terraform: re-enable dot-graphs

command/graph.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"os"
 	"strings"
+
+	"github.com/hashicorp/terraform/terraform"
 )
 
 // GraphCommand is a Command implementation that takes a Terraform
@@ -56,7 +58,7 @@ func (c *GraphCommand) Run(args []string) int {
 		return 1
 	}
 
-	c.Ui.Output(g.String())
+	c.Ui.Output(terraform.GraphDot(g, nil))
 
 	return 0
 }

terraform/graph_config_node.go

@@ -173,6 +173,17 @@ func (n *GraphNodeConfigProvider) ProviderName() string {
 	return n.Provider.Name
 }
 
+// GraphNodeDotter impl.
+func (n *GraphNodeConfigProvider) Dot(name string) string {
+	return fmt.Sprintf(
+		"\"%s\" [\n"+
+			"\tlabel=\"%s\"\n"+
+			"\tshape=diamond\n"+
+			"];",
+		name,
+		n.Name())
+}
+
 // GraphNodeConfigResource represents a resource within the config graph.
 type GraphNodeConfigResource struct {
 	Resource *config.Resource
@@ -235,6 +246,21 @@ func (n *GraphNodeConfigResource) Name() string {
 	return result
 }
 
+// GraphNodeDotter impl.
+func (n *GraphNodeConfigResource) Dot(name string) string {
+	if n.DestroyMode != DestroyNone {
+		return ""
+	}
+
+	return fmt.Sprintf(
+		"\"%s\" [\n"+
+			"\tlabel=\"%s\"\n"+
+			"\tshape=box\n"+
+			"];",
+		name,
+		n.Name())
+}
+
 // GraphNodeDynamicExpandable impl.
 func (n *GraphNodeConfigResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
 	state, lock := ctx.State()
@@ -476,6 +502,17 @@ func (n *graphNodeModuleExpanded) Name() string {
 	return fmt.Sprintf("%s (expanded)", dag.VertexName(n.Original))
 }
 
+// GraphNodeDotter impl.
+func (n *graphNodeModuleExpanded) Dot(name string) string {
+	return fmt.Sprintf(
+		"\"%s\" [\n"+
+			"\tlabel=\"%s\"\n"+
+			"\tshape=component\n"+
+			"];",
+		name,
+		dag.VertexName(n.Original))
+}
+
 // GraphNodeEvalable impl.
 func (n *graphNodeModuleExpanded) EvalTree() EvalNode {
 	var resourceConfig *ResourceConfig

terraform/graph_dot.go

@@ -0,0 +1,71 @@
+package terraform
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/terraform/dag"
+)
+
+// GraphNodeDotter can be implemented by a node to cause it to be included
+// in the dot graph. The Dot method will be called which is expected to
+// return a representation of this node.
+type GraphNodeDotter interface {
+	// Dot is called to return the dot formatting for the node.
+	// The parameter must be the title of the node.
+	Dot(string) string
+}
+
+// GraphDotOpts are the options for generating a dot formatted Graph.
+type GraphDotOpts struct{}
+
+// GraphDot returns the dot formatting of a visual representation of
+// the given Terraform graph.
+func GraphDot(g *Graph, opts *GraphDotOpts) string {
+	buf := new(bytes.Buffer)
+
+	// Start the graph
+	buf.WriteString("digraph {\n")
+	buf.WriteString("\tcompound = true;\n")
+
+	// Go through all the vertices and draw it
+	vertices := g.Vertices()
+	dotVertices := make(map[dag.Vertex]struct{}, len(vertices))
+	for _, v := range vertices {
+		if dn, ok := v.(GraphNodeDotter); !ok {
+			continue
+		} else if dn.Dot("fake") == "" {
+			continue
+		}
+
+		dotVertices[v] = struct{}{}
+	}
+
+	for v, _ := range dotVertices {
+		dn := v.(GraphNodeDotter)
+		scanner := bufio.NewScanner(strings.NewReader(
+			dn.Dot(dag.VertexName(v))))
+		for scanner.Scan() {
+			buf.WriteString("\t" + scanner.Text() + "\n")
+		}
+
+		// Draw all the edges
+		for _, t := range g.DownEdges(v).List() {
+			target := t.(dag.Vertex)
+			if _, ok := dotVertices[target]; !ok {
+				continue
+			}
+
+			buf.WriteString(fmt.Sprintf(
+				"\t\"%s\" -> \"%s\";\n",
+				dag.VertexName(v),
+				dag.VertexName(target)))
+		}
+	}
+
+	// End the graph
+	buf.WriteString("}\n")
+	return buf.String()
+}

terraform/transform_provider.go

@@ -111,6 +111,17 @@ func (n *graphNodeMissingProvider) ProviderName() string {
 	return n.ProviderNameValue
 }
 
+// GraphNodeDotter impl.
+func (n *graphNodeMissingProvider) Dot(name string) string {
+	return fmt.Sprintf(
+		"\"%s\" [\n"+
+			"\tlabel=\"%s\"\n"+
+			"\tshape=diamond\n"+
+			"];",
+		name,
+		n.Name())
+}
+
 func providerVertexMap(g *Graph) map[string]dag.Vertex {
 	m := make(map[string]dag.Vertex)
 	for _, v := range g.Vertices() {

terraform/transform_root.go

@@ -1,6 +1,8 @@
 package terraform
 
 import (
+	"fmt"
+
 	"github.com/hashicorp/terraform/dag"
 )
 
@@ -36,3 +38,7 @@ type graphNodeRoot struct{}
 func (n graphNodeRoot) Name() string {
 	return "root"
 }
+
+func (n graphNodeRoot) Dot(name string) string {
+	return fmt.Sprintf("\"%s\" [shape=circle];", name)
+}