terraform: filter eval nodes on operation

terraform/context.go

@@ -71,6 +71,21 @@ func (c *Context2) GraphBuilder() GraphBuilder {
 	}
 }
 
+// Refresh goes through all the resources in the state and refreshes them
+// to their latest state. This will update the state that this context
+// works with, along with returning it.
+//
+// Even in the case an error is returned, the state will be returned and
+// will potentially be partially updated.
+func (c *Context2) Refresh() (*State, []error) {
+	if _, err := c.walk(walkRefresh); err != nil {
+		var errs error
+		return nil, multierror.Append(errs, err).Errors
+	}
+
+	return nil, nil
+}
+
 // Validate validates the configuration and returns any warnings or errors.
 func (c *Context2) Validate() ([]string, []error) {
 	var errs error
@@ -89,17 +104,25 @@ func (c *Context2) Validate() ([]string, []error) {
 		}
 	}
 
-	// Build the graph
-	graph, err := c.GraphBuilder().Build(RootModulePath)
+	// Walk
+	walker, err := c.walk(walkValidate)
 	if err != nil {
 		return nil, multierror.Append(errs, err).Errors
 	}
 
-	// Walk the graph
-	walker := &ContextGraphWalker{Context: c, Operation: walkValidate}
-	graph.Walk(walker)
-
 	// Return the result
 	rerrs := multierror.Append(errs, walker.ValidationErrors...)
 	return walker.ValidationWarnings, rerrs.Errors
 }
+
+func (c *Context2) walk(operation walkOperation) (*ContextGraphWalker, error) {
+	// Build the graph
+	graph, err := c.GraphBuilder().Build(RootModulePath)
+	if err != nil {
+		return nil, err
+	}
+
+	// Walk the graph
+	walker := &ContextGraphWalker{Context: c, Operation: operation}
+	return walker, graph.Walk(walker)
+}

terraform/context_test.go

@@ -2,6 +2,7 @@ package terraform
 
 import (
 	"fmt"
+	"reflect"
 	"strings"
 	"testing"
 )
@@ -565,6 +566,58 @@ func TestContext2Validate_varRefFilled(t *testing.T) {
 	}
 }
 
+func TestContext2Refresh(t *testing.T) {
+	p := testProvider("aws")
+	m := testModule(t, "refresh-basic")
+	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.web": &ResourceState{
+							Type: "aws_instance",
+							Primary: &InstanceState{
+								ID: "foo",
+							},
+						},
+					},
+				},
+			},
+		},
+	})
+
+	p.RefreshFn = nil
+	p.RefreshReturn = &InstanceState{
+		ID: "foo",
+	}
+
+	s, err := ctx.Refresh()
+	mod := s.RootModule()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if !p.RefreshCalled {
+		t.Fatal("refresh should be called")
+	}
+	if p.RefreshState.ID != "foo" {
+		t.Fatalf("bad: %#v", p.RefreshState)
+	}
+	if !reflect.DeepEqual(mod.Resources["aws_instance.web"].Primary, p.RefreshReturn) {
+		t.Fatalf("bad: %#v %#v", mod.Resources["aws_instance.web"], p.RefreshReturn)
+	}
+
+	for _, r := range mod.Resources {
+		if r.Type == "" {
+			t.Fatalf("no type: %#v", r)
+		}
+	}
+}
+
 /*
 func TestContextInput(t *testing.T) {
 	input := new(MockUIInput)
@@ -4158,58 +4211,6 @@ func TestContextPlan_varListErr(t *testing.T) {
 	}
 }
 
-func TestContextRefresh(t *testing.T) {
-	p := testProvider("aws")
-	m := testModule(t, "refresh-basic")
-	ctx := testContext(t, &ContextOpts{
-		Module: m,
-		Providers: map[string]ResourceProviderFactory{
-			"aws": testProviderFuncFixed(p),
-		},
-		State: &State{
-			Modules: []*ModuleState{
-				&ModuleState{
-					Path: rootModulePath,
-					Resources: map[string]*ResourceState{
-						"aws_instance.web": &ResourceState{
-							Type: "aws_instance",
-							Primary: &InstanceState{
-								ID: "foo",
-							},
-						},
-					},
-				},
-			},
-		},
-	})
-
-	p.RefreshFn = nil
-	p.RefreshReturn = &InstanceState{
-		ID: "foo",
-	}
-
-	s, err := ctx.Refresh()
-	mod := s.RootModule()
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
-	if !p.RefreshCalled {
-		t.Fatal("refresh should be called")
-	}
-	if p.RefreshState.ID != "foo" {
-		t.Fatalf("bad: %#v", p.RefreshState)
-	}
-	if !reflect.DeepEqual(mod.Resources["aws_instance.web"].Primary, p.RefreshReturn) {
-		t.Fatalf("bad: %#v %#v", mod.Resources["aws_instance.web"], p.RefreshReturn)
-	}
-
-	for _, r := range mod.Resources {
-		if r.Type == "" {
-			t.Fatalf("no type: %#v", r)
-		}
-	}
-}
-
 func TestContextRefresh_delete(t *testing.T) {
 	p := testProvider("aws")
 	m := testModule(t, "refresh-basic")

terraform/eval_filter_operation.go

@@ -0,0 +1,23 @@
+package terraform
+
+// EvalNodeOpFilterable is an interface that EvalNodes can implement
+// to be filterable by the operation that is being run on Terraform.
+type EvalNodeOpFilterable interface {
+	IncludeInOp(walkOperation) bool
+}
+
+// EvalNodeFilterOp returns a filter function that filters nodes that
+// include themselves in specific operations.
+func EvalNodeFilterOp(op walkOperation) EvalNodeFilterFunc {
+	return func(n EvalNode) EvalNode {
+		include := true
+		if of, ok := n.(EvalNodeOpFilterable); ok {
+			include = of.IncludeInOp(op)
+		}
+		if include {
+			return n
+		}
+
+		return EvalNoop{}
+	}
+}

terraform/eval_noop.go

@@ -0,0 +1,10 @@
+package terraform
+
+// EvalNoop is an EvalNode that does nothing.
+type EvalNoop struct{}
+
+func (EvalNoop) Args() ([]EvalNode, []EvalType) { return nil, nil }
+func (EvalNoop) Eval(EvalContext, []interface{}) (interface{}, error) {
+	return nil, nil
+}
+func (EvalNoop) Type() EvalType { return EvalTypeNull }

terraform/graph.go

@@ -117,9 +117,8 @@ func (g *Graph) Dependable(n string) dag.Vertex {
 // Walk walks the graph with the given walker for callbacks. The graph
 // will be walked with full parallelism, so the walker should expect
 // to be called in concurrently.
-func (g *Graph) Walk(walker GraphWalker) {
-	// TODO: test
-	g.walk(walker)
+func (g *Graph) Walk(walker GraphWalker) error {
+	return g.walk(walker)
 }
 
 func (g *Graph) init() {

terraform/graph_walk_context.go

@@ -53,6 +53,12 @@ func (w *ContextGraphWalker) EnterGraph(g *Graph) EvalContext {
 	}
 }
 
+func (w *ContextGraphWalker) EnterEvalTree(v dag.Vertex, n EvalNode) EvalNode {
+	// We want to filter the evaluation tree to only include operations
+	// that belong in this operation.
+	return EvalFilter(n, EvalNodeFilterOp(w.Operation))
+}
+
 func (w *ContextGraphWalker) ExitEvalTree(
 	v dag.Vertex, output interface{}, err error) {
 	if err == nil {