hashicorp/nomad · error

failed reading template contents: %w

Error message

failed reading template contents: %w

What it means

In the template-render child process, writeTemplate failed reading the rendered template contents piped on stdin (io.Copy from os.Stdin), so the destination file cannot be written and rendering aborts.

Source

Thrown at client/allocrunner/taskrunner/template/renderer/z_template_render.go:115

func writeTemplate() (*renderer.RenderResult, error) {

	var (
		sandboxPath, destPath, perms, user, group string
	)

	flags := flag.NewFlagSet("template-render", flag.ExitOnError)
	flags.StringVar(&sandboxPath, "sandbox-path", "", "")
	flags.StringVar(&destPath, "dest-path", "", "")
	flags.StringVar(&perms, "perms", "", "")
	flags.StringVar(&user, "user", "", "")
	flags.StringVar(&group, "group", "", "")

	flags.Parse(os.Args[3:])

	contents := new(bytes.Buffer)
	_, err := io.Copy(contents, os.Stdin)
	if err != nil {
		return nil, fmt.Errorf("failed reading template contents: %w", err)
	}

	destPath, err = sandbox(sandboxPath, destPath) // platform-specific sandboxing
	if err != nil {
		return nil, fmt.Errorf("failed to sandbox alloc dir %q: %w", sandboxPath, err)
	}

	// perms must parse into a valid file permission
	fileMode := os.FileMode(DefaultFilePerms)
	if perms != "" {
		fileModeInt, err := strconv.ParseUint(perms, 8, 32)
		if err != nil {
			return nil, fmt.Errorf(
				"Invalid file mode %q: Must be a valid octal number: %w", perms, err)

		}
		fileMode = fs.FileMode(fileModeInt)
		if fileMode.Perm() != fileMode {

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Check parent process logs for the error passing template contents
2. Verify pipe/stdio is intact for the subprocess
3. Retry the template render; check system resource limits

When it happens

Trigger: Thrown at client/allocrunner/taskrunner/template/renderer/z_template_render.go:115 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/4c82f5219ebf1237. Report an issue: GitHub.