terraform: GraphNodeDependent

terraform/graph.go

@@ -51,15 +51,21 @@ func (g *Graph) Add(v dag.Vertex) dag.Vertex {
 	return v
 }
 
-// ConnectTo is a helper to create edges between a node and a list of
-// targets by their DependableNames.
-func (g *Graph) ConnectTo(source dag.Vertex, target []string) []string {
+// ConnectDependent connects a GraphNodeDependent to all of its
+// GraphNodeDependables. It returns the list of dependents it was
+// unable to connect to.
+func (g *Graph) ConnectDependent(raw dag.Vertex) []string {
 	g.once.Do(g.init)
 
+	v, ok := raw.(GraphNodeDependent)
+	if !ok {
+		return nil
+	}
+
 	var missing []string
-	for _, t := range target {
+	for _, t := range v.DependentOn() {
 		if dest := g.dependableMap[t]; dest != nil {
-			g.Connect(dag.BasicEdge(source, dest))
+			g.Connect(dag.BasicEdge(v, dest))
 		} else {
 			missing = append(missing, t)
 		}
@@ -68,6 +74,20 @@ func (g *Graph) ConnectTo(source dag.Vertex, target []string) []string {
 	return missing
 }
 
+// ConnectDependents goes through the graph, connecting all the
+// GraphNodeDependents to GraphNodeDependables. This is safe to call
+// multiple times.
+//
+// To get details on whether dependencies could be found/made, the more
+// specific ConnectDependent should be used.
+func (g *Graph) ConnectDependents() {
+	for _, v := range g.Vertices() {
+		if dv, ok := v.(GraphNodeDependent); ok {
+			g.ConnectDependent(dv)
+		}
+	}
+}
+
 func (g *Graph) init() {
 	if g.Graph == nil {
 		g.Graph = new(dag.Graph)
@@ -86,3 +106,11 @@ func (g *Graph) init() {
 type GraphNodeDependable interface {
 	DependableName() []string
 }
+
+// GraphNodeDependent is an interface which says that a node depends
+// on another GraphNodeDependable by some name. By implementing this
+// interface, Graph.ConnectDependents() can be called multiple times
+// safely and efficiently.
+type GraphNodeDependent interface {
+	DependentOn() []string
+}

terraform/graph_config_node.go

@@ -14,10 +14,10 @@ import (
 type graphNodeConfig interface {
 	dag.NamedVertex
 
-	// Variables returns the full list of variables that this node
-	// depends on. The values within the slice should map to the VarName()
-	// values that are returned by any nodes.
-	Variables() []string
+	// All graph nodes should be dependent on other things, and able to
+	// be depended on.
+	GraphNodeDependable
+	GraphNodeDependent
 }
 
 // GraphNodeConfigModule represents a module within the configuration graph.
@@ -29,20 +29,23 @@ type GraphNodeConfigModule struct {
 func (n *GraphNodeConfigModule) DependableName() []string {
 	return []string{n.Name()}
 }
-func (n *GraphNodeConfigModule) Name() string {
-	return fmt.Sprintf("module.%s", n.Module.Name)
-}
 
-func (n *GraphNodeConfigModule) Variables() []string {
+func (n *GraphNodeConfigModule) DependentOn() []string {
 	vars := n.Module.RawConfig.Variables
 	result := make([]string, 0, len(vars))
 	for _, v := range vars {
-		result = append(result, varNameForVar(v))
+		if vn := varNameForVar(v); vn != "" {
+			result = append(result, vn)
+		}
 	}
 
 	return result
 }
 
+func (n *GraphNodeConfigModule) Name() string {
+	return fmt.Sprintf("module.%s", n.Module.Name)
+}
+
 // GraphNodeConfigProvider represents a configured provider within the
 // configuration graph. These are only immediately in the graph when an
 // explicit `provider` configuration block is in the configuration.
@@ -54,11 +57,17 @@ func (n *GraphNodeConfigProvider) Name() string {
 	return fmt.Sprintf("provider.%s", n.Provider.Name)
 }
 
-func (n *GraphNodeConfigProvider) Variables() []string {
+func (n *GraphNodeConfigProvider) DependableName() []string {
+	return []string{n.Name()}
+}
+
+func (n *GraphNodeConfigProvider) DependentOn() []string {
 	vars := n.Provider.RawConfig.Variables
 	result := make([]string, 0, len(vars))
 	for _, v := range vars {
-		result = append(result, varNameForVar(v))
+		if vn := varNameForVar(v); vn != "" {
+			result = append(result, vn)
+		}
 	}
 
 	return result
@@ -73,22 +82,26 @@ func (n *GraphNodeConfigResource) DependableName() []string {
 	return []string{n.Resource.Id()}
 }
 
-func (n *GraphNodeConfigResource) Name() string {
-	return n.Resource.Id()
-}
-
-func (n *GraphNodeConfigResource) Variables() []string {
+func (n *GraphNodeConfigResource) DependentOn() []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))
+		if vn := varNameForVar(v); vn != "" {
+			result = append(result, vn)
+		}
 	}
 	for _, v := range n.Resource.RawConfig.Variables {
-		result = append(result, varNameForVar(v))
+		if vn := varNameForVar(v); vn != "" {
+			result = append(result, vn)
+		}
 	}
 
 	return result
 }
+
+func (n *GraphNodeConfigResource) Name() string {
+	return n.Resource.Id()
+}

terraform/graph_test.go

@@ -18,12 +18,15 @@ func TestGraphAdd(t *testing.T) {
 	}
 }
 
-func TestGraphConnectTo(t *testing.T) {
+func TestGraphConnectDependent(t *testing.T) {
 	var g Graph
 	g.Add(&testGraphDependable{VertexName: "a", Mock: []string{"a"}})
-	b := g.Add(&testGraphDependable{VertexName: "b"})
+	b := g.Add(&testGraphDependable{
+		VertexName:      "b",
+		DependentOnMock: []string{"a"},
+	})
 
-	if missing := g.ConnectTo(b, []string{"a"}); len(missing) > 0 {
+	if missing := g.ConnectDependent(b); len(missing) > 0 {
 		t.Fatalf("bad: %#v", missing)
 	}
 
@@ -35,8 +38,9 @@ func TestGraphConnectTo(t *testing.T) {
 }
 
 type testGraphDependable struct {
-	VertexName string
-	Mock       []string
+	VertexName      string
+	DependentOnMock []string
+	Mock            []string
 }
 
 func (v *testGraphDependable) Name() string {
@@ -47,6 +51,10 @@ func (v *testGraphDependable) DependableName() []string {
 	return v.Mock
 }
 
+func (v *testGraphDependable) DependentOn() []string {
+	return v.DependentOnMock
+}
+
 const testGraphAddStr = `
 42
 84

terraform/transform_config.go

@@ -63,14 +63,7 @@ func (t *ConfigTransformer) Transform(g *Graph) error {
 	// Build up the dependencies. We have to do this outside of the above
 	// loop since the nodes need to be in place for us to build the deps.
 	for _, n := range nodes {
-		vars := n.Variables()
-		targets := make([]string, 0, len(vars))
-		for _, t := range vars {
-			if t != "" {
-				targets = append(targets, t)
-			}
-		}
-		if missing := g.ConnectTo(n, targets); len(missing) > 0 {
+		if missing := g.ConnectDependent(n); len(missing) > 0 {
 			for _, m := range missing {
 				err = multierror.Append(err, fmt.Errorf(
 					"%s: missing dependency: %s", n.Name(), m))

terraform/transform_orphan.go

@@ -29,17 +29,21 @@ func (t *OrphanTransformer) Transform(g *Graph) error {
 	resourceOrphans := state.Orphans(t.Config)
 	resourceVertexes := make([]dag.Vertex, len(resourceOrphans))
 	for i, k := range resourceOrphans {
-		resourceVertexes[i] = g.Add(&graphNodeOrphanResource{ResourceName: k})
+		resourceVertexes[i] = g.Add(&graphNodeOrphanResource{
+			ResourceName: k,
+			dependentOn:  state.Resources[k].Dependencies,
+		})
 	}
 
 	// Go over each module orphan and add it to the graph. We store the
 	// vertexes and states outside so that we can connect dependencies later.
 	moduleOrphans := t.State.ModuleOrphans(g.Path, t.Config)
 	moduleVertexes := make([]dag.Vertex, len(moduleOrphans))
-	moduleStates := make([]*ModuleState, len(moduleVertexes))
 	for i, path := range moduleOrphans {
-		moduleVertexes[i] = g.Add(&graphNodeOrphanModule{Path: path})
-		moduleStates[i] = t.State.ModuleByPath(path)
+		moduleVertexes[i] = g.Add(&graphNodeOrphanModule{
+			Path:        path,
+			dependentOn: t.State.ModuleByPath(path).Dependencies,
+		})
 	}
 
 	// Now do the dependencies. We do this _after_ adding all the orphan
@@ -47,13 +51,13 @@ func (t *OrphanTransformer) Transform(g *Graph) error {
 	// depend on other orphans.
 
 	// Resource dependencies
-	for i, v := range resourceVertexes {
-		g.ConnectTo(v, state.Resources[resourceOrphans[i]].Dependencies)
+	for _, v := range resourceVertexes {
+		g.ConnectDependent(v)
 	}
 
 	// Module dependencies
-	for i, v := range moduleVertexes {
-		g.ConnectTo(v, moduleStates[i].Dependencies)
+	for _, v := range moduleVertexes {
+		g.ConnectDependent(v)
 	}
 
 	return nil
@@ -62,12 +66,18 @@ func (t *OrphanTransformer) Transform(g *Graph) error {
 // graphNodeOrphanModule is the graph vertex representing an orphan resource..
 type graphNodeOrphanModule struct {
 	Path []string
+
+	dependentOn []string
 }
 
 func (n *graphNodeOrphanModule) DependableName() []string {
 	return []string{n.dependableName()}
 }
 
+func (n *graphNodeOrphanModule) DependentOn() []string {
+	return n.dependentOn
+}
+
 func (n *graphNodeOrphanModule) Name() string {
 	return fmt.Sprintf("%s (orphan)", n.dependableName())
 }
@@ -79,12 +89,18 @@ func (n *graphNodeOrphanModule) dependableName() string {
 // graphNodeOrphanResource is the graph vertex representing an orphan resource..
 type graphNodeOrphanResource struct {
 	ResourceName string
+
+	dependentOn []string
 }
 
 func (n *graphNodeOrphanResource) DependableName() []string {
 	return []string{n.dependableName()}
 }
 
+func (n *graphNodeOrphanResource) DependentOn() []string {
+	return n.dependentOn
+}
+
 func (n *graphNodeOrphanResource) Name() string {
 	return fmt.Sprintf("%s (orphan)", n.ResourceName)
 }