Unwrap exec.ExitError on all our special errors

And respond to errors.Is for Context errors

Author: paultyng

tfexec/apply.go

@@ -91,7 +91,7 @@ func (tf *Terraform) Apply(ctx context.Context, opts ...ApplyOption) error {
 	if err != nil {
 		return err
 	}
-	return tf.runTerraformCmd(cmd)
+	return tf.runTerraformCmd(ctx, cmd)
 }
 
 func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.Cmd, error) {

tfexec/cmd.go

@@ -135,27 +135,27 @@ func (tf *Terraform) buildTerraformCmd(ctx context.Context, mergeEnv map[string]
 	return cmd
 }
 
-func (tf *Terraform) runTerraformCmdJSON(cmd *exec.Cmd, v interface{}) error {
+func (tf *Terraform) runTerraformCmdJSON(ctx context.Context, cmd *exec.Cmd, v interface{}) error {
 	var outbuf = bytes.Buffer{}
 	cmd.Stdout = mergeWriters(cmd.Stdout, &outbuf)
 
-	err := tf.runTerraformCmd(cmd)
+	err := tf.runTerraformCmd(ctx, cmd)
 	if err != nil {
 		return err
 	}
 
 	return json.Unmarshal(outbuf.Bytes(), v)
 }
 
-func (tf *Terraform) runTerraformCmd(cmd *exec.Cmd) error {
+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)
 
 	err := cmd.Run()
 	if err != nil {
-		return tf.parseError(err, errBuf.String())
+		return tf.wrapExitError(ctx, err, errBuf.String())
 	}
 	return nil
 }

tfexec/destroy.go

@@ -92,7 +92,7 @@ func (tf *Terraform) Destroy(ctx context.Context, opts ...DestroyOption) error {
 	if err != nil {
 		return err
 	}
-	return tf.runTerraformCmd(cmd)
+	return tf.runTerraformCmd(ctx, cmd)
 }
 
 func (tf *Terraform) destroyCmd(ctx context.Context, opts ...DestroyOption) (*exec.Cmd, error) {

tfexec/errors.go

@@ -12,6 +12,10 @@ func (e *ErrNoSuitableBinary) Error() string {
 	return fmt.Sprintf("no suitable terraform binary could be found: %s", e.err.Error())
 }
 
+func (e *ErrNoSuitableBinary) Unwrap() error {
+	return e.err
+}
+
 // ErrVersionMismatch is returned when the detected Terraform version is not compatible with the
 // command or flags being used in this invocation.
 type ErrVersionMismatch struct {
@@ -27,9 +31,9 @@ func (e *ErrVersionMismatch) Error() string {
 // ErrManualEnvVar is returned when an env var that should be set programatically via an option or method
 // is set via the manual environment passing functions.
 type ErrManualEnvVar struct {
-	name string
+	Name string
 }
 
 func (err *ErrManualEnvVar) Error() string {
-	return fmt.Sprintf("manual setting of env var %q detected", err.name)
+	return fmt.Sprintf("manual setting of env var %q detected", err.Name)
 }

tfexec/exit_errors.go

@@ -1,6 +1,7 @@
 package tfexec
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"os/exec"
@@ -30,12 +31,21 @@ var (
 	tfVersionMismatchConstraintRegexp = regexp.MustCompile(`required_version = "(.+)"|Required version: (.+)\b`)
 )
 
-func (tf *Terraform) parseError(err error, stderr string) error {
-	ee, ok := err.(*exec.ExitError)
+func (tf *Terraform) wrapExitError(ctx context.Context, err error, stderr string) error {
+	exitErr, ok := err.(*exec.ExitError)
 	if !ok {
+		// not an exit error, short circuit, nothing to wrap
 		return err
 	}
 
+	ctxErr := ctx.Err()
+
+	// nothing to parse, return early
+	errString := strings.TrimSpace(stderr)
+	if errString == "" {
+		return &unwrapper{exitErr, ctxErr}
+	}
+
 	switch {
 	case tfVersionMismatchErrRegexp.MatchString(stderr):
 		constraint := ""
@@ -59,6 +69,8 @@ func (tf *Terraform) parseError(err error, stderr string) error {
 		}
 
 		return &ErrTFVersionMismatch{
+			unwrapper: unwrapper{exitErr, ctxErr},
+
 			Constraint: constraint,
 			TFVersion:  ver,
 		}
@@ -72,33 +84,76 @@ func (tf *Terraform) parseError(err error, stderr string) error {
 			}
 		}
 
-		return &ErrMissingVar{name}
+		return &ErrMissingVar{
+			unwrapper: unwrapper{exitErr, ctxErr},
+
+			VariableName: name,
+		}
 	case usageRegexp.MatchString(stderr):
-		return &ErrCLIUsage{stderr: stderr}
+		return &ErrCLIUsage{
+			unwrapper: unwrapper{exitErr, ctxErr},
+
+			stderr: stderr,
+		}
 	case noInitErrRegexp.MatchString(stderr):
-		return &ErrNoInit{stderr: stderr}
+		return &ErrNoInit{
+			unwrapper: unwrapper{exitErr, ctxErr},
+
+			stderr: stderr,
+		}
 	case noConfigErrRegexp.MatchString(stderr):
-		return &ErrNoConfig{stderr: stderr}
+		return &ErrNoConfig{
+			unwrapper: unwrapper{exitErr, ctxErr},
+
+			stderr: stderr,
+		}
 	case workspaceDoesNotExistRegexp.MatchString(stderr):
 		submatches := workspaceDoesNotExistRegexp.FindStringSubmatch(stderr)
 		if len(submatches) == 2 {
-			return &ErrNoWorkspace{submatches[1]}
+			return &ErrNoWorkspace{
+				unwrapper: unwrapper{exitErr, ctxErr},
+
+				Name: submatches[1],
+			}
 		}
 	case workspaceAlreadyExistsRegexp.MatchString(stderr):
 		submatches := workspaceAlreadyExistsRegexp.FindStringSubmatch(stderr)
 		if len(submatches) == 2 {
-			return &ErrWorkspaceExists{submatches[1]}
+			return &ErrWorkspaceExists{
+				unwrapper: unwrapper{exitErr, ctxErr},
+
+				Name: submatches[1],
+			}
 		}
 	}
-	errString := strings.TrimSpace(stderr)
-	if errString == "" {
-		// if stderr is empty, return the ExitError directly, as it will have a better message
-		return ee
+
+	return fmt.Errorf("%w\n%s", &unwrapper{exitErr, ctxErr}, stderr)
+}
+
+type unwrapper struct {
+	err    error
+	ctxErr error
+}
+
+func (u *unwrapper) Unwrap() error {
+	return u.err
+}
+
+func (u *unwrapper) Is(target error) bool {
+	switch target {
+	case context.DeadlineExceeded, context.Canceled:
+		return errors.Is(u.ctxErr, target)
 	}
-	return errors.New(stderr)
+	return false
+}
+
+func (u *unwrapper) Error() string {
+	return u.err.Error()
 }
 
 type ErrMissingVar struct {
+	unwrapper
+
 	VariableName string
 }
 
@@ -107,6 +162,8 @@ func (err *ErrMissingVar) Error() string {
 }
 
 type ErrNoWorkspace struct {
+	unwrapper
+
 	Name string
 }
 
@@ -116,6 +173,8 @@ func (err *ErrNoWorkspace) Error() string {
 
 // ErrWorkspaceExists is returned when creating a workspace that already exists
 type ErrWorkspaceExists struct {
+	unwrapper
+
 	Name string
 }
 
@@ -124,6 +183,8 @@ func (err *ErrWorkspaceExists) Error() string {
 }
 
 type ErrNoInit struct {
+	unwrapper
+
 	stderr string
 }
 
@@ -132,6 +193,8 @@ func (e *ErrNoInit) Error() string {
 }
 
 type ErrNoConfig struct {
+	unwrapper
+
 	stderr string
 }
 
@@ -148,6 +211,8 @@ func (e *ErrNoConfig) Error() string {
 // Currently cases 1 and 2 are handled.
 // TODO KEM: Handle exit 127 case. How does this work on non-Unix platforms?
 type ErrCLIUsage struct {
+	unwrapper
+
 	stderr string
 }
 
@@ -158,6 +223,8 @@ func (e *ErrCLIUsage) Error() string {
 // ErrTFVersionMismatch is returned when the running Terraform version is not compatible with the
 // value specified for required_version in the terraform block.
 type ErrTFVersionMismatch struct {
+	unwrapper
+
 	TFVersion string
 
 	// Constraint is not returned in the error messaging on 0.12

tfexec/fmt.go

@@ -52,7 +52,7 @@ func (tf *Terraform) FormatString(ctx context.Context, content string) (string,
 	var outBuf bytes.Buffer
 	cmd.Stdout = mergeWriters(cmd.Stdout, &outBuf)
 
-	err = tf.runTerraformCmd(cmd)
+	err = tf.runTerraformCmd(ctx, cmd)
 	if err != nil {
 		return "", err
 	}
@@ -76,7 +76,7 @@ func (tf *Terraform) FormatWrite(ctx context.Context, opts ...FormatOption) erro
 		return err
 	}
 
-	return tf.runTerraformCmd(cmd)
+	return tf.runTerraformCmd(ctx, cmd)
 }
 
 // FormatCheck returns true if the config files in the working or selected (via DirOption) directory are already formatted.
@@ -98,7 +98,7 @@ func (tf *Terraform) FormatCheck(ctx context.Context, opts ...FormatOption) (boo
 	var outBuf bytes.Buffer
 	cmd.Stdout = mergeWriters(cmd.Stdout, &outBuf)
 
-	err = tf.runTerraformCmd(cmd)
+	err = tf.runTerraformCmd(ctx, cmd)
 	if err == nil {
 		return true, nil, nil
 	}

tfexec/import.go

@@ -78,7 +78,7 @@ func (tf *Terraform) Import(ctx context.Context, address, id string, opts ...Imp
 	if err != nil {
 		return err
 	}
-	return tf.runTerraformCmd(cmd)
+	return tf.runTerraformCmd(ctx, cmd)
 }
 
 func (tf *Terraform) importCmd(ctx context.Context, address, id string, opts ...ImportOption) (*exec.Cmd, error) {

tfexec/init.go

@@ -98,7 +98,7 @@ func (tf *Terraform) Init(ctx context.Context, opts ...InitOption) error {
 	if err != nil {
 		return err
 	}
-	return tf.runTerraformCmd(cmd)
+	return tf.runTerraformCmd(ctx, cmd)
 }
 
 func (tf *Terraform) initCmd(ctx context.Context, opts ...InitOption) (*exec.Cmd, error) {