fixtures/transform-flat-config-basic/main.tf
@@ -0,0 +1,6 @@
+resource "aws_instance" "foo" {}
+resource "aws_instance" "bar" { value = "${aws_instance.foo.value}" }
+
+module "child" {
+    source = "./child"
+}
diff --git a/terraform/transform_config_flat.go b/terraform/transform_config_flat.go
new file mode 100644
index 000000000..9d13130d6
--- /dev/null
+++ b/terraform/transform_config_flat.go
@@ -0,0 +1,72 @@
+package terraform
+
+import (
+	"errors"
+
+	"github.com/hashicorp/terraform/config/module"
+	"github.com/hashicorp/terraform/dag"
+)
+
+// FlatConfigTransformer is a GraphTransformer that adds the configuration
+// to the graph. The module used to configure this transformer must be
+// the root module.
+//
+// In relation to ConfigTransformer: this is a newer generation config
+// transformer. It puts the _entire_ config into the graph (there is no
+// "flattening" step as before).
+type FlatConfigTransformer struct {
+	Concrete ConcreteResourceNodeFunc // What to turn resources into
+
+	Module *module.Tree
+}
+
+func (t *FlatConfigTransformer) Transform(g *Graph) error {
+	// If no module, we do nothing
+	if t.Module == nil {
+		return nil
+	}
+
+	// If the module is not loaded, that is an error
+	if !t.Module.Loaded() {
+		return errors.New("module must be loaded")
+	}
+
+	return t.transform(g, t.Module)
+}
+
+func (t *FlatConfigTransformer) transform(g *Graph, m *module.Tree) error {
+	// If no module, no problem
+	if m == nil {
+		return nil
+	}
+
+	// Transform all the children.
+	for _, c := range m.Children() {
+		if err := t.transform(g, c); err != nil {
+			return err
+		}
+	}
+
+	// Get the configuration for this module
+	config := m.Config()
+
+	// Write all the resources out
+	for _, r := range config.Resources {
+		// Grab the address for this resource
+		addr, err := parseResourceAddressConfig(r)
+		if err != nil {
+			return err
+		}
+		addr.Path = m.Path()
+
+		abstract := &NodeAbstractResource{Addr: addr}
+		var node dag.Vertex = abstract
+		if f := t.Concrete; f != nil {
+			node = f(abstract)
+		}
+
+		g.Add(node)
+	}
+
+	return nil
+}
diff --git a/terraform/transform_config_flat_test.go b/terraform/transform_config_flat_test.go
new file mode 100644
index 000000000..aa393d5a9
--- /dev/null
+++ b/terraform/transform_config_flat_test.go
@@ -0,0 +1,40 @@
+package terraform
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestFlatConfigTransformer_nilModule(t *testing.T) {
+	g := Graph{Path: RootModulePath}
+	tf := &FlatConfigTransformer{}
+	if err := tf.Transform(&g); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if len(g.Vertices()) > 0 {
+		t.Fatal("graph should be empty")
+	}
+}
+
+func TestFlatConfigTransformer(t *testing.T) {
+	g := Graph{Path: RootModulePath}
+	tf := &FlatConfigTransformer{
+		Module: testModule(t, "transform-flat-config-basic"),
+	}
+	if err := tf.Transform(&g); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(testTransformFlatConfigBasicStr)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
+const testTransformFlatConfigBasicStr = `
+aws_instance.bar
+aws_instance.foo
+module.child.aws_instance.baz
+`