hashicorp/nomad · error

command contains extra white space: %q

Error message

command contains extra white space: %q

What it means

The same validateCommand helper rejects a command string with leading/trailing or extra internal whitespace, since only a single value is allowed in the target config field. The message directs users to the args field for multiple tokens.

Source

Thrown at drivers/docker/driver.go:1743

		// be caused by races between listing
		// containers and this container being removed.
		// See #2802
		return nil, nstructs.NewRecoverableError(err, true)
	}
	return &container, nil
}

// validateCommand validates that the command only has a single value and
// returns a user friendly error message telling them to use the passed
// argField.
func validateCommand(command, argField string) error {
	trimmed := strings.TrimSpace(command)
	if len(trimmed) == 0 {
		return fmt.Errorf("command empty: %q", command)
	}

	if len(trimmed) != len(command) {
		return fmt.Errorf("command contains extra white space: %q", command)
	}

	return nil
}

func (d *Driver) WaitTask(ctx context.Context, taskID string) (<-chan *drivers.ExitResult, error) {
	h, ok := d.tasks.Get(taskID)
	if !ok {
		return nil, drivers.ErrTaskNotFound
	}
	ch := make(chan *drivers.ExitResult)
	go d.handleWait(ctx, ch, h)
	return ch, nil
}

func (d *Driver) handleWait(ctx context.Context, ch chan *drivers.ExitResult, h *taskHandle) {
	defer close(ch)
	select {

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Remove surrounding whitespace from the command value.
2. Split multiple tokens into the args field.
3. Render the template with trim (e.g. tmpl function or `trim()` in HCL) to strip stray newlines.

Example fix

// before
config {
  entrypoint = "/bin/myapp --flag"
}
// after
config {
  entrypoint = "/bin/myapp"
  args = ["--flag"]
}

func isSingleToken(v string) bool { return strings.TrimSpace(v) != "" && strings.TrimSpace(v) == v }
// reject before submit if extra whitespace detected

When it happens

Trigger: A config field like `entrypoint = "/bin/app "` or `"/bin myapp"` contains stray spaces or a trailing newline from templating, so len(TrimSpace(cmd)) != len(cmd).

Common situations: HCL templates injecting trailing newlines, users putting multiple words into the single-value field instead of args, copy-paste with trailing whitespace.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• does not match registry specification
• invalid cgroup permission string: %q
• invalid mount type, must be "bind", "volume", "tmpfs": %q
• command empty: %q
• missing secret ID

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/784343b7c54d1a9f. Report an issue: GitHub.