terraform: config graph respects depends_on

terraform/graph_config.go

@@ -54,8 +54,7 @@ func Graph2(mod *module.Tree) (*depgraph.Graph, error) {
 	// of var names to the actual node with that name.
 	for _, n := range nodes {
 		m := make(map[string]depgraph.Node)
-		for _, v := range n.Variables() {
-			id := varNameForVar(v)
+		for _, id := range n.Variables() {
 			m[id] = fullMap[id]
 		}
 

terraform/graph_config_node.go

@@ -14,8 +14,9 @@ type graphNodeConfig interface {
 	depgraph.Node
 
 	// Variables returns the full list of variables that this node
-	// depends on.
-	Variables() map[string]config.InterpolatedVariable
+	// depends on. The values within the slice should map to the VarName()
+	// values that are returned by any nodes.
+	Variables() []string
 
 	// VarName returns the name that is used to identify a variable
 	// maps to this node. It should match the result of the
@@ -67,8 +68,14 @@ func (n *GraphNodeConfigModule) Name() string {
 	return fmt.Sprintf("module.%s", n.Module.Name)
 }
 
-func (n *GraphNodeConfigModule) Variables() map[string]config.InterpolatedVariable {
-	return n.Module.RawConfig.Variables
+func (n *GraphNodeConfigModule) Variables() []string {
+	vars := n.Module.RawConfig.Variables
+	result := make([]string, 0, len(vars))
+	for _, v := range vars {
+		result = append(result, varNameForVar(v))
+	}
+
+	return result
 }
 
 func (n *GraphNodeConfigModule) VarName() string {
@@ -88,8 +95,14 @@ func (n *GraphNodeConfigProvider) Name() string {
 	return fmt.Sprintf("provider.%s", n.Provider.Name)
 }
 
-func (n *GraphNodeConfigProvider) Variables() map[string]config.InterpolatedVariable {
-	return n.Provider.RawConfig.Variables
+func (n *GraphNodeConfigProvider) Variables() []string {
+	vars := n.Provider.RawConfig.Variables
+	result := make([]string, 0, len(vars))
+	for _, v := range vars {
+		result = append(result, varNameForVar(v))
+	}
+
+	return result
 }
 
 func (n *GraphNodeConfigProvider) VarName() string {
@@ -107,19 +120,20 @@ func (n *GraphNodeConfigResource) Name() string {
 	return n.Resource.Id()
 }
 
-func (n *GraphNodeConfigResource) Variables() map[string]config.InterpolatedVariable {
-	var m map[string]config.InterpolatedVariable
-	if n.Resource != nil {
-		m = make(map[string]config.InterpolatedVariable)
-		for k, v := range n.Resource.RawCount.Variables {
-			m[k] = v
-		}
-		for k, v := range n.Resource.RawConfig.Variables {
-			m[k] = v
-		}
+func (n *GraphNodeConfigResource) Variables() []string {
+	result := make([]string, len(n.Resource.DependsOn),
+		len(n.Resource.RawCount.Variables)+
+			len(n.Resource.RawConfig.Variables)+
+			len(n.Resource.DependsOn))
+	copy(result, n.Resource.DependsOn)
+	for _, v := range n.Resource.RawCount.Variables {
+		result = append(result, varNameForVar(v))
+	}
+	for _, v := range n.Resource.RawConfig.Variables {
+		result = append(result, varNameForVar(v))
 	}
 
-	return m
+	return result
 }
 
 func (n *GraphNodeConfigResource) VarName() string {

terraform/graph_config_test.go

@@ -40,6 +40,19 @@ func TestGraph(t *testing.T) {
 	}
 }
 
+func TestGraph2_dependsOn(t *testing.T) {
+	g, err := Graph2(testModule(t, "graph-depends-on"))
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(testGraphDependsOnStr)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
 func TestGraph2_modules(t *testing.T) {
 	g, err := Graph2(testModule(t, "graph-modules"))
 	if err != nil {
@@ -64,6 +77,12 @@ provider.aws
   openstack_floating_ip.random
 `
 
+const testGraphDependsOnStr = `
+aws_instance.db
+  aws_instance.web
+aws_instance.web
+`
+
 const testGraphModulesStr = `
 aws_instance.web
   aws_security_group.firewall