Add JSON option for "plan" and "apply"

tfexec/apply.go

@@ -12,6 +12,7 @@ type applyConfig struct {
 	dirOrPlan string
 	lock      bool
 
+	json bool
 	// LockTimeout must be a string with time unit, e.g. '10s'
 	lockTimeout  string
 	parallelism  int
@@ -66,6 +67,10 @@ func (opt *VarFileOption) configureApply(conf *applyConfig) {
 	conf.varFiles = append(conf.varFiles, opt.path)
 }
 
+func (opt *JSONOption) configureApply(conf *applyConfig) {
+	conf.json = opt.json
+}
+
 func (opt *LockOption) configureApply(conf *applyConfig) {
 	conf.lock = opt.lock
 }
@@ -121,6 +126,9 @@ func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.C
 	if c.stateOut != "" {
 		args = append(args, "-state-out="+c.stateOut)
 	}
+	if c.json {
+		args = append(args, "-json")
+	}
 	for _, vf := range c.varFiles {
 		args = append(args, "-var-file="+vf)
 	}

tfexec/apply_test.go

@@ -26,6 +26,7 @@ func TestApplyCmd(t *testing.T) {
 			StateOut("teststateout"),
 			VarFile("foo.tfvars"),
 			VarFile("bar.tfvars"),
+			JSON(true),
 			Lock(false),
 			Parallelism(99),
 			Refresh(false),
@@ -50,6 +51,7 @@ func TestApplyCmd(t *testing.T) {
 			"-lock-timeout=200s",
 			"-state=teststate",
 			"-state-out=teststateout",
+			"-json",
 			"-var-file=foo.tfvars",
 			"-var-file=bar.tfvars",
 			"-lock=false",

tfexec/cmd_default.go

@@ -1,3 +1,4 @@
+//go:build !linux
 // +build !linux
 
 package tfexec
@@ -10,9 +11,10 @@ import (
 
 func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	var errBuf strings.Builder
-
-	cmd.Stdout = mergeWriters(cmd.Stdout, tf.stdout)
-	cmd.Stderr = mergeWriters(cmd.Stderr, tf.stderr, &errBuf)
+	// ensure we don't mix up stdout and stderr
+	sw := &syncWriter{w: &errBuf}
+	cmd.Stdout = mergeWriters(cmd.Stdout, tf.stdout, sw)
+	cmd.Stderr = mergeWriters(cmd.Stderr, tf.stderr, sw)
 
 	go func() {
 		<-ctx.Done()

tfexec/cmd_linux.go

@@ -2,16 +2,32 @@ package tfexec
 
 import (
 	"context"
+	"io"
 	"os/exec"
 	"strings"
+	"sync"
 	"syscall"
 )
 
+// syncWriter is an io.Writer protected by a sync.Mutex.
+type syncWriter struct {
+	sync.Mutex
+	w io.Writer
+}
+
+// Write implements io.Writer.
+func (w *syncWriter) Write(p []byte) (int, error) {
+	w.Lock()
+	defer w.Unlock()
+	return w.w.Write(p)
+}
+
 func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	var errBuf strings.Builder
-
-	cmd.Stdout = mergeWriters(cmd.Stdout, tf.stdout)
-	cmd.Stderr = mergeWriters(cmd.Stderr, tf.stderr, &errBuf)
+	// ensure we don't mix up stdout and stderr
+	sw := &syncWriter{w: &errBuf}
+	cmd.Stdout = mergeWriters(cmd.Stdout, tf.stdout, sw)
+	cmd.Stderr = mergeWriters(cmd.Stderr, tf.stderr, sw)
 
 	cmd.SysProcAttr = &syscall.SysProcAttr{
 		// kill children if parent is dead

tfexec/options.go

@@ -185,6 +185,16 @@ func GetPlugins(getPlugins bool) *GetPluginsOption {
 	return &GetPluginsOption{getPlugins}
 }
 
+// JSONOption represents the -json flag.
+type JSONOption struct {
+	json bool
+}
+
+// JSON represents the -json flag.
+func JSON(json bool) *JSONOption {
+	return &JSONOption{json}
+}
+
 // LockOption represents the -lock flag.
 type LockOption struct {
 	lock bool

tfexec/plan.go

@@ -11,6 +11,7 @@ type planConfig struct {
 	destroy      bool
 	dir          string
 	lock         bool
+	json         bool
 	lockTimeout  string
 	out          string
 	parallelism  int
@@ -76,6 +77,10 @@ func (opt *OutOption) configurePlan(conf *planConfig) {
 	conf.out = opt.path
 }
 
+func (opt *JSONOption) configurePlan(conf *planConfig) {
+	conf.json = opt.json
+}
+
 func (opt *LockTimeoutOption) configurePlan(conf *planConfig) {
 	conf.lockTimeout = opt.timeout
 }
@@ -127,6 +132,9 @@ func (tf *Terraform) planCmd(ctx context.Context, opts ...PlanOption) (*exec.Cmd
 	if c.state != "" {
 		args = append(args, "-state="+c.state)
 	}
+	if c.json {
+		args = append(args, "-json")
+	}
 	for _, vf := range c.varFiles {
 		args = append(args, "-var-file="+vf)
 	}

tfexec/plan_test.go

@@ -39,6 +39,7 @@ func TestPlanCmd(t *testing.T) {
 	t.Run("override all defaults", func(t *testing.T) {
 		planCmd, err := tf.planCmd(context.Background(),
 			Destroy(true),
+			JSON(true),
 			Lock(false),
 			LockTimeout("22s"),
 			Out("whale"),
@@ -65,6 +66,7 @@ func TestPlanCmd(t *testing.T) {
 			"-lock-timeout=22s",
 			"-out=whale",
 			"-state=marvin",
+			"-json",
 			"-var-file=trillian",
 			"-lock=false",
 			"-parallelism=42",