tfexec: add InterruptChannel option to allow a user triggered interrupt

tfexec/apply.go

@@ -8,6 +8,8 @@ import (
 )
 
 type applyConfig struct {
+	interruptCh <-chan struct{}
+
 	backup    string
 	dirOrPlan string
 	lock      bool
@@ -42,6 +44,10 @@ func (opt *ParallelismOption) configureApply(conf *applyConfig) {
 	conf.parallelism = opt.parallelism
 }
 
+func (opt *InterruptChannelOption) configureApply(conf *applyConfig) {
+	conf.interruptCh = opt.interrupt
+}
+
 func (opt *BackupOption) configureApply(conf *applyConfig) {
 	conf.backup = opt.path
 }
@@ -92,14 +98,17 @@ func (opt *ReattachOption) configureApply(conf *applyConfig) {
 
 // Apply represents the terraform apply subcommand.
 func (tf *Terraform) Apply(ctx context.Context, opts ...ApplyOption) error {
-	cmd, err := tf.applyCmd(ctx, opts...)
+	cmd, cfg, err := tf.applyCmd(ctx, opts...)
 	if err != nil {
 		return err
 	}
+	if cfg.interruptCh != nil {
+		ctx = context.WithValue(ctx, interruptContext, cfg.interruptCh)
+	}
 	return tf.runTerraformCmd(ctx, cmd)
 }
 
-func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.Cmd, error) {
+func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.Cmd, *applyConfig, error) {
 	c := defaultApplyOptions
 
 	for _, o := range opts {
@@ -134,7 +143,7 @@ func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.C
 	if c.replaceAddrs != nil {
 		err := tf.compatible(ctx, tf0_15_2, nil)
 		if err != nil {
-			return nil, fmt.Errorf("replace option was introduced in Terraform 0.15.2: %w", err)
+			return nil, nil, fmt.Errorf("replace option was introduced in Terraform 0.15.2: %w", err)
 		}
 		for _, addr := range c.replaceAddrs {
 			args = append(args, "-replace="+addr)
@@ -160,10 +169,10 @@ func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.C
 	if c.reattachInfo != nil {
 		reattachStr, err := c.reattachInfo.marshalString()
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 		mergeEnv[reattachEnvVar] = reattachStr
 	}
 
-	return tf.buildTerraformCmd(ctx, mergeEnv, args...), nil
+	return tf.buildTerraformCmd(ctx, mergeEnv, args...), &c, nil
 }

tfexec/apply_test.go

@@ -19,7 +19,7 @@ func TestApplyCmd(t *testing.T) {
 	tf.SetEnv(map[string]string{})
 
 	t.Run("basic", func(t *testing.T) {
-		applyCmd, err := tf.applyCmd(context.Background(),
+		applyCmd, cfg, err := tf.applyCmd(context.Background(),
 			Backup("testbackup"),
 			LockTimeout("200s"),
 			State("teststate"),
@@ -36,6 +36,7 @@ func TestApplyCmd(t *testing.T) {
 			Var("var1=foo"),
 			Var("var2=bar"),
 			DirOrPlan("testfile"),
+			InterruptChannel(make(chan struct{})),
 		)
 		if err != nil {
 			t.Fatal(err)
@@ -63,5 +64,9 @@ func TestApplyCmd(t *testing.T) {
 			"-var", "var2=bar",
 			"testfile",
 		}, nil, applyCmd)
+
+		if cfg.interruptCh == nil {
+			t.Fatal("interrupt signal is unexpectedly nil")
+		}
 	})
 }

tfexec/cmd.go

@@ -16,6 +16,12 @@ import (
 	"github.com/hashicorp/terraform-exec/internal/version"
 )
 
+// If using the InterruptSignal option, we stuff the interrupt channel into the
+// context to keep our APIs simpler (and non-changing).
+//
+//     context.WithValue(ctx, interruptContext, interruptCh)
+var interruptContext = new(struct{})
+
 const (
 	checkpointDisableEnvVar  = "CHECKPOINT_DISABLE"
 	cliArgsEnvVar            = "TF_CLI_ARGS"
@@ -191,7 +197,7 @@ func (tf *Terraform) buildTerraformCmd(ctx context.Context, mergeEnv map[string]
 }
 
 func (tf *Terraform) runTerraformCmdJSON(ctx context.Context, cmd *exec.Cmd, v interface{}) error {
-	var outbuf = bytes.Buffer{}
+	var outbuf bytes.Buffer
 	cmd.Stdout = mergeWriters(cmd.Stdout, &outbuf)
 
 	err := tf.runTerraformCmd(ctx, cmd)

tfexec/cmd_default_test.go → tfexec/cmd_all_platforms_test.go

@@ -1,18 +1,16 @@
-//go:build !linux
-// +build !linux
-
 package tfexec
 
 import (
 	"bytes"
 	"context"
+	"errors"
 	"log"
 	"strings"
 	"testing"
 	"time"
 )
 
-func Test_runTerraformCmd_default(t *testing.T) {
+func Test_runTerraformCmd(t *testing.T) {
 	// Checks runTerraformCmd for race condition when using
 	// go test -race -run Test_runTerraformCmd_default ./tfexec
 	var buf bytes.Buffer
@@ -37,3 +35,26 @@ func Test_runTerraformCmd_default(t *testing.T) {
 		t.Fatal("canceling context should not lead to logging an error")
 	}
 }
+
+func Test_runTerraformCmdCancel(t *testing.T) {
+	var buf bytes.Buffer
+
+	tf := &Terraform{
+		logger:   log.New(&buf, "", 0),
+		execPath: "sleep",
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	cmd := tf.buildTerraformCmd(ctx, nil, "10")
+	go func() {
+		time.Sleep(time.Second)
+		cancel()
+	}()
+
+	err := tf.runTerraformCmd(ctx, cmd)
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("expected context.Canceled, got %T %s", err, err)
+	}
+}

tfexec/cmd_default.go

@@ -1,5 +1,6 @@
-//go:build !linux
-// +build !linux
+// list taken from https://github.com/golang/go/blob/91ef076562dfcf783074dbd84ad7c6db60fdd481/src/go/build/syslist.go#L38-L51
+//go:build !aix && !android && !darwin && !dragonfly && !freebsd && !hurd && !illumos && !ios && !linux && !netbsd && !openbsd && !solaris
+// +build !aix,!android,!darwin,!dragonfly,!freebsd,!hurd,!illumos,!ios,!linux,!netbsd,!openbsd,!solaris
 
 package tfexec
 

tfexec/cmd_sys_proc_attr_default.go

@@ -0,0 +1,8 @@
+//go:build !linux
+// +build !linux
+
+package tfexec
+
+import "syscall"
+
+var defaultSysProcAttr = &syscall.SysProcAttr{}

tfexec/cmd_sys_proc_attr_linux.go

@@ -0,0 +1,13 @@
+//go:build linux
+// +build linux
+
+package tfexec
+
+import "syscall"
+
+var defaultSysProcAttr = &syscall.SysProcAttr{
+	// kill children if parent is dead
+	Pdeathsig: syscall.SIGKILL,
+	// set process group ID
+	Setpgid: true,
+}

tfexec/cmd_linux.go → tfexec/cmd_unix.go

@@ -1,22 +1,21 @@
+// list taken from https://github.com/golang/go/blob/91ef076562dfcf783074dbd84ad7c6db60fdd481/src/go/build/syslist.go#L38-L51
+//go:build aix || android || darwin || dragonfly || freebsd || hurd || illumos || ios || linux || netbsd || openbsd || solaris
+// +build aix android darwin dragonfly freebsd hurd illumos ios linux netbsd openbsd solaris
+
 package tfexec
 
 import (
 	"context"
+	"os"
 	"os/exec"
 	"strings"
 	"sync"
-	"syscall"
 )
 
 func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	var errBuf strings.Builder
 
-	cmd.SysProcAttr = &syscall.SysProcAttr{
-		// kill children if parent is dead
-		Pdeathsig: syscall.SIGKILL,
-		// set process group ID
-		Setpgid: true,
-	}
+	cmd.SysProcAttr = defaultSysProcAttr
 
 	// check for early cancellation
 	select {
@@ -52,6 +51,19 @@ func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 		return tf.wrapExitError(ctx, err, "")
 	}
 
+	if interruptCh := ctx.Value(interruptContext); interruptCh != nil {
+		exited := make(chan struct{})
+		defer close(exited)
+		go func() {
+			select {
+			case <-interruptCh.(<-chan struct{}):
+				cmd.Process.Signal(os.Interrupt)
+			case <-exited:
+			case <-ctx.Done():
+			}
+		}()
+	}
+
 	var errStdout, errStderr error
 	var wg sync.WaitGroup
 	wg.Add(1)

tfexec/destroy.go

@@ -8,6 +8,8 @@ import (
 )
 
 type destroyConfig struct {
+	interruptCh <-chan struct{}
+
 	backup string
 	dir    string
 	lock   bool
@@ -46,6 +48,10 @@ func (opt *ParallelismOption) configureDestroy(conf *destroyConfig) {
 	conf.parallelism = opt.parallelism
 }
 
+func (opt *InterruptChannelOption) configureDestroy(conf *destroyConfig) {
+	conf.interruptCh = opt.interrupt
+}
+
 func (opt *BackupOption) configureDestroy(conf *destroyConfig) {
 	conf.backup = opt.path
 }
@@ -88,14 +94,17 @@ func (opt *ReattachOption) configureDestroy(conf *destroyConfig) {
 
 // Destroy represents the terraform destroy subcommand.
 func (tf *Terraform) Destroy(ctx context.Context, opts ...DestroyOption) error {
-	cmd, err := tf.destroyCmd(ctx, opts...)
+	cmd, cfg, err := tf.destroyCmd(ctx, opts...)
 	if err != nil {
 		return err
 	}
+	if cfg.interruptCh != nil {
+		ctx = context.WithValue(ctx, interruptContext, cfg.interruptCh)
+	}
 	return tf.runTerraformCmd(ctx, cmd)
 }
 
-func (tf *Terraform) destroyCmd(ctx context.Context, opts ...DestroyOption) (*exec.Cmd, error) {
+func (tf *Terraform) destroyCmd(ctx context.Context, opts ...DestroyOption) (*exec.Cmd, *destroyConfig, error) {
 	c := defaultDestroyOptions
 
 	for _, o := range opts {
@@ -147,10 +156,10 @@ func (tf *Terraform) destroyCmd(ctx context.Context, opts ...DestroyOption) (*ex
 	if c.reattachInfo != nil {
 		reattachStr, err := c.reattachInfo.marshalString()
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 		mergeEnv[reattachEnvVar] = reattachStr
 	}
 
-	return tf.buildTerraformCmd(ctx, mergeEnv, args...), nil
+	return tf.buildTerraformCmd(ctx, mergeEnv, args...), &c, nil
 }

tfexec/destroy_test.go

@@ -19,7 +19,7 @@ func TestDestroyCmd(t *testing.T) {
 	tf.SetEnv(map[string]string{})
 
 	t.Run("defaults", func(t *testing.T) {
-		destroyCmd, err := tf.destroyCmd(context.Background())
+		destroyCmd, cfg, err := tf.destroyCmd(context.Background())
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -34,10 +34,14 @@ func TestDestroyCmd(t *testing.T) {
 			"-parallelism=10",
 			"-refresh=true",
 		}, nil, destroyCmd)
+
+		if cfg.interruptCh != nil {
+			t.Fatal("interrupt signal is unexpectedly non-nil")
+		}
 	})
 
 	t.Run("override all defaults", func(t *testing.T) {
-		destroyCmd, err := tf.destroyCmd(context.Background(), Backup("testbackup"), LockTimeout("200s"), State("teststate"), StateOut("teststateout"), VarFile("testvarfile"), Lock(false), Parallelism(99), Refresh(false), Target("target1"), Target("target2"), Var("var1=foo"), Var("var2=bar"), Dir("destroydir"))
+		destroyCmd, cfg, err := tf.destroyCmd(context.Background(), Backup("testbackup"), LockTimeout("200s"), State("teststate"), StateOut("teststateout"), VarFile("testvarfile"), Lock(false), Parallelism(99), Refresh(false), Target("target1"), Target("target2"), Var("var1=foo"), Var("var2=bar"), Dir("destroydir"), InterruptChannel(make(chan struct{})))
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -61,5 +65,9 @@ func TestDestroyCmd(t *testing.T) {
 			"-var", "var2=bar",
 			"destroydir",
 		}, nil, destroyCmd)
+
+		if cfg.interruptCh == nil {
+			t.Fatal("interrupt signal is unexpectedly nil")
+		}
 	})
 }