terraform: evaluation interpolater connect

terraform/context.go

@@ -30,6 +30,8 @@ type Context2 struct {
 	module    *module.Tree
 	providers map[string]ResourceProviderFactory
 	state     *State
+	stateLock sync.RWMutex
+	variables map[string]string
 }
 
 // NewContext creates a new Context structure.
@@ -42,6 +44,7 @@ func NewContext2(opts *ContextOpts) *Context2 {
 		module:    opts.Module,
 		providers: opts.Providers,
 		state:     opts.State,
+		variables: opts.Variables,
 	}
 }
 
@@ -71,8 +74,7 @@ func (c *Context2) Validate() ([]string, []error) {
 		errs = append(errs, err)
 	}
 
-	evalCtx := c.evalContext()
-	evalCtx.ComputeMissing = true
+	evalCtx := c.evalContext(walkValidate)
 
 	// Build the graph
 	graph, err := c.GraphBuilder().Build(RootModulePath)
@@ -114,8 +116,17 @@ func (c *Context2) Validate() ([]string, []error) {
 	return warns, errs
 }
 
-func (c *Context2) evalContext() *BuiltinEvalContext {
+func (c *Context2) evalContext(op walkOperation) *BuiltinEvalContext {
 	return &BuiltinEvalContext{
+		Path:      RootModulePath,
 		Providers: c.providers,
+
+		Interpolater: &Interpolater{
+			Operation: op,
+			Module:    c.module,
+			State:     c.state,
+			StateLock: &c.stateLock,
+			Variables: nil,
+		},
 	}
 }

terraform/context_test.go

@@ -162,7 +162,6 @@ func TestContext2Validate_requiredVar(t *testing.T) {
 	if len(w) > 0 {
 		t.Fatalf("bad: %#v", w)
 	}
-	// TODO: fail
 	if len(e) == 0 {
 		t.Fatalf("bad: %s", e)
 	}

terraform/eval_context.go

@@ -18,7 +18,10 @@ type EvalContext interface {
 
 	// Interpolate takes the given raw configuration and completes
 	// the interpolations, returning the processed ResourceConfig.
-	Interpolate(*config.RawConfig) (*ResourceConfig, error)
+	//
+	// The resource argument is optional. If given, it is the resource
+	// that is currently being acted upon.
+	Interpolate(*config.RawConfig, *Resource) (*ResourceConfig, error)
 }
 
 // MockEvalContext is a mock version of EvalContext that can be used
@@ -35,6 +38,7 @@ type MockEvalContext struct {
 
 	InterpolateCalled       bool
 	InterpolateConfig       *config.RawConfig
+	InterpolateResource     *Resource
 	InterpolateConfigResult *ResourceConfig
 	InterpolateError        error
 }
@@ -52,8 +56,9 @@ func (c *MockEvalContext) Provider(n string) ResourceProvider {
 }
 
 func (c *MockEvalContext) Interpolate(
-	config *config.RawConfig) (*ResourceConfig, error) {
+	config *config.RawConfig, resource *Resource) (*ResourceConfig, error) {
 	c.InterpolateCalled = true
 	c.InterpolateConfig = config
+	c.InterpolateResource = resource
 	return c.InterpolateConfigResult, c.InterpolateError
 }

terraform/eval_context_builtin.go

@@ -5,14 +5,14 @@ import (
 	"sync"
 
 	"github.com/hashicorp/terraform/config"
-	"github.com/hashicorp/terraform/config/lang/ast"
 )
 
 // BuiltinEvalContext is an EvalContext implementation that is used by
 // Terraform by default.
 type BuiltinEvalContext struct {
-	Providers      map[string]ResourceProviderFactory
-	ComputeMissing bool
+	Path         []string
+	Interpolater *Interpolater
+	Providers    map[string]ResourceProviderFactory
 
 	providers map[string]ResourceProvider
 	once      sync.Once
@@ -45,42 +45,23 @@ func (ctx *BuiltinEvalContext) Provider(n string) ResourceProvider {
 }
 
 func (ctx *BuiltinEvalContext) Interpolate(
-	cfg *config.RawConfig) (*ResourceConfig, error) {
-	vs := make(map[string]ast.Variable)
-
-	// If we don't have a config, use the blank config
-	if cfg == nil {
-		goto INTERPOLATE_RESULT
-	}
-
-	for n, rawV := range cfg.Variables {
-		switch rawV.(type) {
-		case *config.ModuleVariable:
-			if ctx.ComputeMissing {
-				vs[n] = ast.Variable{
-					Value: config.UnknownVariableValue,
-					Type:  ast.TypeString,
-				}
-			}
-		case *config.ResourceVariable:
-			if ctx.ComputeMissing {
-				vs[n] = ast.Variable{
-					Value: config.UnknownVariableValue,
-					Type:  ast.TypeString,
-				}
-			}
-		default:
-			return nil, fmt.Errorf(
-				"unknown interpolation type: %#v", rawV)
+	cfg *config.RawConfig, r *Resource) (*ResourceConfig, error) {
+	if cfg != nil {
+		scope := &InterpolationScope{
+			Path:     ctx.Path,
+			Resource: r,
+		}
+		vs, err := ctx.Interpolater.Values(scope, cfg.Variables)
+		if err != nil {
+			return nil, err
 		}
-	}
 
-	// Do the interpolation
-	if err := cfg.Interpolate(vs); err != nil {
-		return nil, err
+		// Do the interpolation
+		if err := cfg.Interpolate(vs); err != nil {
+			return nil, err
+		}
 	}
 
-INTERPOLATE_RESULT:
 	result := NewResourceConfig(cfg)
 	result.interpolateForce()
 	return result, nil

terraform/eval_interpolate.go

@@ -7,7 +7,8 @@ import (
 // EvalInterpolate is an EvalNode implementation that takes a raw
 // configuration and interpolates it.
 type EvalInterpolate struct {
-	Config *config.RawConfig
+	Config   *config.RawConfig
+	Resource *Resource
 }
 
 func (n *EvalInterpolate) Args() ([]EvalNode, []EvalType) {
@@ -16,7 +17,7 @@ func (n *EvalInterpolate) Args() ([]EvalNode, []EvalType) {
 
 func (n *EvalInterpolate) Eval(
 	ctx EvalContext, args []interface{}) (interface{}, error) {
-	return ctx.Interpolate(n.Config)
+	return ctx.Interpolate(n.Config, n.Resource)
 }
 
 func (n *EvalInterpolate) Type() EvalType {