Merge pull request #11426 from hashicorp/f-new-graph

core: Refresh, Validate, Input on new graph builders

terraform/context.go

@@ -216,14 +216,35 @@ func (c *Context) Graph(typ GraphType, opts *ContextGraphOpts) (*Graph, error) {
 			Validate:     opts.Validate,
 		}).Build(RootModulePath)
 
+	case GraphTypeInput:
+		// The input graph is just a slightly modified plan graph
+		fallthrough
+	case GraphTypeValidate:
+		// The validate graph is just a slightly modified plan graph
+		fallthrough
 	case GraphTypePlan:
-		return (&PlanGraphBuilder{
+		// Create the plan graph builder
+		p := &PlanGraphBuilder{
 			Module:    c.module,
 			State:     c.state,
 			Providers: c.components.ResourceProviders(),
 			Targets:   c.targets,
 			Validate:  opts.Validate,
-		}).Build(RootModulePath)
+		}
+
+		// Some special cases for other graph types shared with plan currently
+		var b GraphBuilder = p
+		switch typ {
+		case GraphTypeInput:
+			b = InputGraphBuilder(p)
+		case GraphTypeValidate:
+			// We need to set the provisioners so those can be validated
+			p.Provisioners = c.components.ResourceProvisioners()
+
+			b = ValidateGraphBuilder(p)
+		}
+
+		return b.Build(RootModulePath)
 
 	case GraphTypePlanDestroy:
 		return (&DestroyPlanGraphBuilder{
@@ -233,6 +254,15 @@ func (c *Context) Graph(typ GraphType, opts *ContextGraphOpts) (*Graph, error) {
 			Validate: opts.Validate,
 		}).Build(RootModulePath)
 
+	case GraphTypeRefresh:
+		return (&RefreshGraphBuilder{
+			Module:    c.module,
+			State:     c.state,
+			Providers: c.components.ResourceProviders(),
+			Targets:   c.targets,
+			Validate:  opts.Validate,
+		}).Build(RootModulePath)
+
 	case GraphTypeLegacy:
 		return c.graphBuilder(opts).Build(RootModulePath)
 	}
@@ -402,7 +432,7 @@ func (c *Context) Input(mode InputMode) error {
 
 	if mode&InputModeProvider != 0 {
 		// Build the graph
-		graph, err := c.Graph(GraphTypeLegacy, nil)
+		graph, err := c.Graph(GraphTypeInput, nil)
 		if err != nil {
 			return err
 		}
@@ -569,8 +599,15 @@ func (c *Context) Refresh() (*State, error) {
 	// Copy our own state
 	c.state = c.state.DeepCopy()
 
-	// Build the graph
+	// Used throughout below
-	graph, err := c.Graph(GraphTypeLegacy, nil)
+	X_legacyGraph := experiment.Enabled(experiment.X_legacyGraph)
+
+	// Build the graph.
+	graphType := GraphTypeLegacy
+	if !X_legacyGraph {
+		graphType = GraphTypeRefresh
+	}
+	graph, err := c.Graph(graphType, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -641,7 +678,7 @@ func (c *Context) Validate() ([]string, []error) {
 	// We also validate the graph generated here, but this graph doesn't
 	// necessarily match the graph that Plan will generate, so we'll validate the
 	// graph again later after Planning.
-	graph, err := c.Graph(GraphTypeLegacy, nil)
+	graph, err := c.Graph(GraphTypeValidate, nil)
 	if err != nil {
 		return nil, []error{err}
 	}

terraform/context_graph_type.go

@@ -10,9 +10,12 @@ type GraphType byte
 const (
 	GraphTypeInvalid GraphType = 0
 	GraphTypeLegacy  GraphType = iota
+	GraphTypeRefresh
 	GraphTypePlan
 	GraphTypePlanDestroy
 	GraphTypeApply
+	GraphTypeInput
+	GraphTypeValidate
 )
 
 // GraphTypeMap is a mapping of human-readable string to GraphType. This
@@ -20,7 +23,10 @@ const (
 // graph types.
 var GraphTypeMap = map[string]GraphType{
 	"apply":        GraphTypeApply,
+	"input":        GraphTypeInput,
 	"plan":         GraphTypePlan,
 	"plan-destroy": GraphTypePlanDestroy,
+	"refresh":      GraphTypeRefresh,
 	"legacy":       GraphTypeLegacy,
+	"validate":     GraphTypeValidate,
 }

terraform/context_refresh_test.go

@@ -520,7 +520,7 @@ func TestContext2Refresh_outputPartial(t *testing.T) {
 	}
 }
 
-func TestContext2Refresh_state(t *testing.T) {
+func TestContext2Refresh_stateBasic(t *testing.T) {
 	p := testProvider("aws")
 	m := testModule(t, "refresh-basic")
 	state := &State{
@@ -529,6 +529,7 @@ func TestContext2Refresh_state(t *testing.T) {
 				Path: rootModulePath,
 				Resources: map[string]*ResourceState{
 					"aws_instance.web": &ResourceState{
+						Type: "aws_instance",
 						Primary: &InstanceState{
 							ID: "bar",
 						},
@@ -737,6 +738,21 @@ func TestContext2Refresh_unknownProvider(t *testing.T) {
 	ctx := testContext2(t, &ContextOpts{
 		Module:    m,
 		Providers: map[string]ResourceProviderFactory{},
+		State: &State{
+			Modules: []*ModuleState{
+				&ModuleState{
+					Path: rootModulePath,
+					Resources: map[string]*ResourceState{
+						"aws_instance.web": &ResourceState{
+							Type: "aws_instance",
+							Primary: &InstanceState{
+								ID: "foo",
+							},
+						},
+					},
+				},
+			},
+		},
 	})
 
 	if _, err := ctx.Refresh(); err == nil {

terraform/eval_validate_selfref.go

@@ -0,0 +1,74 @@
+package terraform
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/terraform/config"
+)
+
+// EvalValidateResourceSelfRef is an EvalNode implementation that validates that
+// a configuration doesn't contain a reference to the resource itself.
+//
+// This must be done prior to interpolating configuration in order to avoid
+// any infinite loop scenarios.
+type EvalValidateResourceSelfRef struct {
+	Addr   **ResourceAddress
+	Config **config.RawConfig
+}
+
+func (n *EvalValidateResourceSelfRef) Eval(ctx EvalContext) (interface{}, error) {
+	addr := *n.Addr
+	conf := *n.Config
+
+	// Go through the variables and find self references
+	var errs []error
+	for k, raw := range conf.Variables {
+		rv, ok := raw.(*config.ResourceVariable)
+		if !ok {
+			continue
+		}
+
+		// Build an address from the variable
+		varAddr := &ResourceAddress{
+			Path:         addr.Path,
+			Mode:         rv.Mode,
+			Type:         rv.Type,
+			Name:         rv.Name,
+			Index:        rv.Index,
+			InstanceType: TypePrimary,
+		}
+
+		// If the variable access is a multi-access (*), then we just
+		// match the index so that we'll match our own addr if everything
+		// else matches.
+		if rv.Multi && rv.Index == -1 {
+			varAddr.Index = addr.Index
+		}
+
+		// This is a weird thing where ResourceAddres has index "-1" when
+		// index isn't set at all. This means index "0" for resource access.
+		// So, if we have this scenario, just set our varAddr to -1 so it
+		// matches.
+		if addr.Index == -1 && varAddr.Index == 0 {
+			varAddr.Index = -1
+		}
+
+		// If the addresses match, then this is a self reference
+		if varAddr.Equals(addr) && varAddr.Index == addr.Index {
+			errs = append(errs, fmt.Errorf(
+				"%s: self reference not allowed: %q",
+				addr, k))
+		}
+	}
+
+	// If no errors, no errors!
+	if len(errs) == 0 {
+		return nil, nil
+	}
+
+	// Wrap the errors in the proper wrapper so we can handle validation
+	// formatting properly upstream.
+	return nil, &EvalValidateError{
+		Errors: errs,
+	}
+}

terraform/eval_validate_selfref_test.go

@@ -0,0 +1,99 @@
+package terraform
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/config"
+)
+
+func TestEvalValidateResourceSelfRef(t *testing.T) {
+	cases := []struct {
+		Name   string
+		Addr   string
+		Config map[string]interface{}
+		Err    bool
+	}{
+		{
+			"no interpolations",
+			"aws_instance.foo",
+			map[string]interface{}{
+				"foo": "bar",
+			},
+			false,
+		},
+
+		{
+			"non self reference",
+			"aws_instance.foo",
+			map[string]interface{}{
+				"foo": "${aws_instance.bar.id}",
+			},
+			false,
+		},
+
+		{
+			"self reference",
+			"aws_instance.foo",
+			map[string]interface{}{
+				"foo": "hello ${aws_instance.foo.id}",
+			},
+			true,
+		},
+
+		{
+			"self reference other index",
+			"aws_instance.foo",
+			map[string]interface{}{
+				"foo": "hello ${aws_instance.foo.4.id}",
+			},
+			false,
+		},
+
+		{
+			"self reference same index",
+			"aws_instance.foo[4]",
+			map[string]interface{}{
+				"foo": "hello ${aws_instance.foo.4.id}",
+			},
+			true,
+		},
+
+		{
+			"self reference multi",
+			"aws_instance.foo[4]",
+			map[string]interface{}{
+				"foo": "hello ${aws_instance.foo.*.id}",
+			},
+			true,
+		},
+
+		{
+			"self reference multi single",
+			"aws_instance.foo",
+			map[string]interface{}{
+				"foo": "hello ${aws_instance.foo.*.id}",
+			},
+			true,
+		},
+	}
+
+	for i, tc := range cases {
+		t.Run(fmt.Sprintf("%d-%s", i, tc.Name), func(t *testing.T) {
+			addr, err := ParseResourceAddress(tc.Addr)
+			if err != nil {
+				t.Fatalf("err: %s", err)
+			}
+			conf := config.TestRawConfig(t, tc.Config)
+
+			n := &EvalValidateResourceSelfRef{Addr: &addr, Config: &conf}
+			result, err := n.Eval(nil)
+			if result != nil {
+				t.Fatal("result should always be nil")
+			}
+			if (err != nil) != tc.Err {
+				t.Fatalf("err: %s", err)
+			}
+		})
+	}
+}

terraform/graph_builder_input.go

@@ -0,0 +1,27 @@
+package terraform
+
+import (
+	"github.com/hashicorp/terraform/dag"
+)
+
+// InputGraphBuilder creates the graph for the input operation.
+//
+// Unlike other graph builders, this is a function since it currently modifies
+// and is based on the PlanGraphBuilder. The PlanGraphBuilder passed in will be
+// modified and should not be used for any other operations.
+func InputGraphBuilder(p *PlanGraphBuilder) GraphBuilder {
+	// We're going to customize the concrete functions
+	p.CustomConcrete = true
+
+	// Set the provider to the normal provider. This will ask for input.
+	p.ConcreteProvider = func(a *NodeAbstractProvider) dag.Vertex {
+		return &NodeApplyableProvider{
+			NodeAbstractProvider: a,
+		}
+	}
+
+	// We purposely don't set any more concrete fields since the remainder
+	// should be no-ops.
+
+	return p
+}

terraform/graph_builder_plan.go

@@ -1,6 +1,8 @@
 package terraform
 
 import (
+	"sync"
+
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/dag"
 )
@@ -26,6 +28,9 @@ type PlanGraphBuilder struct {
 	// Providers is the list of providers supported.
 	Providers []string
 
+	// Provisioners is the list of provisioners supported.
+	Provisioners []string
+
 	// Targets are resources to target
 	Targets []string
 
@@ -34,6 +39,16 @@ type PlanGraphBuilder struct {
 
 	// Validate will do structural validation of the graph.
 	Validate bool
+
+	// CustomConcrete can be set to customize the node types created
+	// for various parts of the plan. This is useful in order to customize
+	// the plan behavior.
+	CustomConcrete         bool
+	ConcreteProvider       ConcreteProviderNodeFunc
+	ConcreteResource       ConcreteResourceNodeFunc
+	ConcreteResourceOrphan ConcreteResourceNodeFunc
+
+	once sync.Once
 }
 
 // See GraphBuilder
@@ -47,29 +62,12 @@ func (b *PlanGraphBuilder) Build(path []string) (*Graph, error) {
 
 // See GraphBuilder
 func (b *PlanGraphBuilder) Steps() []GraphTransformer {
-	// Custom factory for creating providers.
+	b.once.Do(b.init)
-	concreteProvider := func(a *NodeAbstractProvider) dag.Vertex {
-		return &NodeApplyableProvider{
-			NodeAbstractProvider: a,
-		}
-	}
-
-	concreteResource := func(a *NodeAbstractResource) dag.Vertex {
-		return &NodePlannableResource{
-			NodeAbstractResource: a,
-		}
-	}
-
-	concreteResourceOrphan := func(a *NodeAbstractResource) dag.Vertex {
-		return &NodePlannableResourceOrphan{
-			NodeAbstractResource: a,
-		}
-	}
 
 	steps := []GraphTransformer{
 		// Creates all the resources represented in the config
 		&ConfigTransformer{
-			Concrete: concreteResource,
+			Concrete: b.ConcreteResource,
 			Module:   b.Module,
 		},
 
@@ -78,7 +76,7 @@ func (b *PlanGraphBuilder) Steps() []GraphTransformer {
 
 		// Add orphan resources
 		&OrphanResourceTransformer{
-			Concrete: concreteResourceOrphan,
+			Concrete: b.ConcreteResourceOrphan,
 			State:    b.State,
 			Module:   b.Module,
 		},
@@ -93,12 +91,21 @@ func (b *PlanGraphBuilder) Steps() []GraphTransformer {
 		&RootVariableTransformer{Module: b.Module},
 
 		// Create all the providers
-		&MissingProviderTransformer{Providers: b.Providers, Concrete: concreteProvider},
+		&MissingProviderTransformer{Providers: b.Providers, Concrete: b.ConcreteProvider},
 		&ProviderTransformer{},
 		&DisableProviderTransformer{},
 		&ParentProviderTransformer{},
 		&AttachProviderConfigTransformer{Module: b.Module},
 
+		// Provisioner-related transformations. Only add these if requested.
+		GraphTransformIf(
+			func() bool { return b.Provisioners != nil },
+			GraphTransformMulti(
+				&MissingProvisionerTransformer{Provisioners: b.Provisioners},
+				&ProvisionerTransformer{},
+			),
+		),
+
 		// Add module variables
 		&ModuleVariableTransformer{Module: b.Module},
 
@@ -121,3 +128,30 @@ func (b *PlanGraphBuilder) Steps() []GraphTransformer {
 
 	return steps
 }
+
+func (b *PlanGraphBuilder) init() {
+	// Do nothing if the user requests customizing the fields
+	if b.CustomConcrete {
+		return
+	}
+
+	b.ConcreteProvider = func(a *NodeAbstractProvider) dag.Vertex {
+		return &NodeApplyableProvider{
+			NodeAbstractProvider: a,
+		}
+	}
+
+	b.ConcreteResource = func(a *NodeAbstractResource) dag.Vertex {
+		return &NodePlannableResource{
+			NodeAbstractCountResource: &NodeAbstractCountResource{
+				NodeAbstractResource: a,
+			},
+		}
+	}
+
+	b.ConcreteResourceOrphan = func(a *NodeAbstractResource) dag.Vertex {
+		return &NodePlannableResourceOrphan{
+			NodeAbstractResource: a,
+		}
+	}
+}

terraform/graph_builder_refresh.go

@@ -0,0 +1,129 @@
+package terraform
+
+import (
+	"github.com/hashicorp/terraform/config"
+	"github.com/hashicorp/terraform/config/module"
+	"github.com/hashicorp/terraform/dag"
+)
+
+// RefreshGraphBuilder implements GraphBuilder and is responsible for building
+// a graph for refreshing (updating the Terraform state).
+//
+// The primary difference between this graph and others:
+//
+//   * Based on the state since it represents the only resources that
+//     need to be refreshed.
+//
+//   * Ignores lifecycle options since no lifecycle events occur here. This
+//     simplifies the graph significantly since complex transforms such as
+//     create-before-destroy can be completely ignored.
+//
+type RefreshGraphBuilder struct {
+	// Module is the root module for the graph to build.
+	Module *module.Tree
+
+	// State is the current state
+	State *State
+
+	// Providers is the list of providers supported.
+	Providers []string
+
+	// Targets are resources to target
+	Targets []string
+
+	// DisableReduce, if true, will not reduce the graph. Great for testing.
+	DisableReduce bool
+
+	// Validate will do structural validation of the graph.
+	Validate bool
+}
+
+// See GraphBuilder
+func (b *RefreshGraphBuilder) Build(path []string) (*Graph, error) {
+	return (&BasicGraphBuilder{
+		Steps:    b.Steps(),
+		Validate: b.Validate,
+		Name:     "RefreshGraphBuilder",
+	}).Build(path)
+}
+
+// See GraphBuilder
+func (b *RefreshGraphBuilder) Steps() []GraphTransformer {
+	// Custom factory for creating providers.
+	concreteProvider := func(a *NodeAbstractProvider) dag.Vertex {
+		return &NodeApplyableProvider{
+			NodeAbstractProvider: a,
+		}
+	}
+
+	concreteResource := func(a *NodeAbstractResource) dag.Vertex {
+		return &NodeRefreshableResource{
+			NodeAbstractResource: a,
+		}
+	}
+
+	concreteDataResource := func(a *NodeAbstractResource) dag.Vertex {
+		return &NodeRefreshableDataResource{
+			NodeAbstractCountResource: &NodeAbstractCountResource{
+				NodeAbstractResource: a,
+			},
+		}
+	}
+
+	steps := []GraphTransformer{
+		// Creates all the resources represented in the state
+		&StateTransformer{
+			Concrete: concreteResource,
+			State:    b.State,
+		},
+
+		// Creates all the data resources that aren't in the state
+		&ConfigTransformer{
+			Concrete:   concreteDataResource,
+			Module:     b.Module,
+			Unique:     true,
+			ModeFilter: true,
+			Mode:       config.DataResourceMode,
+		},
+
+		// Attach the state
+		&AttachStateTransformer{State: b.State},
+
+		// Attach the configuration to any resources
+		&AttachResourceConfigTransformer{Module: b.Module},
+
+		// Add root variables
+		&RootVariableTransformer{Module: b.Module},
+
+		// Create all the providers
+		&MissingProviderTransformer{Providers: b.Providers, Concrete: concreteProvider},
+		&ProviderTransformer{},
+		&DisableProviderTransformer{},
+		&ParentProviderTransformer{},
+		&AttachProviderConfigTransformer{Module: b.Module},
+
+		// Add the outputs
+		&OutputTransformer{Module: b.Module},
+
+		// Add module variables
+		&ModuleVariableTransformer{Module: b.Module},
+
+		// Connect so that the references are ready for targeting. We'll
+		// have to connect again later for providers and so on.
+		&ReferenceTransformer{},
+
+		// Target
+		&TargetsTransformer{Targets: b.Targets},
+
+		// Single root
+		&RootTransformer{},
+	}
+
+	if !b.DisableReduce {
+		// Perform the transitive reduction to make our graph a bit
+		// more sane if possible (it usually is possible).
+		steps = append(steps, &TransitiveReductionTransformer{})
+	}
+
+	return steps
+}

terraform/graph_builder_validate.go

@@ -0,0 +1,36 @@
+package terraform
+
+import (
+	"github.com/hashicorp/terraform/dag"
+)
+
+// ValidateGraphBuilder creates the graph for the validate operation.
+//
+// ValidateGraphBuilder is based on the PlanGraphBuilder. We do this so that
+// we only have to validate what we'd normally plan anyways. The
+// PlanGraphBuilder given will be modified so it shouldn't be used for anything
+// else after calling this function.
+func ValidateGraphBuilder(p *PlanGraphBuilder) GraphBuilder {
+	// We're going to customize the concrete functions
+	p.CustomConcrete = true
+
+	// Set the provider to the normal provider. This will ask for input.
+	p.ConcreteProvider = func(a *NodeAbstractProvider) dag.Vertex {
+		return &NodeApplyableProvider{
+			NodeAbstractProvider: a,
+		}
+	}
+
+	p.ConcreteResource = func(a *NodeAbstractResource) dag.Vertex {
+		return &NodeValidatableResource{
+			NodeAbstractCountResource: &NodeAbstractCountResource{
+				NodeAbstractResource: a,
+			},
+		}
+	}
+
+	// We purposely don't set any other concrete types since they don't
+	// require validation.
+
+	return p
+}

terraform/graphtype_string.go

@@ -4,9 +4,9 @@ package terraform
 
 import "fmt"
 
-const _GraphType_name = "GraphTypeInvalidGraphTypeLegacyGraphTypePlanGraphTypePlanDestroyGraphTypeApply"
+const _GraphType_name = "GraphTypeInvalidGraphTypeLegacyGraphTypeRefreshGraphTypePlanGraphTypePlanDestroyGraphTypeApply"
 
-var _GraphType_index = [...]uint8{0, 16, 31, 44, 64, 78}
+var _GraphType_index = [...]uint8{0, 16, 31, 47, 60, 80, 94}
 
 func (i GraphType) String() string {
 	if i >= GraphType(len(_GraphType_index)-1) {

terraform/node_data_refresh.go

@@ -0,0 +1,209 @@
+package terraform
+
+import (
+	"github.com/hashicorp/terraform/dag"
+)
+
+// NodeRefreshableDataResource represents a resource that is "plannable":
+// it is ready to be planned in order to create a diff.
+type NodeRefreshableDataResource struct {
+	*NodeAbstractCountResource
+}
+
+// GraphNodeDynamicExpandable
+func (n *NodeRefreshableDataResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
+	// Grab the state which we read
+	state, lock := ctx.State()
+	lock.RLock()
+	defer lock.RUnlock()
+
+	// Expand the resource count which must be available by now from EvalTree
+	count, err := n.Config.Count()
+	if err != nil {
+		return nil, err
+	}
+
+	// The concrete resource factory we'll use
+	concreteResource := func(a *NodeAbstractResource) dag.Vertex {
+		// Add the config and state since we don't do that via transforms
+		a.Config = n.Config
+
+		return &NodeRefreshableDataResourceInstance{
+			NodeAbstractResource: a,
+		}
+	}
+
+	// Start creating the steps
+	steps := []GraphTransformer{
+		// Expand the count.
+		&ResourceCountTransformer{
+			Concrete: concreteResource,
+			Count:    count,
+			Addr:     n.ResourceAddr(),
+		},
+
+		// Attach the state
+		&AttachStateTransformer{State: state},
+
+		// Targeting
+		&TargetsTransformer{ParsedTargets: n.Targets},
+
+		// Connect references so ordering is correct
+		&ReferenceTransformer{},
+
+		// Make sure there is a single root
+		&RootTransformer{},
+	}
+
+	// Build the graph
+	b := &BasicGraphBuilder{
+		Steps:    steps,
+		Validate: true,
+		Name:     "NodeRefreshableDataResource",
+	}
+
+	return b.Build(ctx.Path())
+}
+
+// NodeRefreshableDataResourceInstance represents a _single_ resource instance
+// that is refreshable.
+type NodeRefreshableDataResourceInstance struct {
+	*NodeAbstractResource
+}
+
+// GraphNodeEvalable
+func (n *NodeRefreshableDataResourceInstance) EvalTree() EvalNode {
+	addr := n.NodeAbstractResource.Addr
+
+	// stateId is the ID to put into the state
+	stateId := addr.stateId()
+
+	// Build the instance info. More of this will be populated during eval
+	info := &InstanceInfo{
+		Id:   stateId,
+		Type: addr.Type,
+	}
+
+	// Get the state if we have it, if not we build it
+	rs := n.ResourceState
+	if rs == nil {
+		rs = &ResourceState{}
+	}
+
+	// If the config isn't empty we update the state
+	if n.Config != nil {
+		// Determine the dependencies for the state. We use some older
+		// code for this that we've used for a long time.
+		var stateDeps []string
+		{
+			oldN := &graphNodeExpandedResource{
+				Resource: n.Config,
+				Index:    addr.Index,
+			}
+			stateDeps = oldN.StateDependencies()
+		}
+
+		rs = &ResourceState{
+			Type:         n.Config.Type,
+			Provider:     n.Config.Provider,
+			Dependencies: stateDeps,
+		}
+	}
+
+	// Build the resource for eval
+	resource := &Resource{
+		Name:       addr.Name,
+		Type:       addr.Type,
+		CountIndex: addr.Index,
+	}
+	if resource.CountIndex < 0 {
+		resource.CountIndex = 0
+	}
+
+	// Declare a bunch of variables that are used for state during
+	// evaluation. Most of this are written to by-address below.
+	var config *ResourceConfig
+	var diff *InstanceDiff
+	var provider ResourceProvider
+	var state *InstanceState
+
+	return &EvalSequence{
+		Nodes: []EvalNode{
+			// Always destroy the existing state first, since we must
+			// make sure that values from a previous read will not
+			// get interpolated if we end up needing to defer our
+			// loading until apply time.
+			&EvalWriteState{
+				Name:         stateId,
+				ResourceType: rs.Type,
+				Provider:     rs.Provider,
+				Dependencies: rs.Dependencies,
+				State:        &state, // state is nil here
+			},
+
+			&EvalInterpolate{
+				Config:   n.Config.RawConfig.Copy(),
+				Resource: resource,
+				Output:   &config,
+			},
+
+			// The rest of this pass can proceed only if there are no
+			// computed values in our config.
+			// (If there are, we'll deal with this during the plan and
+			// apply phases.)
+			&EvalIf{
+				If: func(ctx EvalContext) (bool, error) {
+					if config.ComputedKeys != nil && len(config.ComputedKeys) > 0 {
+						return true, EvalEarlyExitError{}
+					}
+
+					// If the config explicitly has a depends_on for this
+					// data source, assume the intention is to prevent
+					// refreshing ahead of that dependency.
+					if len(n.Config.DependsOn) > 0 {
+						return true, EvalEarlyExitError{}
+					}
+
+					return true, nil
+				},
+
+				Then: EvalNoop{},
+			},
+
+			// The remainder of this pass is the same as running
+			// a "plan" pass immediately followed by an "apply" pass,
+			// populating the state early so it'll be available to
+			// provider configurations that need this data during
+			// refresh/plan.
+			&EvalGetProvider{
+				Name:   n.ProvidedBy()[0],
+				Output: &provider,
+			},
+
+			&EvalReadDataDiff{
+				Info:        info,
+				Config:      &config,
+				Provider:    &provider,
+				Output:      &diff,
+				OutputState: &state,
+			},
+
+			&EvalReadDataApply{
+				Info:     info,
+				Diff:     &diff,
+				Provider: &provider,
+				Output:   &state,
+			},
+
+			&EvalWriteState{
+				Name:         stateId,
+				ResourceType: rs.Type,
+				Provider:     rs.Provider,
+				Dependencies: rs.Dependencies,
+				State:        &state,
+			},
+
+			&EvalUpdateStateHook{},
+		},
+	}
+}

terraform/node_resource_abstract_count.go

@@ -0,0 +1,41 @@
+package terraform
+
+// NodeAbstractCountResource should be embedded instead of NodeAbstractResource
+// if the resource has a `count` value that needs to be expanded.
+//
+// The embedder should implement `DynamicExpand` to process the count.
+type NodeAbstractCountResource struct {
+	*NodeAbstractResource
+
+	// Validate, if true, will perform the validation for the count.
+	// This should only be turned on for the "validate" operation.
+	Validate bool
+}
+
+// GraphNodeEvalable
+func (n *NodeAbstractCountResource) EvalTree() EvalNode {
+	return &EvalSequence{
+		Nodes: []EvalNode{
+			// The EvalTree for a plannable resource primarily involves
+			// interpolating the count since it can contain variables
+			// we only just received access to.
+			//
+			// With the interpolated count, we can then DynamicExpand
+			// into the proper number of instances.
+			&EvalInterpolate{Config: n.Config.RawCount},
+
+			&EvalCountCheckComputed{Resource: n.Config},
+
+			// If validation is enabled, perform the validation
+			&EvalIf{
+				If: func(ctx EvalContext) (bool, error) {
+					return n.Validate, nil
+				},
+
+				Then: &EvalValidateCount{Resource: n.Config},
+			},
+
+			&EvalCountFixZeroOneBoundary{Resource: n.Config},
+		},
+	}
+}

terraform/node_resource_plan.go

@@ -7,34 +7,7 @@ import (
 // NodePlannableResource represents a resource that is "plannable":
 // it is ready to be planned in order to create a diff.
 type NodePlannableResource struct {
-	*NodeAbstractResource
+	*NodeAbstractCountResource
-
-	// Set by GraphNodeTargetable and used during DynamicExpand to
-	// forward targets downwards.
-	targets []ResourceAddress
-}
-
-// GraphNodeTargetable
-func (n *NodePlannableResource) SetTargets(targets []ResourceAddress) {
-	n.targets = targets
-}
-
-// GraphNodeEvalable
-func (n *NodePlannableResource) EvalTree() EvalNode {
-	return &EvalSequence{
-		Nodes: []EvalNode{
-			// The EvalTree for a plannable resource primarily involves
-			// interpolating the count since it can contain variables
-			// we only just received access to.
-			//
-			// With the interpolated count, we can then DynamicExpand
-			// into the proper number of instances.
-			&EvalInterpolate{Config: n.Config.RawCount},
-
-			&EvalCountCheckComputed{Resource: n.Config},
-			&EvalCountFixZeroOneBoundary{Resource: n.Config},
-		},
-	}
 }
 
 // GraphNodeDynamicExpandable
@@ -91,7 +64,7 @@ func (n *NodePlannableResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
 		&AttachStateTransformer{State: state},
 
 		// Targeting
-		&TargetsTransformer{ParsedTargets: n.targets},
+		&TargetsTransformer{ParsedTargets: n.Targets},
 
 		// Connect references so ordering is correct
 		&ReferenceTransformer{},

terraform/node_resource_refresh.go

@@ -0,0 +1,90 @@
+package terraform
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/terraform/config"
+)
+
+// NodeRefreshableResource represents a resource that is "applyable":
+// it is ready to be applied and is represented by a diff.
+type NodeRefreshableResource struct {
+	*NodeAbstractResource
+}
+
+// GraphNodeDestroyer
+func (n *NodeRefreshableResource) DestroyAddr() *ResourceAddress {
+	return n.Addr
+}
+
+// GraphNodeEvalable
+func (n *NodeRefreshableResource) EvalTree() EvalNode {
+	// Eval info is different depending on what kind of resource this is
+	switch mode := n.Addr.Mode; mode {
+	case config.ManagedResourceMode:
+		return n.evalTreeManagedResource()
+	case config.DataResourceMode:
+		dn := &NodeRefreshableDataResourceInstance{
+			NodeAbstractResource: n.NodeAbstractResource,
+		}
+
+		return dn.EvalTree()
+	default:
+		panic(fmt.Errorf("unsupported resource mode %s", mode))
+	}
+}
+
+func (n *NodeRefreshableResource) evalTreeManagedResource() EvalNode {
+	addr := n.NodeAbstractResource.Addr
+
+	// stateId is the ID to put into the state
+	stateId := addr.stateId()
+
+	// Build the instance info. More of this will be populated during eval
+	info := &InstanceInfo{
+		Id:   stateId,
+		Type: addr.Type,
+	}
+
+	// Declare a bunch of variables that are used for state during
+	// evaluation. Most of this are written to by-address below.
+	var provider ResourceProvider
+	var state *InstanceState
+
+	// This happened during initial development. All known cases were
+	// fixed and tested but as a sanity check let's assert here.
+	if n.ResourceState == nil {
+		err := fmt.Errorf(
+			"No resource state attached for addr: %s\n\n"+
+				"This is a bug. Please report this to Terraform with your configuration\n"+
+				"and state attached. Please be careful to scrub any sensitive information.",
+			addr)
+		return &EvalReturnError{Error: &err}
+	}
+
+	return &EvalSequence{
+		Nodes: []EvalNode{
+			&EvalGetProvider{
+				Name:   n.ProvidedBy()[0],
+				Output: &provider,
+			},
+			&EvalReadState{
+				Name:   stateId,
+				Output: &state,
+			},
+			&EvalRefresh{
+				Info:     info,
+				Provider: &provider,
+				State:    &state,
+				Output:   &state,
+			},
+			&EvalWriteState{
+				Name:         stateId,
+				ResourceType: n.ResourceState.Type,
+				Provider:     n.ResourceState.Provider,
+				Dependencies: n.ResourceState.Dependencies,
+				State:        &state,
+			},
+		},
+	}
+}

terraform/node_resource_validate.go

@@ -0,0 +1,142 @@
+package terraform
+
+import (
+	"github.com/hashicorp/terraform/dag"
+)
+
+// NodeValidatableResource represents a resource that is used for validation
+// only.
+type NodeValidatableResource struct {
+	*NodeAbstractCountResource
+}
+
+// GraphNodeEvalable
+func (n *NodeValidatableResource) EvalTree() EvalNode {
+	// Ensure we're validating
+	c := n.NodeAbstractCountResource
+	c.Validate = true
+	return c.EvalTree()
+}
+
+// GraphNodeDynamicExpandable
+func (n *NodeValidatableResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
+	// Grab the state which we read
+	state, lock := ctx.State()
+	lock.RLock()
+	defer lock.RUnlock()
+
+	// Expand the resource count which must be available by now from EvalTree
+	count, err := n.Config.Count()
+	if err != nil {
+		return nil, err
+	}
+
+	// The concrete resource factory we'll use
+	concreteResource := func(a *NodeAbstractResource) dag.Vertex {
+		// Add the config and state since we don't do that via transforms
+		a.Config = n.Config
+
+		return &NodeValidatableResourceInstance{
+			NodeAbstractResource: a,
+		}
+	}
+
+	// Start creating the steps
+	steps := []GraphTransformer{
+		// Expand the count.
+		&ResourceCountTransformer{
+			Concrete: concreteResource,
+			Count:    count,
+			Addr:     n.ResourceAddr(),
+		},
+
+		// Attach the state
+		&AttachStateTransformer{State: state},
+
+		// Targeting
+		&TargetsTransformer{ParsedTargets: n.Targets},
+
+		// Connect references so ordering is correct
+		&ReferenceTransformer{},
+
+		// Make sure there is a single root
+		&RootTransformer{},
+	}
+
+	// Build the graph
+	b := &BasicGraphBuilder{
+		Steps:    steps,
+		Validate: true,
+		Name:     "NodeValidatableResource",
+	}
+
+	return b.Build(ctx.Path())
+}
+
+// This represents a _single_ resource instance to validate.
+type NodeValidatableResourceInstance struct {
+	*NodeAbstractResource
+}
+
+// GraphNodeEvalable
+func (n *NodeValidatableResourceInstance) EvalTree() EvalNode {
+	addr := n.NodeAbstractResource.Addr
+
+	// Build the resource for eval
+	resource := &Resource{
+		Name:       addr.Name,
+		Type:       addr.Type,
+		CountIndex: addr.Index,
+	}
+	if resource.CountIndex < 0 {
+		resource.CountIndex = 0
+	}
+
+	// Declare a bunch of variables that are used for state during
+	// evaluation. Most of this are written to by-address below.
+	var config *ResourceConfig
+	var provider ResourceProvider
+
+	seq := &EvalSequence{
+		Nodes: []EvalNode{
+			&EvalValidateResourceSelfRef{
+				Addr:   &addr,
+				Config: &n.Config.RawConfig,
+			},
+			&EvalGetProvider{
+				Name:   n.ProvidedBy()[0],
+				Output: &provider,
+			},
+			&EvalInterpolate{
+				Config:   n.Config.RawConfig.Copy(),
+				Resource: resource,
+				Output:   &config,
+			},
+			&EvalValidateResource{
+				Provider:     &provider,
+				Config:       &config,
+				ResourceName: n.Config.Name,
+				ResourceType: n.Config.Type,
+				ResourceMode: n.Config.Mode,
+			},
+		},
+	}
+
+	// Validate all the provisioners
+	for _, p := range n.Config.Provisioners {
+		var provisioner ResourceProvisioner
+		seq.Nodes = append(seq.Nodes, &EvalGetProvisioner{
+			Name:   p.Type,
+			Output: &provisioner,
+		}, &EvalInterpolate{
+			Config:   p.RawConfig.Copy(),
+			Resource: resource,
+			Output:   &config,
+		}, &EvalValidateProvisioner{
+			Provisioner: &provisioner,
+			Config:      &config,
+		})
+	}
+
+	return seq
+}

terraform/state_filter.go

@@ -85,15 +85,22 @@ func (f *StateFilter) filterSingle(a *ResourceAddress) []*StateFilterResult {
 	// the modules to find relevant resources.
 	for _, m := range modules {
 		for n, r := range m.Resources {
-			if f.relevant(a, r) {
+			// The name in the state contains valuable information. Parse.
-				// The name in the state contains valuable information. Parse.
+			key, err := ParseResourceStateKey(n)
-				key, err := ParseResourceStateKey(n)
+			if err != nil {
-				if err != nil {
+				// If we get an error parsing, then just ignore it
-					// If we get an error parsing, then just ignore it
+				// out of the state.
-					// out of the state.
+				continue
-					continue
+			}
-				}
 
+			// Older states and test fixtures often don't contain the
+			// type directly on the ResourceState. We add this so StateFilter
+			// is a bit more robust.
+			if r.Type == "" {
+				r.Type = key.Type
+			}
+
+			if f.relevant(a, r) {
 				if a.Name != "" && a.Name != key.Name {
 					// Name doesn't match
 					continue

terraform/state_filter_test.go

@@ -38,6 +38,15 @@ func TestStateFilterFilter(t *testing.T) {
 			},
 		},
 
+		"single resource from minimal state": {
+			"single-minimal-resource.tfstate",
+			[]string{"aws_instance.web"},
+			[]string{
+				"*terraform.ResourceState: aws_instance.web",
+				"*terraform.InstanceState: aws_instance.web",
+			},
+		},
+
 		"single resource with similar names": {
 			"small_test_instance.tfstate",
 			[]string{"test_instance.foo"},

terraform/test-fixtures/state-filter/single-minimal-resource.tfstate

@@ -0,0 +1,18 @@
+{
+    "version": 1,
+    "serial": 12,
+    "modules": [
+        {
+            "path": [
+                "root"
+            ],
+            "resources": {
+                "aws_instance.web": {
+                    "primary": {
+                        "id": "onprem"
+                    }
+                }
+            }
+        }
+    ]
+}

terraform/test-fixtures/transform-config-mode-data/main.tf

@@ -0,0 +1,3 @@
+data "aws_ami" "foo" {}
+
+resource "aws_instance" "web" {}

terraform/transform_attach_state.go

@@ -45,8 +45,10 @@ func (t *AttachStateTransformer) Transform(g *Graph) error {
 		}
 
 		// Attach the first resource state we get
+		log.Printf("SEARCH: %s", addr)
 		found := false
 		for _, result := range results {
+			log.Printf("WTF: %s %#v", addr, result)
 			if rs, ok := result.Value.(*ResourceState); ok {
 				log.Printf(
 					"[DEBUG] Attaching resource state to %q: %s",

terraform/transform_config.go

@@ -4,7 +4,9 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"sync"
 
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/dag"
 )
@@ -23,10 +25,25 @@ import (
 type ConfigTransformer struct {
 	Concrete ConcreteResourceNodeFunc
 
+	// Module is the module to add resources from.
 	Module *module.Tree
+
+	// Unique will only add resources that aren't already present in the graph.
+	Unique bool
+
+	// Mode will only add resources that match the given mode
+	ModeFilter bool
+	Mode       config.ResourceMode
+
+	l         sync.Mutex
+	uniqueMap map[string]struct{}
 }
 
 func (t *ConfigTransformer) Transform(g *Graph) error {
+	// Lock since we use some internal state
+	t.l.Lock()
+	defer t.l.Unlock()
+
 	// If no module is given, we don't do anything
 	if t.Module == nil {
 		return nil
@@ -37,6 +54,18 @@ func (t *ConfigTransformer) Transform(g *Graph) error {
 		return errors.New("module must be loaded for ConfigTransformer")
 	}
 
+	// Reset the uniqueness map. If we're tracking uniques, then populate
+	// it with addresses.
+	t.uniqueMap = make(map[string]struct{})
+	defer func() { t.uniqueMap = nil }()
+	if t.Unique {
+		for _, v := range g.Vertices() {
+			if rn, ok := v.(GraphNodeResource); ok {
+				t.uniqueMap[rn.ResourceAddr().String()] = struct{}{}
+			}
+		}
+	}
+
 	// Start the transformation process
 	return t.transform(g, t.Module)
 }
@@ -66,13 +95,13 @@ func (t *ConfigTransformer) transformSingle(g *Graph, m *module.Tree) error {
 	log.Printf("[TRACE] ConfigTransformer: Starting for path: %v", m.Path())
 
 	// Get the configuration for this module
-	config := m.Config()
+	conf := m.Config()
 
 	// Build the path we're at
 	path := m.Path()
 
 	// Write all the resources out
-	for _, r := range config.Resources {
+	for _, r := range conf.Resources {
 		// Build the resource address
 		addr, err := parseResourceAddressConfig(r)
 		if err != nil {
@@ -81,6 +110,16 @@ func (t *ConfigTransformer) transformSingle(g *Graph, m *module.Tree) error {
 		}
 		addr.Path = path
 
+		// If this is already in our uniqueness map, don't add it again
+		if _, ok := t.uniqueMap[addr.String()]; ok {
+			continue
+		}
+
+		// Remove non-matching modes
+		if t.ModeFilter && addr.Mode != t.Mode {
+			continue
+		}
+
 		// Build the abstract node and the concrete one
 		abstract := &NodeAbstractResource{Addr: addr}
 		var node dag.Vertex = abstract

terraform/transform_config_test.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/config/module"
 )
 
@@ -48,6 +49,80 @@ func TestConfigTransformer(t *testing.T) {
 	}
 }
 
+func TestConfigTransformer_mode(t *testing.T) {
+	g := Graph{Path: RootModulePath}
+	tf := &ConfigTransformer{
+		Module:     testModule(t, "transform-config-mode-data"),
+		ModeFilter: true,
+		Mode:       config.DataResourceMode,
+	}
+	if err := tf.Transform(&g); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(`
+data.aws_ami.foo
+`)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
+func TestConfigTransformer_nonUnique(t *testing.T) {
+	addr, err := ParseResourceAddress("aws_instance.web")
+	if err != nil {
+		t.Fatalf("bad: %s", err)
+	}
+
+	g := Graph{Path: RootModulePath}
+	g.Add(&NodeAbstractResource{Addr: addr})
+	tf := &ConfigTransformer{Module: testModule(t, "graph-basic")}
+	if err := tf.Transform(&g); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(`
+aws_instance.web
+aws_instance.web
+aws_load_balancer.weblb
+aws_security_group.firewall
+openstack_floating_ip.random
+`)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
+func TestConfigTransformer_unique(t *testing.T) {
+	addr, err := ParseResourceAddress("aws_instance.web")
+	if err != nil {
+		t.Fatalf("bad: %s", err)
+	}
+
+	g := Graph{Path: RootModulePath}
+	g.Add(&NodeAbstractResource{Addr: addr})
+	tf := &ConfigTransformer{
+		Module: testModule(t, "graph-basic"),
+		Unique: true,
+	}
+	if err := tf.Transform(&g); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(`
+aws_instance.web
+aws_load_balancer.weblb
+aws_security_group.firewall
+openstack_floating_ip.random
+`)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
 const testConfigTransformerGraphBasicStr = `
 aws_instance.web
 aws_load_balancer.weblb