core: formalize resource addressing

Only used in targets for now. The plan is to use this for interpolation
as well.

This allows us to target:

 * individual resources expanded by `count` using bracket / index notation.
 * deposed / tainted resources with an `InstanceType` field after name

Docs to follow.

terraform/context_test.go

@@ -1535,6 +1535,98 @@ func TestContext2Refresh_targeted(t *testing.T) {
 	}
 }
 
+func TestContext2Refresh_targetedCount(t *testing.T) {
+	p := testProvider("aws")
+	m := testModule(t, "refresh-targeted-count")
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: &State{
+			Modules: []*ModuleState{
+				&ModuleState{
+					Path: rootModulePath,
+					Resources: map[string]*ResourceState{
+						"aws_vpc.metoo":      resourceState("aws_vpc", "vpc-abc123"),
+						"aws_instance.notme": resourceState("aws_instance", "i-bcd345"),
+						"aws_instance.me.0":  resourceState("aws_instance", "i-abc123"),
+						"aws_instance.me.1":  resourceState("aws_instance", "i-cde567"),
+						"aws_instance.me.2":  resourceState("aws_instance", "i-cde789"),
+						"aws_elb.meneither":  resourceState("aws_elb", "lb-abc123"),
+					},
+				},
+			},
+		},
+		Targets: []string{"aws_instance.me"},
+	})
+
+	refreshedResources := make([]string, 0, 2)
+	p.RefreshFn = func(i *InstanceInfo, is *InstanceState) (*InstanceState, error) {
+		refreshedResources = append(refreshedResources, i.Id)
+		return is, nil
+	}
+
+	_, err := ctx.Refresh()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	// Target didn't specify index, so we should get all our instances
+	expected := []string{
+		"aws_vpc.metoo",
+		"aws_instance.me.0",
+		"aws_instance.me.1",
+		"aws_instance.me.2",
+	}
+	if !reflect.DeepEqual(refreshedResources, expected) {
+		t.Fatalf("expected: %#v, got: %#v", expected, refreshedResources)
+	}
+}
+
+func TestContext2Refresh_targetedCountIndex(t *testing.T) {
+	p := testProvider("aws")
+	m := testModule(t, "refresh-targeted-count")
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: &State{
+			Modules: []*ModuleState{
+				&ModuleState{
+					Path: rootModulePath,
+					Resources: map[string]*ResourceState{
+						"aws_vpc.metoo":      resourceState("aws_vpc", "vpc-abc123"),
+						"aws_instance.notme": resourceState("aws_instance", "i-bcd345"),
+						"aws_instance.me.0":  resourceState("aws_instance", "i-abc123"),
+						"aws_instance.me.1":  resourceState("aws_instance", "i-cde567"),
+						"aws_instance.me.2":  resourceState("aws_instance", "i-cde789"),
+						"aws_elb.meneither":  resourceState("aws_elb", "lb-abc123"),
+					},
+				},
+			},
+		},
+		Targets: []string{"aws_instance.me[0]"},
+	})
+
+	refreshedResources := make([]string, 0, 2)
+	p.RefreshFn = func(i *InstanceInfo, is *InstanceState) (*InstanceState, error) {
+		refreshedResources = append(refreshedResources, i.Id)
+		return is, nil
+	}
+
+	_, err := ctx.Refresh()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	expected := []string{"aws_vpc.metoo", "aws_instance.me.0"}
+	if !reflect.DeepEqual(refreshedResources, expected) {
+		t.Fatalf("expected: %#v, got: %#v", expected, refreshedResources)
+	}
+}
+
 func TestContext2Refresh_delete(t *testing.T) {
 	p := testProvider("aws")
 	m := testModule(t, "refresh-basic")
@@ -5274,6 +5366,66 @@ aws_instance.foo:
 	`)
 }
 
+func TestContext2Apply_targetedCount(t *testing.T) {
+	m := testModule(t, "apply-targeted-count")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		Targets: []string{"aws_instance.foo"},
+	})
+
+	if _, err := ctx.Plan(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	checkStateString(t, state, `
+aws_instance.foo.0:
+  ID = foo
+aws_instance.foo.1:
+  ID = foo
+aws_instance.foo.2:
+  ID = foo
+	`)
+}
+
+func TestContext2Apply_targetedCountIndex(t *testing.T) {
+	m := testModule(t, "apply-targeted-count")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		Targets: []string{"aws_instance.foo[1]"},
+	})
+
+	if _, err := ctx.Plan(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	checkStateString(t, state, `
+aws_instance.foo.1:
+  ID = foo
+	`)
+}
+
 func TestContext2Apply_targetedDestroy(t *testing.T) {
 	m := testModule(t, "apply-targeted")
 	p := testProvider("aws")
@@ -5319,6 +5471,59 @@ aws_instance.bar:
 	`)
 }
 
+func TestContext2Apply_targetedDestroyCountIndex(t *testing.T) {
+	m := testModule(t, "apply-targeted-count")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: &State{
+			Modules: []*ModuleState{
+				&ModuleState{
+					Path: rootModulePath,
+					Resources: map[string]*ResourceState{
+						"aws_instance.foo.0": resourceState("aws_instance", "i-bcd345"),
+						"aws_instance.foo.1": resourceState("aws_instance", "i-bcd345"),
+						"aws_instance.foo.2": resourceState("aws_instance", "i-bcd345"),
+						"aws_instance.bar.0": resourceState("aws_instance", "i-abc123"),
+						"aws_instance.bar.1": resourceState("aws_instance", "i-abc123"),
+						"aws_instance.bar.2": resourceState("aws_instance", "i-abc123"),
+					},
+				},
+			},
+		},
+		Targets: []string{
+			"aws_instance.foo[2]",
+			"aws_instance.bar[1]",
+		},
+		Destroy: true,
+	})
+
+	if _, err := ctx.Plan(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	checkStateString(t, state, `
+aws_instance.bar.0:
+  ID = i-abc123
+aws_instance.bar.2:
+  ID = i-abc123
+aws_instance.foo.0:
+  ID = i-bcd345
+aws_instance.foo.1:
+  ID = i-bcd345
+	`)
+}
+
 func TestContext2Apply_unknownAttribute(t *testing.T) {
 	m := testModule(t, "apply-unknown")
 	p := testProvider("aws")

terraform/graph_builder.go

@@ -89,7 +89,11 @@ func (b *BuiltinGraphBuilder) Steps() []GraphTransformer {
 	return []GraphTransformer{
 		// Create all our resources from the configuration and state
 		&ConfigTransformer{Module: b.Root},
-		&OrphanTransformer{State: b.State, Module: b.Root},
+		&OrphanTransformer{
+			State:     b.State,
+			Module:    b.Root,
+			Targeting: (len(b.Targets) > 0),
+		},
 
 		// Provider-related transformations
 		&MissingProviderTransformer{Providers: b.Providers},

terraform/graph_config_node.go

@@ -21,6 +21,26 @@ type graphNodeConfig interface {
 	GraphNodeDependent
 }
 
+// GraphNodeAddressable is an interface that all graph nodes for the
+// configuration graph need to implement in order to be be addressed / targeted
+// properly.
+type GraphNodeAddressable interface {
+	graphNodeConfig
+
+	ResourceAddress() *ResourceAddress
+}
+
+// GraphNodeTargetable is an interface for graph nodes to implement when they
+// need to be told about incoming targets. This is useful for nodes that need
+// to respect targets as they dynamically expand. Note that the list of targets
+// provided will contain every target provided, and each implementing graph
+// node must filter this list to targets considered relevant.
+type GraphNodeTargetable interface {
+	GraphNodeAddressable
+
+	SetTargets([]ResourceAddress)
+}
+
 // GraphNodeConfigModule represents a module within the configuration graph.
 type GraphNodeConfigModule struct {
 	Path   []string
@@ -191,6 +211,9 @@ type GraphNodeConfigResource struct {
 	// If this is set to anything other than destroyModeNone, then this
 	// resource represents a resource that will be destroyed in some way.
 	DestroyMode GraphNodeDestroyMode
+
+	// Used during DynamicExpand to target indexes
+	Targets []ResourceAddress
 }
 
 func (n *GraphNodeConfigResource) DependableName() []string {
@@ -279,6 +302,7 @@ func (n *GraphNodeConfigResource) DynamicExpand(ctx EvalContext) (*Graph, error)
 		steps = append(steps, &ResourceCountTransformer{
 			Resource: n.Resource,
 			Destroy:  n.DestroyMode != DestroyNone,
+			Targets:  n.Targets,
 		})
 	}
 
@@ -291,6 +315,7 @@ func (n *GraphNodeConfigResource) DynamicExpand(ctx EvalContext) (*Graph, error)
 		steps = append(steps, &OrphanTransformer{
 			State:     state,
 			View:      n.Resource.Id(),
+			Targeting: (len(n.Targets) > 0),
 		})
 
 		steps = append(steps, &DeposedTransformer{
@@ -314,6 +339,22 @@ func (n *GraphNodeConfigResource) DynamicExpand(ctx EvalContext) (*Graph, error)
 	return b.Build(ctx.Path())
 }
 
+// GraphNodeAddressable impl.
+func (n *GraphNodeConfigResource) ResourceAddress() *ResourceAddress {
+	return &ResourceAddress{
+		// Indicates no specific index; will match on other three fields
+		Index:        -1,
+		InstanceType: TypePrimary,
+		Name:         n.Resource.Name,
+		Type:         n.Resource.Type,
+	}
+}
+
+// GraphNodeTargetable impl.
+func (n *GraphNodeConfigResource) SetTargets(targets []ResourceAddress) {
+	n.Targets = targets
+}
+
 // GraphNodeEvalable impl.
 func (n *GraphNodeConfigResource) EvalTree() EvalNode {
 	return &EvalSequence{

terraform/instancetype.go

@@ -0,0 +1,13 @@
+package terraform
+
+//go:generate stringer -type=InstanceType instancetype.go
+
+// InstanceType is an enum of the various types of instances store in the State
+type InstanceType int
+
+const (
+	TypeInvalid InstanceType = iota
+	TypePrimary
+	TypeTainted
+	TypeDeposed
+)

terraform/instancetype_string.go

@@ -0,0 +1,16 @@
+// generated by stringer -type=InstanceType instancetype.go; DO NOT EDIT
+
+package terraform
+
+import "fmt"
+
+const _InstanceType_name = "TypeInvalidTypePrimaryTypeTaintedTypeDeposed"
+
+var _InstanceType_index = [...]uint8{0, 11, 22, 33, 44}
+
+func (i InstanceType) String() string {
+	if i < 0 || i+1 >= InstanceType(len(_InstanceType_index)) {
+		return fmt.Sprintf("InstanceType(%d)", i)
+	}
+	return _InstanceType_name[_InstanceType_index[i]:_InstanceType_index[i+1]]
+}

terraform/resource_address.go

@@ -0,0 +1,98 @@
+package terraform
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+// ResourceAddress is a way of identifying an individual resource (or,
+// eventually, a subset of resources) within the state. It is used for Targets.
+type ResourceAddress struct {
+	Index        int
+	InstanceType InstanceType
+	Name         string
+	Type         string
+}
+
+func ParseResourceAddress(s string) (*ResourceAddress, error) {
+	matches, err := tokenizeResourceAddress(s)
+	if err != nil {
+		return nil, err
+	}
+	resourceIndex := -1
+	if matches["index"] != "" {
+		var err error
+		if resourceIndex, err = strconv.Atoi(matches["index"]); err != nil {
+			return nil, err
+		}
+	}
+	instanceType := TypePrimary
+	if matches["instance_type"] != "" {
+		var err error
+		if instanceType, err = ParseInstanceType(matches["instance_type"]); err != nil {
+			return nil, err
+		}
+	}
+
+	return &ResourceAddress{
+		Index:        resourceIndex,
+		InstanceType: instanceType,
+		Name:         matches["name"],
+		Type:         matches["type"],
+	}, nil
+}
+
+func (addr *ResourceAddress) Equals(raw interface{}) bool {
+	other, ok := raw.(*ResourceAddress)
+	if !ok {
+		return false
+	}
+
+	indexMatch := (addr.Index == -1 ||
+		other.Index == -1 ||
+		addr.Index == other.Index)
+
+	return (indexMatch &&
+		addr.InstanceType == other.InstanceType &&
+		addr.Name == other.Name &&
+		addr.Type == other.Type)
+}
+
+func ParseInstanceType(s string) (InstanceType, error) {
+	switch s {
+	case "primary":
+		return TypePrimary, nil
+	case "deposed":
+		return TypeDeposed, nil
+	case "tainted":
+		return TypeTainted, nil
+	default:
+		return TypeInvalid, fmt.Errorf("Unexpected value for InstanceType field: %q", s)
+	}
+}
+
+func tokenizeResourceAddress(s string) (map[string]string, error) {
+	// Example of portions of the regexp below using the
+	// string "aws_instance.web.tainted[1]"
+	re := regexp.MustCompile(`\A` +
+		// "aws_instance"
+		`(?P<type>\w+)\.` +
+		// "web"
+		`(?P<name>\w+)` +
+		// "tainted" (optional, omission implies: "primary")
+		`(?:\.(?P<instance_type>\w+))?` +
+		// "1" (optional, omission implies: "0")
+		`(?:\[(?P<index>\d+)\])?` +
+		`\z`)
+	groupNames := re.SubexpNames()
+	rawMatches := re.FindAllStringSubmatch(s, -1)
+	if len(rawMatches) != 1 {
+		return nil, fmt.Errorf("Problem parsing address: %q", s)
+	}
+	matches := make(map[string]string)
+	for i, m := range rawMatches[0] {
+		matches[groupNames[i]] = m
+	}
+	return matches, nil
+}

terraform/resource_address_test.go

@@ -0,0 +1,207 @@
+package terraform
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseResourceAddress(t *testing.T) {
+	cases := map[string]struct {
+		Input    string
+		Expected *ResourceAddress
+	}{
+		"implicit primary, no specific index": {
+			Input: "aws_instance.foo",
+			Expected: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        -1,
+			},
+		},
+		"implicit primary, explicit index": {
+			Input: "aws_instance.foo[2]",
+			Expected: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        2,
+			},
+		},
+		"explicit primary, explicit index": {
+			Input: "aws_instance.foo.primary[2]",
+			Expected: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        2,
+			},
+		},
+		"tainted": {
+			Input: "aws_instance.foo.tainted",
+			Expected: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypeTainted,
+				Index:        -1,
+			},
+		},
+		"deposed": {
+			Input: "aws_instance.foo.deposed",
+			Expected: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypeDeposed,
+				Index:        -1,
+			},
+		},
+	}
+
+	for tn, tc := range cases {
+		out, err := ParseResourceAddress(tc.Input)
+		if err != nil {
+			t.Fatalf("unexpected err: %#v", err)
+		}
+
+		if !reflect.DeepEqual(out, tc.Expected) {
+			t.Fatalf("bad: %q\n\nexpected:\n%#v\n\ngot:\n%#v", tn, tc.Expected, out)
+		}
+	}
+}
+
+func TestResourceAddressEquals(t *testing.T) {
+	cases := map[string]struct {
+		Address *ResourceAddress
+		Other   interface{}
+		Expect  bool
+	}{
+		"basic match": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Expect: true,
+		},
+		"address does not set index": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        -1,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        3,
+			},
+			Expect: true,
+		},
+		"other does not set index": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        3,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        -1,
+			},
+			Expect: true,
+		},
+		"neither sets index": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        -1,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        -1,
+			},
+			Expect: true,
+		},
+		"different type": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_vpc",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Expect: false,
+		},
+		"different name": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "bar",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Expect: false,
+		},
+		"different instance type": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypeTainted,
+				Index:        0,
+			},
+			Expect: false,
+		},
+		"different index": {
+			Address: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        0,
+			},
+			Other: &ResourceAddress{
+				Type:         "aws_instance",
+				Name:         "foo",
+				InstanceType: TypePrimary,
+				Index:        1,
+			},
+			Expect: false,
+		},
+	}
+
+	for tn, tc := range cases {
+		actual := tc.Address.Equals(tc.Other)
+		if actual != tc.Expect {
+			t.Fatalf("%q: expected equals: %t, got %t for:\n%#v\n%#v",
+				tn, tc.Expect, actual, tc.Address, tc.Other)
+		}
+	}
+}

terraform/test-fixtures/apply-targeted-count/main.tf

@@ -0,0 +1,7 @@
+resource "aws_instance" "foo" {
+  count = 3
+}
+
+resource "aws_instance" "bar" {
+  count = 3
+}

terraform/test-fixtures/refresh-targeted-count/main.tf

@@ -0,0 +1,9 @@
+resource "aws_vpc" "metoo" {}
+resource "aws_instance" "notme" { }
+resource "aws_instance" "me" {
+  vpc_id = "${aws_vpc.metoo.id}"
+  count = 3
+}
+resource "aws_elb" "meneither" {
+  instances = ["${aws_instance.me.*.id}"]
+}

terraform/transform_orphan.go

@@ -2,6 +2,7 @@ package terraform
 
 import (
 	"fmt"
+	"log"
 
 	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/config/module"
@@ -25,6 +26,11 @@ type OrphanTransformer struct {
 	// using the graph path.
 	Module *module.Tree
 
+	// Targets are user-specified resources to target. We need to be aware of
+	// these so we don't improperly identify orphans when they've just been
+	// filtered out of the graph via targeting.
+	Targeting bool
+
 	// View, if non-nil will set a view on the module state.
 	View string
 }
@@ -35,6 +41,13 @@ func (t *OrphanTransformer) Transform(g *Graph) error {
 		return nil
 	}
 
+	if t.Targeting {
+		log.Printf("Skipping orphan transformer because we have targets.")
+		// If we are in a run where we are targeting nodes, we won't process
+		// orphans for this run.
+		return nil
+	}
+
 	// Build up all our state representatives
 	resourceRep := make(map[string]struct{})
 	for _, v := range g.Vertices() {

terraform/transform_resource.go

@@ -12,6 +12,7 @@ import (
 type ResourceCountTransformer struct {
 	Resource *config.Resource
 	Destroy  bool
+	Targets  []ResourceAddress
 }
 
 func (t *ResourceCountTransformer) Transform(g *Graph) error {
@@ -27,7 +28,7 @@ func (t *ResourceCountTransformer) Transform(g *Graph) error {
 	}
 
 	// For each count, build and add the node
-	nodes := make([]dag.Vertex, count)
+	nodes := make([]dag.Vertex, 0, count)
 	for i := 0; i < count; i++ {
 		// Set the index. If our count is 1 we special case it so that
 		// we handle the "resource.0" and "resource" boundary properly.
@@ -49,9 +50,14 @@ func (t *ResourceCountTransformer) Transform(g *Graph) error {
 			}
 		}
 
+		// Skip nodes if targeting excludes them
+		if !t.nodeIsTargeted(node) {
+			continue
+		}
+
 		// Add the node now
-		nodes[i] = node
+		nodes = append(nodes, node)
-		g.Add(nodes[i])
+		g.Add(node)
 	}
 
 	// Make the dependency connections
@@ -64,6 +70,25 @@ func (t *ResourceCountTransformer) Transform(g *Graph) error {
 	return nil
 }
 
+func (t *ResourceCountTransformer) nodeIsTargeted(node dag.Vertex) bool {
+	// no targets specified, everything stays in the graph
+	if len(t.Targets) == 0 {
+		return true
+	}
+	addressable, ok := node.(GraphNodeAddressable)
+	if !ok {
+		return false
+	}
+
+	addr := addressable.ResourceAddress()
+	for _, targetAddr := range t.Targets {
+		if targetAddr.Equals(addr) {
+			return true
+		}
+	}
+	return false
+}
+
 type graphNodeExpandedResource struct {
 	Index    int
 	Resource *config.Resource
@@ -77,6 +102,23 @@ func (n *graphNodeExpandedResource) Name() string {
 	return fmt.Sprintf("%s #%d", n.Resource.Id(), n.Index)
 }
 
+// GraphNodeAddressable impl.
+func (n *graphNodeExpandedResource) ResourceAddress() *ResourceAddress {
+	// We want this to report the logical index properly, so we must undo the
+	// special case from the expand
+	index := n.Index
+	if index == -1 {
+		index = 0
+	}
+	return &ResourceAddress{
+		Index: index,
+		// TODO: kjkjkj
+		InstanceType: TypePrimary,
+		Name:         n.Resource.Name,
+		Type:         n.Resource.Type,
+	}
+}
+
 // GraphNodeDependable impl.
 func (n *graphNodeExpandedResource) DependableName() []string {
 	return []string{

terraform/transform_targets.go

@@ -16,13 +16,20 @@ type TargetsTransformer struct {
 
 func (t *TargetsTransformer) Transform(g *Graph) error {
 	if len(t.Targets) > 0 {
-		targetedNodes, err := t.selectTargetedNodes(g)
+		// TODO: duplicated in OrphanTransformer; pull up parsing earlier
+		addrs, err := t.parseTargetAddresses()
+		if err != nil {
+			return err
+		}
+
+		targetedNodes, err := t.selectTargetedNodes(g, addrs)
 		if err != nil {
 			return err
 		}
 
 		for _, v := range g.Vertices() {
-			if !targetedNodes.Include(v) {
+			if targetedNodes.Include(v) {
+			} else {
 				g.Remove(v)
 			}
 		}
@@ -30,7 +37,20 @@ func (t *TargetsTransformer) Transform(g *Graph) error {
 	return nil
 }
 
-func (t *TargetsTransformer) selectTargetedNodes(g *Graph) (*dag.Set, error) {
+func (t *TargetsTransformer) parseTargetAddresses() ([]ResourceAddress, error) {
+	addrs := make([]ResourceAddress, len(t.Targets))
+	for i, target := range t.Targets {
+		ta, err := ParseResourceAddress(target)
+		if err != nil {
+			return nil, err
+		}
+		addrs[i] = *ta
+	}
+	return addrs, nil
+}
+
+func (t *TargetsTransformer) selectTargetedNodes(
+	g *Graph, addrs []ResourceAddress) (*dag.Set, error) {
 	targetedNodes := new(dag.Set)
 	for _, v := range g.Vertices() {
 		// Keep all providers; they'll be pruned later if necessary
@@ -39,14 +59,18 @@ func (t *TargetsTransformer) selectTargetedNodes(g *Graph) (*dag.Set, error) {
 			continue
 		}
 
-		// For the remaining filter, we only care about Resources and their deps
+		// For the remaining filter, we only care about addressable nodes
-		r, ok := v.(*GraphNodeConfigResource)
+		r, ok := v.(GraphNodeAddressable)
 		if !ok {
 			continue
 		}
 
-		if t.resourceIsTarget(r) {
+		if t.nodeIsTarget(r, addrs) {
 			targetedNodes.Add(r)
+			// If the node would like to know about targets, tell it.
+			if n, ok := r.(GraphNodeTargetable); ok {
+				n.SetTargets(addrs)
+			}
 
 			var deps *dag.Set
 			var err error
@@ -67,9 +91,11 @@ func (t *TargetsTransformer) selectTargetedNodes(g *Graph) (*dag.Set, error) {
 	return targetedNodes, nil
 }
 
-func (t *TargetsTransformer) resourceIsTarget(r *GraphNodeConfigResource) bool {
+func (t *TargetsTransformer) nodeIsTarget(
-	for _, target := range t.Targets {
+	r GraphNodeAddressable, addrs []ResourceAddress) bool {
-		if target == r.Name() {
+	addr := r.ResourceAddress()
+	for _, targetAddr := range addrs {
+		if targetAddr.Equals(addr) {
 			return true
 		}
 	}