terraform: prefix the Id for configuring providers

terraform/context.go

@@ -569,11 +569,17 @@ func (c *walkContext) inputWalkFn() depgraph.WalkFunc {
 			}
 			rc := NewResourceConfig(raw)
 
+			// Wrap the input into a namespace
+			input := &PrefixUIInput{
+				IdPrefix: fmt.Sprintf("provider.%s", rn.ID),
+				UIInput:  c.Context.uiInput,
+			}
+
 			// Go through each provider and capture the input necessary
 			// to satisfy it.
 			configs := make(map[string]map[string]interface{})
 			for k, p := range sharedProvider.Providers {
-				newc, err := p.Input(c.Context.uiInput, rc)
+				newc, err := p.Input(input, rc)
 				if err != nil {
 					return fmt.Errorf(
 						"Error configuring %s: %s", k, err)

terraform/context_test.go

@@ -499,6 +499,56 @@ func TestContextInput_provider(t *testing.T) {
 	}
 }
 
+func TestContextInput_providerId(t *testing.T) {
+	input := new(MockUIInput)
+	m := testModule(t, "input-provider")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	ctx := testContext(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		UIInput: input,
+	})
+
+	var actual interface{}
+	p.InputFn = func(i UIInput, c *ResourceConfig) (*ResourceConfig, error) {
+		v, err := i.Input(&InputOpts{Id: "foo"})
+		if err != nil {
+			return nil, err
+		}
+
+		c.Raw["foo"] = v
+		return c, nil
+	}
+	p.ConfigureFn = func(c *ResourceConfig) error {
+		actual = c.Raw["foo"]
+		return nil
+	}
+
+	input.InputReturnMap = map[string]string{
+		"provider.aws.foo": "bar",
+	}
+
+	if err := ctx.Input(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if _, err := ctx.Plan(nil); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if _, err := ctx.Apply(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if !reflect.DeepEqual(actual, "bar") {
+		t.Fatalf("bad: %#v", actual)
+	}
+}
+
 func TestContextApply(t *testing.T) {
 	m := testModule(t, "apply-good")
 	p := testProvider("aws")

terraform/ui_input_prefix.go

@@ -0,0 +1,17 @@
+package terraform
+
+import (
+	"fmt"
+)
+
+// PrefixUIInput is an implementation of UIInput that prefixes the ID
+// with a string, allowing queries to be namespaced.
+type PrefixUIInput struct {
+	IdPrefix string
+	UIInput  UIInput
+}
+
+func (i *PrefixUIInput) Input(opts *InputOpts) (string, error) {
+	opts.Id = fmt.Sprintf("%s.%s", i.IdPrefix, opts.Id)
+	return i.UIInput.Input(opts)
+}

terraform/ui_input_prefix_test.go

@@ -0,0 +1,26 @@
+package terraform
+
+import (
+	"testing"
+)
+
+func TestPrefixUIInput_impl(t *testing.T) {
+	var _ UIInput = new(PrefixUIInput)
+}
+
+func testPrefixUIInput(t *testing.T) {
+	input := new(MockUIInput)
+	prefix := &PrefixUIInput{
+		IdPrefix: "foo",
+		UIInput:  input,
+	}
+
+	_, err := prefix.Input(&InputOpts{Id: "bar"})
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if input.InputOpts.Id != "foo.bar" {
+		t.Fatalf("bad: %#v", input.InputOpts)
+	}
+}