command/apply: Handle remote state in a plan file

command/apply_test.go

@@ -15,6 +15,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/terraform/remote"
 	"github.com/hashicorp/terraform/terraform"
 	"github.com/mitchellh/cli"
 )
@@ -368,6 +369,70 @@ func TestApply_plan(t *testing.T) {
 	}
 }
 
+func TestApply_plan_remoteState(t *testing.T) {
+	// Disable test mode so input would be asked
+	test = false
+	defer func() { test = true }()
+	tmp, cwd := testCwd(t)
+	defer testFixCwd(t, tmp, cwd)
+	if err := remote.EnsureDirectory(); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Set some default reader/writers for the inputs
+	defaultInputReader = new(bytes.Buffer)
+	defaultInputWriter = new(bytes.Buffer)
+
+	// Create a remote state
+	state := testState()
+	conf, srv := testRemoteState(t, state, 200)
+	defer srv.Close()
+	state.Remote = conf
+
+	planPath := testPlanFile(t, &terraform.Plan{
+		Module: testModule(t, "apply"),
+		State:  state,
+	})
+
+	p := testProvider()
+	ui := new(cli.MockUi)
+	c := &ApplyCommand{
+		Meta: Meta{
+			ContextOpts: testCtxConfig(p),
+			Ui:          ui,
+		},
+	}
+
+	args := []string{
+		planPath,
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	if p.InputCalled {
+		t.Fatalf("input should not be called for plans")
+	}
+
+	// State file should be not be installed
+	exists, err := remote.ExistsFile(DefaultStateFilename)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if exists {
+		t.Fatalf("State path should not exist")
+	}
+
+	// Check for remote state
+	output, _, err := remote.ReadLocalState()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if output == nil {
+		t.Fatalf("missing remote state")
+	}
+}
+
 func TestApply_planWithVarFile(t *testing.T) {
 	varFileDir := testTempDir(t)
 	varFilePath := filepath.Join(varFileDir, "terraform.tfvars")

command/meta.go

@@ -106,6 +106,14 @@ func (m *Meta) Context(copts contextOpts) (*terraform.Context, bool, error) {
 		plan, err := terraform.ReadPlan(f)
 		f.Close()
 		if err == nil {
+			// Check if remote state is enabled, but do not refresh.
+			// Since a plan is supposed to lock-in the changes, we do not
+			// attempt a state refresh.
+			if plan.State.Remote != nil && plan.State.Remote.Type != "" {
+				log.Printf("[INFO] Enabling remote state from plan")
+				m.useRemoteState = true
+			}
+
 			if len(m.variables) > 0 {
 				return nil, false, fmt.Errorf(
 					"You can't set variables with the '-var' or '-var-file' flag\n" +