terraform: start Graph2 to make logical config graph

depgraph2/graph.go

@@ -0,0 +1,70 @@
+package depgraph
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+)
+
+// Graph is used to represent a dependency graph.
+type Graph struct {
+	Nodes []Node
+}
+
+// Node is an element of the graph that has other dependencies.
+type Node interface {
+	Deps() []Node
+}
+
+// NamedNode is an optional interface implementation of a Node that
+// can have a name. If this is implemented, this will be used for various
+// output.
+type NamedNode interface {
+	Node
+	Name() string
+}
+
+func (g *Graph) String() string {
+	var buf bytes.Buffer
+
+	// Build the list of node names and a mapping so that we can more
+	// easily alphabetize the output to remain deterministic.
+	names := make([]string, 0, len(g.Nodes))
+	mapping := make(map[string]Node, len(g.Nodes))
+	for _, n := range g.Nodes {
+		name := nodeName(n)
+		names = append(names, name)
+		mapping[name] = n
+	}
+	sort.Strings(names)
+
+	// Write each node in order...
+	for _, name := range names {
+		n := mapping[name]
+		buf.WriteString(fmt.Sprintf("%s\n", name))
+
+		// Alphabetize dependencies
+		depsRaw := n.Deps()
+		deps := make([]string, 0, len(depsRaw))
+		for _, d := range depsRaw {
+			deps = append(deps, nodeName(d))
+		}
+		sort.Strings(deps)
+
+		// Write dependencies
+		for _, d := range deps {
+			buf.WriteString(fmt.Sprintf("  %s\n", d))
+		}
+	}
+
+	return buf.String()
+}
+
+func nodeName(n Node) string {
+	switch v := n.(type) {
+	case NamedNode:
+		return v.Name()
+	default:
+		return fmt.Sprintf("%s", v)
+	}
+}

terraform/graph2.go

@@ -0,0 +1,146 @@
+package terraform
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/hashicorp/terraform/config"
+	"github.com/hashicorp/terraform/config/module"
+	"github.com/hashicorp/terraform/depgraph2"
+)
+
+// Graph takes a module tree and builds a logical graph of all the nodes
+// in that module.
+func Graph2(mod *module.Tree) (*depgraph.Graph, error) {
+	// A module is required and also must be completely loaded.
+	if mod == nil {
+		return nil, errors.New("module must not be nil")
+	}
+	if !mod.Loaded() {
+		return nil, errors.New("module must be loaded")
+	}
+
+	// Get the configuration for this module
+	config := mod.Config()
+
+	// Create the node list we'll use for the graph
+	nodes := make([]graphNodeConfig, 0,
+		(len(config.Modules)+len(config.Resources))*2)
+
+	// Write all the resources out
+	for _, r := range config.Resources {
+		nodes = append(nodes, &GraphNodeConfigResource{
+			Resource: r,
+		})
+	}
+
+	// Write all the modules out
+	// TODO
+
+	// Build the full map of the var names to the nodes.
+	fullMap := make(map[string]depgraph.Node)
+	for _, n := range nodes {
+		fullMap[n.VarName()] = n
+	}
+
+	// Go through all the nodes and build up the actual dependency map. We
+	// do this by getting the variables that each node depends on and then
+	// building the dep map based on the fullMap which contains the mapping
+	// 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)
+			m[id] = fullMap[id]
+		}
+
+		n.setDepMap(m)
+	}
+
+	// Build the graph and return it
+	g := &depgraph.Graph{Nodes: make([]depgraph.Node, 0, len(nodes))}
+	for _, n := range nodes {
+		g.Nodes = append(g.Nodes, n)
+	}
+
+	return g, nil
+}
+
+// graphNodeConfig is an interface that all graph nodes for the
+// configuration graph need to implement in order to build the variable
+// dependencies properly.
+type graphNodeConfig interface {
+	depgraph.Node
+
+	// Variables returns the full list of variables that this node
+	// depends on.
+	Variables() map[string]config.InterpolatedVariable
+
+	// VarName returns the name that is used to identify a variable
+	// maps to this node. It should match the result of the
+	// `VarName` function.
+	VarName() string
+
+	// setDepMap sets the dependency map for this node. If the node is
+	// nil, then it wasn't found.
+	setDepMap(map[string]depgraph.Node)
+}
+
+// GraphNodeConfigResource represents a resource within the configuration
+// graph.
+type GraphNodeConfigResource struct {
+	Resource *config.Resource
+	DepMap   map[string]depgraph.Node
+}
+
+func (n *GraphNodeConfigResource) Deps() []depgraph.Node {
+	r := make([]depgraph.Node, 0, len(n.DepMap))
+	for _, v := range n.DepMap {
+		if v != nil {
+			r = append(r, v)
+		}
+	}
+
+	return r
+}
+
+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
+		}
+	}
+
+	return m
+}
+
+func (n *GraphNodeConfigResource) VarName() string {
+	return n.Resource.Id()
+}
+
+func (n *GraphNodeConfigResource) setDepMap(m map[string]depgraph.Node) {
+	n.DepMap = m
+}
+
+// varNameForVar returns the VarName value for an interpolated variable.
+// This value is compared to the VarName() value for the nodes within the
+// graph to build the graph edges.
+func varNameForVar(raw config.InterpolatedVariable) string {
+	switch v := raw.(type) {
+	case *config.ModuleVariable:
+		return fmt.Sprintf("module.%s", v.Name)
+	case *config.ResourceVariable:
+		return v.ResourceId()
+	default:
+		return ""
+	}
+}

terraform/graph2_test.go

@@ -0,0 +1,50 @@
+package terraform
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/terraform/config/module"
+)
+
+func TestGraph_nilModule(t *testing.T) {
+	_, err := Graph2(nil)
+	if err == nil {
+		t.Fatal("should error")
+	}
+}
+
+func TestGraph_unloadedModule(t *testing.T) {
+	mod, err := module.NewTreeModule(
+		"", filepath.Join(fixtureDir, "graph-basic"))
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if _, err := Graph2(mod); err == nil {
+		t.Fatal("should error")
+	}
+}
+
+func TestGraph(t *testing.T) {
+	g, err := Graph2(testModule(t, "graph-basic"))
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(testGraphBasicStr)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
+const testGraphBasicStr = `
+aws_instance.web
+  aws_security_group.firewall
+aws_load_balancer.weblb
+  aws_instance.web
+aws_security_group.firewall
+openstack_floating_ip.random
+`