add error wrapping for locked state (#221)

* add error wrapping for locked state

* use strings.Builder instead of bytes.Buffer

* parse date for LockInfo created field

* revert date parsing; fix LockInfo regexp

* add test for StateLockErr; update build tags

* replace build tags

* Update tfexec/exit_errors.go

Co-authored-by: Radek Simko <radek.simko@gmail.com>

tfexec/exit_errors.go

@@ -6,6 +6,7 @@ import (
 	"os/exec"
 	"regexp"
 	"strings"
+	"text/template"
 )
 
 // this file contains errors parsed from stderr
@@ -30,6 +31,9 @@ var (
 	tfVersionMismatchErrRegexp        = regexp.MustCompile(`Error: The currently running version of Terraform doesn't meet the|Error: Unsupported Terraform Core version`)
 	tfVersionMismatchConstraintRegexp = regexp.MustCompile(`required_version = "(.+)"|Required version: (.+)\b`)
 	configInvalidErrRegexp            = regexp.MustCompile(`There are some problems with the configuration, described below.`)
+
+	stateLockErrRegexp  = regexp.MustCompile(`Error acquiring the state lock`)
+	stateLockInfoRegexp = regexp.MustCompile(`Lock Info:\n\s*ID:\s*([^\n]+)\n\s*Path:\s*([^\n]+)\n\s*Operation:\s*([^\n]+)\n\s*Who:\s*([^\n]+)\n\s*Version:\s*([^\n]+)\n\s*Created:\s*([^\n]+)\n`)
 )
 
 func (tf *Terraform) wrapExitError(ctx context.Context, err error, stderr string) error {
@@ -128,6 +132,20 @@ func (tf *Terraform) wrapExitError(ctx context.Context, err error, stderr string
 		}
 	case configInvalidErrRegexp.MatchString(stderr):
 		return &ErrConfigInvalid{stderr: stderr}
+	case stateLockErrRegexp.MatchString(stderr):
+		submatches := stateLockInfoRegexp.FindStringSubmatch(stderr)
+		if len(submatches) == 7 {
+			return &ErrStateLocked{
+				unwrapper: unwrapper{exitErr, ctxErr},
+
+				ID:        submatches[1],
+				Path:      submatches[2],
+				Operation: submatches[3],
+				Who:       submatches[4],
+				Version:   submatches[5],
+				Created:   submatches[6],
+			}
+		}
 	}
 
 	return fmt.Errorf("%w\n%s", &unwrapper{exitErr, ctxErr}, stderr)
@@ -257,3 +275,33 @@ func (e *ErrTFVersionMismatch) Error() string {
 	return fmt.Sprintf("terraform %s not supported by configuration%s",
 		version, requirement)
 }
+
+// ErrStateLocked is returned when the state lock is already held by another process.
+type ErrStateLocked struct {
+	unwrapper
+
+	ID        string
+	Path      string
+	Operation string
+	Who       string
+	Version   string
+	Created   string
+}
+
+func (e *ErrStateLocked) Error() string {
+	tmpl := `Lock Info:
+  ID:        {{.ID}}
+  Path:      {{.Path}}
+  Operation: {{.Operation}}
+  Who:       {{.Who}}
+  Version:   {{.Version}}
+  Created:   {{.Created}}
+`
+
+	t := template.Must(template.New("LockInfo").Parse(tmpl))
+	var out strings.Builder
+	if err := t.Execute(&out, e); err != nil {
+		return "error acquiring the state lock"
+	}
+	return fmt.Sprintf("error acquiring the state lock: %v", out.String())
+}

tfexec/internal/e2etest/errors_test.go

@@ -127,6 +127,25 @@ func TestTFVersionMismatch(t *testing.T) {
 	})
 }
 
+func TestLockedState(t *testing.T) {
+	runTest(t, "inmem-backend-locked", func(t *testing.T, tfv *version.Version, tf *tfexec.Terraform) {
+		err := tf.Init(context.Background())
+		if err != nil {
+			t.Fatalf("err during init: %s", err)
+		}
+
+		err = tf.Apply(context.Background())
+		if err == nil {
+			t.Fatal("expected error, but didn't find one")
+		}
+
+		var stateLockedErr *tfexec.ErrStateLocked
+		if !errors.As(err, &stateLockedErr) {
+			t.Fatalf("expected ErrTFVersionMismatch, got %T, %s", err, err)
+		}
+	})
+}
+
 func TestContext_alreadyPastDeadline(t *testing.T) {
 	runTest(t, "", func(t *testing.T, tfv *version.Version, tf *tfexec.Terraform) {
 		ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(-1*time.Second))

tfexec/internal/e2etest/testdata/inmem-backend-locked/main.tf

@@ -0,0 +1,5 @@
+terraform {
+	backend "inmem" {
+		lock_id = "2b6a6738-5dd5-50d6-c0ae-f6352977666b"
+	}
+}