terraform: diff is split down into modules

terraform/context.go

@@ -831,7 +831,7 @@ func (c *Context) planWalkFn(result *Plan) depgraph.WalkFunc {
 
 		l.Lock()
 		if !diff.Empty() {
-			result.Diff.Resources[r.Id] = diff
+			result.Diff.RootModule().Resources[r.Id] = diff
 		}
 		l.Unlock()
 
@@ -872,7 +872,7 @@ func (c *Context) planDestroyWalkFn(result *Plan) depgraph.WalkFunc {
 
 			l.Lock()
 			defer l.Unlock()
-			result.Diff.Resources[r.Id] = &InstanceDiff{Destroy: true}
+			result.Diff.RootModule().Resources[r.Id] = &InstanceDiff{Destroy: true}
 		} else {
 			log.Printf("[DEBUG] %s: Not marking for destroy, no ID", r.Id)
 		}

terraform/context_test.go

@@ -1394,8 +1394,8 @@ func TestContextPlan(t *testing.T) {
 		t.Fatalf("err: %s", err)
 	}
 
-	if len(plan.Diff.Resources) < 2 {
+	if len(plan.Diff.RootModule().Resources) < 2 {
-		t.Fatalf("bad: %#v", plan.Diff.Resources)
+		t.Fatalf("bad: %#v", plan.Diff.RootModule().Resources)
 	}
 
 	actual := strings.TrimSpace(plan.String())
@@ -1458,8 +1458,8 @@ func TestContextPlan_nil(t *testing.T) {
 	if err != nil {
 		t.Fatalf("err: %s", err)
 	}
-	if len(plan.Diff.Resources) != 0 {
+	if len(plan.Diff.RootModule().Resources) != 0 {
-		t.Fatalf("bad: %#v", plan.Diff.Resources)
+		t.Fatalf("bad: %#v", plan.Diff.RootModule().Resources)
 	}
 }
 
@@ -1525,8 +1525,8 @@ func TestContextPlan_count(t *testing.T) {
 		t.Fatalf("err: %s", err)
 	}
 
-	if len(plan.Diff.Resources) < 6 {
+	if len(plan.Diff.RootModule().Resources) < 6 {
-		t.Fatalf("bad: %#v", plan.Diff.Resources)
+		t.Fatalf("bad: %#v", plan.Diff.RootModule().Resources)
 	}
 
 	actual := strings.TrimSpace(plan.String())
@@ -1715,8 +1715,8 @@ func TestContextPlan_destroy(t *testing.T) {
 		t.Fatalf("err: %s", err)
 	}
 
-	if len(plan.Diff.Resources) != 2 {
+	if len(plan.Diff.RootModule().Resources) != 2 {
-		t.Fatalf("bad: %#v", plan.Diff.Resources)
+		t.Fatalf("bad: %#v", plan.Diff.RootModule().Resources)
 	}
 
 	actual := strings.TrimSpace(plan.String())
@@ -1880,8 +1880,8 @@ func TestContextPlan_state(t *testing.T) {
 		t.Fatalf("err: %s", err)
 	}
 
-	if len(plan.Diff.Resources) < 2 {
+	if len(plan.Diff.RootModule().Resources) < 2 {
-		t.Fatalf("bad: %#v", plan.Diff.Resources)
+		t.Fatalf("bad: %#v", plan.Diff.RootModule().Resources)
 	}
 
 	actual := strings.TrimSpace(plan.String())

terraform/diff.go

@@ -1,29 +1,98 @@
 package terraform
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
+	"reflect"
 	"sort"
 	"strings"
-	"sync"
 )
 
-// Diff tracks the differences between resources to apply.
+// Diff trackes the changes that are necessary to apply a configuration
+// to an existing infrastructure.
 type Diff struct {
-	Resources map[string]*InstanceDiff
+	// Modules contains all the modules that have a diff
-	once      sync.Once
+	Modules []*ModuleDiff
+}
+
+// ModuleByPath is used to lookup the module diff for the given path.
+// This should be the prefered lookup mechanism as it allows for future
+// lookup optimizations.
+func (d *Diff) ModuleByPath(path []string) *ModuleDiff {
+	if d == nil {
+		return nil
+	}
+	for _, mod := range d.Modules {
+		if mod.Path == nil {
+			panic("missing module path")
+		}
+		if reflect.DeepEqual(mod.Path, path) {
+			return mod
+		}
+	}
+	return nil
+}
+
+// RootModule returns the ModuleState for the root module
+func (d *Diff) RootModule() *ModuleDiff {
+	root := d.ModuleByPath(rootModulePath)
+	if root == nil {
+		panic("missing root module")
+	}
+	return root
+}
+
+func (d *Diff) String() string {
+	var buf bytes.Buffer
+	for _, m := range d.Modules {
+		mStr := m.String()
+
+		// If we're the root module, we just write the output directly.
+		if reflect.DeepEqual(m.Path, rootModulePath) {
+			buf.WriteString(mStr + "\n")
+			continue
+		}
+
+		buf.WriteString(fmt.Sprintf("module.%s:\n", strings.Join(m.Path[1:], ".")))
+
+		s := bufio.NewScanner(strings.NewReader(mStr))
+		for s.Scan() {
+			buf.WriteString(fmt.Sprintf("  %s\n", s.Text()))
+		}
+	}
+
+	return strings.TrimSpace(buf.String())
 }
 
 func (d *Diff) init() {
-	d.once.Do(func() {
+	if d.Modules == nil {
+		rootDiff := &ModuleDiff{Path: rootModulePath}
+		d.Modules = []*ModuleDiff{rootDiff}
+	}
+	for _, m := range d.Modules {
+		m.init()
+	}
+}
+
+// ModuleDiff tracks the differences between resources to apply within
+// a single module.
+type ModuleDiff struct {
+	Path      []string
+	Resources map[string]*InstanceDiff
+}
+
+func (d *ModuleDiff) init() {
 	if d.Resources == nil {
 		d.Resources = make(map[string]*InstanceDiff)
 	}
-	})
+	for _, r := range d.Resources {
+		r.init()
+	}
 }
 
-// Empty returns true if the diff has no changes.
+// Empty returns true if the diff has no changes within this module.
-func (d *Diff) Empty() bool {
+func (d *ModuleDiff) Empty() bool {
 	if len(d.Resources) == 0 {
 		return true
 	}
@@ -39,7 +108,7 @@ func (d *Diff) Empty() bool {
 
 // String outputs the diff in a long but command-line friendly output
 // format that users can read to quickly inspect a diff.
-func (d *Diff) String() string {
+func (d *ModuleDiff) String() string {
 	var buf bytes.Buffer
 
 	names := make([]string, 0, len(d.Resources))
@@ -110,8 +179,6 @@ type InstanceDiff struct {
 	Attributes     map[string]*ResourceAttrDiff
 	Destroy        bool
 	DestroyTainted bool
-
-	once sync.Once
 }
 
 // ResourceAttrDiff is the diff of a single attribute of a resource.
@@ -143,11 +210,9 @@ const (
 )
 
 func (d *InstanceDiff) init() {
-	d.once.Do(func() {
 	if d.Attributes == nil {
 		d.Attributes = make(map[string]*ResourceAttrDiff)
 	}
-	})
 }
 
 // Empty returns true if this diff encapsulates no changes.

terraform/diff_test.go

@@ -5,8 +5,8 @@ import (
 	"testing"
 )
 
-func TestDiff_Empty(t *testing.T) {
+func TestModuleDiff_Empty(t *testing.T) {
-	diff := new(Diff)
+	diff := new(ModuleDiff)
 	if !diff.Empty() {
 		t.Fatal("should be empty")
 	}
@@ -38,8 +38,8 @@ func TestDiff_Empty(t *testing.T) {
 	}
 }
 
-func TestDiff_String(t *testing.T) {
+func TestModuleDiff_String(t *testing.T) {
-	diff := &Diff{
+	diff := &ModuleDiff{
 		Resources: map[string]*InstanceDiff{
 			"nodeA": &InstanceDiff{
 				Attributes: map[string]*ResourceAttrDiff{
@@ -62,7 +62,7 @@ func TestDiff_String(t *testing.T) {
 	}
 
 	actual := strings.TrimSpace(diff.String())
-	expected := strings.TrimSpace(diffStrBasic)
+	expected := strings.TrimSpace(moduleDiffStrBasic)
 	if actual != expected {
 		t.Fatalf("bad:\n%s", actual)
 	}
@@ -206,7 +206,7 @@ func TestResourceDiffSame(t *testing.T) {
 	}
 }
 
-const diffStrBasic = `
+const moduleDiffStrBasic = `
 CREATE: nodeA
   bar:     "foo" => "<computed>"
   foo:     "foo" => "bar"

terraform/graph.go

@@ -132,10 +132,14 @@ func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
 
 	config := currentModule.Config()
 
-	// Get the state of the module that we're working with.
+	// Get the state and diff of the module that we're working with.
-	var mod *ModuleState
+	var modDiff *ModuleDiff
+	var modState *ModuleState
+	if opts.Diff != nil {
+		modDiff = opts.Diff.ModuleByPath(opts.ModulePath)
+	}
 	if opts.State != nil {
-		mod = opts.State.ModuleByPath(opts.ModulePath)
+		modState = opts.State.ModuleByPath(opts.ModulePath)
 	}
 
 	log.Printf("[DEBUG] Creating graph...")
@@ -145,7 +149,7 @@ func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
 	// First, build the initial resource graph. This only has the resources
 	// and no dependencies. This only adds resources that are in the config
 	// and not "orphans" (that are in the state, but not in the config).
-	graphAddConfigResources(g, config, mod)
+	graphAddConfigResources(g, config, modState)
 
 	// Add the modules that are in the configuration.
 	if err := graphAddConfigModules(g, config, opts); err != nil {
@@ -155,12 +159,12 @@ func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
 	// Add explicit dependsOn dependencies to the graph
 	graphAddExplicitDeps(g)
 
-	if mod != nil {
+	if modState != nil {
 		// Next, add the state orphans if we have any
-		graphAddOrphans(g, config, mod)
+		graphAddOrphans(g, config, modState)
 
 		// Add tainted resources if we have any.
-		graphAddTainted(g, mod)
+		graphAddTainted(g, modState)
 	}
 
 	// Map the provider configurations to all of the resources
@@ -198,8 +202,8 @@ func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
 	}
 
 	// If we have a diff, then make sure to add that in
-	if opts.Diff != nil {
+	if modDiff != nil {
-		if err := graphAddDiff(g, opts.Diff); err != nil {
+		if err := graphAddDiff(g, modDiff); err != nil {
 			return nil, err
 		}
 	}
@@ -423,7 +427,7 @@ func graphAddConfigResources(
 // destroying the VPC's subnets first, whereas creating a VPC requires
 // doing it before the subnets are created. This function handles inserting
 // these nodes for you.
-func graphAddDiff(g *depgraph.Graph, d *Diff) error {
+func graphAddDiff(g *depgraph.Graph, d *ModuleDiff) error {
 	var nlist []*depgraph.Noun
 	for _, n := range g.Nouns {
 		rn, ok := n.Meta.(*GraphNodeResource)

terraform/graph_test.go

@@ -357,6 +357,9 @@ func TestGraphProvisioners(t *testing.T) {
 func TestGraphAddDiff(t *testing.T) {
 	m := testModule(t, "graph-diff")
 	diff := &Diff{
+		Modules: []*ModuleDiff{
+			&ModuleDiff{
+				Path: rootModulePath,
 				Resources: map[string]*InstanceDiff{
 					"aws_instance.foo": &InstanceDiff{
 						Attributes: map[string]*ResourceAttrDiff{
@@ -366,6 +369,8 @@ func TestGraphAddDiff(t *testing.T) {
 						},
 					},
 				},
+			},
+		},
 	}
 
 	g, err := Graph(&GraphOpts{Module: m, Diff: diff})
@@ -383,7 +388,7 @@ func TestGraphAddDiff(t *testing.T) {
 	n := g.Noun("aws_instance.foo")
 	rn := n.Meta.(*GraphNodeResource)
 
-	expected2 := diff.Resources["aws_instance.foo"]
+	expected2 := diff.RootModule().Resources["aws_instance.foo"]
 	actual2 := rn.Resource.Diff
 	if !reflect.DeepEqual(actual2, expected2) {
 		t.Fatalf("bad: %#v", actual2)
@@ -393,6 +398,9 @@ func TestGraphAddDiff(t *testing.T) {
 func TestGraphAddDiff_destroy(t *testing.T) {
 	m := testModule(t, "graph-diff-destroy")
 	diff := &Diff{
+		Modules: []*ModuleDiff{
+			&ModuleDiff{
+				Path: rootModulePath,
 				Resources: map[string]*InstanceDiff{
 					"aws_instance.foo": &InstanceDiff{
 						Destroy: true,
@@ -401,6 +409,8 @@ func TestGraphAddDiff_destroy(t *testing.T) {
 						Destroy: true,
 					},
 				},
+			},
+		},
 	}
 	state := &State{
 		Modules: []*ModuleState{
@@ -463,6 +473,9 @@ func TestGraphAddDiff_destroy(t *testing.T) {
 func TestGraphAddDiff_destroy_counts(t *testing.T) {
 	m := testModule(t, "graph-count")
 	diff := &Diff{
+		Modules: []*ModuleDiff{
+			&ModuleDiff{
+				Path: rootModulePath,
 				Resources: map[string]*InstanceDiff{
 					"aws_instance.web.0": &InstanceDiff{
 						Destroy: true,
@@ -477,6 +490,8 @@ func TestGraphAddDiff_destroy_counts(t *testing.T) {
 						Destroy: true,
 					},
 				},
+			},
+		},
 	}
 	state := &State{
 		Modules: []*ModuleState{

terraform/plan.go

@@ -55,7 +55,7 @@ func (p *Plan) String() string {
 	buf := new(bytes.Buffer)
 	buf.WriteString("DIFF:\n\n")
 	buf.WriteString(p.Diff.String())
-	buf.WriteString("\nSTATE:\n\n")
+	buf.WriteString("\n\nSTATE:\n\n")
 	buf.WriteString(p.State.String())
 	return buf.String()
 }

terraform/plan_test.go

@@ -11,6 +11,9 @@ func TestReadWritePlan(t *testing.T) {
 	plan := &Plan{
 		Config: testConfig(t, "new-good"),
 		Diff: &Diff{
+			Modules: []*ModuleDiff{
+				&ModuleDiff{
+					Path: rootModulePath,
 					Resources: map[string]*InstanceDiff{
 						"nodeA": &InstanceDiff{
 							Attributes: map[string]*ResourceAttrDiff{
@@ -31,6 +34,8 @@ func TestReadWritePlan(t *testing.T) {
 						},
 					},
 				},
+			},
+		},
 		State: &State{
 			Modules: []*ModuleState{
 				&ModuleState{