dagger/dagger · error

no such user: %s

Error message

no such user: %s

What it means

findUID parsed /etc/passwd successfully but no entry matches the requested user name. The container image has no such user; the user specified for the container or file ownership does not exist in the image.

Source

Thrown at core/util.go:58

	}

	if workDir == "" {
		workDir = "/"
	}

	return path.Join(workDir, containerPath)
}

func findUID(f io.Reader, uname string) (int, error) {
	users, err := user.ParsePasswdFilter(f, func(u user.User) bool {
		return u.Name == uname
	})
	if err != nil {
		return -1, fmt.Errorf("parse /etc/passwd: %w", err)
	}

	if len(users) == 0 {
		return -1, fmt.Errorf("no such user: %s", uname)
	}

	return users[0].Uid, nil
}

func findGID(f io.Reader, gname string) (int, error) {
	groups, err := user.ParseGroupFilter(f, func(g user.Group) bool {
		return g.Name == gname
	})
	if err != nil {
		return -1, fmt.Errorf("parse /etc/group: %w", err)
	}

	if len(groups) == 0 {
		return -1, fmt.Errorf("no such group: %s", gname)
	}

	return groups[0].Gid, nil

View on GitHub (pinned to 82ba2681db)

Solutions

1. Use a user that exists in the image (check with `getent passwd` in the image)
2. Reference the user by numeric UID instead of name
3. Add the user to the image before running

When it happens

Trigger: Thrown at core/util.go:58 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of dagger/dagger@82ba2681db (2026-09-05). Data as JSON: /api/errors/65b67b86608eb59d. Report an issue: GitHub.