Merge pull request #1065 from hashicorp/f-taint

Add "taint" command

command/command_test.go

@@ -4,6 +4,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/hashicorp/terraform/config/module"
@@ -131,6 +132,43 @@ func testStateFile(t *testing.T, s *terraform.State) string {
 	return path
 }
 
+// testStateFileDefault writes the state out to the default statefile
+// in the cwd. Use `testCwd` to change into a temp cwd.
+func testStateFileDefault(t *testing.T, s *terraform.State) string {
+	f, err := os.Create(DefaultStateFilename)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer f.Close()
+
+	if err := terraform.WriteState(s, f); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	return DefaultStateFilename
+}
+
+// testStateOutput tests that the state at the given path contains
+// the expected state string.
+func testStateOutput(t *testing.T, path string, expected string) {
+	f, err := os.Open(path)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	newState, err := terraform.ReadState(f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(newState.String())
+	expected = strings.TrimSpace(expected)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s", actual)
+	}
+}
+
 func testProvider() *terraform.MockResourceProvider {
 	p := new(terraform.MockResourceProvider)
 	p.DiffReturn = &terraform.InstanceDiff{}
@@ -175,7 +213,7 @@ func testTempDir(t *testing.T) string {
 	return d
 }
 
-// testCwdDir is used to change the current working directory
+// testCwd is used to change the current working directory
 // into a test directory that should be remoted after
 func testCwd(t *testing.T) (string, string) {
 	tmp, err := ioutil.TempDir("", "tf")

command/taint.go

@@ -0,0 +1,171 @@
+package command
+
+import (
+	"fmt"
+	"log"
+	"strings"
+)
+
+// TaintCommand is a cli.Command implementation that manually taints
+// a resource, marking it for recreation.
+type TaintCommand struct {
+	Meta
+}
+
+func (c *TaintCommand) Run(args []string) int {
+	args = c.Meta.process(args, false)
+
+	var allowMissing bool
+	var module string
+	cmdFlags := c.Meta.flagSet("taint")
+	cmdFlags.BoolVar(&allowMissing, "allow-missing", false, "module")
+	cmdFlags.StringVar(&module, "module", "", "module")
+	cmdFlags.StringVar(&c.Meta.statePath, "state", DefaultStateFilename, "path")
+	cmdFlags.StringVar(&c.Meta.stateOutPath, "state-out", "", "path")
+	cmdFlags.StringVar(&c.Meta.backupPath, "backup", "", "path")
+	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
+	if err := cmdFlags.Parse(args); err != nil {
+		return 1
+	}
+
+	// Require the one argument for the resource to taint
+	args = cmdFlags.Args()
+	if len(args) != 1 {
+		c.Ui.Error("The taint command expects exactly one argument.")
+		cmdFlags.Usage()
+		return 1
+	}
+
+	name := args[0]
+	if module == "" {
+		module = "root"
+	} else {
+		module = "root." + module
+	}
+
+	// Get the state that we'll be modifying
+	state, err := c.State()
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load state: %s", err))
+		return 1
+	}
+
+	// Get the actual state structure
+	s := state.State()
+	if s.Empty() {
+		if allowMissing {
+			return c.allowMissingExit(name, module)
+		}
+
+		c.Ui.Error(fmt.Sprintf(
+			"The state is empty. The most common reason for this is that\n" +
+				"an invalid state file path was given or Terraform has never\n " +
+				"been run for this infrastructure. Infrastructure must exist\n" +
+				"for it to be tainted."))
+		return 1
+	}
+
+	// Get the proper module we want to taint
+	modPath := strings.Split(module, ".")
+	mod := s.ModuleByPath(modPath)
+	if mod == nil {
+		if allowMissing {
+			return c.allowMissingExit(name, module)
+		}
+
+		c.Ui.Error(fmt.Sprintf(
+			"The module %s could not be found. There is nothing to taint.",
+			module))
+		return 1
+	}
+
+	// If there are no resources in this module, it is an error
+	if len(mod.Resources) == 0 {
+		if allowMissing {
+			return c.allowMissingExit(name, module)
+		}
+
+		c.Ui.Error(fmt.Sprintf(
+			"The module %s has no resources. There is nothing to taint.",
+			module))
+		return 1
+	}
+
+	// Get the resource we're looking for
+	rs, ok := mod.Resources[name]
+	if !ok {
+		if allowMissing {
+			return c.allowMissingExit(name, module)
+		}
+
+		c.Ui.Error(fmt.Sprintf(
+			"The resource %s couldn't be found in the module %s.",
+			name,
+			module))
+		return 1
+	}
+
+	// Taint the resource
+	rs.Taint()
+
+	log.Printf("[INFO] Writing state output to: %s", c.Meta.StateOutPath())
+	if err := c.Meta.PersistState(s); err != nil {
+		c.Ui.Error(fmt.Sprintf("Error writing state file: %s", err))
+		return 1
+	}
+
+	c.Ui.Output(fmt.Sprintf(
+		"The resource %s in the module %s has been marked as tainted!",
+		name, module))
+	return 0
+}
+
+func (c *TaintCommand) Help() string {
+	helpText := `
+Usage: terraform taint [options] name
+
+  Manually mark a resource as tainted, forcing a destroy and recreate
+  on the next plan/apply.
+
+  This will not modify your infrastructure. This command changes your
+  state to mark a resource as tainted so that during the next plan or
+  apply, that resource will be destroyed and recreated. This command on
+  its own will not modify infrastructure. This command can be undone by
+  reverting the state backup file that is created.
+
+Options:
+
+  -allow-missing      If specified, the command will succeed (exit code 0)
+                      even if the resource is missing.
+
+  -backup=path        Path to backup the existing state file before
+                      modifying. Defaults to the "-state-out" path with
+                      ".backup" extension. Set to "-" to disable backup.
+
+  -module=path        The module path where the resource lives. By
+                      default this will be root. Child modules can be specified
+                      by names. Ex. "consul" or "consul.vpc" (nested modules).
+
+  -no-color           If specified, output won't contain any color.
+
+  -state=path         Path to read and save state (unless state-out
+                      is specified). Defaults to "terraform.tfstate".
+
+  -state-out=path     Path to write updated state file. By default, the
+                      "-state" path will be used.
+
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *TaintCommand) Synopsis() string {
+	return "Manually mark a resource for recreation"
+}
+
+func (c *TaintCommand) allowMissingExit(name, module string) int {
+	c.Ui.Output(fmt.Sprintf(
+		"The resource %s in the module %s was not found, but\n"+
+			"-allow-missing is set, so we're exiting successfully.",
+		name, module))
+	return 0
+}

command/taint_test.go

@@ -0,0 +1,368 @@
+package command
+
+import (
+	"os"
+	"testing"
+
+	"github.com/hashicorp/terraform/terraform"
+	"github.com/mitchellh/cli"
+)
+
+func TestTaint(t *testing.T) {
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	statePath := testStateFile(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-state", statePath,
+		"test_instance.foo",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	testStateOutput(t, statePath, testTaintStr)
+}
+
+func TestTaint_backup(t *testing.T) {
+	// Get a temp cwd
+	tmp, cwd := testCwd(t)
+	defer testFixCwd(t, tmp, cwd)
+
+	// Write the temp state
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	path := testStateFileDefault(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"test_instance.foo",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	testStateOutput(t, path+".backup", testTaintDefaultStr)
+	testStateOutput(t, path, testTaintStr)
+}
+
+func TestTaint_backupDisable(t *testing.T) {
+	// Get a temp cwd
+	tmp, cwd := testCwd(t)
+	defer testFixCwd(t, tmp, cwd)
+
+	// Write the temp state
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	path := testStateFileDefault(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-backup", "-",
+		"test_instance.foo",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	if _, err := os.Stat(path + ".backup"); err == nil {
+		t.Fatal("backup path should not exist")
+	}
+
+	testStateOutput(t, path, testTaintStr)
+}
+
+func TestTaint_badState(t *testing.T) {
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-state", "i-should-not-exist-ever",
+		"foo",
+	}
+	if code := c.Run(args); code != 1 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+}
+
+func TestTaint_defaultState(t *testing.T) {
+	// Get a temp cwd
+	tmp, cwd := testCwd(t)
+	defer testFixCwd(t, tmp, cwd)
+
+	// Write the temp state
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	path := testStateFileDefault(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"test_instance.foo",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	testStateOutput(t, path, testTaintStr)
+}
+
+func TestTaint_missing(t *testing.T) {
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	statePath := testStateFile(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-state", statePath,
+		"test_instance.bar",
+	}
+	if code := c.Run(args); code == 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.OutputWriter.String())
+	}
+}
+
+func TestTaint_missingAllow(t *testing.T) {
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	statePath := testStateFile(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-allow-missing",
+		"-state", statePath,
+		"test_instance.bar",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+}
+
+func TestTaint_stateOut(t *testing.T) {
+	// Get a temp cwd
+	tmp, cwd := testCwd(t)
+	defer testFixCwd(t, tmp, cwd)
+
+	// Write the temp state
+	state := &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",
+						},
+					},
+				},
+			},
+		},
+	}
+	path := testStateFileDefault(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-state-out", "foo",
+		"test_instance.foo",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	testStateOutput(t, path, testTaintDefaultStr)
+	testStateOutput(t, "foo", testTaintStr)
+}
+
+func TestTaint_module(t *testing.T) {
+	state := &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",
+						},
+					},
+				},
+			},
+			&terraform.ModuleState{
+				Path: []string{"root", "child"},
+				Resources: map[string]*terraform.ResourceState{
+					"test_instance.blah": &terraform.ResourceState{
+						Type: "test_instance",
+						Primary: &terraform.InstanceState{
+							ID: "blah",
+						},
+					},
+				},
+			},
+		},
+	}
+	statePath := testStateFile(t, state)
+
+	ui := new(cli.MockUi)
+	c := &TaintCommand{
+		Meta: Meta{
+			Ui: ui,
+		},
+	}
+
+	args := []string{
+		"-module=child",
+		"-state", statePath,
+		"test_instance.blah",
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	testStateOutput(t, statePath, testTaintModuleStr)
+}
+
+const testTaintStr = `
+test_instance.foo: (1 tainted)
+  ID = <not created>
+  Tainted ID 1 = bar
+`
+
+const testTaintDefaultStr = `
+test_instance.foo:
+  ID = bar
+`
+
+const testTaintModuleStr = `
+test_instance.foo:
+  ID = bar
+
+module.child:
+  test_instance.blah: (1 tainted)
+    ID = <not created>
+    Tainted ID 1 = blah
+`

commands.go

@@ -110,6 +110,12 @@ func init() {
 			}, nil
 		},
 
+		"taint": func() (cli.Command, error) {
+			return &command.TaintCommand{
+				Meta: meta,
+			}, nil
+		},
+
 		"version": func() (cli.Command, error) {
 			return &command.VersionCommand{
 				Meta:              meta,

terraform/context_test.go

@@ -4714,6 +4714,132 @@ func TestContext2Apply_taint(t *testing.T) {
 	}
 }
 
+func TestContext2Apply_taintDep(t *testing.T) {
+	m := testModule(t, "apply-taint-dep")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	s := &State{
+		Modules: []*ModuleState{
+			&ModuleState{
+				Path: rootModulePath,
+				Resources: map[string]*ResourceState{
+					"aws_instance.foo": &ResourceState{
+						Type: "aws_instance",
+						Tainted: []*InstanceState{
+							&InstanceState{
+								ID: "baz",
+								Attributes: map[string]string{
+									"num":  "2",
+									"type": "aws_instance",
+								},
+							},
+						},
+					},
+					"aws_instance.bar": &ResourceState{
+						Type: "aws_instance",
+						Primary: &InstanceState{
+							ID: "bar",
+							Attributes: map[string]string{
+								"foo":  "baz",
+								"num":  "2",
+								"type": "aws_instance",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: s,
+	})
+
+	if p, err := ctx.Plan(nil); err != nil {
+		t.Fatalf("err: %s", err)
+	} else {
+		t.Logf("plan: %s", p)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(state.String())
+	expected := strings.TrimSpace(testTerraformApplyTaintDepStr)
+	if actual != expected {
+		t.Fatalf("bad:\n%s", actual)
+	}
+}
+
+func TestContext2Apply_taintDepRequiresNew(t *testing.T) {
+	m := testModule(t, "apply-taint-dep-requires-new")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	s := &State{
+		Modules: []*ModuleState{
+			&ModuleState{
+				Path: rootModulePath,
+				Resources: map[string]*ResourceState{
+					"aws_instance.foo": &ResourceState{
+						Type: "aws_instance",
+						Tainted: []*InstanceState{
+							&InstanceState{
+								ID: "baz",
+								Attributes: map[string]string{
+									"num":  "2",
+									"type": "aws_instance",
+								},
+							},
+						},
+					},
+					"aws_instance.bar": &ResourceState{
+						Type: "aws_instance",
+						Primary: &InstanceState{
+							ID: "bar",
+							Attributes: map[string]string{
+								"foo":  "baz",
+								"num":  "2",
+								"type": "aws_instance",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: s,
+	})
+
+	if p, err := ctx.Plan(nil); err != nil {
+		t.Fatalf("err: %s", err)
+	} else {
+		t.Logf("plan: %s", p)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(state.String())
+	expected := strings.TrimSpace(testTerraformApplyTaintDepRequireNewStr)
+	if actual != expected {
+		t.Fatalf("bad:\n%s", actual)
+	}
+}
+
 func TestContext2Apply_unknownAttribute(t *testing.T) {
 	m := testModule(t, "apply-unknown")
 	p := testProvider("aws")
@@ -4966,7 +5092,13 @@ func testApplyFn(
 	}
 
 	result := &InstanceState{
-		ID: id,
+		ID:         id,
+		Attributes: make(map[string]string),
+	}
+
+	// Copy all the prior attributes
+	for k, v := range s.Attributes {
+		result.Attributes[k] = v
 	}
 
 	if d != nil {

terraform/state.go

@@ -260,6 +260,10 @@ func (s *State) GoString() string {
 }
 
 func (s *State) String() string {
+	if s == nil {
+		return "<nil>"
+	}
+
 	var buf bytes.Buffer
 	for _, m := range s.Modules {
 		mStr := m.String()
@@ -699,6 +703,19 @@ func (s *ResourceState) Equal(other *ResourceState) bool {
 	return true
 }
 
+// Taint takes the primary state and marks it as tainted. If there is no
+// primary state, this does nothing.
+func (r *ResourceState) Taint() {
+	// If there is no primary, nothing to do
+	if r.Primary == nil {
+		return
+	}
+
+	// Shuffle to the end of the taint list and set primary to nil
+	r.Tainted = append(r.Tainted, r.Primary)
+	r.Primary = nil
+}
+
 func (r *ResourceState) init() {
 	if r.Primary == nil {
 		r.Primary = &InstanceState{}
@@ -710,16 +727,24 @@ func (r *ResourceState) deepcopy() *ResourceState {
 	if r == nil {
 		return nil
 	}
+
 	n := &ResourceState{
 		Type:         r.Type,
-		Dependencies: make([]string, len(r.Dependencies)),
+		Dependencies: nil,
 		Primary:      r.Primary.deepcopy(),
-		Tainted:      make([]*InstanceState, 0, len(r.Tainted)),
+		Tainted:      nil,
 	}
-	copy(n.Dependencies, r.Dependencies)
+	if r.Dependencies != nil {
-	for _, inst := range r.Tainted {
+		n.Dependencies = make([]string, len(r.Dependencies))
-		n.Tainted = append(n.Tainted, inst.deepcopy())
+		copy(n.Dependencies, r.Dependencies)
 	}
+	if r.Tainted != nil {
+		n.Tainted = make([]*InstanceState, 0, len(r.Tainted))
+		for _, inst := range r.Tainted {
+			n.Tainted = append(n.Tainted, inst.deepcopy())
+		}
+	}
+
 	return n
 }
 

terraform/state_test.go

@@ -275,6 +275,53 @@ func TestResourceStateEqual(t *testing.T) {
 	}
 }
 
+func TestResourceStateTaint(t *testing.T) {
+	cases := map[string]struct {
+		Input  *ResourceState
+		Output *ResourceState
+	}{
+		"no primary": {
+			&ResourceState{},
+			&ResourceState{},
+		},
+
+		"primary, no tainted": {
+			&ResourceState{
+				Primary: &InstanceState{ID: "foo"},
+			},
+			&ResourceState{
+				Tainted: []*InstanceState{
+					&InstanceState{ID: "foo"},
+				},
+			},
+		},
+
+		"primary, with tainted": {
+			&ResourceState{
+				Primary: &InstanceState{ID: "foo"},
+				Tainted: []*InstanceState{
+					&InstanceState{ID: "bar"},
+				},
+			},
+			&ResourceState{
+				Tainted: []*InstanceState{
+					&InstanceState{ID: "bar"},
+					&InstanceState{ID: "foo"},
+				},
+			},
+		},
+	}
+
+	for k, tc := range cases {
+		tc.Input.Taint()
+		if !reflect.DeepEqual(tc.Input, tc.Output) {
+			t.Fatalf(
+				"Failure: %s\n\nExpected: %#v\n\nGot: %#v",
+				k, tc.Output, tc.Input)
+		}
+	}
+}
+
 func TestInstanceStateEqual(t *testing.T) {
 	cases := []struct {
 		Result   bool

terraform/terraform_test.go

@@ -433,6 +433,36 @@ aws_instance.bar:
   type = aws_instance
 `
 
+const testTerraformApplyTaintDepStr = `
+aws_instance.bar:
+  ID = bar
+  foo = foo
+  num = 2
+  type = aws_instance
+
+  Dependencies:
+    aws_instance.foo
+aws_instance.foo:
+  ID = foo
+  num = 2
+  type = aws_instance
+`
+
+const testTerraformApplyTaintDepRequireNewStr = `
+aws_instance.bar:
+  ID = foo
+  foo = foo
+  require_new = yes
+  type = aws_instance
+
+  Dependencies:
+    aws_instance.foo
+aws_instance.foo:
+  ID = foo
+  num = 2
+  type = aws_instance
+`
+
 const testTerraformApplyOutputStr = `
 aws_instance.bar:
   ID = foo

terraform/test-fixtures/apply-taint-dep-requires-new/main.tf

@@ -0,0 +1,10 @@
+resource "aws_instance" "foo" {
+    id = "foo"
+    num = "2"
+}
+
+resource "aws_instance" "bar" {
+    id = "bar"
+    foo = "${aws_instance.foo.id}"
+    require_new = "yes"
+}

terraform/test-fixtures/apply-taint-dep/main.tf

@@ -0,0 +1,10 @@
+resource "aws_instance" "foo" {
+    id = "foo"
+    num = "2"
+}
+
+resource "aws_instance" "bar" {
+    id = "bar"
+    num = "2"
+    foo = "${aws_instance.foo.id}"
+}

website/source/docs/commands/taint.html.markdown

@@ -0,0 +1,61 @@
+---
+layout: "docs"
+page_title: "Command: taint"
+sidebar_current: "docs-commands-taint"
+description: |-
+  The `terraform taint` command manually marks a Terraform-managed resource as tainted, forcing it to be destroyed and recreated on the next apply.
+---
+
+# Command: taint
+
+The `terraform taint` command manually marks a Terraform-managed resource
+as tainted, forcing it to be destroyed and recreated on the next apply.
+
+This command _will not_ modify infrastructure, but does modify the
+state file in order to mark a resource as tainted. Once a resource is
+marked as tainted, the next
+[plan](/docs/commands/plan.html) will show that the resource will
+be destroyed and recreated and the next
+[apply](/docs/commands/apply.html) will implement this change.
+
+Forcing the recreation of a resource is useful when you want a certain
+side effect of recreation that is not visible in the attributes of a resource.
+For example: re-running provisioners will cause the node to be different
+or rebooting the machine from a base image will cause new startup scripts
+to run.
+
+Note that tainting a resource for recreation may affect resources that
+depend on the newly tainted resource. For example, a DNS resource that
+uses the IP address of a server may need to be modified to reflect
+the potentially new IP address of a tainted server. The
+[plan command](/docs/commands/plan.html) will show this if this is
+the case.
+
+## Usage
+
+Usage: `terraform taint [options] name`
+
+The `name` argument is the name of the resource to mark as tainted.
+The format of this argument is `TYPE.NAME`, such as `aws_instance.foo`.
+
+The command-line flags are all optional. The list of available flags are:
+
+* `-allow-missing` - If specified, the command will succeed (exit code 0)
+    even if the resource is missing. The command can still error, but only
+    in critically erroneous cases.
+
+* `-backup=path` - Path to the backup file. Defaults to `-state-out` with
+  the ".backup" extension. Disabled by setting to "-".
+
+* `-module=path` - The module path where the resource to taint exists.
+    By default this is the root path. Other modules can be specified by
+    a period-separated list. Example: "foo" would reference the module
+    "foo" but "foo.bar" would reference the "bar" module in the "foo"
+    module.
+
+* `-no-color` - Disables output with coloring
+
+* `-state=path` - Path to read and write the state file to. Defaults to "terraform.tfstate".
+
+* `-state-out=path` - Path to write updated state file. By default, the
+  `-state` path will be used.

website/source/layouts/docs.erb

@@ -98,6 +98,10 @@
 					<li<%= sidebar_current("docs-commands-show") %>>
 					<a href="/docs/commands/show.html">show</a>
 					</li>
+
+					<li<%= sidebar_current("docs-commands-taint") %>>
+					<a href="/docs/commands/taint.html">taint</a>
+					</li>
 				</ul>
 				</li>