terraform: expand count in plan

terraform/node_resource_plan.go

@@ -1,5 +1,9 @@
 package terraform
 
+import (
+	"github.com/hashicorp/terraform/dag"
+)
+
 // NodePlannableResource represents a resource that is "plannable":
 // it is ready to be planned in order to create a diff.
 type NodePlannableResource struct {
@@ -21,21 +25,33 @@ func (n *NodePlannableResource) EvalTree() EvalNode {
 	}
 }
 
-/*
 // GraphNodeDynamicExpandable
 func (n *NodePlannableResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
-	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
+		a.ResourceState = n.ResourceState
+
+		return &NodePlannableResourceInstance{
+			NodeAbstractResource: a,
+		}
+	}
 
 	// Start creating the steps
 	steps := make([]GraphTransformer, 0, 5)
 
 	// Expand counts.
 	steps = append(steps, &ResourceCountTransformer{
-		Resource: n.Resource,
-		Destroy:  n.Destroy,
-		Targets:  n.Targets,
+		Concrete: concreteResource,
+		Count:    count,
+		Addr:     n.ResourceAddr(),
 	})
 
 	// Always end with the root being added
@@ -45,4 +61,3 @@ func (n *NodePlannableResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
 	b := &BasicGraphBuilder{Steps: steps, Validate: true}
 	return b.Build(ctx.Path())
 }
-*/

terraform/transform_resource_count.go

@@ -0,0 +1,51 @@
+package terraform
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/terraform/dag"
+)
+
+// ResourceCountTransformer is a GraphTransformer that expands the count
+// out for a specific resource.
+//
+// This assumes that the count is already interpolated.
+type ResourceCountTransformer struct {
+	Concrete ConcreteResourceNodeFunc
+
+	Count int
+	Addr  *ResourceAddress
+}
+
+func (t *ResourceCountTransformer) Transform(g *Graph) error {
+	// Don't allow the count to be negative
+	if t.Count < 0 {
+		return fmt.Errorf("negative count: %d", t.Count)
+	}
+
+	// For each count, build and add the node
+	for i := 0; i < t.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.
+		index := i
+		if t.Count == 1 {
+			index = -1
+		}
+
+		// Build the resource address
+		addr := t.Addr.Copy()
+		addr.Index = index
+
+		// Build the abstract node and the concrete one
+		abstract := &NodeAbstractResource{Addr: addr}
+		var node dag.Vertex = abstract
+		if f := t.Concrete; f != nil {
+			node = f(abstract)
+		}
+
+		// Add it to the graph
+		g.Add(node)
+	}
+
+	return nil
+}