config: RawConfig works, plus tests

config/raw_config.go

@@ -1,5 +1,10 @@
 package config
 
+import (
+	"github.com/mitchellh/copystructure"
+	"github.com/mitchellh/reflectwalk"
+)
+
 // UnknownVariableValue is a sentinel value that can be used
 // to denote that the value of a variable is unknown at this time.
 // RawConfig uses this information to build up data about
@@ -18,6 +23,23 @@ const UnknownVariableValue = "74D93920-ED26-11E3-AC10-0800200C9A66"
 type RawConfig struct {
 	Raw       map[string]interface{}
 	Variables map[string]InterpolatedVariable
+
+	config      map[string]interface{}
+	unknownKeys []string
+}
+
+// NewRawConfig creates a new RawConfig structure and populates the
+// publicly readable struct fields.
+func NewRawConfig(raw map[string]interface{}) (*RawConfig, error) {
+	walker := new(variableDetectWalker)
+	if err := reflectwalk.Walk(raw, walker); err != nil {
+		return nil, err
+	}
+
+	return &RawConfig{
+		Raw:       raw,
+		Variables: walker.Variables,
+	}, nil
 }
 
 // Interpolate uses the given mapping of variable values and uses
@@ -27,7 +49,21 @@ type RawConfig struct {
 // Any prior calls to Interpolate are replaced with this one.
 //
 // If a variable key is missing, this will panic.
-func (r *RawConfig) Interpolate(map[string]string) {
+func (r *RawConfig) Interpolate(vs map[string]string) error {
+	config, err := copystructure.Copy(r.Raw)
+	if err != nil {
+		return err
+	}
+
+	w := &variableReplaceWalker{Values: vs}
+	r.config = config.(map[string]interface{})
+	err = reflectwalk.Walk(r.config, w)
+	if err != nil {
+		return err
+	}
+
+	r.unknownKeys = w.UnknownKeys
+	return nil
 }
 
 // Config returns the entire configuration with the variables
@@ -42,5 +78,11 @@ func (r *RawConfig) Interpolate(map[string]string) {
 // structure will always successfully decode into its ultimate
 // structure using something like mapstructure.
 func (r *RawConfig) Config() map[string]interface{} {
-	return nil
+	return r.config
+}
+
+// UnknownKeys returns the keys of the configuration that are unknown
+// because they had interpolated variables that must be computed.
+func (r *RawConfig) UnknownKeys() []string {
+	return r.unknownKeys
 }

config/raw_config_test.go

@@ -1 +1,77 @@
 package config
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNewRawConfig(t *testing.T) {
+	raw := map[string]interface{}{
+		"foo": "${var.bar}",
+	}
+
+	rc, err := NewRawConfig(raw)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if len(rc.Variables) != 1 {
+		t.Fatalf("bad: %#v", rc.Variables)
+	}
+}
+
+func TestRawConfig(t *testing.T) {
+	raw := map[string]interface{}{
+		"foo": "${var.bar}",
+	}
+
+	rc, err := NewRawConfig(raw)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	vars := map[string]string{"var.bar": "baz"}
+	if err := rc.Interpolate(vars); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := rc.Config()
+	expected := map[string]interface{}{
+		"foo": "baz",
+	}
+
+	if !reflect.DeepEqual(actual, expected) {
+		t.Fatalf("bad: %#v", actual)
+	}
+	if len(rc.UnknownKeys()) != 0 {
+		t.Fatalf("bad: %#v", rc.UnknownKeys())
+	}
+}
+
+func TestRawConfig_unknown(t *testing.T) {
+	raw := map[string]interface{}{
+		"foo": "${var.bar}",
+	}
+
+	rc, err := NewRawConfig(raw)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	vars := map[string]string{"var.bar": UnknownVariableValue}
+	if err := rc.Interpolate(vars); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := rc.Config()
+	expected := map[string]interface{}{}
+
+	if !reflect.DeepEqual(actual, expected) {
+		t.Fatalf("bad: %#v", actual)
+	}
+
+	expectedKeys := []string{"foo"}
+	if !reflect.DeepEqual(rc.UnknownKeys(), expectedKeys) {
+		t.Fatalf("bad: %#v", rc.UnknownKeys())
+	}
+}