Merge pull request #12182 from hashicorp/jbardin/environments

Environments

backend/backend.go

@@ -6,12 +6,18 @@ package backend
 
 import (
 	"context"
+	"errors"
 
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/state"
 	"github.com/hashicorp/terraform/terraform"
 )
 
+const DefaultStateName = "default"
+
+// Error value to return when a named state operation isn't supported
+var ErrNamedStatesNotSupported = errors.New("named states not supported")
+
 // Backend is the minimal interface that must be implemented to enable Terraform.
 type Backend interface {
 	// Ask for input and configure the backend. Similar to
@@ -24,7 +30,21 @@ type Backend interface {
 	// not be loaded locally: the proper APIs should be called on state.State
 	// to load the state. If the state.State is a state.Locker, it's up to the
 	// caller to call Lock and Unlock as needed.
-	State() (state.State, error)
+	//
+	// If the named state doesn't exist it will be created. The "default" state
+	// is always assumed to exist.
+	State(name string) (state.State, error)
+
+	// DeleteState removes the named state if it exists. It is an error
+	// to delete the default state.
+	//
+	// DeleteState does not prevent deleting a state that is in use. It is the
+	// responsibility of the caller to hold a Lock on the state when calling
+	// this method.
+	DeleteState(name string) error
+
+	// States returns a list of configured named states.
+	States() ([]string, error)
 }
 
 // Enhanced implements additional behavior on top of a normal backend.
@@ -107,6 +127,9 @@ type Operation struct {
 	// If LockState is true, the Operation must Lock any
 	// state.Lockers for its duration, and Unlock when complete.
 	LockState bool
+
+	// Environment is the named state that should be loaded from the Backend.
+	Environment string
 }
 
 // RunningOperation is the result of starting an operation.

backend/legacy/backend.go

@@ -3,6 +3,7 @@ package legacy
 import (
 	"fmt"
 
+	"github.com/hashicorp/terraform/backend"
 	"github.com/hashicorp/terraform/state"
 	"github.com/hashicorp/terraform/state/remote"
 	"github.com/hashicorp/terraform/terraform"
@@ -53,10 +54,22 @@ func (b *Backend) Configure(c *terraform.ResourceConfig) error {
 	return nil
 }
 
-func (b *Backend) State() (state.State, error) {
+func (b *Backend) State(name string) (state.State, error) {
+	if name != backend.DefaultStateName {
+		return nil, backend.ErrNamedStatesNotSupported
+	}
+
 	if b.client == nil {
 		panic("State called with nil remote state client")
 	}
 
 	return &remote.State{Client: b.client}, nil
 }
+
+func (b *Backend) States() ([]string, error) {
+	return nil, backend.ErrNamedStatesNotSupported
+}
+
+func (b *Backend) DeleteState(string) error {
+	return backend.ErrNamedStatesNotSupported
+}

backend/legacy/backend_test.go

@@ -34,7 +34,7 @@ func TestBackend(t *testing.T) {
 	}
 
 	// Grab state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("err: %s", err)
 	}

backend/local/backend.go

@@ -2,7 +2,13 @@ package local
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
 	"sync"
 
 	"github.com/hashicorp/terraform/backend"
@@ -13,6 +19,14 @@ import (
 	"github.com/mitchellh/colorstring"
 )
 
+const (
+	DefaultEnvDir          = "terraform.tfstate.d"
+	DefaultEnvFile         = "environment"
+	DefaultStateFilename   = "terraform.tfstate"
+	DefaultDataDir         = ".terraform"
+	DefaultBackupExtension = ".backup"
+)
+
 // Local is an implementation of EnhancedBackend that performs all operations
 // locally. This is the "default" backend and implements normal Terraform
 // behavior as it is well known.
@@ -22,21 +36,25 @@ type Local struct {
 	CLI      cli.Ui
 	CLIColor *colorstring.Colorize
 
+	// The State* paths are set from the CLI options, and may be left blank to
+	// use the defaults. If the actual paths for the local backend state are
+	// needed, use the StatePaths method.
+	//
 	// StatePath is the local path where state is read from.
 	//
 	// StateOutPath is the local path where the state will be written.
 	// If this is empty, it will default to StatePath.
 	//
 	// StateBackupPath is the local path where a backup file will be written.
-	// If this is empty, no backup will be taken.
+	// Set this to "-" to disable state backup.
 	StatePath       string
 	StateOutPath    string
 	StateBackupPath string
 
-	// we only want to create a single instance of the local state
-	state state.State
+	// We only want to create a single instance of a local state, so store them
+	// here as they're loaded.
+	states map[string]state.State
 
-	// ContextOpts are the base context options to set when initializing a
 	// Terraform context. Many of these will be overridden or merged by
 	// Operation. See Operation for more details.
 	ContextOpts *terraform.ContextOpts
@@ -96,31 +114,91 @@ func (b *Local) Configure(c *terraform.ResourceConfig) error {
 	return f(c)
 }
 
-func (b *Local) State() (state.State, error) {
+func (b *Local) States() ([]string, error) {
 	// If we have a backend handling state, defer to that.
 	if b.Backend != nil {
-		return b.Backend.State()
+		return b.Backend.States()
 	}
 
-	if b.state != nil {
-		return b.state, nil
+	// the listing always start with "default"
+	envs := []string{backend.DefaultStateName}
+
+	entries, err := ioutil.ReadDir(DefaultEnvDir)
+	// no error if there's no envs configured
+	if os.IsNotExist(err) {
+		return envs, nil
+	}
+	if err != nil {
+		return nil, err
 	}
 
-	// Otherwise, we need to load the state.
-	var s state.State = &state.LocalState{
-		Path:    b.StatePath,
-		PathOut: b.StateOutPath,
-	}
-
-	// If we are backing up the state, wrap it
-	if path := b.StateBackupPath; path != "" {
-		s = &state.BackupState{
-			Real: s,
-			Path: path,
+	var listed []string
+	for _, entry := range entries {
+		if entry.IsDir() {
+			listed = append(listed, filepath.Base(entry.Name()))
 		}
 	}
 
-	b.state = s
+	sort.Strings(listed)
+	envs = append(envs, listed...)
+
+	return envs, nil
+}
+
+// DeleteState removes a named state.
+// The "default" state cannot be removed.
+func (b *Local) DeleteState(name string) error {
+	// If we have a backend handling state, defer to that.
+	if b.Backend != nil {
+		return b.Backend.DeleteState(name)
+	}
+
+	if name == "" {
+		return errors.New("empty state name")
+	}
+
+	if name == backend.DefaultStateName {
+		return errors.New("cannot delete default state")
+	}
+
+	delete(b.states, name)
+	return os.RemoveAll(filepath.Join(DefaultEnvDir, name))
+}
+
+func (b *Local) State(name string) (state.State, error) {
+	// If we have a backend handling state, defer to that.
+	if b.Backend != nil {
+		return b.Backend.State(name)
+	}
+
+	if s, ok := b.states[name]; ok {
+		return s, nil
+	}
+
+	if err := b.createState(name); err != nil {
+		return nil, err
+	}
+
+	statePath, stateOutPath, backupPath := b.StatePaths(name)
+
+	// Otherwise, we need to load the state.
+	var s state.State = &state.LocalState{
+		Path:    statePath,
+		PathOut: stateOutPath,
+	}
+
+	// If we are backing up the state, wrap it
+	if backupPath != "" {
+		s = &state.BackupState{
+			Real: s,
+			Path: backupPath,
+		}
+	}
+
+	if b.states == nil {
+		b.states = map[string]state.State{}
+	}
+	b.states[name] = s
 	return s, nil
 }
 
@@ -212,3 +290,77 @@ func (b *Local) schemaConfigure(ctx context.Context) error {
 
 	return nil
 }
+
+// StatePaths returns the StatePath, StateOutPath, and StateBackupPath as
+// configured from the CLI.
+func (b *Local) StatePaths(name string) (string, string, string) {
+	statePath := b.StatePath
+	stateOutPath := b.StateOutPath
+	backupPath := b.StateBackupPath
+
+	if name == "" {
+		name = backend.DefaultStateName
+	}
+
+	if name == backend.DefaultStateName {
+		if statePath == "" {
+			statePath = DefaultStateFilename
+		}
+	} else {
+		statePath = filepath.Join(DefaultEnvDir, name, DefaultStateFilename)
+	}
+
+	if stateOutPath == "" {
+		stateOutPath = statePath
+	}
+
+	switch backupPath {
+	case "-":
+		backupPath = ""
+	case "":
+		backupPath = stateOutPath + DefaultBackupExtension
+	}
+
+	return statePath, stateOutPath, backupPath
+}
+
+// this only ensures that the named directory exists
+func (b *Local) createState(name string) error {
+	if name == backend.DefaultStateName {
+		return nil
+	}
+
+	stateDir := filepath.Join(DefaultEnvDir, name)
+	s, err := os.Stat(stateDir)
+	if err == nil && s.IsDir() {
+		// no need to check for os.IsNotExist, since that is covered by os.MkdirAll
+		// which will catch the other possible errors as well.
+		return nil
+	}
+
+	err = os.MkdirAll(stateDir, 0755)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// currentStateName returns the name of the current named state as set in the
+// configuration files.
+// If there are no configured environments, currentStateName returns "default"
+func (b *Local) currentStateName() (string, error) {
+	contents, err := ioutil.ReadFile(filepath.Join(DefaultDataDir, DefaultEnvFile))
+	if os.IsNotExist(err) {
+		return backend.DefaultStateName, nil
+	}
+	if err != nil {
+		return "", err
+	}
+
+	if fromFile := strings.TrimSpace(string(contents)); fromFile != "" {
+		return fromFile, nil
+	}
+
+	return backend.DefaultStateName, nil
+}

backend/local/backend_local.go

@@ -23,7 +23,7 @@ func (b *Local) Context(op *backend.Operation) (*terraform.Context, state.State,
 
 func (b *Local) context(op *backend.Operation) (*terraform.Context, state.State, error) {
 	// Get the state.
-	s, err := b.State()
+	s, err := b.State(op.Environment)
 	if err != nil {
 		return nil, nil, errwrap.Wrapf("Error loading state: {{err}}", err)
 	}

backend/local/backend_test.go

@@ -1,11 +1,16 @@
 package local
 
 import (
+	"errors"
+	"io/ioutil"
 	"os"
+	"path/filepath"
+	"reflect"
 	"strings"
 	"testing"
 
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/state"
 	"github.com/hashicorp/terraform/terraform"
 )
 
@@ -34,3 +39,188 @@ func checkState(t *testing.T, path, expected string) {
 		t.Fatalf("state does not match! actual:\n%s\n\nexpected:\n%s", actual, expected)
 	}
 }
+
+func TestLocal_StatePaths(t *testing.T) {
+	b := &Local{}
+
+	// Test the defaults
+	path, out, back := b.StatePaths("")
+
+	if path != DefaultStateFilename {
+		t.Fatalf("expected %q, got %q", DefaultStateFilename, path)
+	}
+
+	if out != DefaultStateFilename {
+		t.Fatalf("expected %q, got %q", DefaultStateFilename, out)
+	}
+
+	dfltBackup := DefaultStateFilename + DefaultBackupExtension
+	if back != dfltBackup {
+		t.Fatalf("expected %q, got %q", dfltBackup, back)
+	}
+
+	// check with env
+	testEnv := "test_env"
+	path, out, back = b.StatePaths(testEnv)
+
+	expectedPath := filepath.Join(DefaultEnvDir, testEnv, DefaultStateFilename)
+	expectedOut := expectedPath
+	expectedBackup := expectedPath + DefaultBackupExtension
+
+	if path != expectedPath {
+		t.Fatalf("expected %q, got %q", expectedPath, path)
+	}
+
+	if out != expectedOut {
+		t.Fatalf("expected %q, got %q", expectedOut, out)
+	}
+
+	if back != expectedBackup {
+		t.Fatalf("expected %q, got %q", expectedBackup, back)
+	}
+
+}
+
+func TestLocal_addAndRemoveStates(t *testing.T) {
+	defer testTmpDir(t)()
+	dflt := backend.DefaultStateName
+	expectedStates := []string{dflt}
+
+	b := &Local{}
+	states, err := b.States()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !reflect.DeepEqual(states, expectedStates) {
+		t.Fatalf("expected []string{%q}, got %q", dflt, states)
+	}
+
+	expectedA := "test_A"
+	if _, err := b.State(expectedA); err != nil {
+		t.Fatal(err)
+	}
+
+	states, err = b.States()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedStates = append(expectedStates, expectedA)
+	if !reflect.DeepEqual(states, expectedStates) {
+		t.Fatalf("expected %q, got %q", expectedStates, states)
+	}
+
+	expectedB := "test_B"
+	if _, err := b.State(expectedB); err != nil {
+		t.Fatal(err)
+	}
+
+	states, err = b.States()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedStates = append(expectedStates, expectedB)
+	if !reflect.DeepEqual(states, expectedStates) {
+		t.Fatalf("expected %q, got %q", expectedStates, states)
+	}
+
+	if err := b.DeleteState(expectedA); err != nil {
+		t.Fatal(err)
+	}
+
+	states, err = b.States()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedStates = []string{dflt, expectedB}
+	if !reflect.DeepEqual(states, expectedStates) {
+		t.Fatalf("expected %q, got %q", expectedStates, states)
+	}
+
+	if err := b.DeleteState(expectedB); err != nil {
+		t.Fatal(err)
+	}
+
+	states, err = b.States()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedStates = []string{dflt}
+	if !reflect.DeepEqual(states, expectedStates) {
+		t.Fatalf("expected %q, got %q", expectedStates, states)
+	}
+
+	if err := b.DeleteState(dflt); err == nil {
+		t.Fatal("expected error deleting default state")
+	}
+}
+
+// a local backend which returns sentinel errors for NamedState methods to
+// verify it's being called.
+type testDelegateBackend struct {
+	*Local
+}
+
+var errTestDelegateState = errors.New("State called")
+var errTestDelegateStates = errors.New("States called")
+var errTestDelegateDeleteState = errors.New("Delete called")
+
+func (b *testDelegateBackend) State(name string) (state.State, error) {
+	return nil, errTestDelegateState
+}
+
+func (b *testDelegateBackend) States() ([]string, error) {
+	return nil, errTestDelegateStates
+}
+
+func (b *testDelegateBackend) DeleteState(name string) error {
+	return errTestDelegateDeleteState
+}
+
+// verify that the MultiState methods are dispatched to the correct Backend.
+func TestLocal_multiStateBackend(t *testing.T) {
+	// assign a separate backend where we can read the state
+	b := &Local{
+		Backend: &testDelegateBackend{},
+	}
+
+	if _, err := b.State("test"); err != errTestDelegateState {
+		t.Fatal("expected errTestDelegateState, got:", err)
+	}
+
+	if _, err := b.States(); err != errTestDelegateStates {
+		t.Fatal("expected errTestDelegateStates, got:", err)
+	}
+
+	if err := b.DeleteState("test"); err != errTestDelegateDeleteState {
+		t.Fatal("expected errTestDelegateDeleteState, got:", err)
+	}
+
+}
+
+// change into a tmp dir and return a deferable func to change back and cleanup
+func testTmpDir(t *testing.T) func() {
+	tmp, err := ioutil.TempDir("", "tf")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	old, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := os.Chdir(tmp); err != nil {
+		t.Fatal(err)
+	}
+
+	return func() {
+		// ignore errors and try to clean up
+		os.Chdir(old)
+		os.RemoveAll(tmp)
+	}
+}

backend/nil.go

@@ -25,7 +25,15 @@ func (Nil) Configure(*terraform.ResourceConfig) error {
 	return nil
 }
 
-func (Nil) State() (state.State, error) {
+func (Nil) State(string) (state.State, error) {
 	// We have to return a non-nil state to adhere to the interface
 	return &state.InmemState{}, nil
 }
+
+func (Nil) DeleteState(string) error {
+	return nil
+}
+
+func (Nil) States() ([]string, error) {
+	return []string{DefaultStateName}, nil
+}

backend/remote-state/backend.go

@@ -6,6 +6,7 @@ package remotestate
 import (
 	"context"
 
+	"github.com/hashicorp/terraform/backend"
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/state"
 	"github.com/hashicorp/terraform/state/remote"
@@ -46,12 +47,24 @@ func (b *Backend) Configure(rc *terraform.ResourceConfig) error {
 	return b.Backend.Configure(rc)
 }
 
-func (b *Backend) State() (state.State, error) {
+func (b *Backend) States() ([]string, error) {
+	return nil, backend.ErrNamedStatesNotSupported
+}
+
+func (b *Backend) DeleteState(name string) error {
+	return backend.ErrNamedStatesNotSupported
+}
+
+func (b *Backend) State(name string) (state.State, error) {
 	// This shouldn't happen
 	if b.client == nil {
 		panic("nil remote client")
 	}
 
+	if name != backend.DefaultStateName {
+		return nil, backend.ErrNamedStatesNotSupported
+	}
+
 	s := &remote.State{Client: b.client}
 	return s, nil
 }

backend/remote-state/consul/client_test.go

@@ -46,7 +46,7 @@ func TestConsul_stateLock(t *testing.T) {
 	sA, err := backend.TestBackendConfig(t, New(), map[string]interface{}{
 		"address": addr,
 		"path":    path,
-	}).State()
+	}).State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -54,7 +54,7 @@ func TestConsul_stateLock(t *testing.T) {
 	sB, err := backend.TestBackendConfig(t, New(), map[string]interface{}{
 		"address": addr,
 		"path":    path,
-	}).State()
+	}).State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatal(err)
 	}

backend/remote-state/inmem/client_test.go

@@ -19,7 +19,7 @@ func TestRemoteClient(t *testing.T) {
 }
 
 func TestInmemLocks(t *testing.T) {
-	s, err := backend.TestBackendConfig(t, New(), nil).State()
+	s, err := backend.TestBackendConfig(t, New(), nil).State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatal(err)
 	}

builtin/providers/terraform/data_source_state.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"time"
 
+	"github.com/hashicorp/terraform/backend"
 	backendinit "github.com/hashicorp/terraform/backend/init"
 	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/helper/schema"
@@ -36,6 +37,12 @@ func dataSourceRemoteState() *schema.Resource {
 				Optional: true,
 			},
 
+			"environment": {
+				Type:     schema.TypeString,
+				Optional: true,
+				Default:  backend.DefaultStateName,
+			},
+
 			"__has_dynamic_attributes": {
 				Type:     schema.TypeString,
 				Optional: true,
@@ -73,7 +80,8 @@ func dataSourceRemoteStateRead(d *schema.ResourceData, meta interface{}) error {
 	}
 
 	// Get the state
-	state, err := b.State()
+	env := d.Get("environment").(string)
+	state, err := b.State(env)
 	if err != nil {
 		return fmt.Errorf("error loading the remote state: %s", err)
 	}

command/env_command.go

@@ -0,0 +1,73 @@
+package command
+
+import "strings"
+
+// EnvCommand is a Command Implementation that manipulates local state
+// environments.
+type EnvCommand struct {
+	Meta
+}
+
+func (c *EnvCommand) Run(args []string) int {
+	args = c.Meta.process(args, true)
+
+	cmdFlags := c.Meta.flagSet("env")
+	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
+
+	c.Ui.Output(c.Help())
+	return 0
+}
+
+func (c *EnvCommand) Help() string {
+	helpText := `
+Usage: terraform env
+
+  Create, change and delete Terraform environments. 
+
+
+Subcommands:
+
+    list      List environments.
+    select    Select an environment.
+    new       Create a new environment.
+    delete    Delete an existing environment.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *EnvCommand) Synopsis() string {
+	return "Environment management"
+}
+
+const (
+	envNotSupported = `Backend does not support environments`
+
+	envExists = `Environment %q already exists`
+
+	envDoesNotExist = `Environment %q doesn't exist!
+You can create this environment with the "-new" option.`
+
+	envChanged = `[reset][green]Switched to environment %q!`
+
+	envCreated = `[reset][green]Created environment %q!`
+
+	envDeleted = `[reset][green]Deleted environment %q!`
+
+	envNotEmpty = `Environment %[1]q is not empty!
+Deleting %[1]q can result in dangling resources: resources that 
+exist but are no longer manageable by Terraform. Please destroy
+these resources first.  If you want to delete this environment
+anyways and risk dangling resources, use the '-force' flag.
+`
+
+	envWarnNotEmpty = `[reset][yellow]WARNING: %q was non-empty. 
+The resources managed by the deleted environment may still exist,
+but are no longer manageable by Terraform since the state has
+been deleted.
+`
+
+	envDelCurrent = `Environment %[1]q is your active environment!
+You cannot delete the currently active environment. Please switch
+to another environment and try again.
+`
+)

command/env_command_test.go

@@ -0,0 +1,252 @@
+package command
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/backend/local"
+	"github.com/hashicorp/terraform/state"
+	"github.com/hashicorp/terraform/terraform"
+	"github.com/mitchellh/cli"
+)
+
+func TestEnv_createAndChange(t *testing.T) {
+	// Create a temporary working directory that is empty
+	td := tempDir(t)
+	os.MkdirAll(td, 0755)
+	defer os.RemoveAll(td)
+	defer testChdir(t, td)()
+
+	newCmd := &EnvNewCommand{}
+
+	current := newCmd.Env()
+	if current != backend.DefaultStateName {
+		t.Fatal("current env should be 'default'")
+	}
+
+	args := []string{"test"}
+	ui := new(cli.MockUi)
+	newCmd.Meta = Meta{Ui: ui}
+	if code := newCmd.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter)
+	}
+
+	current = newCmd.Env()
+	if current != "test" {
+		t.Fatalf("current env should be 'test', got %q", current)
+	}
+
+	selCmd := &EnvSelectCommand{}
+	args = []string{backend.DefaultStateName}
+	ui = new(cli.MockUi)
+	selCmd.Meta = Meta{Ui: ui}
+	if code := selCmd.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter)
+	}
+
+	current = newCmd.Env()
+	if current != backend.DefaultStateName {
+		t.Fatal("current env should be 'default'")
+	}
+
+}
+
+// Create some environments and test the list output.
+// This also ensures we switch to the correct env after each call
+func TestEnv_createAndList(t *testing.T) {
+	// Create a temporary working directory that is empty
+	td := tempDir(t)
+	os.MkdirAll(td, 0755)
+	defer os.RemoveAll(td)
+	defer testChdir(t, td)()
+
+	newCmd := &EnvNewCommand{}
+
+	envs := []string{"test_a", "test_b", "test_c"}
+
+	// create multiple envs
+	for _, env := range envs {
+		ui := new(cli.MockUi)
+		newCmd.Meta = Meta{Ui: ui}
+		if code := newCmd.Run([]string{env}); code != 0 {
+			t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter)
+		}
+	}
+
+	listCmd := &EnvListCommand{}
+	ui := new(cli.MockUi)
+	listCmd.Meta = Meta{Ui: ui}
+
+	if code := listCmd.Run(nil); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter)
+	}
+
+	actual := strings.TrimSpace(ui.OutputWriter.String())
+	expected := "default\n  test_a\n  test_b\n* test_c"
+
+	if actual != expected {
+		t.Fatalf("\nexpcted: %q\nactual:  %q", expected, actual)
+	}
+}
+
+func TestEnv_createWithState(t *testing.T) {
+	td := tempDir(t)
+	os.MkdirAll(td, 0755)
+	defer os.RemoveAll(td)
+	defer testChdir(t, td)()
+
+	// create a non-empty state
+	originalState := &terraform.State{
+		Modules: []*terraform.ModuleState{
+			&terraform.ModuleState{
+				Path: []string{"root"},
+				Resources: map[string]*terraform.ResourceState{
+					"test_instance.foo": &terraform.ResourceState{
+						Type: "test_instance",
+						Primary: &terraform.InstanceState{
+							ID: "bar",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	err := (&state.LocalState{Path: "test.tfstate"}).WriteState(originalState)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	args := []string{"-state", "test.tfstate", "test"}
+	ui := new(cli.MockUi)
+	newCmd := &EnvNewCommand{
+		Meta: Meta{Ui: ui},
+	}
+	if code := newCmd.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter)
+	}
+
+	newPath := filepath.Join(local.DefaultEnvDir, "test", DefaultStateFilename)
+	envState := state.LocalState{Path: newPath}
+	err = envState.RefreshState()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	newState := envState.State()
+	if !originalState.Equal(newState) {
+		t.Fatalf("states not equal\norig: %s\nnew: %s", originalState, newState)
+	}
+}
+
+func TestEnv_delete(t *testing.T) {
+	td := tempDir(t)
+	os.MkdirAll(td, 0755)
+	defer os.RemoveAll(td)
+	defer testChdir(t, td)()
+
+	// create the env directories
+	if err := os.MkdirAll(filepath.Join(local.DefaultEnvDir, "test"), 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	// create the environment file
+	if err := os.MkdirAll(DefaultDataDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := ioutil.WriteFile(filepath.Join(DefaultDataDir, local.DefaultEnvFile), []byte("test"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	ui := new(cli.MockUi)
+	delCmd := &EnvDeleteCommand{
+		Meta: Meta{Ui: ui},
+	}
+
+	current := delCmd.Env()
+	if current != "test" {
+		t.Fatal("wrong env:", current)
+	}
+
+	// we can't delete out current environment
+	args := []string{"test"}
+	if code := delCmd.Run(args); code == 0 {
+		t.Fatal("expected error deleting current env")
+	}
+
+	// change back to default
+	if err := delCmd.SetEnv(backend.DefaultStateName); err != nil {
+		t.Fatal(err)
+	}
+
+	// try the delete again
+	ui = new(cli.MockUi)
+	delCmd.Meta.Ui = ui
+	if code := delCmd.Run(args); code != 0 {
+		t.Fatalf("error deleting env: %s", ui.ErrorWriter)
+	}
+
+	current = delCmd.Env()
+	if current != backend.DefaultStateName {
+		t.Fatalf("wrong env: %q", current)
+	}
+}
+func TestEnv_deleteWithState(t *testing.T) {
+	td := tempDir(t)
+	os.MkdirAll(td, 0755)
+	defer os.RemoveAll(td)
+	defer testChdir(t, td)()
+
+	// create the env directories
+	if err := os.MkdirAll(filepath.Join(local.DefaultEnvDir, "test"), 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	// create a non-empty state
+	originalState := &terraform.State{
+		Modules: []*terraform.ModuleState{
+			&terraform.ModuleState{
+				Path: []string{"root"},
+				Resources: map[string]*terraform.ResourceState{
+					"test_instance.foo": &terraform.ResourceState{
+						Type: "test_instance",
+						Primary: &terraform.InstanceState{
+							ID: "bar",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	envStatePath := filepath.Join(local.DefaultEnvDir, "test", DefaultStateFilename)
+	err := (&state.LocalState{Path: envStatePath}).WriteState(originalState)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ui := new(cli.MockUi)
+	delCmd := &EnvDeleteCommand{
+		Meta: Meta{Ui: ui},
+	}
+	args := []string{"test"}
+	if code := delCmd.Run(args); code == 0 {
+		t.Fatalf("expected failure without -force.\noutput: %s", ui.OutputWriter)
+	}
+
+	ui = new(cli.MockUi)
+	delCmd.Meta.Ui = ui
+
+	args = []string{"-force", "test"}
+	if code := delCmd.Run(args); code != 0 {
+		t.Fatalf("failure: %s", ui.ErrorWriter)
+	}
+
+	if _, err := os.Stat(filepath.Join(local.DefaultEnvDir, "test")); !os.IsNotExist(err) {
+		t.Fatal("env 'test' still exists!")
+	}
+}

command/env_delete.go

@@ -0,0 +1,139 @@
+package command
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/terraform/state"
+	"github.com/mitchellh/cli"
+
+	clistate "github.com/hashicorp/terraform/command/state"
+)
+
+type EnvDeleteCommand struct {
+	Meta
+}
+
+func (c *EnvDeleteCommand) Run(args []string) int {
+	args = c.Meta.process(args, true)
+
+	force := false
+	cmdFlags := c.Meta.flagSet("env")
+	cmdFlags.BoolVar(&force, "force", false, "force removal of a non-empty environment")
+	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
+	if err := cmdFlags.Parse(args); err != nil {
+		return 1
+	}
+	args = cmdFlags.Args()
+	if len(args) == 0 {
+		c.Ui.Error("expected NAME.\n")
+		return cli.RunResultHelp
+	}
+
+	delEnv := args[0]
+
+	configPath, err := ModulePath(args[1:])
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// Load the backend
+	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
+		return 1
+	}
+
+	states, err := b.States()
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	exists := false
+	for _, s := range states {
+		if delEnv == s {
+			exists = true
+			break
+		}
+	}
+
+	if !exists {
+		c.Ui.Error(fmt.Sprintf(envDoesNotExist, delEnv))
+		return 1
+	}
+
+	if delEnv == c.Env() {
+		c.Ui.Error(fmt.Sprintf(envDelCurrent, delEnv))
+		return 1
+	}
+
+	// we need the actual state to see if it's empty
+	sMgr, err := b.State(delEnv)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	if err := sMgr.RefreshState(); err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	hasResources := sMgr.State().HasResources()
+
+	if hasResources && !force {
+		c.Ui.Error(fmt.Sprintf(envNotEmpty, delEnv))
+		return 1
+	}
+
+	// Lock the state if we can
+	lockInfo := state.NewLockInfo()
+	lockInfo.Operation = "env delete"
+	lockID, err := clistate.Lock(sMgr, lockInfo, c.Ui, c.Colorize())
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
+		return 1
+	}
+	defer clistate.Unlock(sMgr, lockID, c.Ui, c.Colorize())
+
+	err = b.DeleteState(delEnv)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	c.Ui.Output(
+		c.Colorize().Color(
+			fmt.Sprintf(envDeleted, delEnv),
+		),
+	)
+
+	if hasResources {
+		c.Ui.Output(
+			c.Colorize().Color(
+				fmt.Sprintf(envWarnNotEmpty, delEnv),
+			),
+		)
+	}
+
+	return 0
+}
+func (c *EnvDeleteCommand) Help() string {
+	helpText := `
+Usage: terraform env delete [OPTIONS] NAME [DIR]
+
+  Delete a Terraform environment
+
+
+Options:
+
+    -force    remove a non-empty environment.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *EnvDeleteCommand) Synopsis() string {
+	return "Delete an environment"
+}

command/env_list.go

@@ -0,0 +1,68 @@
+package command
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+)
+
+type EnvListCommand struct {
+	Meta
+}
+
+func (c *EnvListCommand) Run(args []string) int {
+	args = c.Meta.process(args, true)
+
+	cmdFlags := c.Meta.flagSet("env list")
+	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
+	if err := cmdFlags.Parse(args); err != nil {
+		return 1
+	}
+
+	configPath, err := ModulePath(args)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// Load the backend
+	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
+		return 1
+	}
+
+	states, err := b.States()
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	env := c.Env()
+
+	var out bytes.Buffer
+	for _, s := range states {
+		if s == env {
+			out.WriteString("* ")
+		} else {
+			out.WriteString("  ")
+		}
+		out.WriteString(s + "\n")
+	}
+
+	c.Ui.Output(out.String())
+	return 0
+}
+
+func (c *EnvListCommand) Help() string {
+	helpText := `
+Usage: terraform env list [DIR]
+
+  List Terraform environments.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *EnvListCommand) Synopsis() string {
+	return "List Environments"
+}

command/env_new.go

@@ -0,0 +1,138 @@
+package command
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/hashicorp/terraform/state"
+	"github.com/hashicorp/terraform/terraform"
+	"github.com/mitchellh/cli"
+
+	clistate "github.com/hashicorp/terraform/command/state"
+)
+
+type EnvNewCommand struct {
+	Meta
+}
+
+func (c *EnvNewCommand) Run(args []string) int {
+	args = c.Meta.process(args, true)
+
+	statePath := ""
+
+	cmdFlags := c.Meta.flagSet("env new")
+	cmdFlags.StringVar(&statePath, "state", "", "terraform state file")
+	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
+	if err := cmdFlags.Parse(args); err != nil {
+		return 1
+	}
+	args = cmdFlags.Args()
+	if len(args) == 0 {
+		c.Ui.Error("expected NAME.\n")
+		return cli.RunResultHelp
+	}
+
+	newEnv := args[0]
+
+	configPath, err := ModulePath(args[1:])
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// Load the backend
+	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
+		return 1
+	}
+
+	states, err := b.States()
+	for _, s := range states {
+		if newEnv == s {
+			c.Ui.Error(fmt.Sprintf(envExists, newEnv))
+			return 1
+		}
+	}
+
+	_, err = b.State(newEnv)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// now save the current env locally
+	if err := c.SetEnv(newEnv); err != nil {
+		c.Ui.Error(fmt.Sprintf("error saving new environment name: %s", err))
+		return 1
+	}
+
+	c.Ui.Output(
+		c.Colorize().Color(
+			fmt.Sprintf(envCreated, newEnv),
+		),
+	)
+
+	if statePath == "" {
+		// if we're not loading a state, then we're done
+		return 0
+	}
+
+	// load the new Backend state
+	sMgr, err := b.State(newEnv)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// Lock the state if we can
+	lockInfo := state.NewLockInfo()
+	lockInfo.Operation = "env new"
+	lockID, err := clistate.Lock(sMgr, lockInfo, c.Ui, c.Colorize())
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
+		return 1
+	}
+	defer clistate.Unlock(sMgr, lockID, c.Ui, c.Colorize())
+
+	// read the existing state file
+	stateFile, err := os.Open(statePath)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	s, err := terraform.ReadState(stateFile)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// save the existing state in the new Backend.
+	err = sMgr.WriteState(s)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	return 0
+}
+
+func (c *EnvNewCommand) Help() string {
+	helpText := `
+Usage: terraform env new [OPTIONS] NAME [DIR]
+
+  Create a new Terraform environment.
+
+
+Options:
+
+    -state=path    Copy an existing state file into the new environment.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *EnvNewCommand) Synopsis() string {
+	return "Create a new environment"
+}

command/env_select.go

@@ -0,0 +1,93 @@
+package command
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/mitchellh/cli"
+)
+
+type EnvSelectCommand struct {
+	Meta
+}
+
+func (c *EnvSelectCommand) Run(args []string) int {
+	args = c.Meta.process(args, true)
+
+	cmdFlags := c.Meta.flagSet("env select")
+	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
+	if err := cmdFlags.Parse(args); err != nil {
+		return 1
+	}
+	args = cmdFlags.Args()
+	if len(args) == 0 {
+		c.Ui.Error("expected NAME.\n")
+		return cli.RunResultHelp
+	}
+
+	configPath, err := ModulePath(args[1:])
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	// Load the backend
+	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
+		return 1
+	}
+
+	name := args[0]
+
+	states, err := b.States()
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	if name == c.Env() {
+		// already using this env
+		return 0
+	}
+
+	found := false
+	for _, s := range states {
+		if name == s {
+			found = true
+			break
+		}
+	}
+
+	if !found {
+		c.Ui.Error(fmt.Sprintf(envDoesNotExist, name))
+		return 1
+	}
+
+	err = c.SetEnv(name)
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	c.Ui.Output(
+		c.Colorize().Color(
+			fmt.Sprintf(envChanged, name),
+		),
+	)
+
+	return 0
+}
+
+func (c *EnvSelectCommand) Help() string {
+	helpText := `
+Usage: terraform env select NAME [DIR]
+
+  Change Terraform environment.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *EnvSelectCommand) Synopsis() string {
+	return "Change environments"
+}

command/meta.go

@@ -2,6 +2,7 @@ package command
 
 import (
 	"bufio"
+	"bytes"
 	"flag"
 	"fmt"
 	"io"
@@ -14,6 +15,8 @@ import (
 	"time"
 
 	"github.com/hashicorp/go-getter"
+	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/backend/local"
 	"github.com/hashicorp/terraform/helper/experiment"
 	"github.com/hashicorp/terraform/helper/variables"
 	"github.com/hashicorp/terraform/helper/wrappedstreams"
@@ -406,3 +409,44 @@ func (m *Meta) outputShadowError(err error, output bool) bool {
 
 	return true
 }
+
+// Env returns the name of the currently configured environment, corresponding
+// to the desired named state.
+func (m *Meta) Env() string {
+	dataDir := m.dataDir
+	if m.dataDir == "" {
+		dataDir = DefaultDataDir
+	}
+
+	envData, err := ioutil.ReadFile(filepath.Join(dataDir, local.DefaultEnvFile))
+	current := string(bytes.TrimSpace(envData))
+	if current == "" {
+		current = backend.DefaultStateName
+	}
+
+	if err != nil && !os.IsNotExist(err) {
+		// always return the default if we can't get an environment name
+		log.Printf("[ERROR] failed to read current environment: %s", err)
+	}
+
+	return current
+}
+
+// SetEnv saves the named environment to the local filesystem.
+func (m *Meta) SetEnv(name string) error {
+	dataDir := m.dataDir
+	if m.dataDir == "" {
+		dataDir = DefaultDataDir
+	}
+
+	err := os.MkdirAll(dataDir, 0755)
+	if err != nil {
+		return err
+	}
+
+	err = ioutil.WriteFile(filepath.Join(dataDir, local.DefaultEnvFile), []byte(name), 0644)
+	if err != nil {
+		return err
+	}
+	return nil
+}

command/meta_backend.go

@@ -72,24 +72,6 @@ func (m *Meta) Backend(opts *BackendOpts) (backend.Enhanced, error) {
 		opts = &BackendOpts{}
 	}
 
-	// Setup the local state paths
-	statePath := m.statePath
-	stateOutPath := m.stateOutPath
-	backupPath := m.backupPath
-	if statePath == "" {
-		statePath = DefaultStateFilename
-	}
-	if stateOutPath == "" {
-		stateOutPath = statePath
-	}
-	if backupPath == "" {
-		backupPath = stateOutPath + DefaultBackupExtension
-	}
-	if backupPath == "-" {
-		// The local backend expects an empty string for not taking backups.
-		backupPath = ""
-	}
-
 	// Initialize a backend from the config unless we're forcing a purely
 	// local operation.
 	var b backend.Backend
@@ -114,9 +96,9 @@ func (m *Meta) Backend(opts *BackendOpts) (backend.Enhanced, error) {
 	cliOpts := &backend.CLIOpts{
 		CLI:             m.Ui,
 		CLIColor:        m.Colorize(),
-		StatePath:       statePath,
-		StateOutPath:    stateOutPath,
-		StateBackupPath: backupPath,
+		StatePath:       m.statePath,
+		StateOutPath:    m.stateOutPath,
+		StateBackupPath: m.backupPath,
 		ContextOpts:     m.contextOpts(),
 		Input:           m.Input(),
 		Validation:      true,
@@ -166,6 +148,7 @@ func (m *Meta) Operation() *backend.Operation {
 		PlanOutBackend: m.backendState,
 		Targets:        m.targets,
 		UIIn:           m.UIInput(),
+		Environment:    m.Env(),
 	}
 }
 
@@ -544,8 +527,10 @@ func (m *Meta) backendFromPlan(opts *BackendOpts) (backend.Backend, error) {
 		return nil, err
 	}
 
+	env := m.Env()
+
 	// Get the state so we can determine the effect of using this plan
-	realMgr, err := b.State()
+	realMgr, err := b.State(env)
 	if err != nil {
 		return nil, fmt.Errorf("Error reading state: %s", err)
 	}
@@ -660,7 +645,10 @@ func (m *Meta) backend_c_r_S(
 		if err != nil {
 			return nil, fmt.Errorf(strings.TrimSpace(errBackendLocalRead), err)
 		}
-		localState, err := localB.State()
+
+		env := m.Env()
+
+		localState, err := localB.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(strings.TrimSpace(errBackendLocalRead), err)
 		}
@@ -674,7 +662,7 @@ func (m *Meta) backend_c_r_S(
 			return nil, fmt.Errorf(
 				strings.TrimSpace(errBackendSavedUnsetConfig), s.Backend.Type, err)
 		}
-		backendState, err := b.State()
+		backendState, err := b.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(
 				strings.TrimSpace(errBackendSavedUnsetConfig), s.Backend.Type, err)
@@ -769,7 +757,10 @@ func (m *Meta) backend_c_R_S(
 	if err != nil {
 		return nil, fmt.Errorf(errBackendLocalRead, err)
 	}
-	localState, err := localB.State()
+
+	env := m.Env()
+
+	localState, err := localB.State(env)
 	if err != nil {
 		return nil, fmt.Errorf(errBackendLocalRead, err)
 	}
@@ -800,7 +791,7 @@ func (m *Meta) backend_c_R_S(
 		if err != nil {
 			return nil, err
 		}
-		oldState, err := oldB.State()
+		oldState, err := oldB.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(
 				strings.TrimSpace(errBackendSavedUnsetConfig), s.Backend.Type, err)
@@ -902,7 +893,10 @@ func (m *Meta) backend_C_R_s(
 		if err != nil {
 			return nil, err
 		}
-		oldState, err := oldB.State()
+
+		env := m.Env()
+
+		oldState, err := oldB.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(
 				strings.TrimSpace(errBackendSavedUnsetConfig), s.Backend.Type, err)
@@ -913,7 +907,7 @@ func (m *Meta) backend_C_R_s(
 		}
 
 		// Get the new state
-		newState, err := b.State()
+		newState, err := b.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(strings.TrimSpace(errBackendNewRead), err)
 		}
@@ -967,7 +961,10 @@ func (m *Meta) backend_C_r_s(
 	if err != nil {
 		return nil, fmt.Errorf(errBackendLocalRead, err)
 	}
-	localState, err := localB.State()
+
+	env := m.Env()
+
+	localState, err := localB.State(env)
 	if err != nil {
 		return nil, fmt.Errorf(errBackendLocalRead, err)
 	}
@@ -978,7 +975,7 @@ func (m *Meta) backend_C_r_s(
 	// If the local state is not empty, we need to potentially do a
 	// state migration to the new backend (with user permission).
 	if localS := localState.State(); !localS.Empty() {
-		backendState, err := b.State()
+		backendState, err := b.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(errBackendRemoteRead, err)
 		}
@@ -1083,7 +1080,9 @@ func (m *Meta) backend_C_r_S_changed(
 				"Error loading previously configured backend: %s", err)
 		}
 
-		oldState, err := oldB.State()
+		env := m.Env()
+
+		oldState, err := oldB.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(
 				strings.TrimSpace(errBackendSavedUnsetConfig), s.Backend.Type, err)
@@ -1094,7 +1093,7 @@ func (m *Meta) backend_C_r_S_changed(
 		}
 
 		// Get the new state
-		newState, err := b.State()
+		newState, err := b.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(strings.TrimSpace(errBackendNewRead), err)
 		}
@@ -1244,7 +1243,10 @@ func (m *Meta) backend_C_R_S_unchanged(
 		if err != nil {
 			return nil, err
 		}
-		oldState, err := oldB.State()
+
+		env := m.Env()
+
+		oldState, err := oldB.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(
 				strings.TrimSpace(errBackendSavedUnsetConfig), s.Remote.Type, err)
@@ -1255,7 +1257,7 @@ func (m *Meta) backend_C_R_S_unchanged(
 		}
 
 		// Get the new state
-		newState, err := b.State()
+		newState, err := b.State(env)
 		if err != nil {
 			return nil, fmt.Errorf(strings.TrimSpace(errBackendNewRead), err)
 		}

command/meta_backend_test.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/hashicorp/terraform/backend"
 	"github.com/hashicorp/terraform/helper/copy"
 	"github.com/hashicorp/terraform/state"
 	"github.com/hashicorp/terraform/terraform"
@@ -29,7 +30,7 @@ func TestMetaBackend_emptyDir(t *testing.T) {
 	}
 
 	// Write some state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -99,7 +100,7 @@ func TestMetaBackend_emptyWithDefaultState(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -172,7 +173,7 @@ func TestMetaBackend_emptyWithExplicitState(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -231,7 +232,7 @@ func TestMetaBackend_emptyLegacyRemote(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -280,7 +281,7 @@ func TestMetaBackend_configureNew(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -349,7 +350,7 @@ func TestMetaBackend_configureNewWithState(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -425,7 +426,7 @@ func TestMetaBackend_configureNewWithStateNoMigrate(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -470,7 +471,7 @@ func TestMetaBackend_configureNewWithStateExisting(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -544,7 +545,7 @@ func TestMetaBackend_configureNewWithStateExistingNoMigrate(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -618,7 +619,7 @@ func TestMetaBackend_configureNewLegacy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -712,7 +713,7 @@ func TestMetaBackend_configureNewLegacyCopy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -798,7 +799,7 @@ func TestMetaBackend_configuredUnchanged(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -845,7 +846,7 @@ func TestMetaBackend_configuredChange(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -924,7 +925,7 @@ func TestMetaBackend_configuredChangeCopy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -971,7 +972,7 @@ func TestMetaBackend_configuredUnset(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1055,7 +1056,7 @@ func TestMetaBackend_configuredUnsetCopy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1134,7 +1135,7 @@ func TestMetaBackend_configuredUnchangedLegacy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1237,7 +1238,7 @@ func TestMetaBackend_configuredUnchangedLegacyCopy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1340,7 +1341,7 @@ func TestMetaBackend_configuredChangedLegacy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1440,7 +1441,7 @@ func TestMetaBackend_configuredChangedLegacyCopyBackend(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1543,7 +1544,7 @@ func TestMetaBackend_configuredChangedLegacyCopyLegacy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1646,7 +1647,7 @@ func TestMetaBackend_configuredChangedLegacyCopyBoth(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1749,7 +1750,7 @@ func TestMetaBackend_configuredUnsetWithLegacyNoCopy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1839,7 +1840,7 @@ func TestMetaBackend_configuredUnsetWithLegacyCopyBackend(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -1937,7 +1938,7 @@ func TestMetaBackend_configuredUnsetWithLegacyCopyLegacy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2035,7 +2036,7 @@ func TestMetaBackend_configuredUnsetWithLegacyCopyBoth(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2136,7 +2137,7 @@ func TestMetaBackend_planLocal(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2233,7 +2234,7 @@ func TestMetaBackend_planLocalStatePath(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2319,7 +2320,7 @@ func TestMetaBackend_planLocalMatch(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2519,7 +2520,7 @@ func TestMetaBackend_planBackendEmptyDir(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2621,7 +2622,7 @@ func TestMetaBackend_planBackendMatch(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}
@@ -2784,7 +2785,7 @@ func TestMetaBackend_planLegacy(t *testing.T) {
 	}
 
 	// Check the state
-	s, err := b.State()
+	s, err := b.State(backend.DefaultStateName)
 	if err != nil {
 		t.Fatalf("bad: %s", err)
 	}

command/meta_test.go

@@ -8,6 +8,7 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/hashicorp/terraform/backend"
 	"github.com/hashicorp/terraform/terraform"
 )
 
@@ -272,3 +273,37 @@ func TestMeta_addModuleDepthFlag(t *testing.T) {
 		}
 	}
 }
+
+func TestMeta_Env(t *testing.T) {
+	td := tempDir(t)
+	os.MkdirAll(td, 0755)
+	defer os.RemoveAll(td)
+	defer testChdir(t, td)()
+
+	m := new(Meta)
+
+	env := m.Env()
+
+	if env != backend.DefaultStateName {
+		t.Fatalf("expected env %q, got env %q", backend.DefaultStateName, env)
+	}
+
+	testEnv := "test_env"
+	if err := m.SetEnv(testEnv); err != nil {
+		t.Fatal("error setting env:", err)
+	}
+
+	env = m.Env()
+	if env != testEnv {
+		t.Fatalf("expected env %q, got env %q", testEnv, env)
+	}
+
+	if err := m.SetEnv(backend.DefaultStateName); err != nil {
+		t.Fatal("error setting env:", err)
+	}
+
+	env = m.Env()
+	if env != backend.DefaultStateName {
+		t.Fatalf("expected env %q, got env %q", backend.DefaultStateName, env)
+	}
+}

command/output.go

@@ -50,8 +50,10 @@ func (c *OutputCommand) Run(args []string) int {
 		return 1
 	}
 
+	env := c.Env()
+
 	// Get the state
-	stateStore, err := b.State()
+	stateStore, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1

command/show.go

@@ -74,8 +74,10 @@ func (c *ShowCommand) Run(args []string) int {
 			return 1
 		}
 
+		env := c.Env()
+
 		// Get the state
-		stateStore, err := b.State()
+		stateStore, err := b.State(env)
 		if err != nil {
 			c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 			return 1

command/state_command.go

@@ -9,7 +9,7 @@ import (
 // StateCommand is a Command implementation that just shows help for
 // the subcommands nested below it.
 type StateCommand struct {
-	Meta
+	StateMeta
 }
 
 func (c *StateCommand) Run(args []string) int {

command/state_list.go

@@ -12,6 +12,7 @@ import (
 // within a state file.
 type StateListCommand struct {
 	Meta
+	StateMeta
 }
 
 func (c *StateListCommand) Run(args []string) int {
@@ -31,8 +32,9 @@ func (c *StateListCommand) Run(args []string) int {
 		return 1
 	}
 
+	env := c.Env()
 	// Get the state
-	state, err := b.State()
+	state, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1

command/state_meta.go

@@ -13,9 +13,10 @@ import (
 // StateMeta is the meta struct that should be embedded in state subcommands.
 type StateMeta struct{}
 
-// State returns the state for this meta. This is different then Meta.State
-// in the way that backups are done. This configures backups to be timestamped
-// rather than just the original state path plus a backup path.
+// State returns the state for this meta. This gets the appropriate state from
+// the backend, but changes the way that backups are done. This configures
+// backups to be timestamped rather than just the original state path plus a
+// backup path.
 func (c *StateMeta) State(m *Meta) (state.State, error) {
 	// Load the backend
 	b, err := m.Backend(nil)
@@ -23,8 +24,9 @@ func (c *StateMeta) State(m *Meta) (state.State, error) {
 		return nil, err
 	}
 
+	env := m.Env()
 	// Get the state
-	s, err := b.State()
+	s, err := b.State(env)
 	if err != nil {
 		return nil, err
 	}
@@ -36,12 +38,16 @@ func (c *StateMeta) State(m *Meta) (state.State, error) {
 		panic(err)
 	}
 	localB := localRaw.(*backendlocal.Local)
+	_, stateOutPath, _ := localB.StatePaths(env)
+	if err != nil {
+		return nil, err
+	}
 
 	// Determine the backup path. stateOutPath is set to the resulting
 	// file where state is written (cached in the case of remote state)
 	backupPath := fmt.Sprintf(
 		"%s.%d%s",
-		localB.StateOutPath,
+		stateOutPath,
 		time.Now().UTC().Unix(),
 		DefaultBackupExtension)
 

command/state_pull.go

@@ -32,7 +32,8 @@ func (c *StatePullCommand) Run(args []string) int {
 	}
 
 	// Get the state
-	state, err := b.State()
+	env := c.Env()
+	state, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1

command/state_push.go

@@ -52,7 +52,8 @@ func (c *StatePushCommand) Run(args []string) int {
 	}
 
 	// Get the state
-	state, err := b.State()
+	env := c.Env()
+	state, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load destination state: %s", err))
 		return 1

command/state_show.go

@@ -34,7 +34,8 @@ func (c *StateShowCommand) Run(args []string) int {
 	}
 
 	// Get the state
-	state, err := b.State()
+	env := c.Env()
+	state, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1

command/taint.go

@@ -67,7 +67,8 @@ func (c *TaintCommand) Run(args []string) int {
 	}
 
 	// Get the state
-	st, err := b.State()
+	env := c.Env()
+	st, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1

command/unlock.go

@@ -52,7 +52,8 @@ func (c *UnlockCommand) Run(args []string) int {
 		return 1
 	}
 
-	st, err := b.State()
+	env := c.Env()
+	st, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1
@@ -102,7 +103,6 @@ func (c *UnlockCommand) Run(args []string) int {
 		}
 	}
 
-	// FIXME: unlock should require the lock ID
 	if err := s.Unlock(lockID); err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to unlock state: %s", err))
 		return 1

command/untaint.go

@@ -55,7 +55,8 @@ func (c *UntaintCommand) Run(args []string) int {
 	}
 
 	// Get the state
-	st, err := b.State()
+	env := c.Env()
+	st, err := b.State(env)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
 		return 1

commands.go

@@ -69,6 +69,36 @@ func init() {
 			}, nil
 		},
 
+		"env": func() (cli.Command, error) {
+			return &command.EnvCommand{
+				Meta: meta,
+			}, nil
+		},
+
+		"env list": func() (cli.Command, error) {
+			return &command.EnvListCommand{
+				Meta: meta,
+			}, nil
+		},
+
+		"env select": func() (cli.Command, error) {
+			return &command.EnvSelectCommand{
+				Meta: meta,
+			}, nil
+		},
+
+		"env new": func() (cli.Command, error) {
+			return &command.EnvNewCommand{
+				Meta: meta,
+			}, nil
+		},
+
+		"env delete": func() (cli.Command, error) {
+			return &command.EnvDeleteCommand{
+				Meta: meta,
+			}, nil
+		},
+
 		"fmt": func() (cli.Command, error) {
 			return &command.FmtCommand{
 				Meta: meta,
@@ -186,9 +216,7 @@ func init() {
 		},
 
 		"state": func() (cli.Command, error) {
-			return &command.StateCommand{
-				Meta: meta,
-			}, nil
+			return &command.StateCommand{}, nil
 		},
 
 		"state list": func() (cli.Command, error) {